Tesis

Effects of atmospheric deposition on microbial dynamics and composition in two anthropogenically-influenced contrasted coastal sites

Autor: I. Marín Beltrán
Director/es tesi: F. Peters
Any publicació: 2017
Institució: Universitat Politècnica de Catalunya
Resum: Veure
The Mediterranean Sea is an oligotrophic basin. The atmosphere above it is affected by continuous emissions of anthropogenic aerosols and episodic Saharan dust events. Part of these aerosols deposit (as wet or dry deposition) over the sea, delivering macronutrients and trace metals to surface waters. [...]

Advanced optical technologies for phytoplankton discrimination: Applications in adaptive ocean sampling networks

Autor: I.F. Aymerich
Director/es tesi: J. Piera; A.M. Sánchez
Any publicació: 2016
Institució: Universitat Politècnica de Catalunya
Resum: Veure
There is a lack on ocean dynamics understanding, and that lead oceanographers to the need of acquiring more reliable data to study ocean characteristics. Oceanographic measurements are difficult and expensive but essential for effective study oceanic and atmospheric systems. Despite rapid advances in ocean sampling capabilities, the number of disciplinary variables that are necessary to solve oceanographic problems is large. In addition, the time scales of important processes span over ten orders of magnitude, and due to technology limitations, there are important spectral gaps in the sampling methods obtained in the last decades. Thus, the main limitation to understand these dynamics is an inaccurate measurement of the process due to undersampling. But fortunately, recent advances in ocean platforms and in situ autonomous sampling systems and satellite sensors are enabling unprecedented rates of data acquisition as well as the expansion of temporal and spatial coverage. Many advances in technologies involving different areas such as computing, nanotechnology, robotics, molecular biology, etc. are being developed. There exist the effort that these advantages could be applied to ocean sciences and will prove to extremely beneficial for oceanographers in the next few decades. Autonomous underwater vehicles, in situ automatic sampling devices, high spectral resolution optical and chemical sensors are some of the new advances that are being utilized by a limited number of oceanographers, and in a few years are expected to be widely used. Thanks to new technologies and, for instance, utilization of data assimilation models coupled with autonomous sampling platforms can increase temporal and spatial sampling capabilities. For instance, studies of phytoplankton dynamics in the water column, or the transportation and aggregation of organisms need a high rate of sampling because of their rapid evolution, that is why new strategies and technologies to increase sampling rate and coverage would be really useful. However, other challenges come up when increasing the variety and quantity of ocean measurements. For instance, number of measurements are limited by costs of instruments and their deployment, as well as data processing and production of useful data products and visualizations. In some studies, there exists the necessity to discriminate and detect different phytoplankton species present in sea water, and even track their evolution. The use of their optical properties is one of the approximations used by some of them. Acquiring optical properties is a non-invasive and non-destructive method to study phytoplankton communities. Phytoplankton species are then organized thanks to presenting similar optical characteristics. Fluorescence spectroscopy has been used and found as a really potential technique for this goal, although passive optical techniques such as the study of the absorption can be also useful, or even their combination can be studied. Specifically speaking about fluorescence, the majority of the studies have centered their effort in discriminating phytoplankton groups using their excitation spectra because the emission spectra contains less information. The inconvenient of using this kind of information, is that the acquisition is not instantaneous and it is necessary to spend some time (over a second) exciting the sample at different wavelengths sequentially. In contrast, the whole emission spectra can be acquired instantaneously. Therefore, the aim of this thesis is to explore new and powerful signal processing techniques able to discriminate between different phytoplankton groups from their emission fluorescence spectra. This document presents important results that demonstrate the capabilities of these methods.

Biodiversity patterns of coralligenous outcrops over broad spatial and temporal scales in the NW Mediterranean Sea: baseline data for conservation

Autor: E. Casas i Güell
Director/es tesi: N. Teixidó Ullod, E. Cebrian i Pujol
Any publicació: 2016
Institució: Universitat de Barcelona
Resum: Veure
Increasing anthropogenic pressures and its effects on marine ecosystems urge enhanced knowledge and understanding of the current state of marine biodiversity. This baseline information is pivotal to establish the actual state, detect future changes, explore possible trends and propose adequate management actions for marine ecosystems. Coralligenous outcrops are a highly diverse and structurally complex habitat faced with major threats in the Mediterranean Sea. Despite its ecological, aesthetic and economic value, coralligenous biodiversity patterns are still poorly understood. Information on the spatial and temporal variability of the composition and structure of coralligenous assemblages is scarce for most regions. Specially, data on species diversity and structure in coralligenous outcrops dominated by Corallium rubrum and Paramuricea clavata are essentially lacking. Gathering these data is needed to build robust baselines in order to assess the responses of this highly threatened habitat to anthropogenic disturbances (e.g. mass mortality events, sedimentation and invasive species). There is currently no single sampling method that has been demonstrated to be sufficiently representative to ensure adequate community assessment and monitoring in this habitat. In Chapter 3, we propose a rapid non-destructive protocol for biodiversity assessment and monitoring of coralligenous outcrops providing good estimates of its structure and species composition, based on photographic sampling and the determination of presence/absence of macrobenthic species. We followed a hierarchical sampling survey, covering more than 400 km of rocky coasts in NW Mediterranean (Catalan coast –Spain-, Provence and NW Corsica –France). This approach allowed us to determine the minimal sampling area for each assemblage (5000 cm2 for P. clavata and 2500 cm2 for C. rubrum). In addition, we concluded that 3 replicates provided an optimal sampling effort in order to maximize the species number and to assess the main biodiversity patterns of studied assemblages in variability studies requiring replicates. We followed the mentioned hierarchical sampling survey in Chapter 3 to characterize the spatial and temporal variability of structure, composition, abundance and diversity of perennial species inhabiting coralligenous outcrops dominated by C. rubrum or P. clavata (Chapter 4 and Chapter 5 respectively). In Chapter 4 spatial variability of species composition, structure and diversity in coralligenous assemblages dominated by C. rubrum was assessed. We also pooled the identified species/taxa into morphofunctional groups according to their life-span and growth to characterize the structural complexity of the assemblages. Finally, we analyzed the number, size and shape of patches (landscape pattern indices) for each group in order to describe the spatial arrangement within the C. rubrum assemblage. Landscape pattern indices in C.rubrum assemblages exhibited important differences among sites in the same locality whereas localities showed similar values. In Chapter 5, the spatial and temporal variability of species composition, structure and diversity in coralligenous assemblages dominated by P. clavata was assessed. According to ordination analyses, species composition and the structural complexity of coralligenous assemblages differed consistently across all spatial scales considered. The lowest and the highest variability were found among localities (100 km) and within sites (1-5 km), respectively. Despite the differences, the sites displayed high similarity (average similarity 55.7 %) and shared approximately 50 % of the species. Similarly, differences in diversity indices (alpha, beta and gamma) were found. Furthermore, the study of P. clavata addressed diversity patterns over 5-year period. Overall, no temporal changes were detected in either species composition or the morphofunctional groups considered. In Chapter 6, we showed how an extreme storm event affected the dynamics of benthic coralligenous outcrops in the NW Mediterranean Sea using data acquired before (2006–2008) and after the impact (2009–2010) at four different sites. The loss of cover of benthic species resulted between 22% and 58%. The damage across these species (e.g. calcareous algae, sponges, anthozoans, bryozoans, tunicates) was uneven, and those with fragile forms were the most impacted, showing cover losses up to 50 to 100%. Interestingly, small patches survived after the storm and began to grow slightly during the following year. In contrast, sheltered sites showed no significant changes in all the studied parameters, indicating no variations due to the storm. Overall, the results presented in this thesis furnishes a basis for the implementation of monitoring schemes of coralligenous assemblages complementing the scarce available information on assemblage composition and structure of the emblematic Mediterranean coralligenous outcrops dominated by C. rubrum and P. clavata over large spatial scales. Our results demonstrate the moderate spatial and the extremely low temporal variability in biodiversity patterns in the NW Mediterranean region, providing the first baselines for detecting potential changes due to global change effects. We also provide new insights into the responses of these assemblages to a large and rare extreme event. The development of similar sampling schemes in other Mediterranean regions will provide a global view of the biodiversity of coralligenous outcrops.

Biology, ecology and ecophysiology of the box jellyfish Carybdea marsupialis (Cnidaria: Cubozoa)

Autor: M.J. Acevedo Dudley
Director/es tesi: A. Calbet, V. Fuentes
Any publicació: 2016
Lloc d'edició: Barcelona
Institució: Universitat Politècnica de Catalunya. Institut de Ciències del Mar
Resum: Veure
Over the last years, the sightings of the cubomedusa Carybdea marsupialis have increased in the Mediterranean Sea and this has been linked to an increase in its abundance. Consequently, this phD thesis addresses some questions regarding the possible causes and effects of this phenomenon. Firstly, the taxonomy and distribution of the species have been revised and updated. Moreover, laboratory experiments were conducted to study the development and ecophysiology of this animal. These results were complemented with field studies on the gut contents and trophic markers of C. marsupialis. Finally, the results of a four years monitoring in the coast of Denia (Spain), as well as the sightings of the species reported along the Mediterranean, provided solid evidence on the main factors affecting the distribution of C. marsupialis. Overall, the species seems to be favoured by high nutrient inputs from anthropogenic origin, and other human activities as coastal constructions. Los avistamientos de la cubomedusa Carybdea marsupialis han aumentado en el Mar Mediterráneo en los últimos años, hecho que ha sido atribuido a un incremento en su abundancia. El objetivo de esta tesis doctoral es responder algunas preguntas relacionadas con las posibles causas y efectos de este fenómeno. En primer lugar, se han actualizado la taxonomía y la distribución de la especie. Además, se han llevado a cabo experimentos relacionados con su desarrollo y ecofisiología. Estos resultados se han complementado con estudios de sus contenidos estomacales y marcadores tróficos en el campo. Finalmente, un monitoreo durante cuatro años en la costa de Denia (España), junto con los avistamientos de esta cubomedusa en el Mediterráneo, han proporcionado evidencias sólidas acerca de los factores principales que afectan la distribución de C. marsupialis. En general, la especie parece verse favorecida por el aporte de nutrientes de origen antropogénico, y por otras actividades humanas como las construcciones costeras.

Do-it-yourself instruments and data processing methods for developing Marine Citizen Observatories

Autor: S. Pons
Director/es tesi: Jaume Piera, Luigi Ceccaroni
Any publicació: 2016
Institució: Universitat Politècnica de Catalunya
Resum: Veure
Water is the most important resource for living on planet Earth, covering more than 70% of its surface. The oceans represent more than 97% of the planet total water and they are where more than the 99.5% of the living beings are concentrated. A great number of ecosystems depend on the health of these oceans; their study and protection are necessary. Large datasets over long periods of time and over wide geographical areas can be required to assess the health of aquatic ecosystems. The funding needed for data collection is considerable and limited, so it is important to look at new cost-effective ways of obtaining and processing marine environmental data. The feasible solution at present is to develop observational infrastructures that may increase significantly the conventional sampling capabilities. In this study we promote to achieve this solution with the implementation of Citizen Observatories, based on volunteer participation. Citizen observatories are platforms that integrate the latest information technologies to digitally connect citizens, improving observation skills for developing a new type of research known as Citizen Science. Citizen science has the potential to increase the knowledge of the environment, and aquatic ecosystems in particular, through the use of people with no specific scientific training to collect and analyze large data sets. We believe that citizen science based tools —open source software coupled with low-cost do-it-yourself hardware— can help to close the gap between science and citizens in the oceanographic field. As the public is actively engaged in the analysis of data, the research also provides a strong avenue for public education. This is the objective of this thesis, to demonstrate how open source software and low-cost do-it-yourself hardware are effectively applied to oceanographic research and how can it develop into citizen science. We analyze four different scenarios where this idea is demonstrated: an example of using open source software for video analysis where lobsters were monitored; a demonstration of using similar video processing techniques on in-situ low-cost do-it-yourself hardware for submarine fauna monitoring; a study using open source machine learning software as a method to improve biological observations; and last but not least, some preliminar results, as proof of concept, of how manual water sampling could be replaced by low-cost do-it-yourself hardware with optical sensors.

Ecological study of benthic communities in the continental shelf and upper slope in the Menorca Channel (North Western Mediterranean Sea)

Autor: J. Grinyó Andreu
Director/es tesi: J.M.Gili Sardà, A. Gori
Any publicació: 2016
Institució: Universitat Politècnica de Catalunya. Institut de Ciències del Mar
Resum: Veure
Technological development and increased availability of remotely operated vehicles (ROVs) and manned submersibles have significantly increased accessibility to deep environments revealing the presence of rich and diverse macrobenthic assemblages dominated by suspension feeders. These assemblages have been largely exposed to the impacts of fishing activities (especially bottom trawling) in the Mediterranean Sea. Consequently, it is currently urgent to increase knowledge on their distribution, as well as on the ecology and biology of the main species that constitute these macrobenthic assemblages in order to implement effective management and conservation measures. This thesis addressed the characterization of macrobenthic assemblages in the continental shelf and upper slope (40–360 m depth) of the Menorca Channel through a multidisciplinary approach at different ecological levels. Six macrobenthic assemblages mainly segregated by substrate and depth. Hard substrates hosted sponge grounds and coral gardens, whereas crinoid and brachiopod beds occurred on soft sediments. Highest diversity values were found in the shelf edge, probably as a consequence of the bottom heterogeneity and the constant hydrodynamic conditions. Gorgonians were one of the most important and diverse bioengineering organisms in the Menorca Channel, forming dense assemblages that extended over vast areas. Gorgonian assemblages on the continental shelf and upper slope were mostly monospecific, whereas shelf edge assemblages were highly multispecific. Small colonies were dominant throughout the studied bathymetric range, but in deeper environments intermediate and large colonies were more abundant. The good preservation state of most of the observed benthic assemblages and gorgonian populations is probably related to the low pressure of bottom trawling, which is mostly concentrated in deeper areas of the continental and the exceptional fishing practices exerted by the local artisanal fisherman. Paramuricea macrospina is the most abundant gorgonian species in the Menorca Channel. Throughout its distribution, three different chromatic forms were observed. Two forms occurred on the continental shelf, and a third occurred on the shelf edge. Colony shape, sclerite size and shape, and the genetic variability of mitochondrial markers were compared to elucidate if these chromatic forms represented different taxonomic units. Colony morphology barely changed among the three forms resulting as a high conservative character. Conversely, sclerite size and shape significantly differed amongst the three forms, possibly conditioned by genetic and environmental factors. However, no significant differences were observed in the studied mitochondrial markers. The reproductive cycle, energy storage and metabolic requirements of P. macrospina showed significant differences compared to Mediterranean coastal gorgonians. Its reproductive cycle was delayed 2–3 months respect to shallow species, possibly following the late summer increase in seawater temperature occurring on the Mediterranean continental shelf. Moreover, internal brooding in P. macrospina contrasts with surface brooding in the congeneric Paramuricea clavata. Lipid content was lower and more constant in P. macrospina than in shallow species, and ∂13C and ∂15N composition showed almost no seasonal variation, suggesting that food availability in the continental shelf is lower but more constant than in shallower environments. The high oligotrophic conditions of the Balearic Sea apparently contrasts with the high abundance and diversity of active and passive suspension feeders observed in the Menorca Channel. Indeed, the downward particle fluxes quantified during two consecutive years in the Menorca Canyon were comparatively low within the Mediterranean context, reflecting the oligotrophic nature of the study area and the lack of continental inputs of particulate matter. Hydrodynamic settings and physical processes that cause sediment resuspension appeared to be more important than surface primary production in the control of the magnitude and composition of the total mass flux in the study area, likely playing a major role in determining the distribution of the macrobenthic assemblages.

Ecosystem based management in the Mediterranean Sea: Scientific Challenges and Advances

Autor: C. Piroddi
Director/es tesi: M. Coll Monton,. M. del Camino Liquete
Any publicació: 2016
Institució: Universitat de Barcelona
Resum: Veure
In this thesis I investigated the status of the Mediterranean Sea ecosystem and the sustainability of its marine resources using an interdisciplinary approach, which combined data integration and modelling approaches. Results highlighted a series of commonalities for Mediterranean marine ecosystems: they indicate that ‘small pelagic fishes’, mainly European pilchards and anchovies, both with high biomasses and high proportions in catches, are important structuring species for the Mediterranean ecosystem (at regional, sub-regional and local scales). ‘Large pelagic fishes’ are the main keystone species for both the past and current Mediterranean ecosystem configuration, while ‘sharks’ and ‘medium pelagic fishes’ played a key role in the past, but their ecological role is currently replaced by benthopelagic and benthic cephalopods. In addition, the ‘Mediterranean monk seal’ “Monachus monachus”, where it still occurs, is the species with the highest TL followed by ‘piscivorous cetaceans’ and ‘large pelagic fish’. [...]

Effects of ocean acidification on Mediterranean Corals

Autor: J.I. Movilla
Director/es tesi: C. Pelejero; E. Calvo
Any publicació: 2016
Institució: Instituto de Ciencias del Mar, Universidad de Las Palmas de Gran Canaria
Resum: Veure
Desde el comienzo de la era industrial, los océanos han absorbido casi un tercio del dióxido de carbono (CO2) liberado a la atmósfera por las actividades antropogénicas, mitigando su efecto invernadero y su influencia en el clima de la Tierra. Sin embargo, una consecuencia de esta absorción es la acidificación del océano (OA), un proceso que ha surgido como potencialmente alarmante para los ecosistemas marinos y se ha convertido en una prioridad el la investigación durante los últimos años. El Mediterráneo es actualmente uno de los mares más afectados del mundo, enfrentándose a muchas presiones antropogénicas. Sin embargo, sigue siendo objeto de debate si el impacto de la OA en este mar semi-cerrado será más fuerte que en el océano global. En esta tesis, contribuimos al conocimiento aún limitado de los efectos de medio a largo plazo de la OA en nueve especies bentónicas clave de los dos ecosistemas calcáreos del Mediterráneo más importantes en términos de diversidad, el coralígeno somero y las comunidades de aguas profundas. Para ello, desarrollamos un sistema para la manipulación experimental del pH en acuarios que nos ha permitido exponer los organismos a diferentes condiciones de pH y temperatura, simulando así los valores actuales y los previstos para el año 2100. Se evaluó la respuesta en la tasa de calcificación, en el estado de la estructura carbonatada de soporte (microestructura, microdensidad y porosidad específica del esqueleto) y en el balance metabólico (contenido en materia orgánica, hidratos de carbono, lípidos y proteínas del tejido) en cada una de las especies. En términos de calcificación, la especie más afectada fue el octocoral Corallium rubrum, exhibiendo una disminución promedio entorno al 59%, seguido de los corales zooxantelados Cladocora caespitosa y Oculina patagonica, con una disminución del 35 y 32%, respectivamente. Curiosamente, los corales azooxantelados mostraron una mayor resistencia a las condiciones acidificadas esperadas para finales de siglo, tanto en el caso de las especies temperadas Astroides calycularis y Leptopsammia pruvoti, como en las especies de aguas frías Lophelia pertusa, Madrepora oculata y Dendrophyllia cornigera. La única excepción fue Desmophyllum dianthus que presentó una reducción significativa del 70% en la calcificación de los especímenes más jóvenes tras la exposición a condiciones acidificadas. Nuestros resultados también muestran un cierto grado de variabilidad especie-específico en la respuesta metabólica, sugiriendo que diferentes estrategias y habilidades para la translocación del balance energético podrían explicar parte de la variabilidad observada en la respuesta de estos organismos a las condiciones de pH bajo. Esta tesis ilustra los efectos variables que la acidificación y el calentamiento global pueden tener en organismos calcificadores marinos pertenecientes a ecosistemas bentónicos Mediterráneos y pone de manifiesto los posibles cambios en la composición de estas comunidades en un futuro próximo.

In situ direct study of filtration and respiration rate of Mediterranean sponge

Autor: T.M. Morganti
Director/es tesi: R. Coma Bau, M. Ribes Llordés
Any publicació: 2016
Institució: Universitat Politècnica de Catalunya. Institut de Ciències del Mar. Centre d’Estudis Avançats de Blanes
Resum: Veure
Sponges play important roles in the functioning of marine ecosystem in which they are abundant. These roles range from stabilizers of substrate, to acting as major link between benthic and pelagic realms by filtering large quantities of water and retaining the particles with high efficiency. Despite sponges have been the focus of much interest in the past years our knowledge on sponge physiology is still poorly understood. This study focused on ecophysiology of five of the most prominent sponge species dwelling the coralligenous community in the NW Mediterranea Sea, and employed an energetic approach to understanding the complex interactions between physiological constrains and seasonal fluctuations of environmental factors experienced by the organism under natural conditions. In this thesis, we contributed to the still limited knowledge of energetic mechanisms that regulate seasonal dynamics and elucidated divergent metabolic profiles between high microbial (HMA) and low microbial (LMA) abundance species accordingly to their different adaptive life strategies. For this purpose we examined the in situ feeding, filtering and respiration activity over annual cycle. Firstly, we started by developing a system for quantifying the particulate and dissolved compounds processed by sponges under natural conditions. In terms of feeding, we observed that all species retained plankton at high efficiency and DOC was the main source of carbon. However, the nitrogen fluxes showed a markedly different trophic niche between the two groups: HMA species mostly rely on dissolved compound as main source of N, while LMA solely rely on particulate fractions. Interestingly, natural variation of sponge pump did not follow natural temperature changes. During the period of maximum temperature the sponge pump did not reach its maximum values, suggesting that intrinsic mechanism as a decrease in choanocytes during reproductive cycle may regulate this metabolic process. On the other hand respiration clearly showed a seasonal pattern following natural temperature fluctuation. Combined, these results allowed us to estimate the overall energy budget, which appeared to be regulated by an increase of energy demand in summer as well as the availability of dissolved organic carbon fraction in the water column. Our result also showed different limited energetic profiles between HMA and LMA species accordingly to their different feeding strategies. LMA species appeared to procure sufficient energy to meet metabolic requirements for maintenance and growth by filtering suspended particulates, and dissolved fraction represented an additional input of carbon when available. On the contrary the heterotrophic nutrition in the natural environment may be insufficient to meet basal metabolic requirements in HMA species, suggesting other metabolic pathways as relevant for the energy budget of these species.
Paraules clau: benthic ecology, nutrient fluxes, energetic metabolism, eco-physiology, feeding acgivity, pumping and respiration rates

Intrinsic and environmental influences on DNA methylation and gene expression in fish

Autor: D. Anastasiadi
Director/es tesi: F. Piferrer Circuns
Any publicació: 2016
Lloc d'edició: Barcelona
Institució: Universitat Pompeu Fabra
Resum: Veure
Epigenetic mechanisms, influenced by intrinsic and environmental factors are crucial for the regulation of gene expression and, ultimately, the phenotype. The European sea bass is used as a model to study these influences on DNA methylation and the phenotype during early development and later in life. We identify loci altered with age, suggestive of the existence of a piscine epigenetic clock. We show that moderate early developmental temperature increases are associated with genome-wide changes in DNA methylation and with parent-specific responses of genes involved in sexual development. Furthermore, we highlight a genome-wide inverse relationship of gene expression with the DNA methylation of the first intron. Lastly, we provide one of the first empirical demonstrations in support of the neural crest cell deficit hypothesis to explain Darwin’s domestication syndrome. Together, these results constitute the most integrative analysis of DNA methylation patterns in a fish species under intrinsic and ecologically relevant contexts

Marine photosysthetic picoeukaryotes: community structure at different spatial scales

Autor: A.M. Cabello Pérez
Director/es tesi: M. Latasa, R. Massana
Any publicació: 2016
Lloc d'edició: Las Palmas de Gran Canaria
Institució: Universidad de Las Palmas de Gran Canaria
Resum: Veure
Marine photosynthetic picoeukaryotes or PPEs, single-celled algae from 0.8 to 3 µm in size, are major contributors to phytoplankton biomass and primary production in marine systems and form diverse communities dominated by prymnesiophytes, chlorophytes, pelagophytes, and chrysophytes. Due to their ecological relevance it is important to characterize PPE community structure over temporal and spatial scales and to identify the environmental factors shaping community assembly. In this thesis we focused on major PPE groups, with the aim of determining.

Modelling social-ecological systems in the Catalan coastal zones

Autor: B. Tomlinson
Director/es tesi: Francesc Maynou, Miquel Canals
Any publicació: 2016
Institució: Universitat de Barcelona
Resum: Veure
The Systems Approach Framework (SAF) is a methodological framework designed to enhance the efficacy of human decision-making processes within social-ecological systems with regard to sustainability. The SAF was applied in two case studies in the coastal zone of Catalonia, in two separate European Commission Framework Programme projects entitled “Science and Policy Integration for Coastal System Assessment” (SPICOSA) and “Vectors of Change in Oceans and Seas-marine Life, Impact on Economic Sectors\" (VECTORS). During the SPICOSA application, a common issue of interest to most stakeholders was the water quality (harmful bacteria and water clarity) of the local city beaches, particularly following combined sewer overflow events, and mitigating this impact by using stormwater collectors. Water quality influences the beach users’ decision whether to stay at the beach or to leave, thus affecting the revenue received by the bars and restaurants on the beach front. A social-ecological model was constructed using the methodology outlined in the SAF to represent this issue, so that it could be used as a tool for deliberation between the stakeholders. The model output implies that the stormwater collectors have been useful in improving beach water quality in Barcelona, but there will be diminished returns in constructing more. The value of the beach is clearly large in terms of both non-market value and revenues generated in the nearby bars and restaurants. However, the impact changes in water quality would have on the recreational appeal of the beach is estimated to be low and further research is recommended to determine beach users’ sensitivity to beach closures (bacteria limit exceeded) and turbidity. At the beginning of the VECTORS project, stakeholders who had participated during the previous SAF application expressed a lack of willingness to engage due to a lack of human resources. The scientific team therefore chose to continue the application with the aspiration of demonstrating the SAF model and results at a later date if the stakeholders found the required resources to engage with the process. There is a general perception that jellyfish abundances are increasing along the Catalan coast. Local authorities are concerned about the stranding events and arrivals of jellyfish to beaches and believe it could reduce the recreational appeal of the beaches. Previous studies also demonstrate the predation of jellyfish (Pelagia noctiluca ephyrae) upon some small pelagic fish larvae (Engraulis encrasicolus). Small pelagics are the principal source of revenue for the local fisheries. A social-ecological model was created in order to capture the effects of changes in abundance of Pelagia noctiluca upon the local fisheries, the tourist industry and the wider economy.Various future scenarios for different abundances of jellyfish blooms were run. Given the changes that these scenarios would cause on the regional gross domestic product and employment, this study concludes that the overall impact of either of these scenarios on the economy would not be significant at the regional scale. The inclusion of stakeholders in the SAF methodology is rightly fundamental, but in practice, it can be extremely difficult to persuade key stakeholders to participate, and this is a flaw in the SAF which needs addressing. SAF Application model builders are dependent on stakeholders sharing important data or knowledge but this may be withheld for a variety of reasons including, but not limited to, lack of resources to participate, disinterest, and concern about how the results will be used. The SAF is a well-structured methodology for cases where a mathematical model is both relevant and feasible and should be considered as a useful step-by-step guide for managing coastal zone systems towards sustainability.

Morphological structure and biodiversity in fish assemblages

Autor: M. Farré Foix
Director/es tesi: V.M. Tuset Andújar, A. Lombarte Carrera
Any publicació: 2016
Lloc d'edició: Barcelona
Institució: Instituto de Ciencias del Mar, Universitat de Barcelona
Resum: Veure
One of the essential principles provided by the Darwin’s theory of natural selection is that the evolution of organisms and their phenotypic features should be assessed by analyzing the interaction between the anatomical structures of organisms with the external environmental conditions acting on them (Darwin, 1859; Allen, 1907; Thompson, 1917; Bock and von Wahlert 1965). Basing on this premise, since then the study of morphology of organisms attracted high attention within the scientific community, in order to describe and understanding the evolution, adaptations and behaviors of organisms from their morphological and anatomical differences. From its early times, the study of morphology of organisms was focused in descriptive and comparative anatomical analyses used with taxonomical and phylogenic purposes (Bock, 1990). The first references manifesting the relation between the morphology of th species with their surrounding environment appeared at the beginning of the 20 century, suggesting the existence of direct correlations between the phenotype (morphology) and the physic external factors (Allen, 1907), and that this association was the main driver of the evolution of species. This hypothesis was accepted, maintained and incorporated to studies of many scientific branches. In its studies of comparative anatomy from natural observations in the wild, Böker (1935) defined the term “ecological anatomy”, which linked again the morphological features of organisms with the environmental conditions. Other disciplines, such as systematic and genetics, also began to consider these statements in its competences (Dobzhansky, 1937; Mayr, 1942).

Multiscale soil moisture retrievals from microwave remote sensing observations

Autor: M. Piles Guillem
Director/es tesi: A. Camps, M. Vall-llossera
Any publicació: 2016
Institució: Universitat de Barcelona
Resum: Veure
Soil moisture is a key state variable of the Earth’s system; it is the main variable that links the Earth’s water, energy and carbon cycles. Soil moisture variations affect the evolution of weather and climate over continental regions, and accurate observations of the Earth’s changing soil moisture are needed to achieve sustainable land and water management, and to enhance weather and climate forecasting skill, flood prediction and drought monitoring. This Ph.D. Thesis focuses on measuring the Earth’s surface soil moisture from space at a global and regional scale. [...]

Saharan dust deposition effects on production in the Mediterranean Sea

Autor: R. Gallisai
Director/es tesi: F. Peters
Any publicació: 2016
Institució: Universitat Politècnica de Catalunya. Institut de Ciències del Mar
Resum: Veure
The potential capacity of fertilization of surface oceans by atmospheric deposition is of scientific interest. This is especially true in the oligotrophic Mediterranean Sea. Its surface waters are extremely poor in nutrients necessary for plankton growth. At the same time, it borders with the largest and most active desert area in the world and the atmosphere over the basin is subject to frequent injections of mineral dust particles. Moreover, future scenarios foresee increases in the region's aridity, thus increasing the dust load, as well as changes in ocean stratification that will increase the potential impact of dust deposition on surface waters. Thus, it is important to study the links between deposition and plankton stimulation. [...]

Spatio-temporal processes explaining salp aggregations in the Catalan Sea, northwestern Mediterranean

Autor: M. Pascual
Director/es tesi: V. Fuentes, J.L. Acuña
Any publicació: 2016
Institució: Universitat Politècnica de Catalunya
Resum: Veure
Salps are marine pelagic tunicates that have opportunistic skills to bloom under favorable conditions and persist during adverse periods. They quan experience population outbursts (blooms) which, combined with their efficient feeding mechanism, produce several ecological and societal consequences. Although salp blooms are common in the Catalan Sea during spring and autumn, their causes and effects on the ecosystem have never been studied in this area before. The general aim of the present thesis is to understand the spatial and temporal processes leading to salp blooms and estimate their trophic impact in the Catalan Sea, northwestern Mediterranean Sea. For this purpose, mechanistic (matrix models) and statistical models (GAMs) combined with in situ observations allowed us to propose the simplest mechanisms to account for bloom development. In contrast to previous hypotheses, we found that changes in female reproduction drive the population to latency under unfavorable conditions and trigger the bloom when conditions improve (Chapter 1). From a spatial scale, hydrodynamic factors mainly drove high local salp abundances, although biological variables (predator abundance) had secondary importance (Chapter 2). We observed the coexistence of contrasting diel vertical migration (DVM) patterns in a salp (nocturnal and diurnal migrations), which explains controversial conclusions in previous studies, but brings new questions about the drivers of DVM in salps (Chapter 3). The two species found produced contrasting trophic impacts: Thalia democratica was less abundant and its effect on the ecosystem seemed to be negligible while, Salpa fusiformis ingested a maximum of 69.92 mg C m-2 day-1 and defecated 35.76 mg C m-2 day-1 , contributing to the transport of organic matter to the deep ocean (Chapter 2). Our findings lead us to consider evolutionary demographic studies to understand the potential benefits of their life cycle for the adaptability to short-time scale environmental changes and the mechanisms which maintain genetic variability after bloom-latency periods.

Spatiotemporal variability of the carbonate system in the North Atlantic ocean

Autor: E. Fernández Guallart
Director/es tesi: F. Pérez, C. Pelejero
Any publicació: 2016
Institució: Universidad de Las Palmas de Gran Canaria
Resum: Veure
The ocean carbon sink contributes to mitigate global warming. However, the resulting anthropogenic CO2 (C ant) oceanic invasion affects the chemical balances of the CO system in seawater, which translates into a decrease in surface ocean pH. The North Atlantic Ocean presents the largest Cant storage rate of all oceans. The key mechanism contributing to this high value is the northward transport of warm tropical and subtropical waters that contain high Cant concentrations from low latitudes poleward into the regions of deep water formation, through the upper limb of the Atlantic Meridional Overturning Circulation. These deep waters return southward into the Deep Western Boundary Current (DWBC) containing moderate but increasing Cant levels. Given the predominant part of the (sub)tropical North Atlantic region in the uptake of atmospheric Cant , the anthropogenically derived acidification and taking into account the role of ocean circulation on the distribution of the absorbed Cant between basins, this thesis assesses de decadal changes and trends in some parameters of the carbonate system along two oceanographic sections located at 24.5°N and at 7.5°N of latitude, occurred between the early 1990s and the early 2010s. We assessed the interactions between ocean circulation and the carbonate system, in particular regarding the processes that control and modulate the storage rates of Cant and the associated acidification. This was accomplished by splitting the water masses present in each of the two sections into separated zonal regions that were defined following oceanographic criteria. This methodological approach showed that the spatiotemporal variability in the storage of Cant along the two sections is strongly related with the deep Cant signal conveyed by the main circulation current (i.e. DWBC) that spreads across the two sections. The deconvolution of the temporal pH differences into anthropogenic and non-anthropogenic (natural) components revealed that these are of similar magnitudes but have different representations with depth and longitude. Our results emphasize the need to provide more insight into natural variability of the parameters of the carbonate system, with the aim of providing further insight on the predictability of the observed trends for time periods over decadal timescales.

Storfjorden Trough Mouth Fan (Western Barents Sea): slope failures in polar continental margins; significance of stress changes and fluid migration induced by glacial cycles

Autor: J. Llopart
Director/es tesi: R. Urgeles, A. Camerlenghi
Any publicació: 2016
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona. Institut de Ciències del Mar
Resum: Veure
Late Quaternary climate variations controlled glacial advances and retreats to the shelf edge and therefore the evolution of high latitude continental margins. The variations in ice extension modulated sediment supply to the continental slope resulting in a particular shape and stratigraphy but also exerted a major control on stresses imposed on marine sediments and likely had a major control on fluid flow pattern. This thesis investigates the sedimentary, stratigraphic and hydrogeologic evolution of two Arctic Trough Mouth Fans (TMFs), the Storfjorden and Kveithola TMFs in the NW Barents Sea, from ~2.7 Ma to Present, and identifies how such evolution affected slope instability of the TMFs. The research is carried out by means of sub-bottom and seismic reflection profiles, multibeam bathymetry data and sediment cores on which sedimentological and geotechnical analysis have been performed. Numerical finite elements models allow inferring the detailed stratigraphic architecture and hydrogeological evolution of the TMFs. We found that the Storfjorden and Kveithola TMFs mainly consist of an alternation of rapidly deposited glacigenic debris flows during glacial maxima and a sequence of well-layered plumites and hemipelagic sediments, which were mainly deposited during the deglaciation phase of the adjacent glacial trough. We have identified eight units above regional reflector R1, which indicate that the ice sheet reached the shelf edge within the Storfjorden Trough on at least three occasions during the last ~200 ka. A shallow subsurface unit of glacigenic debris flows suggests that the ice sheet had a short re-advance over the northern and central part of Storfjorden after the Last Glacial Maximum. From stratigraphy, core and literature data, we estimate that ice sheets reached the shelf edge between 19.5 to 22.5 ka, 61 to 65 ka and 135 to 167 ka. [...]

The influence of bottom-currents on the sedimentary evolution of the Alboran sea during the pliocene and quaternary

Autor: C. Juan Valenzuela
Director/es tesi: G. Ercilla Zarraga, F.J. Hernández Molina, T. Medialdea Cela, M. Canals Artigas
Any publicació: 2016
Institució: Universitat de Barcelona; Institut de ciències del Mar
Resum: Veure
An interdisciplinary study of the geomorphology, sedimentology, stratigraphy and physical oceanography of the deep-sea environments of the Alboran Sea (south western Mediterranean Sea) has been carried out with the purpose of evidencing and understanding the role of bottom currents in the sedimentary evolution of the Spanish and Moroccan continental margins and adjacent basins during the Pliocene and Quaternary. This study was conducted using swath bathymetry data, more than 1900 profiles consisting of parametric, single- and multi-channel seismic records, scientific and commercial wells, sediment cores, and hydrographic data comprising: Conductivity, Temperature and Depth (CTD) profiles, Acoustic Doppler Current (ADCP) profiles, and EK60 echograms. Here, for the first time, a morphosedimentary scenario with a wide spectrum of depositional (plastered, sheeted, channel-related, mounded confined, elongated and separated drifts) and erosional (terraces, escarpments, moats, channels and furrows) contourite features are described in the Alboran Sea, from the shelf break to the basin floor. Hydrographic data offers new insights into the distribution of the Mediterranean water masses, and reveals that the bottom circulation of the Western Intermediate Water (WIW) and the Levantine Intermediate Water (LIW) interact with the Spanish slope, and the Western Mediterranean Deep Water (WMDW) with the Moroccan slope, Spanish baseof- slope and deep basins. The integration of distinct datasets and approaches allow a new sedimentary model to be proposed for the Alboran Sea that underlines the significance of bottom current processes in shaping deep-sea morphology. This model suggests that the bottom circulation of water masses governs physiography, that the interface positions of water-masses with contrasting densities sculpt terraces at a regional scale, and that morphological obstacles play an essential role in the local control of processes and watermass distribution. An analysis of the seismic stratigraphy from the Pliocene and Quaternary sequences has enabled to update and rename the stratigraphic boundaries and establish a new seismic stratigraphy for the Alboran Sea, after relocating the base of the Quaternary from 1.8 to 2.6Ma. Additionally, the seismic analysis involves the presentation and discussion of the evidence for contourite features reaching the scale of the Alboran Basin. Contourite drifts (plastered, sheeted, elongated separated and confined mounded drifts) and erosive features (terraces, escarpments, moats, channels, furrows) were developed under the continuous influence of Mediterranean water masses after the opening of the Strait of Gibraltar (~5.33Ma). At least two primary factors have controlled the contourite features 12 in this sea: i) tectonics, which has governed the relocation of the main Mediterranean flow pathways and their circulation patterns; and ii) climate, which has influenced both watermass conditions (depth and density contrast of the interfaces) and hinterland sediment sources, conditioning the morphoseismic expression and growth pattern of drifts and terrace formation (dimensions). The distribution of contourite features through time and space allows to propose three main scenarios for ocean circulation since the opening of the Strait of Gibraltar: i) Atlantic Zanclean flooding; ii) the Pliocene sea, with two different stages for the dense circulation and characterised by poorly-defined and unstable interfaces for the Atlantic Waters (AW), light and dense Mediterranean waters and the presence of a strong countercurrent in the Western Basin; and iii) the Quaternary sea, characterised by tabular Mediterranean water masses with multiple current dynamics, increasingly important density contrasts, and climate shifts causing major vertical and horizontal displacement of the interfaces. These stages reflect variability in the bottom current regimes and related alongslope efficiency in terms of transport, deposition and erosion. The detailed seismic analysis of the units making up the Pliocene and Quaternary sequences allows for the first time, to make an in-depth analysis of the contourite features, turbidite systems and mass-movement deposits, and map them through time. These maps are enormously helpful when it comes to understanding the sedimentary architecture of the Spanish and Moroccan continental margins and basins, as well as for decoding the palaeoceanographic processes from a geological perspective. Two main contourite depositional systems are defined: the Intermediate Contourite Depositional System (ICDS), formed under the action of the Light Mediterranean Waters (LMW) on the Spanish margin, and the Deep Contourite Depositional System (DCMW), formed under the action of the Dense Mediterranean Waters (DMW) mainly on the Moroccan margin and basins. The characterisation of the terraces as contourite features that form under the combination of two water masses, has also led to the definition of the Atlantic Contourite Depositional System (ACDS). The occurrence of several contourite depositional systems has led to the suggestion of a new term, not heretofore considered in the literature: Multiple Contourite Depositional System (MCDS), which refers to the set of different CDSs that occurs in the same area and evolving under the action of multiple water masses. In addition, twenty turbidite systems have been characterised, revealing that they are responsible for the different sedimentary architecture of the Spanish margin, where they coexist with contourites, as on the Moroccan margin the turbidite systems are less well developed. The mass-movement deposits are mainly related to the reworking of the contourites draping the highs. Mainly contourites but also turbidites, allowed to define from a geological 13 perspective the basic oceanographic processes and to determine their occurrence, relative magnitude and energy, and time of action. This PhD thesis also explains the uneven development of the turbidite systems in the Alboran Sea, which is interpreted to be conditioned by the interaction of alongslope with downslope processes. Several morphological and sedimentary signatures produced by the interaction between both processes have been identified in the Pliocene and Quaternary records, as well as on the present-day seafloor of the Alboran Sea. The interaction scenarios move between two-end-members: from bottom currents dominating gravity flows to gravity flows dominating contour currents. In between these extreme cases, the alternation and mutual influence of both processes can occur. Two different conceptual models of interaction are proposed for the Spanish and Moroccan margins. i) On the Spanish margin, the alongslope and downslope interaction is especially complex and varied, with both regional and local effects on the turbidite systems. This is because here the turbidite systems are influenced at different water depths by Atlantic and Mediterranean water masses and their interfaces, with current flows that change acrossand downslope. ii) On the Moroccan margin, the vigorous action of the WMDW primarily inhibits the formation of canyons and associated deposits. The findings of this PhD thesis suggest that the relevance of bottom-water processes in deep sea must be reevaluated. It is concluded that understanding the influence of bottom currents is not only essential for reconstructing present and past water mass circulation, but also for recognising sea floor morphologies and decoding the sedimentary stacking pattern and evolution of deposits, as well as global climate and periods of eustatic variation.

Tracing the dynamics of dissolved organic matter in marine systems exposed to natural and experimental pertubations

Autor: F.L. Aparicio-Bernat
Director/es tesi: C. Marrasé Peña, M.M. Nieto Cid
Any publicació: 2016
Lloc d'edició: Cèlia Marrasé Peña, María del Mar Nieto Cid
Institució: Universitat Politècnica de Catalunya; Instituto de Ciencias del Mar; Insituto de Investigaciones Marinas de Vigo
Resum: Veure
In the coming decades, global warming will affect the biogeochemical cycles evolution, particularly the carbon cycle. In this context, it is necessary to gain knowledge on the Earth’s natural mechanisms to relieve the atmosphere of the greenhouse gases excess. The ‘biological pump’ is one of the main mechanisms employed by the oceans to \"sequester\" the CO2 accumulated in the atmosphere. Thereby, the organic carbon produced by the biological activity is transferred from surface to deep waters where part of this pool is accumulated in the seafloor. Another mechanism involving the accumulation of carbon in the ocean, called the ‘microbial carbon pump’ (MCP), has been recently described. It is composed by an intricate set of microbial processes that enable the formation of highly recalcitrant dissolved material and therefore facilitate the accumulation of carbon in the deep waters. The oceans store about 660 Pg C in the form of dissolved organic matter (DOM), a quantity comparable to the atmospheric CO2. Understanding the processes that control the dynamics, recycling and exportation of the DOM is crucial to evaluate the oceans capability to gather the excess of atmospheric CO2. On its course down throughout the water column, microorganisms degrade the DOM produced at the surface layers. Concentrations decrease from ~90 μmol C L-1 down to 40-50 μmol C L-1, values homogeneously distributed in the deep oceans throughout the planet. The fact that below 1000 m and deeper the DOM is degraded at lower speed is still unknown. The processes that can affect this DOM degradation have been studied in this thesis. In this regard, we performed experiments with deep Atlantic Ocean microbial communities. These communities were exposed to DOM of different quality. The results revealed that the presence of humic-like allocthonous compounds favored the generation of new humic-like compounds in situ. Consequently, we proved that the composition of the DOM that reach the deep ocean conditions its ease-to-degrade nature. In this thesis we also evaluated the effect of global change (acidification and eutrophication) on the quality of the DOM. With this purpose in mind, we developed mesocosms experiments in tanks of 200 L in which we enclosed coastal planktonic communities from the NW Mediterranean Sea. The planktonic populations were exposed to different treatments of pH and eutrophication (addition of inorganic nutrients). The results of these experiments demonstrated that low pH levels favored the increase of the planktonic organisms’ growth rates, while the input of nutrients promoted the transformation to complex DOM. Finally, a monthly monitoring sampling of several biogeochemical variables was carried out at the Estartit Oceanographic Station (EOS). One of the principal aims consisted in identify the DOM sources and its inter-annual variability. The results revealed the importance of the winds in transporting oceanic DOM inputs to the system, which contrasted with previous results observed in nearby sampling stations (e.g. Bay of Blanes, Bay of Banyuls-sur-mer), where the major DOM contributions were terrestrial inputs.

Two-dimensional modeling and inversion of the controlled-source electromagnetic and magnetotelluric methods using finite elements and full-space PDE-constrained optimization strategies

Autor: S. Galiana
Director/es tesi: X. García Martínez
Any publicació: 2016
Lloc d'edició: Barcelona
Institució: Universidad de Barcelona
Resum: Veure
The controlled-source electromagnetics (CSEM) and magnetotellurics (MT) methods are common geophysical tools for imaging the electrical properties of the Earth’s subsurface and are employed independently, jointly, and in combination with other geophysical techniques for this purpose. In order to appreciate measured data, both methods require forward and inverse modeling of the electrically conductive subsurface to the end that the modeled data reasonably fits the observations. Naturally, the potential goodness of this fit not only depends on the error in the measured data but also on the degree of physical approximation inferred by numerical modeling. Therefore, active research focuses on new methods for modeling and inversion to obtain accurate and reliable models of the Earth’s structure in increasingly complex scenarios. [...]

BENTHIC COMMUNITIES’ RESPONSE TO DIFFERENT TRAWLING IMPACT LEVELS: GENERALIZATION TOWARDS DEVELOPING A MEDITERRANEAN MODEL

Autor: A. Muntadas
Director/es tesi: M. Demestre, S. de Juan
Any publicació: 2015
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona
Resum: Veure
1. FISHERIES’ MANAGEMENT FRAMEWORK: ECOSYSTEM APPROACH TO FISHERIES (EAF) Fishing is one of the most widespread human pressures on marine ecosystems and it could be considered as one of the most harmful chronical human activities in the oceans (Jackson et al. 2001). Although fishing impact on ecosystems is not a recent concern (de Groot 1984, Osio 2012), during the last three decades it has arisen a renewed interest for a more ecological approach to this issue, focused on functional responses of the complex marine ecosystems (Thrush & Dayton 2002, Garcia & Cochrane 2005). Emerging from this interest, the term Ecosystem-based Fisheries Management (EBFM) was first described in 1998 by the US National Research council as “an approach that takes major ecosystem components and services –both structural and functional – into account when managing fisheries”. However, the term did not find consensus in the 2001 FAO Reykjavik Conference, where participants considered that its interpretation could imply that environmental conditions prevailed over socio-economic and cultural ones (Garcia et al. 2003). Therefore, the term Ecosystem Approach to Fisheries (EAF) was adopted by the FAO Technical Consultation in 2002. Despite being essentially the same, this wording involved also socio-economic factors, linking society, economy and ecosystems, which fitted better countries’ interests (Garcia et al. 2003). [...]

Biological rhythms in the Norway lobster (Nephrops Norvegicus L.): Ecological modulation and genetic basis

Autor: V. Sbragaglia
Director/es tesi: J. Aguzzi
Any publicació: 2015
Institució: Universitat Politècnica de Catalunya. Institut de Ciències del Mar
Resum: Veure
Nephrops norvegicus is an important fishery resource for Europe. Its rhythmic burrowing behavior is strictly related to catchability. Here I studied such behavior under laboratory conditions. I investigated the combined effect of light and current cycles demonstrating that tidal current is an important parameter to take in account in fishery management plan not only for Nephrops. Then I used a transcriptomics and RT-qPCR approach on cDNA extracted from the eyestalk to elucidate the putative molecular genetics mechanisms underlying circadian gene regulation. My data are in accordance with the current knowledge of the crustacean circadian clock, reinforcing the idea that the molecular clockwork of this group shows some differences with the established model in Drosophila melanogaster. Finally, I studied the burrow emergence behavior in group of 4 lobsters organized in dominance hierarchy demonstrating that lower ranks are more vulnerable to trawling. I hypothesized common neural mechanisms for agonistic and non-agonistic behaviors
Paraules clau: Nephrops norvegicus, biological rhythms, burrow emergence, catchability, tidal currents, clock genes, gene expression, dominance hierarchy, agonistic interactions

Conservation of marine habitat-forming species under climate change: population genetics and demographic responses of the Mediterranean red gorgonian Paramuricea clavata

Autor: R. Arizmendi
Director/es tesi: C. Linares, J.-B. Ledoux
Any publicació: 2015
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona
Resum: Veure
Climate change, along with other anthropogenic pressures (e.g. water pollution, overfishing and habitat degradation), is severely impacting oceans around the world, producing important changes in its physical and biological structure, and causing marine biodiversity to decline. In this context, the enhancement of conservation and management strategies that mitigate such stressors (e.g. Marine Protected Areas, MPAs) is urgent. In this thesis, we studied the population genetics and ecological responses to warming of the Mediterranean red gorgonian Paramuricea clavata (Risso 1826), in order to contribute to the design of more effective conservation and management measures for this and other similar species. P. clavata is a long-lived, slow-growing, low dispersal and highly vulnerable habitat-forming organism from the coralligenous assemblages. During the last decades, it has been severely impacted by mass mortality events (MME) caused by climate change-related thermal anomalies. P. clavata is essential to maintain biodiversity as it forms habitat for other organisms and it greatly contributes to habitat\'s biomass and complexity. Although the inclusion of habitat formers in the design of MPAs is fundamental to improve the effectiveness of biodiversity protection, these organisms have been generally neglected in the planning of MPAs, which, instead, have been historically designed for the protection of commercially important species. [...]

Ecology of some keystone invertebrates inhabiting shallow soft bottom communities of the Maresme coast (NW mediterranean sea)

Autor: M. Baeta Alacio
Director/es tesi: M. Ramón, M. Ballesteros Vázquez
Any publicació: 2015
Institució: Universidad de Barcelona
Resum: Veure
Bivalves living in large aggregations of individuals (reefs or beds), such as mussels, clams, cockles and some high trophic predators such as sea stars, play an essential ecological role in the structure, integrity, stability, and diversity of the biological communities; being usually considered as keystone species. Their disappearance or decline could lead to disproportionate effects in their communities, even affecting the survival of other species. Although keystone species are crucial for maintaining the Earth biodiversity, often their study has not taken enough attention. The main aim of this Doctoral Thesis was to study the ecology of some keystone invertebrates inhabiting shallow soft bottom communities of the Maresme coast (Northwestern Mediterranean Sea). The results enhance the knowledge of the smooth clam (Callista chione) and also of its potential predators, several species of sea stars (Astropecten spp.) co-occurring in the area. But at the same time, our findings help to understand their trophic interactions, the status of their populations and propose guidelines for their conservation. Maresme coast is close to Barcelona and it has concentrated historically a high anthropogenic pressure that has altered and modified its environment. Our results have showed the critical status of the smooth clam bed as a consequence of the combination of different human coastal uses: sand dredging and clam fisheries. These anthropogenic pressures have also led to significant changes in Astropecten populations. A. aranciacus has been shown to be the most vulnerable, and consequently the most affected, to the extent that its population suffers an important and worrying decline. Moreover, A. aranciacus reproductive cycle, growth and depth segregation between size classes along the continental shelf have been described for the first time. Our results have documented Astropecten species niche segregation, which allow them to co-occur within a biological community scale, without compete for the same available recourses. Sea stars showed a partitioning of the prey (species) and microhabitats in the Maresme coast. This Doctoral Thesis aims to provide a valuable background to improve the conservation of these keystone invertebrates, as well as to promote the sustainable exploitation of shellfish.

Estrategias del procesado y análisis espectral de datos sísmicos para el estudio de procesos dinámicos en oceanografía física

Autor: J.F. Mojica
Director/es tesi: V. Sallarès, B. Biescas
Any publicació: 2015
Institució: Universitat de Barcelona
Resum: Veure
La circulación oceánica de gran escala se encuentra relacionada con la pequeña escala a través de los procesos turbulentos, los cuales hacen posible el intercambio de energía cinética. En equilibrio, el flujo de energía inyectado por el forzamiento climatológico en el rango de producción (macroescala) debe balancearse por los procesos de mezcla en el rango de disipación (meso- y pequeña escala). Alrededor de la frecuencia de Coriolis, el efecto cinemático dominante es el campo de los giros geostróficos, mientras que a mayores frecuencias y especialmente cerca de la frecuencia inercial, los movimientos están dominados por la dinámica de las ondas internas, cuya propagación en el océano transfiere la energía a menores escalas a través de procesos de dispersión y de interacción onda-onda. Dependiendo de las condiciones oceanográficas, cuando las ondas internas rompen, generando como consecuencia, la transferencia de parte de su energía a las escalas más pequeñas mediante procesos de mezcla irreversible, este proceso se puede generar de diversas maneras. [...]

Exploiting the multiscale synergy among ocean variables: Application to the improvement of remote sensing salinity maps

Autor: M. Umbert Ceresuela
Director/es tesi: A. Turiel (ICM), J. Ballabrera (ICM)
Any publicació: 2015
Lloc d'edició: Barcelona
Institució: Universitat Politècnica de Catalunya
Resum: Veure
Remote sensing imagery of the ocean surface provides a synoptic view of the complex geometry of ocean circulation, which is dominated by mesoscale variability. The signature of filaments and vortices is present in different ocean scalars advected by the oceanic flow. The most probable origin of the observed structures is the turbulent character of ocean currents, and those signatures are persistent over time scales compatible with ocean mesoscale dynamics. At spatial scales of kilometers or more, turbulence is mainly 2D, and a complex geometry, full of filaments and eddies of different sizes, emerges in remote sensing images of surface chlorophyll-a concentration and surface salinity, as well as in other scalars acquired with higher quality such as surface temperature and absolute dynamic topography. The aim of this thesis is to explore and apply mapping methodologies to improve the quality of remote sensing maps in general, but focusing in the case of remotely sensed sea surface salinity (SSS) data. The different methodologies studied in this thesis have been applied with the specific goal of improving surface salinity maps generated from data acquired by the European Space Agency’s mission SMOS, the first satellite able to measure soil moisture and ocean salinity from space at a global scale. The first part of this thesis will introduce the characteristics of the operational SMOS Level 2 (L2) SSS products and the classical approaches to produce the best possible SSS maps at Level 3 (L3), namely data filtering, weighted average and Optimal Interpolation. In the course of our research we will obtain a set of recommendations about how to process SMOS data starting from L2 data. A fusion technique designed to exploit the common turbulent signatures between different ocean variables is also explored in this thesis, in what represents a step forward from L3 to Level 4 (L4). This fusion technique is theoretically based on the geometrical properties of advected tracers (Turiel et al., 2005a). Due to the effect of the strong shear in turbulent flows, the spatial structure of tracers inherit some properties of the underlying flow and, in particular, its geometrical arrangement. As a consequence, different ocean variables exhibit scaling properties, similar to the turbulent energy cascade (Seuront and Schmitt, 2005; Nieves et al., 2007; Nieves and Turiel, 2009; Isern-Fontanet et al., 2007). The fusion method takes a signal affected by noise, data gaps and/or low resolution, and improves it in a geophysically meaningful way. This signal improvement is achieved by using an appropriate data, which is another ocean variable acquired with higher quality, greater spatial coverage and/or finer resolution. A key point in this approach is the assumption of the existence of a multifractal structure in ocean images (Lovejoy et al., 2001b), and that singularity lines of the different ocean variables coincide. Under these assumptions, the horizontal gradients of both variables, signal and template, can be related by a smooth matrix. The first, simplest approach to exploit such an hypothesis assumes that the relating matrix is proportional to the identity, leading to a local regression scheme. As shown in the thesis, this simple approach allows reducing the error and improving the coverage of the resulting Level 4 product; Moreover, information about the statistical relationship between the two fields is obtained since the functional dependence between signal and template is determined at each point.

Impact des variations du climat et du niveau marin sur les canyons sous-marins du Golfe du Lion (France) et de la marge de l’Ebre (Catalogne) au cours du Plio-Quaternaire

Autor: M.-A. Mauffrey
Director/es tesi: S. Berne, R. Urgeles
Any publicació: 2015
Lloc d'edició: Perpignan
Institució: Universiteé de Perpignan Via Domitia
Resum: Veure
Les fluctuations du climat et du niveau marin, de plus ou moins grande amplitude, influencent le taux d’érosion sur le continent, le transport de sédiment vers l’océan et sa distribution vers le bassin profond. Les canyons sous-marins, structures érosives de premier abord, sont les zones de transfert privilégiées entre le plateau continental et le bassin profond. Peu d’études se sont concentrées sur la relation entre le remplissage des canyons, l’acheminement des sédiments et les variations du niveau marin. La chronologie de leur mise en place et de leur évolution aux échelles de temps géologiques restent également largement spéculatifs. Ce travail est consacré à la genèse des canyons sous-marins au Plio-Quaternaire sur les marges de l’Ebre et du Golfe du Lion, en Méditerranée occidentale. Cette genèse intervient après la crise de salinité messinienne, qui a conduit au démantèlement par érosion continentale des marges méditerranéennes. Après une initiation par érosion régressive au Pliocène, les canyons sous-marins connaissent un développement majeur lors de la mise en place des cycles climatiques de 100 ka au Quaternaire, en lien avec l’amplification des oscillations du niveau marin pouvant atteindre 150 m. L’utilisation et la comparaison de données sismiques (2D et 3D) de résolution et pénétration différentes, couplées à des calages chrono-stratigraphiques par forages, permettent de mettre en évidence le lien important entre les cycles climatiques de Milankovitch (principalement 100 et 41 ka) et l’architecture des têtes de canyons. Les changements rapides du climat et du niveau marin (cycles de Bond) ont également une influence importante sur le flux sédimentaire et les processus de transport, ainsi que sur la connexion/déconnexion avec les systèmes fluviatiles

Links between dimethylated sulfur and phytoplankton photophysiology in the surface ocean: geographical patterns and short-term variability

Autor: S.J. Royer
Director/es tesi: R. Simó Martorell
Any publicació: 2015
Institució: Universitat de Barcelona
Resum: Veure
Dimethylsulfide (DMS) and its algal precursor, dimethylsulfopropionate (DMSP), are major players in the oceanic and atmospheric sulfur cycle. DMS is the most abundant volatile organic sulfur compound in the upper ocean and its global emission accounts for ca. 28 Tg S per year, thus representing the main natural source of sulfur to the troposphere and about 30% of the global (including anthropogenic) sulfur emissions. [...]

Mecanismes implicats en el metabolisme i desintoxicació dels metalls en peixos de la mar Mediterrània

Autor: R. Siscar
Director/es tesi: M. Solé Rovira
Any publicació: 2015
Institució: Universitat de Valencia
Resum: Veure
El medi marí està exposat a canvis físics i químics que principalment són antropogènics. Cal destacar alguns canvis com l'augment de la temperatura de l'aigua i la presència de metalls els quals poden afectar negativament l'estat de salut dels organismes residents. Les particulars característiques del Mar Mediterrani en quant a l’elevada densitat de població costanera i reduïda circulació d’aigua, entre altres, fa d’aquesta mar un lloc molt vulnerable front als contaminants. La heterogeneïtat que per la presencia de contaminats en general, i metalls tòxics en particular, representa la proximitat a la costa o la profunditat fa necessari estudiar la contaminació i els seus efectes en cadascú dels nínxols marins. Els animals presenten mecanismes desintoxicants per als metalls, com la unió a metal•lotioneïna (MT) i al seleni (Se). Aleshores, és molt important saber fins a quin grau el peixos del Mar Mediterrani utilitzen aquests mecanismes per tal d’evitar els efectes nocius dels metalls, a més també cal esbrinar quin òrgan contribueix en major mesura a la desintoxicació, o si cada espècie utilitza de forma preferencial un d’aquests mecanismes. [...]

Ocean surface currents reconstruction from microwave radiometers measurements

Autor: C. González Haro
Director/es tesi: J. Isern Fontanet (ICM -CSIS)
Any publicació: 2015
Lloc d'edició: Barcelona
Institució: Universitat Politècnica de Catalunya. Institut Català de Ciències del Clima (IC3)
Resum: Veure
Ocean currents are a key component to understanding many oceanic and climatic phenomena and knowledge of them is crucial for both navigation and operational applications. Therefore, a key problem in oceanography is the estimation of the synoptic velocity field. Currently, global ocean surface velocities are routinely estimated from Sea Surface Height (SSH) measurements provided by altimeters. However, the separation between passes, as well as and the limited number of available altimeters leads to errors in the accurate location of oceanic currents when these measurements are used exclusively. Contrarily, satellite images of Sea Surface Temperature (SST) provide a good qualitative view of the location of ocean patterns, which has encouraged the investigation of alternative methodologies to reconstruct the velocity field based on these observations. This Ph.D. thesis has assessed the capability of SST microwave radiometers observations to retrieve ocean surface currents. The reconstruction of the ocean surface currents from SST observations can be expressed in terms of a transfer function notation, that allows to convert SST maps into SSH, and thus into currents. Because under geostrophic balance, the slope of SSH is proportional to ocean surface currents. This transfer function can be theoretically derived using the Surface Quasi-Geostrophic equations (SQG). Two different approaches were analyzed at a global scale: on one side, the analysis of the validity of the SQG approach has been performed, and on the other, an approach based on the synergetic properties between simultaneous SST and SSH observations has been analyzed. Both approaches have been compared with ocean surface currents retrieved from merged altimetric observations. The study has been focused on the period from October 2002 to May 2005, since during that period there were available four different altimeters, and the quality of the merged altimetric observations was enhanced. [...]

On the circulation of the North Atlantic shadow zone

Autor: J. Peña Izquierdo
Director/es tesi: J.L. Pelegrí
Any publicació: 2015
Lloc d'edició: Barcelona
Institució: Instituto de Ciencias del Mar; Universitat Politecnica de Catalunya
Resum: Veure
Regions isolated from the wind-driven circulation are found in the eastern margins of the world’s tropical oceans. The weak and stagnant circulation of these so-called ‘shadow zones’, in combination with the intense respiration of organic matter provided by the overlying highly productive waters, promotes the existence of large oceanic volumes with very low dissolved oxygen. These volumes are known as oxygen minimum zones (OMZs). The last decades of observations have revealed that OMZs are in general expanding, and thus potentially threatening the surrounding rich marine ecosystems. However, it is not clear whether this change is based on natural variability or it has an anthropogenic origin. Furthermore, under a global warming scenario, the future evolution of the OMZs is uncertain due to the complex interaction between the physical and biochemical processes that interplay in the OMZs dynamics. This dissertation seeks to unravel the key elements of the circulation in the North Atlantic shadow zone, aiming to provide a deeper understanding of the physical components that rule the dynamics of the North Atlantic OMZ (naOMZ) – this being the less intense OMZ of the world ocean but the one that has experienced the largest expansion. A comprehensive description of the North Atlantic shadow zone circulation is presented from novel (CANOA08 cruise) and historic observations, including numerical outputs from the assimilative ECCO2 circulation model. The main outcome of our work is that two markedly distinct regimes of circulation exist in the thermocline layers of the naOMZ, above and below σθ=26.8 kg m-3. In the upper layer, within the upper Central Water (uCW), the circulation is governed by the cyclonic regime of the subtropical cell. This stratum is characterized by relatively high oxygenation, with a predominance of South Atlantic Central Water (SACW). The lower layer, within the lower Central Water (lCW), presents a drastic decrease in the oxygen content due to its sluggish circulation; in contrast with the uCW, a mean anticyclonic circulation leads to a marked increase of North Atlantic Central Water (NACW). This result implies an equatorward transfer of mass from the subtropical gyre to the shadow zone, providing a previously unaccounted supply of oxygen from the well-ventilated subtropical thermocline. In fact, at the core of the naOMZ, the contribution of NACW is 50%. Such a mixture of SACW and NACW, with very low oxygen A broad band of eastward flows is located between 10ºN and 20ºN, just south of the westward flowing North Equatorial Current. These flows, here referred as the Cape Verde Current system, emerge as the major contributor in he water mass supply to the naOMZ. Lagrangian simulation reveals that while in the uCW, most of the water supply occurs south of 10ºN, in the 1CM, more than two thirds of the total water supply takes place north of 10ºN, through the Cape Verde Current system with a high contribution of water directly recirculated from the subtropical gyre. The accurate numerical reproduction of the water mass composition within that naOMZ thermocline, as directly deduced from particle-track Lagrangian simulations, supports the goodness of the ECCO2 velocity field. The uCW and lCW strata not only exhibit opposite circulation patterns, they also present opposite large-scale vertical motions with predominant upwelling in the uCW as part of the subtropical cell regime while the lCW presents a broad downwelling pattern. We propose the existence of an inverse subtropical cell within the lCW dynamically coupled to the uCW regime. The major role these cells play in the circulation of the North Atlantic shadow zone, together with their substantial natural inter annual and decadal variability, makes them major players on the oxygen anomalies observed during the last decades in the world OMZs.

Rôle des mécanismes biotiques et abiotiques dans la dynamique de la matière organique dissoute dans les écosystèmes marins pélagiques (Méditerranée Nord Occidentale)

Autor: E.D. Sánchez Pérez
Director/es tesi: P. Conan, C. Marrasé Peña
Any publicació: 2015
Institució: Université Pierre et Marie Curie
Resum: Veure
The role of abiotic and biotic mechanisms controlling the dynamics of the dissolved organic matter in pelagic ecosystem (NW Mediterranean).-- Chromophoric dissolved organic matter (CDOM) is a major fraction of dissolved organic matter (DOM). CDOM absorbs light over a broad range of ultraviolet (UV-R) and visible wavelengths. A small fraction of CDOM can emit fluorescence when excited by ultraviolet radiation; so called fluorescent dissolved organic matter (FDOM). CDOM plays a key role in regulating light penetration into the ocean, absorbing high-energy electromagnetic spectrum (visible and ultraviolet light) waves. On one hand, it protects aquatic organisms of potential photo-damage; in the other hand it induces a negative effect by reducing light for photosynthesis. [...]
Paraules clau: CDOM, FDOM, MOD, déposition de poussière, biotiques, abiotiques, Méditerranée Nord-Occidentale, DOM, atmospheric deposition, abiotic, biotic, Northwest Mediterranean

Sedimentary processes and resulting continental margin configuration during large-scale sea-level drawdown: The Messinian Salinity Crisis in the Western Mediterranean Sea

Autor: A. Lago Cameselle
Director/es tesi: R. Urgeles Esclasans
Any publicació: 2015
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona
Resum: Veure
The Messinian Salinity Crisis (MSC) represents one of the major environmental changes in the recent geological history of the Earth. During this event (5.97-5.33 Ma, Late Miocene), the Mediterranean Sea went into a nearly complete desiccation and more than 1 million km of evaporite deposits accumulated in the Mediterranean basins. Despite the increasing knowledge over the last 40 years, several controversies concerning the mechanisms and timing of the MSC remain currently under discussion. [...]

Sediment dynamics, geomorphology and internal structure of the Gulf of Valencia Continental Margin (NW Mediterranean)

Autor: M. Ribó Gené
Director/es tesi: P. Puig Alenyà
Any publicació: 2015
Lloc d'edició: Barcelona
Institució: Universitat Politècnica de Catalunya, Universitat de Barcelona, Institut de Ciències del Mar
Resum: Veure
This thesis offers an extensive perspective of the hydrodynamics and sediment transport of the Gulf of Valencia (GoV) continental margin (NW Mediterranean), focussing on the geomorphological and internal structure description of the bedforms observed over the margin. A comprehensive dataset using a wide range of methodologies was used during the project, spanning from hydrographic and hydrodynamic datasets, instrumented moorings, swath bathymetry, sediment sample and seismic profiles. [...]

Trophic cascade modelling in bathyal ecosistems

Autor: V. Mamouridis
Director/es tesi: F. Maynou Hernández
Any publicació: 2015
Institució: Universitat Politècnica de Catalunya
Resum: Veure
In this Ph.D. different aspects of the bathyal ecosystem have been treated with the final aim to investigate trophic cascade mechanisms driven by fishery (top-down control), a phenomenon that in bathyal systems has never been studied. This was exemplified by the in-depth study of the exploited soft-bottom continental slope off Catalonia (NW Mediterranean), where the important fishery of the highly priced red shrimp, Aristeus antennatus, is carried out and the structure of mayor pathways of the trophic web is known. However for the (almost complete) lack of information about the fauna in the sediment, this thesis presents a first quantitative seasonal study on the macrobenthos (infauna) in the studied habitat. Also an analysis on the landings per unit effort (LPUE) of the red shrimp has been developed to define the principal influential variables on this stock. All these studies have in common the investigation of the dynamics of the bathyal system at different levels of organization (population, assemblage and ecosystem) in relation to environmental and fisheries drivers. [...]

Understanding the processes that controlles rifting of the Tyrrhenian basin

Autor: M. Guzman Vendrell
Director/es tesi: C.R. Ranero; V. Sallarès
Any publicació: 2015
Institució: Universidad de Barcelona
Resum: Veure
Work carried out in this thesis has the purpose to trace the tectonic and stratigraphic features of the Tyrrhenia Sea, and from these characteristics, to define the processes that get involved into the basin formation. The Tyrrhenian is a back-arc basin belonging to the Western Mediterranean realm. Its formation is directly related with the subduction system of the Ionian slab (African plate) below the Mediterranean domain (European plate). The slab retreat causes an stretching of the overriding plate and triggered the opening of the Liguro-Provençal basin, and later on the Tyrrhenian basin (Faccenna et al., 2001; 2007). [...]

Abundance and diversity of marine microbial eukaryotes

Autor: M.C. Pernice
Director/es tesi: R. Massana Molera
Any publicació: 2014
Lloc d'edició: Las Palmas de Gran Canaria
Institució: Universidad de Las Palmas de Gran Canaria
Resum: Veure
Microeukaryotes are important ecological players in any kind of ecosystem, most notably in the ocean, and it is therefore essential to collect information about their abundance and diversity. To achieve this general goal this thesis was structured in two parts. The first part represents an effort to define our “diversity unit” from studies based on the well-known cloning and Sanger sequencing approach. Basically, we wanted to establish a solid baseline for the second part of the thesis. We started with data from one cruise (Chapter 1) and then continued with the analysis of the complete dataset of 18S rDNA sequences available at that time (Chapter 2). From this analysis we found that the V4 region of the 18S rDNA was a good proxy of the variability of the entire gene. We also determined that the maximal genetic distance for sequences belonging to a same class was 0.25. Once defined this framework, it was used in the second part of the thesis for studying deep ocean microeukaryotes. Thanks to the Malaspina 2010 expedition, we had a comprehensive set of deep samples with associated abiotic and biotic parameters from all over the world. We found that the microeukaryotes abundance averaged 54 cells mL-1 in the mesopelagic layer and 14 cells mL-1 in the bathypelagic layer, and its variability was explained by depth, prokaryotes abundance and oxygen concentration (Chapter 3). Finally, the diversity of deep microeukaryotes was determined by pyrosequencing and metagenomic tags (Chapter 4). The bathypelagic community was mainly composed by Collodaria, Chrysophyceae, MALV-II and Basidiomycota. However, the relative abundance of these classes varies a lot among samples. The variability in community composition between samples was well explained by the water mass they belong and by the abundance ratio between prokaryotes and microeukaryotes.

Development of a new parallel code for 3-D joint refraction and reflection travel-time tomography of wide-angle seismic data - synthetic and real data applications to the study of subduction zones

Autor: A. Meléndez
Director/es tesi: V. Sallarès
Any publicació: 2014
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona, Institut de Ciencies del Mar
Resum: Veure
This dissertation is devoted to seismic tomography. I have implemented a new modelling tool for 3-D joint refraction and reflection travel-time tomography of wide-angle seismic data (TOMO3D). The reason behind this central objective is the evidence that the information based on 2-D seismic data does not allow to capture the structural complexity of many 3-D targets, and in particular that of the seismogenic zone in subduction margins. The scientific rationale for this statement, which justifies the central part of my thesis work, is based on the analysis of 2-D models obtained in the convergent margin of Nicaragua, a seismically active area where a textbook example of tsunami earthquake took place in 1992. In this application I modelled two perpendicular wide-angle seismic profiles for the characterisation of the overriding plate and the interplate fault. To do this, I applied TOMO2D, a state-of-the-art joint refraction and reflection 2-D travel-time tomography code. The inversion outcomes are two 2-D velocity models along both profiles, together with the 1-D geometry of the interplate boundary. In combination with other geophysical data measurements, namely coincident multichannel seismic profiles and gravity data, these models provide new constraints on the nature and structure of the margin, and in particular add new insights on the nucleation and propagation of the said earthquake and its tsunamigenic behaviour. Ultimately, this case study evidences the aforementioned limitations of 2-D modelling in the investigation of 3-D geological structures and phenomena. Following from this first application and with the idea of increasing the amount of data used in travel-time tomography, I focused on an a priori paradoxical phenomenon related to water-layer multiple phases, that under certain circumstances, is observed on wide-angle record sections. The interest of this study lies in the fact that this phenomenon can provide additional constraints on travel-time tomography models. First, I propose and corroborate the hypothesis explaining the apparent paradox, and then derive the most favourable geological conditions for the phenomenon to occur. Subsequently, the possibility to model this multiple-like phases is introduced in TOMO3D. [...]

Diversidad y evolución de gorgonias antárticas (Octocorallia, Primnoidae) distribución y aspectos reproductivos

Autor: R. Zapata Guardiola
Director/es tesi: J.M. Gili i Sardá, P.J. López González
Any publicació: 2014
Lloc d'edició: Sevilla
Institució: Universidad de Sevilla
Resum: Veure
El continente Antártico así como sus aguas circundantes se encuentran bajo protección legal desde 1959, fecha en la que se firmó el Tratado Antártico y gracias al cual hoy en día la Antártida es considerada como uno de los lugares del planeta donde la belleza natural y la pureza de los ambientes que alberga todavía se preservan. Debido a esta peculiaridad la Antártida resulta un escenario ideal dónde la fauna marina se ha diversificado y adaptado a unas condiciones peculiares, convirtiéndola en un laboratorio natural para estudiar procesos ecológicos y evolutivos en la formación de nuevas especies, cuya dinámica evolutiva puede utilizarse como referencia para establecer estándares que permitan explicar los cambios que se han producido a nivel mundial durante las últimas décadas así como extrapolar su futura dinámica.

Ecology of hot spring microbial mats: diversity, microheterogeneity, and biogeography

Autor: R. Mackenzie Calderon
Director/es tesi: C. Pedrós-Alió, B. Díez Moreno
Any publicació: 2014
Institució: Universitat Autònoma de Barcelona
Resum: Veure
The results presented in this PhD thesis include a description on the thermophilic populations thriving in biodiversity hot spots such as the Valdivian Rain Forest in Patagonia, and Cloud Forests in Costa Rica, as well as the Atacama Desert and Deception Island in the South Shetland Archipelago in Antarctica. The bacterial community structure of several hot spring microbial mats was characterized by means of molecular microbial ecology methods, and the relationship between diversity and temperature was measured at different spatial scales. Phylum Cyanobacteria was identified as the major component of the microbial community by at least three different sequencing methods with different taxonomic resolution, and a deeper diversity analysis on this group showed no substantial differences between samples taken in winter and summer, although significant similarities were observed among hot springs with common surrounding environments. The horizontal microheterogeneity of microbial mats at a centímeter scale also revealed Chloroflexi as dominant phylum together with Cyanobacteria, and a temperature differentiation was observed between both potential primary producers. Significant diversity shifts were detected among closely situates samples in single mats, but at the same time, samples within mat patches showed a high community structure similarity. A deeper characterization of the bacterial community structure revealed the presence of several heterotrophic groups such as Cytophagia and Sphingobacteria; Thermales; and Alpha, Beta, and Gammaproteobacteria; among others. When compared with other thermophilic microbial mats along a latitudinal gradient, no relationship was detected between richness and latitude, as samples closer to the equator were not more diverse or harbored more richness than samples closer to the pole. Temperature, on the other hand, influenced significantly the bacterial richness. Finally, samples at local, regional and global scales (up to 1000 m2) showed a decrease in similitude as geographic distance, but not at the continental scale.

Effect of environmental factors on the gonadal transcriptome of European sea bass (Dicentrarchus labrax), juvenile growth and sex ratios

Autor: N. Diaz Blanco
Director/es tesi: F. Piferrer Circuns
Any publicació: 2014
Institució: Universitat Pompeu Fabra
Resum: Veure
In many gonochoristic fish, sex is plastic since it can be altered by the influence of environmental factors. In this thesis, using the European sea bass (Dicentrarchus labrax) model, a teleost fish with a polygenic sex determining system influenced by the environment, we have studied the effects of different environmental factors —including food supply, elevated temperatures and presence of estrogens— on growth, sex differentiation and gonadal development of juveniles. Global analysis of gene expression was carried out by a custom-made microarray. We found that, like in mammals, sex determines growth and that the first sex-related differences in growth are established before the appearance of the first molecular markers indicative of sex. Further, the juvenile testis transcriptome is influenced by poor growth during sex differentiation, while proper food supply during juvenile development is able to rescue the testis transcriptome of previously poor-growing individuals. We found that the previously observed masculinization as a result of elevated temperatures is caused by long-lasting effects at the transcriptomic level, by favoring the expression of male-related genes and decreasing that of female-related genes. In contrast, exposure to estrogen negatively affects both male- and female-related genes and pathways. Interestingly, the expression patterns of a suite of genes related to epigenetic regulatory mechanisms of gene expression showed different degrees of dependency to genetic background, developmental time and external influences according to their functional category.

Feeding ecology and community structure of mesopelagic fishes in the Western Mediterranean

Autor: A. Bernal Bajo
Director/es tesi: P. Olivar Buera, M.L. Fernández de Puelles
Any publicació: 2014
Institució: Universitat Politècnica de Catalunya
Resum: Veure
Mesopelagic fish populations from the orders Myctophiformes and Stomiiformes were investigated to determine the potential effects of physical and biological factors on their trophic ecology, and characterize the ecological role that have in an oligotrophic system such as the western Mediterranean. The relevance of the mesopelagic fish community is connected to the great biomass that they represent worldwide, constituting common dietary resources for large pelagic fishes of commercial interest, marine birds and marine mammals. Myctophids are also key components of the trophic webs since they perform extensive diel vertical migrations throughout the water column, acting as vectors of matter and energy fluxes. This study was developed in a region off the Balearic Islands during two seasonal periods, late autumn (water mixing period) and summer (stratification of the water column). The trophic behaviour and vertical distribution of mesopelagic fishes were analysed, and ontogenetic dietary shifts from young individuals to adulthood were described. These aspects have been hardly reported in juveniles and adults of Mediterranean mesopelagic fishes. The present study comprises the most abundant and frequent species of myctophids (Ceratoscopelus maderensis, Notoscopelus elongatus, Benthosema glaciale, Hygophum hygomii, H. benoiti, Lampanyctus crocodilus, L. pusillus, Lobianchia dofleini, and Myctophum punctatum) and stomiiforms (mainly, the gonostomatid Cyclothone braueri and the sternoptychid Argyropelecus hemigymnus) of the Mediterranean Sea. The first objective of this thesis was to confirm whether the classical larval identification based on morphological and pigmentation characters, for both myctophids and stomiiforms, was supported by using barcoding genetic techniques. [...]

Jellyfish of the spanish mediterranean coast: effects of environmental factors on their spatio-temporal dynamics and economic impacts

Autor: A.J. Canepa Oneto
Director/es tesi: J.M. Gili i Sardà, V. Fuentes
Any publicació: 2014
Institució: Universitat de Barcelona
Resum: Veure
During recent years, jellyfish blooms have become in a passionate issue among marine scientists with a series of studies and reviews. The main concern about this blooms are related with ecosystem and socio-economic impacts and lately with the possibility of a global increase in these blooms. Jellyfish populations are known to follow periodic fluctuations in occurrence, abundance (biomass), where some regions, like the Mediterranean Sea, appear to sustain a long-term increase [...]

Non stationary magnetotelluric data processing

Autor: M. Neukirch
Director/es tesi: X. Garcia Martínez
Any publicació: 2014
Institució: Universitat de Barcelona
Resum: Veure
Studies have proven that the desired signal for Magnetotellurics (MT) in the electromagnetic (EM) field can be regarded as ’quasi stationary’ (i.e. sufficiently stationary to apply a windowed Fourier transform). However, measured time series often contain environmental noise. Hence, they may not fulfill the stationarity requirement for the application of the Fourier Transform (FT) and therefore may lead to false or unreliable results under methods that rely on the FT. In light of paucity of algorithms of MT data processing in the presence of non stationary noise, it is the goal of this thesis to elaborate a robust, non stationary algorithm, which can compete with sophisticated, state-of-the-art algorithms in terms of accuracy and precision. In addition, I proof mathematically the algorithm’s viability and validate its superiority to other codes processing non stationary, synthetic and real MT data. [...]

Ocean velocities as inferred from Argo floats: Methodology and applications

Autor: M. Rosell Fieschi
Director/es tesi: J. L. Pelegrí, J. Gourrion
Any publicació: 2014
Lloc d'edició: Barcelona
Institució: Universitat Politècnica de Catalunya (UPC)
Resum: Veure
The present work has been developed in the frame of the MOC2 project (Ocean Climate Memory: fluxes of intermediate waters in the Southern Atlantic and their transformation into surface waters in the equatorial Atlantic, reference number CTM2008-06438), which was carried out between January 2009 and December 2011 with funding from the Ministerio de Educaci´on y Ciencia of the Spanish Government. The project consisted of two subprojects, being the present PhD thesis part of the first subproject: Ocean Climate Memory: mechanisms and paths of surface water formation in the equatorial Atlantic (reference number CTM2008-06438-C02-01). The main objective of this subproject was to study the processes and velocity of incorporation of the Intermediate Waters towards the superficial ocean in the equatorial Atlantic. The project was funded by the Spanish Government, and carried out at the Physical Oceanography Department of the ICM-CSIC (Institut de Ciències del Mar de Barcelona). Josep Lluís Pelegrí was the project coordinator and PI of the first subproject. He and Jerome Gourrion are the directors of this PhD thesis. The original aim of this PhD thesis was to explore and develop a novel method to study the paths and rates of transformation of Antarctic Intermediate Water (AAIW) in the equatorial Atlantic Ocean by using the information contained in the floats of the Argo program. In particular, the ocean velocities at the sea surface and the parking depth are inferred from the Argo float trajectories; when combined with the salinity and temperature data, this gives information not only on the paths of the water parcels but also on their transformations. During the last years other authors have explored how to extract the velocity field from the Argo float trajectories and have produced velocity data sets that are regularly updated. Having our own method, however, lets us to control the parameters required by the method to produce the velocity fields, hence allowing us to carry numerous sensitivity studies. Other advantages are the generation of the velocity fields with all the available Argo data and the possibility of setting particular configurations of the method for regional studies. Finally, future tests and developments of the method can be planned and executed with relatively minor efforts. In this dissertation the method is first presented, and it is later used to examine the statistics of the ocean horizontal velocities and to explore the dynamics of the currents south of Australia and in the equatorial Atlantic Ocean. The dissertation ends up with a description of several ongoing developments that should lead to a future improvement of the method and its applications

Taxonomy, distribution and community composition of megabenthic non-crustacean invertebrates in the deep Catalan margin

Autor: A. Mechó
Director/es tesi: J.B. Company, E. Ramírez-Llodra, J. Aguzzi
Any publicació: 2014
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona
Resum: Veure
The deep ocean is the largest ecosystem on Earth and also the least explored. Only 5% of the deep sea has been explored with remote instruments and less than 0.01% of the deep sea-floor has been sampled and studied (Ramirez-Llodra et al. 2010a). A series of characteristics as low temperatures, relatively constant salinity, light decreasing and pressure increasing with depth and oxygen concentration generally close to saturation make this environment distinct and unique. [...]

The diversity of dinoflagellates belonging to the gymnodiniales from the catalan coast (NW Mediterranean sea)

Autor: A. Reñé i Vicente
Director/es tesi: J. Camp i Sancho, E. Garcés i Pieres
Any publicació: 2014
Institució: Institut de Ciencies del Mar, Universitat Politècnica de Catalunya
Resum: Veure
Dinoflagellates are one of the most abundant and diverse groups of microalgae. Many dinoflagellates are covered with cellulose plates, whereas others lack these plates and are hence referred to as athecate or unarmoured. Unarmoured species have been historically poorly characterized because they deform when fixed with traditional methods. Most unarmoured genera are included within the order Gymnodiniales and are differentiated by morphological characters, but the recent combination of morphological observations with phylogenetic data concludes that molecular phylogenies do not support the "classical" morphological criteria used to distinguish the genera. It is also known that the order Gymnodiniales is not monophyletic. Consequently, the taxonomy of dinoflagellates has shifted to a combination of morphology and molecular information. The widespread use of molecular techniques has enabled detailed studies on the systematics of a lot of groups. Although many dinoflagellates are not easily cultivable and cannot be sequenced by standard techniques, the single-cell PCR technique has allowed obtaining sequences from a single cell by taking advantage of the large copy number of the ribosomal genes. Extensive identifications of dinoflagellates present in the NW Mediterranean Sea were carried out between the 1960s and 1980s. However, the diversity of unarmoured dinoflagellates was not suitably characterized because of the use of fixed samples and the lack of molecular tools. This thesis studies the diversity of dinoflagellates belonging to the Gymnodiniales order from the Catalan coast, as a representative site of the NW Mediterranean Sea. This thesis presents a revision of their taxonomy by combining morphological studies of live specimens with the respective phylogenetic information. Given that the phylogeny of most of the studied organisms had not been previously determined and the evidence that Gymnodiniales is not monophyletic, a secondary objective was to study the phylogenetic relationships of species. The D1-D2 region of the LSU rDNA sequence was selected to conduct the SC-PCR, but SSU rDNA sequences were obtained when necessary. The combination of morphological and molecular data has led to the identification of 56 unarmoured species belonging to the order Gymnodiniales. Ten morphospecies are detected for the first time in the Mediterranean Sea, and seven, for the first time along the Catalan coast (Chapter 1 and 2). Additionally, the application of single-cell PCR has resulted in the sequencing of 43 unarmoured species, 25 of them for the first time (Chapters 1 and 2). It has also allowed the detection and characterization of species previously undescribed, resulting in the erection of two new species: Gymnodinium litoralis (Chapter 3) and Polykrikos tanit (Chapter 4). Additionally, the toxic species Cochlodinium polykrikoides was detected for the first time along the Catalan coast. Most populations formed a newly differentiated ribotype, but others were included within a previously known one, demonstrating their coexistence in the Mediterranean Sea (Chapter 5). Finally, a Ceratoperidinium specimen was sequenced for the first time and a new phylogenetic clade was obtained, along with other unarmoured dinoflagellates, including Ceratoperidinium margalefii, Gyrodinium falcatum, which was transferred to the genus Ceratoperidinium, three Cochlodinium species, and two Gymnodinium-like organisms. This resulted in the emendation of the Ceratoperidiniaceae family and the genus Ceratoperidinum (Chapter 6). The correct identification of the species has allowed to conclude that there is a high diversity of unarmoured dinoflagellates in the Catalan coast, and to discuss the implications on the distribution and biogeography of the species at a Mediterranean level, as C. polykrikoides (Chapter 5), or globally, as for Gyrodinium spirale (Chapter 2).

The structure and formation of the Tyrrhenian basin in the Western Mediterranean back-arc setting

Autor: M. Prada Dacasa
Director/es tesi: V. Sallarès Casas, C. Rodríguez Ranero
Any publicació: 2014
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona
Resum: Veure
In this thesis I present a geophysical study that aims to define the structure and petrological nature of the main geological domains in the Central Tyrrhenian basin, and to investigate the mechanisms involved in their formation. The geophysical data used in this thesis was acquired during the MEDOC (2010) survey within the framework of the MEDOC project, which was designed to improve our understanding of the origin and evolution of rifted margins. The MEDOC survey was focused on the Tyrrhenian back-arc basin, an extraordinary natural laboratory to investigate the structure and evolution of back-arc basins, and hence rifted margins, since 1) extension evolves from north to south [Kastens and Mascle, 1990], 2) the original structure is preserved, and 3) it is small enough to be investigated with a single marine survey. The present work is based on the analysis, processing, modeling, and interpretation of coincident Wide-Angle Seismic (WAS), Multichannel Seismic (MCS), and gravity data corresponding to the two longest transects acquired during the MEDOC survey in the Central Tyrrhenian basin, the southern Line GH/MEDOC-6 (~450 km) and the northern Line EF/MEDOC-4 (~400 km). Both lines run across the Central Tyrrhenian basin from Sardinia to the Campania margin. [...]

Viruses in the marine environment: community dynamics, phage-host interactions and genomic structure

Autor: E. Lara de la Casa
Director/es tesi: D. Vaqué Vidal, S. González-Acinas
Any publicació: 2014
Institució: Universidad de Las Palmas de Gran Canaria
Resum: Veure
There are an estimated 10 viruses in the world oceans, the majority of which are phages (viruses that infect bacteria). Extensive research has demonstrated the significant influence of marine phages on microbial abundance, community structure, genetic exchange and global biogeochemical cycles. In this thesis, we contribute to increase the knowledge about the ecological role of viruses in marine systems, but also we aimed to provide a better understanding about the interactions between phages and their hosts and the genetic pool and biogeography of some the isolated phages genomes. Firstly, we followed the seasonal variability of viral communities in a coastal marine site (Blanes Bay Microbial Observatory, BBMO) and the environmental and biological factors that could modulate them. Our results showed that viral communities did not follow any clear seasonal patterns during the 5 years studied period and that viruses were mainly negatively correlated with salinity. Secondly, given the actual concern of the climate change effects on marine ecosystems, we evaluated experimentally how increasing temperatures would affect the microbial loop via protists respect to via viruses (“viral shunt”) in two contrasting Arctic marine systems. Lytic life strategy dominated instead the lysogenic strategy when we increased the temperature. But, overall the most important factor controlling bacterial abundance was bacterivory. These two studies provide us a general overview regarding viral dynamics at the community level but without knowing who infects whom and who is doing what. To provide inputs into these relevant issues, we used the model of Pseudoalteromonas bacterial strains and its phages. Our results suggest that interactions between phages and hosts are highly complex in terms on infectivity and susceptibility at microdiversity level but also reflect that phages can infect at larger taxonomic rank reaching to the family boundaries. Pseudoalteromonas marine phages are unrepresented with only 4 genomes public available. Therefore, one of the isolated Pseudoalteromonas phage from BBMO was deeply studied; we investigated its biology, morphology, genomic and proteomic characteristics. Moreover, we carried out a genomic comparison of 3 Pseudoalteromonas phages isolated from the same bacterial specie to get insights into the genome structure and functional diversity. The genomic data analyzed not only contributed to a better understanding of phage-host interactions in marine systems but also demonstrated the complexity of their dynamics and biogeographic patterns.

Water mass variability in the eastern South Pacific and the ventilation of the oxygen minimum zone

Autor: P.J. Llanillo del Rio
Director/es tesi: J. L. Pelegrí
Any publicació: 2014
Lloc d'edició: Barcelona
Institució: Institut de Ciències del Mar - Universitat Politècnica de Catalunya (UPC)
Resum: Veure
The eastern South Pacific (ESP) is a key region of the world ocean with direct influence on the global climate. Two clear examples are the El Niño-Southern Oscillation (ENSO), which occurs in the Pacific but influences the weather worldwide, and the observed slowdown in the rise of global air temperatures since 2001, recently explained in terms of a more vigorous upwelling of cold waters in the ESP and in the Equatorial Pacific. Over the last decade, the oceanographic scientific community has turned its attention to the oxygen minimum zones (OMZs) found in the world oceans, with one of the most intense being located in the ESP. OMZs are apparently expanding under the ongoing global warming, threatening productive marine habitats and weakening the ocean’s ability to sequester atmospheric carbon dioxide by promoting nitrogen loss. Inside suboxic OMZs, the oceanic-fixed nitrogen is released to the atmosphere, partially as nitrous oxide, a powerful greenhouse gas that further disrupts the atmospheric radiative balance. This dissertation aims at extending our knowledge of the ESP OMZ through two main approaches. The first approach is based on tracer analysis and inverse modeling techniques. Such techniques are applied to hydrographic datasets in order to examine the water mass structure, its variability and its role on the ventilation of the ESP OMZ. The second approach brings a more dynamic perspective to the study of the ventilation of the ESP OMZ, with the assessment of the annual-mean advective and turbulent oxygen transports into the ESP OMZ from Argo and dissolved oxygen datasets. We describe the distribution of water masses offshore Chile, Peru and Ecuador and discuss their spreading pathways. A thorough characterization of the water masses has been accomplished, resulting in the first set of ESP water types accounting for inorganic nutrients and dissolved oxygen. The low oxygen waters that compose the ESP OMZ are mainly Equatorial Subsurface Water (ESSW). The ESP OMZ is ventilated from the south by the Antarctic Intermediate Water (AAIW) and by the shallower Subantarctic Water (SAAW). These water masses are transported into this region by the Peru Chile Current (PCC) or by the adjacent flow that forms part of the subtropical gyre. We also examine the changes induced by two opposite phases of ENSO in water mass distribution and biogeochemical activity. During La Niña, vigorous upwelling promotes the rise in depth of the upper part of the ESP OMZ and denitrification strengthens in the subsurface layer. Furthermore, the upward displacement of isopycnals induced by La Niña favors the ventilation of a shallower depth range of the OMZ by the upper portion of the AAIW. The opposite occurs during El Niño conditions. We find that, with a larger oxygen supply, respiration increases balancing most of the extra oxygen gain. This suggests that there is an excess of organic matter waiting to be remineralized whenever oxygen supply increases slightly and this situation favors the maintenance of the ESP OMZ. Furthermore, our results show that AAIW flowed along shallower isopycnals in 2009 than in 1993. Such shoaling is not caused by the ENSO phenomenon and changes the way AAIW ventilates the ESP OMZ. This finding might explain why an increase in oxygen content has been reported between 200 and 700 m off Chile. A global picture of the main processes and predominant paths of oxygen supply into ESP OMZ is provided here for the first time. Two main advective routes are found, the traditional equatorial pathway and a previously unreported subtropical pathway. Remarkably, the subtropical pathway provides more net oxygen gain than the equatorial pathway at the core of the ESP OMZ. This finding challenges the common assumption that the ESP OMZ is only ventilated by the eastward flowing zonal currents of the Equatorial Current System. This result is endorsed by the independent water mass analyses accomplished in the first part of this dissertation where the fingerprint of AAIW and SAAW is clearly found in the ESP OMZ. In addition, an unreported eastward zonal current, located at intermediate depths between 12-15ºS, is found flowing all the way from the central Pacific into the ESP OMZ and its oxygen supply is quantified. Mean advection dominates oxygen supply in the upper layers due to the large contribution by the eastward flowing equatorial zonal currents. However, epineutral turbulent diffusion becomes the dominant term at levels deeper than γn = 26.75 kg m-3. The annual mean oxygen budget for the whole volume of the ESP OMZ is unveiled. Epineutral turbulent diffusion provides a net oxygen supply of 417.4 ± 43.0 kmol s-1, advection supplies 292.7 ± 25.2 kmol s-1 and dianeutral turbulent diffusion provides 85.8 ± 17.6 kmol s-1. The mean biological consumption of oxygen required to close the budget is 795.9 ± 195.0 kmol s-1.

Coral Reef Ecosystem Services Economic Valuation Experiences From The South Pacific

Autor: N. Pascal
Director/es tesi: F. Maynou Hernàndez, E. Clua
Any publicació: 2013
Lloc d'edició: Barcelona
Institució: Universitat Politècnica de Catalunya, Institut de Cièncias del Mar
Resum: Veure
Economic approaches through ecosystem services (ES) valuation are increasingly recommended by several multilateral agencies and conservation organisations to face main market externalities affecting biodiversity in general and coral reef ecosystems. Nonetheless, the ES approach is recent and still has to prove its effectiveness for policymaking and design of market based instruments. In this dissertation, we will analyse the experience of two economic valuations of coral reef ecosystems in the Pacific focusing on two aspects. The first is to evaluate if current methods of Coral Reef Ecosystem Services Valuation (CRESV) permits to transmit a correct signal about ES and the second is to assess the impacts of results on policy-making and market externalities. [...]

Distribution and population biology of pelagic decapod crustaceans of the western Mediterranean

Autor: D. Silveira Simao
Director/es tesi: P. Abelló
Any publicació: 2013
Lloc d'edició: Barcelona
Institució: Universitat Politècnica de Catalunya
Resum: Veure
The present thesis provides new information about pelagic decapod crustaceans, specially so concerning the Mediterranean pasiphaeids. Remarkable differences in the pattern of distributions of the pasiphaeids were observed according to the influence of Atlantic waters. Overall both abundance and biomass of the pasiphaeids in Alboran Sea was higher than in the rest of the Iberian Mediterranean populations. The depth on which the pasiphaeids started to occur in appreciable density was also shallower in the Alboran Sea where the P. sivado presented the widest depth range of distribution as well as the biggest size of first maturity of females. This size was progressively smaller with increasing distance from the Atlantic water source, i.e the Gibraltar Strait area. Overall the two species presented a size structure that changed with depth, with younger individuals occupying shallower depths and biggest adults occupying deeper bathymetries. P. multidentata juveniles were only observed in the Catalan Sea while they were absent in the Alboran Sea. Size and morphological dimorphism of P. sivado were reported for the first time in the present thesis. All the five pleopods of females were thinner and more elongated than male pleopods, which in turn were rounded anteriorly and had robust shapes. A critical size from which the population sex ratio biases changed from females to males dominance was found in all P. sivado populations of the Mediterranean Iberian coast. This critical size was different and progressively larger again from populations nearest the Gibraltar Strait versus those placed in the Catalan Sea, in concordance with the female first maturity size gradient. The present thesis also provides a first attempt to investigate the influence of the Gibraltar Strait on the genetic population structure of the species by using congener benthopelagic shrimps that dwell in different depth strata. The Gibraltar Strait was shown to be a strong and unique geographical barrier to the genetic flux of both P. sivado and P. multidentata , due the presence of a marked genetic structure characterized by two main haplotypes: one Atlantic and another one Mediterranean. Other new information related to the phylogeny of the genus Pasiphaea was that P. sivado a much higher genetic divergence when compared to the rest of pasiphaeid species analysed, indicating that several genetic subgroups do occur within the genus Pasiphaea. [...]

Dynamics of benthopelagic food webs of the Catalan slope (NW Mediterranena sea): environmental drivers and influence on reproductive cycles

Autor: V. Papiol Nieves
Director/es tesi: J.E. Cartes Rodríguez, M. Carrassón López de Letona
Any publicació: 2013
Institució: Institut de Ciencies del Mar, Universitat Autònoma de Barcelona
Resum: Veure
Food is considered the main limiting factor in the Deep Sea, although few studies have tested this hypothesis. At the same way, seasonality observed in diverse aspects of the fauna in this ecosystem has been attributed to seasonal changes in food availability. These relationships have been analysed to date for fauna of low trophic levels, but such links regarding megafaunal predators remain rather untested. […]

Ecology of the marine copepod genus Oithona

Autor: S. Zamora Terol
Director/es tesi: E. Saiz Sendrós
Any publicació: 2013
Institució: Institut de Ciencies del Mar, Universitat Politècnica de Catalunya, Universitat de Barcelona
Resum: Veure
Copepods are probably the most abundant metazoan on earth (Humes 1994), successfully distributed throughout oceans, nearshore habitats, and freshwater systems (Boxshall and Halsey 2004). Within zooplankton, copepods have an important role in the biogeochemical cycles recycling nutrients in the oceans, and are key organisms in trophic pelagic webs as link with higher trophic levels. Although copepods have been deeply studied since the old days, our knowledge of their biology and ecology is still fragmentary. During years the methods used to collect zooplankton have caused a bias on our knowledge on the structure and functioning of plankton communities, neglecting the importance of their smallest fraction, including the small-sized species of copepods (Gallienne and Robins 2001; Calbet et al. 2001). Although in the early XX century the potential relevance of small copepods such as Oithona was already envisaged (Bigellow 1926), historically most of the research on copepods has been focused on the largest species. The difficult handling of small organisms, and the idea that larger copepods were more relevant in marine pelagic communities, probably contributed to the scarce interest devoted to the study of small copepods. The research focused on the smallest zooplankton has received a considerable impulse in the last decades, but still many aspects of the biology and ecology of small copepods are poorly known. In this introduction I will briefly explain how, when and where the interest on plankton research started; and some basic aspects of zooplankton and marine copepods will be described. I will finish it by explaining some characteristics of the ecology and biology of the genus Oithona, and the reasons why this small-sized copepod has an important ecological role in marine plankton communities, and justify its scientific interest.

Expressió gènica en microorganismes marins

Autor: M. Coll Lladó
Director/es tesi: C. Pedrós-Alió, S. G. Acinas
Any publicació: 2013
Resum: Veure
Ara que es comença a treure l’entrellat -o si més no a tenir una nova perspectiva- de la diversitat de microorganismes present als oceans gràcies a la biologia molecular i a la metagenòmica, el següent pas és esbrinar quines són les noves funcions que aquesta amaga i com són utilitzades i per qui a l’oceà. La regulació de l’expressió gènica és la base de la versatilitat i l’adaptabilitat de qualsevol organisme al medi on viu. De l’estudi dels gens expressats d’un organisme es poden deduir correctament moltes de les característiques del medi on la seva vida es desenvolupa habitualment. En cada situació els organismes expressen solament una part del seus gens, responent tant a factors interns (per exemple el cicle cel·lular) com a factors externs (temperatura, llum, aport de nutrients...). Les tecnologies de seqüenciació massiva també s’han aplicat en l’estudi de l’expressió de les comunitats microbianes marines (metatranscriptòmica). Tanmateix, aquestes tecnologies encara no estan prou optimitzades i sovint proporcionen seqüències que no poden ser assignades a cap gen conegut. En aquesta tesi ens hem plantejat l’estudi de l’expressió gènica dels microorganismes marins a tres escales diferents: a escala de comunitat, de genoma, i de gen. L’esforç més gran ha estat estudiar l’expressió gènica a escala de comunitat, on el nostre repte ha estat desenvolupar una tècnica equivalent als mètodes “d’empremta dactilar” (fingerprinting) del DNA que s’usen de forma rutinària –com la DGGE o l’ARISA- per tal d’explorar la dinàmica dels patrons d’expressió gènica de les comunitats de microbis marins, permetent la comparació d’un gran nombre de mostres a un preu assequible i sense la necessitat prèvia de saber les seqüències dels RNA missatgers. Aquesta tècnica, batejada com a TFA (de “Transcriptome Fingerprinting Analysis”), ens ha permès estudiar I) les variacions estacionals en els patrons d’expressió gènica dels picoeucariotes marins de l’Observatori Microbià de la Badia de Blanes durant 4 anys, i II) les variacions dels patrons d’expressió al llarg d’un gradient espacial horitzontal i vertical i d’un gradient temporal. En ambdós casos, els canvis d’expressió s’han comparat amb els canvis en l’estructura de la comunitat (mitjançant l’ARISA). A escala genòmica hem estudiat la resposta transcripcional global d’un microorganisme heteròtrof a la llum. La llum és responsable d’una gran quantitat de respostes fisiològiques. Una gran part dels microorganismes del mar que utilitzen la llum ho fan mitjançant la fotosíntesis, però existeixen d’altres microorganismes que utilitzen la llum de manera diferent, com els fotoheteròtrofs, que la utilitzen per generar energia però no fixen CO2. En un dels estudis de genòmica ambiental es va descobrir la presència d’una proteïna fotoactiva, la proteorodopsina, associada a un grup de bacteris marins no cultivats. Les proteorodopsines són responsables d’un nou mecanisme de fototrofia als oceans; funcionen com a bombes de protons accionades per la llum que generen un gradient de protons a la membrana per tal de sintetitzar ATP. A escala de gen, en aquesta tesi hem estudiat mitjançant RT-PCR l’expressió del gen de la proteorodopsina en un cultiu d’una flavobacteria marina i hem vist que la llum augmentava els seus nivells d’expressió

Geophysical and geological characterization of the active structures and of the nature of the basement in the Eurasia-Africa plate boundary (SW Iberian Margin): Implications for regional geodynamics and seismic hazard assessment

Autor: S. Martínez Loriente
Director/es tesi: E. Gràcia Mont, V. Sallarès Casas
Any publicació: 2013
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona
Resum: Veure
In this PhD Thesis I present a new interpretation of: 1) active structures implicating old oceanic lithosphere; 2) the nature of the basement; and 3) the distribution of the basement domains and the geodynamic reconstruction of the SW Iberian margin, a region that hosts the slow convergent boundary between the African and Eurasian plates. This interpretation is based on new geophysical data acquired, processed and modeled in the framework of this PhD work. The main findings of my study are the following ones: [...]

La modificación del sistema marino reflejada en las poblaciones de las especies de calamares Dosidicus gigas, Illex cointeii, Illex argentinus, Todarodes sagittatus, Doryteuthis gahi y Onykia ingens. Dinámica y función de los calamares en los ecosistemas

Autor: R. Rosas Luis
Director/es tesi: P. Sánchez Zalacain, C.A. Salinas Zavala
Any publicació: 2013
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona, Institut de Ciències del Mar
Resum: Veure
The interactions, between species and environmental variables such as sea surface temperature (SST), salinity, primary production (Chlorophyll a) and variations of biomass estimates of zooplankton, were evaluated in order to know the impact that the environmental variables can produce in the squid species. I. argentinus and D. gigas squid species were used as models because of the availability of fishery and biomass data. Both species are Ommastrephids squids and they are abundant in the ocean, also they are important resources in the fishery activity. The environmental variables were tested using time series analysis, defining the trend and cycles, this analysis eliminated the set data of salinity, because no change was observed in the time series. We observed a positive trend in the SST series and changes along the series were observed. These changes were identified as seasonal (summer-winter), interannual (El Niño-La Niña) and interdecadal (cold and warm periods). El Niño and La Niña events were related with the positive and negative tendency of the chlorophyll a and zooplankton. The gradual warming of the water masses in everyone cycle of the SST and the availability of nutrients produced a decrease in the primary production that was represented during 1990-1992, 1994-1996 and at the end of 1997 to 2000. These periods correspond to the El Niño event characterized by an increase in the SST. [...]

Mediterranean deep-sea ecosystems: biodiversity, functioning and vulnerability

Autor: S. Tecchio
Director/es tesi: F. Sardà Amills, E. Ramírez-Llodra
Any publicació: 2013
Institució: Universitat de Barcelona
Resum: Veure
The deep sea is the portion of the ocean that stands below 200 m depth, both in the water column and in the benthos (Gage & Tyler 1991). It is the largest biome of planet Earth, with about 90% of the ocean area being deep sea (Ramírez-Llodra et al. 2010a). In the past decades, researchers have loved to refrain that “we know more about the surface of the Moon than about our deep oceans”. To date, this still holds true. The deep sea is considered impenetrable, difficult and expensive to reach and observe. [...]

Molecular physiology of a teleost oocyte aquaporin: evolution, regulation and role during oocyte hydration

Autor: M.C. Zapater Cardona
Director/es tesi: J. Cerdà Luque
Any publicació: 2013
Institució: Universitat de Barcelona

Population distribution and reproductive biology of the deep-sea fish community of the northwestern Mediterranean sea

Autor: U. Fernández de Arcaya Redondo
Director/es tesi: J.B. Company Claret, L. Recasens Albaladejo, E.Z. Ramirez Llodra
Any publicació: 2013
Institució: Institut de Ciencies del Mar, Universitat de Barcelona

Relaxation models applied to paleoclimate dynamics: Southern ocean mechanisms controlling glacial-interglacial cycles

Autor: C. Herrero Navarro
Director/es tesi: A. García-Olivares Rodríguez
Any publicació: 2013
Institució: Instituto de ciencias del mar; Universidad de Las Palmas de Gran Canaria
Resum: Veure
Let me start with a fundamental question: why should we study climate? Climate affects our daily life in many ways: on the food we eat, on the houses we live in, on our work, on how we travel... Even affects our culture, our spare time or our health. But all of those are only locally important. What we need to see here is the big picture: climate affects the way all living species have adapted to the biosphere, it is key for our survival, but we are drastically influencing it and we cannot predict the consequences of our actions. It is, then, fundamental to broaden our knowledge on the climate system of Earth, the only home we have ever known, to study the past climatic variability on various time scales to obtain clues that will help society face future climate change. As Carl Sagan foreseen on Cosmos, one of his most known books (Sagan [1980]) [...]

Sediment dynamics and associated heavy metals in a small river- and wave-dominated inner shelf (Barcelona city, NW Mediterranean)

Autor: L. López Fernández
Director/es tesi: J. Guillén, A. Palanques
Any publicació: 2013
Institució: Institut de Ciencies del Mar, Universitat Politècnica de Catalunya, Universitat de Barcelona
Resum: Veure
Wave storms and river inputs have been found to be the dominant forcing mechanism of sediment transport in continental shelves dominated by medium to large rivers around the world (e.g. Drake and Cacchione, 1985; Sherwood et al., 1994; Ogston and Stemberg, 1999; Traykovski et al., 2000; Wadman and McNinch, 2008) and in the northwestern Mediterranean Sea (Jiménez et al., 1999; Puig et al., 2001; Guillén et al., 2002, 2006; Palanques et al., 2002, 2011; Ferré et al., 2005; Roussiez et al., 2005; Ulses et al., 2008). However, the contribution of “small” Mediterranean river systems in fine-grained sediment dynamics is not well known. Flood and storm events redistribute not only sediment but also all the associated matter as well, such a heavy metals, which are indicators of the impact of industrial and urban activities. For these reasons, the present thesis project involves studying the dynamics of sediments and associated heavy metals across the inner continental shelf off the Besòs River (Barcelona), and in particular determining the effect of floods and storms in a littoral system affected by industrial and urban activities. To this end, several oceanographic surveys were carried out between 20 and 40 m water depths in the Barcelona continental shelf to obtain a variety of data: to register vertical hydrographical profiles (temperature, salinity and turbidity); to record time series of physical parameters (currents, salinity, temperature, turbidity and seabed variation) by deploying oceanographic equipment; and to take sediment samples (short cores and Van Veen grabs) and suspended and downward particulate matter from water samples and sediment traps for further sedimentological and geochemical analysis. The time period of the present study comprised three seasons, from autumn 2007 to spring 2008, which showed distinct features between them. The purpose of section 3 was to describe the main hydrographic and hydrodynamic conditions during the study period to support the interpretation of sediment transport processes. Three different periods in terms of storm and river activity matched the natural seasons of the year: The period comprised between end of September 2007 and December 2007 (autumn) was characterized by an intense frequency of northeastern-eastern storms mostly coupled with high but short river discharges and a convergence of the across-shelf current between 20 m and 30 m water depths; between January and early March 2008 (winter), the wave and river activity and frequency were reduced significantly with offshore currents dominating the across component; and finally, from March to mid June 2008 (spring), specially between May and June 2008, river discharges lasted more than one month and occurred under low wave energy conditions or in conjunction with S-SE and SW wave storms.

Uncovering Diversity and Structure of Bacteroidetes Populations in Marine Environments

Autor: C. Díez Vives
Director/es tesi: S.G. Acinas, J.M. Gasol
Any publicació: 2013
Institució: Universidad de las Palmas de Gran Canarias, Institut de Ciències del Mar
Resum: Veure
One of the main questions in microbial ecology is to understand what are the processes that structure and govern the species composition of communities. Answering to this question implies the need to detect bacterial species in environmental samples or at least to define ecologically meaningful “units of differentiation”. The dynamics and distribution of different broad taxonomic groups that constitute the bacterioplankton (at the phylum or class level) has been widely studied. The different large groups are known to follow different spatial distributions and seasonal cycles, but important variations also occur at lower levels (i.e. species or ecologically distinct populations). In this thesis we aimed to study some of these aspects for an important group of marine bacteria: the phylum Bacteroidetes. First at all, we evaluated the existing molecular tools in an updated phylogenetical and methodological context. Strengths and weaknesses of different probes used in different techniques were thoroughly studied and discussed, and alternatives were designed for some specific purposes related with the study of this group in marine environmental samples. Standing on these tools, we studied the phylum at different levels of resolution resulting from assorted molecular approaches. We related entire phylum abundances with environmental parameters as they vary spatially and temporally in the oceanic realm. We identified the most abundant phylotypes forming the Bacteroidetes assemblages and their ecological variability. Both the relative abundance and the changes in the phylotypes constituting the community followed clear spatial and seasonal patterns, which were thoroughly described. To increase the resolution of our study, we built extensive clone libraries including the 16S-ITS-23S ribosomal operon. The phylogenetic study of these sequences from different environmental samples showed that closely related phylotypes were organized in monophyletic clades of habitat-specific sequences. This confirmed that similar bacteria (in terms of the 16S rRNA) seem to present different physiologies, which would drive their distribution and adaption to specific ecological niches. The study of the distributions of these clades would help to understand the ecology of this group. Finally, we integrated the above information to design several clade-specific qPCR primer sets targeting putative Bacteroidetes ecotypes. These primers were thoroughly tested as the best possible compromise between specificity and performance for the intended purpose, and they were extensively evaluated in silico. An optimization of the qPCR technique workflow and a demonstration of its usefulness was carried out using the NS2b group. These primers offer a toolbox for hierarchical quantitative studies characterizing Bacteroidetes populations in different environments. Such studies should help to explore and

Beach Inundation and morphological changes during storms using video monitoring techniques

Autor: A. Sancho García
Director/es tesi: J.Guillén Aranda
Any publicació: 2012
Lloc d'edició: Barcelona
Institució: Departament d'Enginyeria Hidràulica, Marítima i Ambiental. Universitat Politècnica de Catalunya
Resum: Veure
Coasts are subject to erosion and inundation produced by storms, which are very frequent and can produce major damage and economic losses. Storminduced inundation is due to the sum of astronomical tide, surge level and wave runup. The predictability of beach inundation is mainly related to wave runup and most of the formulations that have been developed focus on the hydrodynamics, disregarding the morphological changes caused during storms. For these reasons, the aim of this thesis is to provide more insight into beach inundation processes at embayed and open beaches and to determine how morphological changes can interfere with these processes. To this end, video measurements of beach inundation and the characteristic morphological changes were carried out at two stretches of coast with different wave climates: the stretch comprising La Barceloneta, Somorrostro and Nova Icaria, which are three artificial, tideless embayed beaches located in Barcelona, Spain (NW Mediterranean); and Noordwijk beach, which is an open, microtidal multibarred beach located in Noordwijk, the Netherlands (North Sea).

Bioaccumulation of persistent organic pollutants (POPs) and biomarkers of pollution in Mediterranean deep-sea organisms

Autor: S. Koenig
Director/es tesi: M. Solé Rovira, P. Fernández
Any publicació: 2012
Institució: Universitat de Barcelona

Contribution to the characterization of interferometric radiometers devoted to Earth observation: application to the MIRAS/SMOS payload

Autor: V. González Gambau
Director/es tesi: F. Torres Torres, N. Duffo Úbeda (UPC)
Any publicació: 2012
Lloc d'edició: Barcelona
Institució: Institut de Ciències del Mar - Universitat Politècnica de Catalunya (UPC)
Resum: Veure
The variability of soil moisture and ocean salinity controls the continuous exchange of water between the oceans, the atmosphere and the land. Therefore, the accurate and periodic measurements of these geophysical variables are paramount to improve the climate change prediction and extreme-event forecasting. However, until very recently, global measurements of these parameters with a suitable spatial and temporal resolution have not been available. Real aperture radiometers have been frequently used for Earth observation applications. Nevertheless, for space-borne sensors at a low Earth orbit, the requirements on spatial resolution and coverage, at the operating frequencies (L-band), would require an unfeasibly large antenna. Conversely, synthetic aperture radiometry achieves high resolution using an array of small antennas, becoming a sound alternative to real aperture radiometry at low microwave frequencies. The ESA’s SMOS (Soil Moisture and Ocean Salinity) mission, successfully launched on November 2009, is the first mission ever attempted to frequently and globally measure soil moisture over the continents and sea surface salinity over the oceans. The single payload of the mission, the MIRAS (Microwave Imaging Radiometer by Aperture Synthesis) instrument, is the first space-borne L-band two dimensional synthetic aperture radiometer. This completely new type of instrument implies a technological challenge, for which the development of a detailed error model definition, dedicated calibration and image reconstruction algorithms have been needed. The calibration of MIRAS tackles all activities devoted to retrieve the SMOS scientific products from raw data measurements with the accuracy required by the scientific community. Characterization activities, mainly performed prior to the beginning of the in-orbit operation, have been required to develop and test the calibration activities. Within the framework of the SMOS mission, this Ph.D. Thesis is focused on the characterization of the interferometric radiometers devoted to Earth observation. The main contributions of this Thesis, which are directly related to the MIRAS payload performance assessment, are: (i) the definition of tests for the characterization campaigns, data processing methods and success criteria and (ii) the development of calibration algorithms and tools to fine-tune the instrument in order to fully achieve the system requirements and therefore the scientific requirements of the mission. Most of the work has been done in the framework of the MIRAS/SMOS Pre-Commissioning Phase activities and it has been completed in the framework of the Commissioning Phase preparatory work. Calibration tools and techniques developed for the MIRAS ground characterization have been adapted to fulfill in-orbit instrument characterization during the first months of the Commissioning Phase and contributed to the development and consolidation of the SMOS operational level-1 processing.

Early life history dynamics of European anchovy in the Western Mediterranean: an Individual-Based Modelling approach

Autor: A. Ospina Álvarez
Director/es tesi: I. Palomera Laforga, I. Catalán
Any publicació: 2012
Institució: Universitat de Barcelona
Resum: Veure
The thesis has been organized in two parts written in English and Spanish. The Part 1, Section 1, written in Spanish, deals with introductory issues. The broad philosophical modelling approach is presented along with a general description of individual-based modelling. The coupling of IBMs to hydrodynamic models is explained and the simulation procedures are outlined. A general introduction about life history of anchovy in the NW Mediterranean and management issues is provided. The Section 2 deals with the aims, scope and hypothesis are detailed and the thesis structure is explained. The section 4 synthesises the results of the thesis in terms of the hypotheses tested and addresses the implications of the results for understanding the life history of anchovy in the NW Mediterranean. Current patterns in anchovy spawning behaviour are examined in light of the present ndings and future directions for research are suggested. The second Part, \Chapters and publications>, presents the papers submitted as Journal articles. Chapters 1 to 5 are written in English. Chapter 1 explores the interaction between the biological properties of anchovy eggs (i.e. radius, morphology and buoyancy) and the vertical position of the eggs in the water column. Chapter 1 describes the implementation of a egg-buoyancy sub-model in the SEIBM to simulate the depth adjustment of anchovy eggs during development to variations of water density during the transport from spawning grounds to the location where hatching occurs. Chapter 2 looks at the vertical movement of anchovy larvae in the model caused by physical and biological factors. The aim of this chapter is to assess the relevance of diel vertical migration (DVM) as a mechanism involved in the transport of European anchovy larvae towards nursery areas taking into account age/stage-dependent vertical migration (i.e., the maximum migration). Chapter 2 describes a simplied vertical migration sub-model for anchovy larvae included in an Individual-based (IBM) hydrodynamic coupled model. The eect of vertical movement of anchovy larvae on transport and retention is also examined. Chapter 3 incorporates a temperature-dependent development rate model to explore the possible eects this could have on levels of recruitment to the two proposed nursery grounds. Chapter 3 is a back-calculation experiment using the SEIBM hydrodynamic coupled model and deals with the following hypotheses: 1) that the plausible eective spawning zones (those generating post-larvae at the known nursery grounds) are mainly found at the vicinity of a suggested spawning ground; 2) that observed back-calculated growth of larvae sampled in the nursery grounds can be reasonably simulated by a simple temperature-dependent growth model, and 3) that including biological behaviour to the model signicantly improves the match between observed and modelled larval recruitment and/or growth patterns. The aim of Chapter 4 is provide a method to estimate the daily egg production (number of stage-I eggs per square meter of sea surface) from adult biomass obtained by mean of acoustic surveys and historical fecundity data. Chapter 4 considers dierences in fecundity of each size class of the anchovy stock and uses a size-based fecundity model to examine how this manifests in regional dierences of reproductive output by anchovy in the NW Mediterranean. Chapter 5 is the integration of all sub-models developed in the SEIBM to explore how spawner location and nal nursery ground in uence estimated levels of recruitment from year to year. In Chapter 5, an inter-annual SEIBM experiment is used to examine transport, retention and dispersion processes in the nursery area and hypothesise about the possible essential nursery habitats for anchovy larvae in the NW Mediterranean.

Ecology of an uncultured heterotrophic flagellate lineage: MAST-4

Autor: R. Rodríguez Martínez
Director/es tesi: R. Massana Molera
Any publicació: 2012
Institució: Universidad de Las Palmas de Gran Canaria
Resum: Veure
Heterotrophic flagellates are fundamental in marine microbial food webs. They play a key role in channeling bacteria to higher trophic levels as well as in nutrient recycling. Despite this recognized ecological importance, and contrasting with the significant advances achieved with marine bacteria and archaea, little is known on the diversity of marine heterotrophic flagellates. This heterogeneous group of cells is weakly captured by microscopic and culturing approaches, and has been only recently targeted by environmental molecular surveys. This thesis is about the study of the ecology of one specific uncultured lineage, the MAST-4 (Marine Stramenopiles clade-4) group, which can be viewed as a model heterotrophic flagellate. MAST-4 consists of tiny cells (2-3 μm) that are widely distributed in the photic zone of the oceans with temperatures above ~5°C. On average, it accounts for ~9% of marine heterotrophic flagellates. It actively grazes on bacteria and other picosized cells being well adapted to the typical bacterioplankton abundances and preferring bacteria in a good physiological state. MAST-4 displays low genetic variability, being formed by just five main clades, each representing at least one biological species. This indicates that this successful group has suffered low evolutionary diversification. The most represented MAST-4 clades did not reveal geographical barriers, whereas temperature was the main factor influencing the distribution patterns. Different clades of MAST-4 seemed to have physiological adaptations that allowed them to establish and dominate under different environmental regimes. This ecotypic differentiation could partly explain the success of this flagellate, at the level of global distribution and abundance, allowing it to exploit the whole spectrum of habitat variability.

Ecology of gorgonian dominated communities in the eastern Adriatic sea

Autor: S. Kipson
Director/es tesi: J. Garrabou Vancells
Any publicació: 2012
Lloc d'edició: Zagreb
Institució: Sveučilište u Zagrebu
Resum: Veure
The aims of this thesis were twofold: (i) to provide quantitative baseline data for highly valuable but highly understudied coralligenous assemblages dominated by the red gorgonian Paramuricea clavata and the first assessment of P. clavata and Eunicella cavolini populations in the Eastern Adriatic Sea, as well as (ii) to explore the potential consequences of warming on the coralligenous community by examining the effects on the model organism, the red gorgonian P. clavata. Underwater photo-sampling with comparable sampling effort revealed higher species richness of the Adriatic P. clavata assemblages in comparison to the NW Mediterranean ones and significant inter-site and inter-depth variability of macrobenthic biodiversity, implying future site-based monitoring. High proportion of large adult P. clavata colonies, high abundance of juvenile colonies and low density values contrast with demographic structure reported from the NW Mediterranean. Together with results obtained for scarcely studied E. cavolini populations, these data provide new insights into the demographic structure of Mediterranean gorgonian forests. Further, conservation status of examined populations was assessed as favourable, but potential threats were also detected. The results of experimental studies implied that prolonged starvation after energetically unfavourable summer period significantly decreases P. clavata thermotolerance, while food availability promotes it. However, differences in physiological status cannot explain all of inter-colony and inter-population variability found in response of P. clavata to thermal stress. Further, thermal stress had severe negative effect on P. clavata embryos and larvae, resulting in significantly reduced survivorship, completely abnormal embryonic development and impaired metamorphosis. Their reduced viability would jeopardize the persistence of P. clavata, which relies on successful recruitment for replenishment of its populations

Ecology of marine bacteroidetes: a genomics approach

Autor: B. Fernández Gómez
Director/es tesi: J.M. González, C. Pedrós-Alió
Any publicació: 2012
Institució: Universidad de Las Palmas de Gran Canaria
Resum: Veure
The Bacteroidetes phylum is one of the most abundant groups of bacteria in the oceans. Its members account for a significant fraction of marine bacterioplankton especially in coastal areas, although they are globally distributed. Bacteroidetes are successful in the degradation of particulate organic matter; they are claimed to prefer polymeric substances rather than small molecules. Contrary to most other groups of marine of bacteria, many representatives possess gliding motility and they tend to be more abundant attached to particles than free-living in the water column. Thus, they likely present a different strategy to that of Proteobacteria or Cyanobacteria and, therefore, they will fill different niches. Altogether, the Bacteroidetes are thought to have a unique and important role in the marine carbon cycle. The present dissertation uses a variety of approaches to understand the ecology of some members of this group of bacteria. First, a complete genome analysis of a representative of the Bacteroidetes (Polaribacter sp. MED152) was conducted. This suggested a strategy for survival different from those of other groups. Then, a comparative in silico analysis (using bioinformatics tools) of four marine Bacteroidetes whose genomes had been completely sequenced was carried out. We found that these bacteria had a large number of genes involved in polymer degradation and adhesion to surfaces. From the analyzed representatives, an average of 1.5% of the whole genome corresponded to genes acquired by means of horizontal gene transfer, providing new adaptations and metabolic capabilities. This finding lead to the analysis of genomic islands in marine bacteria, trying to discern possible patterns characteristic of Bacteroidetes. Some of the bacteria analyzed had the proteorhodopsin gene (PR), allowing them to obtain extra energy in the presence of light. Since the use of light by PR-containing bacteria could affect the way DOC is processed in the ocean, the experimental part of the work focused on the responses of two whole genome-sequenced, PR-containing bacteria, Polaribacter sp. MED152 and Dokdonia sp. MED134, to different growth conditions. Finally, an attempt was made to determine the degradation of polymers in a natural environment: the Arctic Ocean from winter to spring, when the Bacteroidetes, among other groups, were becoming progressively more active in the use of organic matter.

Estructura genética poblacional y discontinuidades oceanográficas en crustáceos decápodos

Autor: V.H. García-Merchan
Director/es tesi: P. Abelló Sala, E. Macpherson Mayol, M. Pascual
Any publicació: 2012
Institució: Universitat de Barcelona
Resum: Veure
Los crustáceos decápodos constituyen uno de los grupos marinos más abundantes y diversos de los océanos, existiendo más de 500 especies en el Atlántico nororiental y el Mar Mediterráneo (d'Udekem d’Acoz, 1999). Tienen un papel importante en la mayoría de los ecosistemas marinos, ocupando una variedad de nichos tróficos, desde micrófagos a macrófagos y, muchos de ellos, son presa importante de numerosos predadores (Cartes et al., 2010). Diversas especies de decápodos tienen un alto valor comercial, lo cual ha facilitado durante las últimas décadas los estudios sobre la biología de numerosas especies (Company et al., 2008; Guijarro et al., 2009). No obstante, a pesar del interés en este grupo de crustáceos, los estudios sobre la estructura y variabilidad genética de sus poblaciones, así como sobre la filogeografía de las especies son escasos (Luttikhuizen et al., 2008; Palero et al., 2008; Roldan et al., 2009; Kelly & Palumbi, 2010; Reuschel et al., 2010). La conectividad y la estructura genética de las poblaciones son temas centrales en el estudio de la ecología y evolución de las especies. Existe un considerable número de estudios que han definido los procesos que influyen sobre la genética de poblaciones y filogeografía en las últimas décadas (Avise, 2000; Beheregaray, 2008). Ello ha permitido no sólo sentar las bases conceptuales en genética evolutiva sino también identificar sus múltiples aplicaciones tanto en investigaciones básicas como aplicadas. No obstante, es necesario indicar que, en comparación a los ecosistemas terrestres, existe todavía un gran desconocimiento sobre los procesos que tienen lugar en los ambientes marinos (Etter et al., 2005). Por lo tanto, definir la diversidad genética y la estructura poblacional de los organismos marinos es necesario para determinar cuáles son los procesos presentes y pasados que pueden afectar la dinámica de los ecosistemas que habitan. [...]

Estructura y distribución de la comunidad íctica acompañante en la pesca del camarón (Golfo de Tehuantepec. Pafídico Oriental, México)

Autor: M.A. Martínez-Muñoz
Director/es tesi: D. Lloris Samo, F. Fernández, F. Arregín
Any publicació: 2012
Institució: Universitat de Barcelona
Resum: Veure
En la presente investigación, se estudió la estructura espacial de las asociaciones de peces demersales que forman parte de la captura incidental de la pesca de camarón, en el ecosistema costero del Golfo de Tehuantepec, en el Pacífico Oriental Tropical Mexicano. Los arrastres de pesca se llevaron a cabo en 11 campañas, durante la época de veda 2003, 2004 y 2005, en tres estratos de la plataforma continental (20, 40, 60 m). Para la determinación de las asociaciones, se utilizaron los valores de abundancia (individuos/ha) y las variables ambientales (temperatura, salinidad, sedimento, profundidad). Se aplicaron los análisis de clasificación nodal y el modelo de redundancia sin tendencia (RDA). Para determinar la influencia de los factores ambientales en la comunidad íctica, se estimaron las variaciones espaciales de los parámetros comunitarios diversidad, equitatividad, riqueza y dominancia, así como los indicadores agregados del estatus de la comunidad: curvas de dominancia-k, curvas ABC y espectro de tallas. En la comunidad de peces demersales del Golfo de Tehuantepec se han identificado 229 especies, 101 géneros y 51 familias. Las familias Haemulidae, Scianidae, Paralichthyidae, Gerreidae y Carangidae son las que predominan en los descartes del camarón, aportando más del 70% de la captura. Las especies Haemulopsis axillaris, Syacium ovale, Selene peruviana, Diapterus peruvianus, Larimus acclivins y Stellifer erycimba fueron más frecuentes en la plataforma interna y media, mientras que Prionotus stephanophrys, Scorpaena russula, Porichthys analis y Synodus scituliceps, fueron las especies dominantes en la plataforma externa (≥ 40m). Los valores más altos de biomasa se ubicaron entre los sistemas lagunares Huave y mar Muerto, presentando un gradiente de disminución con la profundidad. La mayor densidad y diversidad se registró frente a los sistemas lagunares Carretas-Pereyra y Chantuto-Panzacola. Los resultados indican que el Golfo de Tehuantepec presenta cinco áreas de asociación (A1-A5), que son consistentemente distinguibles una de otras, tanto por características ambientales, como por la composición de las especies que las estructuran. Las asociaciones A3 y A5 se localizaron entre Salina Cruz y los sistemas Huave y Mar Muerto, la A1 y la A2, se ubicaron dentro de la plataforma interna y media, en la externa. La distribución de estas asociaciones está influenciada por los vientos tehuanos y eventos de surgencias que se registran regularmente en la época seca, que se caracterizan por bajas temperaturas, alta concentración de nutrientes, y predominancia de fondos arenosos con grava, en el estrato somero de la región norte del golfo. Las asociaciones A1, A2 y A4 se ubicaron entre los sistemas lagunares Mar Muerto y Chantuto-Panzacola, se caracterizaron por la influencia de las descargas continentales en la época de lluvias que afectan a las condiciones hidrológicas, lo que determina la presencia de fondos areno-lodosos, en aguas someras (<30 m). Aunque la composición de peces en las asociaciones presenta ligeras variaciones durante los cambios estacionales, estos cambios son temporales, lo que provee un grado de predictibilidad en las capturas. Los indicadores agregados de la comunidad señalan un alto nivel de perturbación, de modo que las comunidades tienden a estar dominadas progresivamente por individuos de pequeñas tallas. Se analizaron las afinidades eco-geográficas, arrojando 36,1 % de especies de amplia distribución, desde la provincia de Cortés a la provincia Panámica, un 27,3% de especies euritérmas, que se distribuyen desde la provincia de San Diego a la Panámica, y un 13,2% de especies de distribución restringida entre la provincia Mexicana y Panámica.

Estudio de la distribución y diversidad ictiofaunística del Mar de Alborán

Autor: C. García Ruiz
Director/es tesi: D. Lloris Samo, L. Gil de Sola
Any publicació: 2012
Lloc d'edició: Málaga
Institució: Universidad de Málaga
Resum: Veure
La Cumbre de la Tierra celebrada por Naciones Unidas en Río de Janeiro en 1992, reconoció la necesidad mundial de conciliar la preservación futura de la biodiversidad con el progreso humano según criterios promulgados en el Convenio Internacional sobre la Diversidad Biológica que fue aprobado en Nairobi el 22 de mayo de 1972. [...]

Interactive effects of vertical mixing, solar radiation and microbial activity on oceanic dimethylated sulfur cycling

Autor: M. Galí Tapias
Director/es tesi: R. Simó Martorell
Any publicació: 2012
Institució: Universitat Politècnica de Catalunya
Resum: Veure
Microscopic plankton thriving in the sunlit upper ocean play a key role in the biogeochemical functioning of the biosphere. The production and subsequent emission of volatile compounds is one of the numerous ways by which they participate in the cycling of elements and in uence the Earth's climate. Dimethylsulde (DMS), produced by enzymatic decomposition of the algal intracellular compound dimethylsulfoniopropionate (DMSP), is the more abundant organic volatile in the upper ocean. Its global emission amounts ca. 28 Tg S per year, and represents the main biogenic source of sulfur to the troposphere and about 30% of the total S emission (anthropogenic, biogenic and volcanic). Atmospheric oxidation of DMS contributes to atmospheric acidity, and is believed to promote the formation and growth of aerosols. Furthermore, DMS-derived sulfate aerosols have been suggested to cool the climate by reducing the amount of shortwave solar radiation reaching the Earth's surface by scattering solar radiation and, more important, by acting as cloud condensation nuclei. The `CLAW' hypothesis postulates that, if oceanic DMS emission was in turn stimulated by solar radiation, a regulatory feedback mechanism could operate between marine plankton and the radiative budget over the oceans. However, the relationship between DMS emission and solar radiation is not straightforward, since a number of biochemical and photochemical transformations come into action from the moment DMSP is synthesized by phytoplankton until DMS is emitted. These transformations are intimately linked to the physical environment, the ecological setting and the microbial interactions, rendering the picture of dimethylated sulfur cycling a lot more complicated. Surprisingly, though, the seasonal cycle of seawater DMS concentration seems to follow that of solar radiation in the majority of oceanic regions, regardless their productivity regimes. This characteristic feature of oceanic DMS, while broadly accepted, is not yet well understood. The premise of this thesis is that, to understand this emerging pattern, we need to understand what regulates the DMS production and consumption processes and their balance (that is, DMS budgets). To this end, we have studied the response of biotic and abiotic DMS cycling to solar radiation by means of incubation experiments. At another level, we have studied the response of ecosystem DMS budgets to dierent radiation climates, and from polar to subtropical areas. Since the depth of the upper mixed layer regulates the amount and spectral composition of the `light' seen by the cells and molecules, our studies have been backed by a careful characterization of underwater radiation elds and vertical mixing dynamics.

Marine aerosols, their precursors and their influence on clouds over the global ocean

Autor: M.A. Lana Celaya
Director/es tesi: R. Simó Martorell, J. Dachs
Any publicació: 2012
Institució: Universitat Politècnica de Catalunya
Resum: Veure
Marine aerosols have a large potential to influence the Earth’s climate through their effects on cloud properties. The CLAW hypothesis goes further, and suggests that marine aerosols formed by the sulphur cycle of the ocean and the atmosphere act as a mechanism for regulating the Earth's climate. This effect is produced through the influence of plankton emissions of sulphur compounds on cloud formation. Phytoplankton produces dimethylsulphide (DMS), a highly volatile sulphur compound. Once in the atmosphere, DMS is oxidized and becomes the main source of natural atmospheric sulphates. These sulphates act as condensation nuclei, particles that are essential for the formation of clouds. Those marine particles in the atmosphere play an important role in the Earth's radiation budget. Indirectly they produce a greater amount of cloud droplets. Higher cloud condensation nuclei imply smaller cloud droplets. The efficiency of smaller droplets in reflecting incident solar radiation is greater, resulting in an increase in cloud albedo, producing a cooling effect on the Earth's surface. To properly study the marine aerosols we need accurate knowledge of the global seawater distribution of the aerosol precursors. Our work focused on the ocean-to-atmosphere emissions of DMS and other biogenic gases that can have an impact on cloud microphysics. During the thesis we updated the monthly global DMS climatology taking advantage of the three-fold increased size and better resolved distribution of the observations available in the DMS database. The emerging patterns found with the previous versions of the database and climatology were explored with the updated version. The statistical relationships between the seasonalities of DMS concentrations and solar radiation doses and chlorophyll a concentrations were here re-examined. Analyses of nine years of satellite data suggested that there is a natural inverse correlation between the spatial cover of low marine clouds and the cloud droplet size, which is related to the presence of small aerosols. This coupled seasonality pushes cloud albedo to contribute higher negative radiative forcing in summer and lower in winter. This relation is disrupted in the marine atmosphere regions heavily impacted by anthropogenic aerosols. Consequently, the potential influence the aerosol precursors have on marine clouds was next analysed over unpolluted and polluted ocean, separately. The 9 years of global satellite data and ocean climatologies were used to derive parameterizations of the production fluxes of secondary aerosols formed by oxidation of DMS and other biogenic organic volatiles. Further, the emission fluxes of biogenic primary organic and sea salt aerosols ejected by wind action on sea surface were also globally studied. Series of weekly estimates of these fluxes were correlated to series of cloud droplet effective radius. The outcome of the statistical analyses indicated that sulphur and organic secondary aerosols might be important in seeding cloud nucleation and droplet activation over mid and high latitude unpolluted oceanic regions. Conversely, primary aerosols (organic and sea salt) showed that, despite contributing to large shares of the marine aerosol mass, they do not seem to be major drivers of the variability of cloud microphysics. Our results provide partial support for the feasibility of the CLAW hypothesis at the seasonal scale. Despite that DMS has drawn much of the attention on the links between marine biota and climate regulation, the implication of other biogenic precursors on cloud formation provides and suggests a wider scope on the formulation of such hypothesis.

Morfodinàmica sedimentària de marges continentals passius silicoclastics

Autor: D. Amblàs
Director/es tesi: M. Canals i Artigas, R. Urgelés i Esclasans
Any publicació: 2012
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona
Resum: Veure
“El present és la clau del passat”. James Hutton (1788), amb aquesta prou coneguda asserció uniformista, posà els fonaments pel desenvolupament de la investigació geològica moderna des de la perspectiva actualista. L’estratigrafia es val d’aquest principi per interpretar l’origen de les formacions geològiques a partir de l’observació de processos i geometries actuals i subactuals. Alhora, la geomorfologia estudia els processos afaiçonadors del relleu per conèixer l’origen i l’evolució del paisatge actual. Conceptualment, aquesta Tesi se situa a cavall entre l’estratigrafia i la geomorfologia amb l’objectiu general de reconèixer el per què i el com de la variabilitat morfosedimentària dels marges continentals passius silicoclàstics a llarg termini. Per atènyer aquest objectiu adoptem la hipòtesi de partida següent: la variabilitat morfològica dels marges continentals silicoclàstics passius pot ésser classificada per categories de forma objectiva i sistemàtica. Les diferències morfològiques observades responen principalment a l’acció d’uns pocs processos sedimentaris claus. Els mètodes i conceptes emprats en aquesta Tesi són propis de la hidrodinàmica i la sedimentologia. L’observació detallada de la morfologia i l’estratigrafia dels marges continentals, junt amb l’estudi dels processos hidrodinàmics que les han generades i l’anàlisi de la variabilitat espaciotemporal de les condicions ambientals en què s’han format, permet establir lleis de transport geomòrfic, altrament dites lleis de la morfodinàmica. En els successius capítols d’aquesta Tesi abordem aquests aspectes mitjançant l’anàlisi de dades geofísiques de reconeixement del fons i del subsòl marins, amb un especial èmfasi en les xarxes de drenatge del talús continental i la conca profunda. Els resultats d’aquesta anàlisi se sintetitzen en el plantejament d’un model morfodinàmic predictiu sobre la forma del perfil longitudinal dels canyons submarins. Aquest model dóna peu a discutir sobre transitorietat i equilibri en les formes de drenatge observades a les dades geofísiques considerades. Així doncs, en aquest treball advoquem per la complementarietat i interdependència de les anàlisis observacionals i la modelització basada en la formulació teòrica de processos. Els principals resultats obtinguts en aquest treball demostren la possibilitat d’extreure informació sobre l’evolució de les conques sedimentàries a partir de l’estudi de les seves morfologies, tan modernes com relictes i fòssils, i indiquen la necessitat d’entendre els canyons submarins com a sistemes capaços d’evolucionar a partir de mecanismes netament deposicionals, a més dels mecanismes erosius ja prou coneguts. Aquests resultats es poden traduir en una millora de les prediccions estratigràfiques al talús continental, en un millor coneixement de la distribució de reservoris sedimentaris d’hidrocarburs o aigua en aquests ambients, i a replantejar els models establerts sobre el desenvolupament dels canyons submarins a escala global

Novel approach to improve the assessment of biodiversity of phytoplankton communities based on hyperspectral data analysis

Autor: E. Torrecilla Ribalta
Director/es tesi: J. Piera (ICM - CSIC), M. Vilaseca (CD6, UPC)
Any publicació: 2012
Institució: Universitat Politècnica de Catalunya
Resum: Veure
Sustainable management of marine ecosystems requires a better knowledge about the space-time distribution and dynamics of ecological parameters such as phytoplankton communities, including critical bloom-forming algal groups. Better understanding of phytoplankton biodiversity and dynamics is essential in evaluating the role of each algal group in the global marine ecosystem and biogeochemical cycles. In attempting to address this question, in situ and remotely-sensed spectrometric optical observations have demonstrated to provide previously unavailable information regarding several optically active constituents in seawater at local and global scales, in particular, regarding phytoplankton community structure. In this sense, the advent of high spectral resolution (hyperspectral) optical sensors have raised new expectations about the possibilities of discriminating phytoplankton community composition in the ocean, beyond the estimation of only the primary pigment in phytoplankton, chlorophyll-a, a proxy for the phytoplankton biomass and primary production since it is common to all taxonomic groups. This PhD thesis has been carried out with the aim of improving our ability to extract information regarding phytoplankton community structure in the ocean by developing and evaluating a novel approach based on hyperspectral data analysis. In particular, a dissimilarity-based cluster technique, which accounts for complete spectral behaviour of hyperspectral data of each seawater sample, has been applied in combination with derivative spectroscopy, which exploits the spectral shape features of each analyzed spectrum. As a novelty, a validating tool has been proposed and proven useful to illustrate the effectiveness of the optical-based classication for discriminating different phytoplankton assemblages. This novel validation approach is based on the pigment composition analyzed in conjunction with concurrently obtained optical data, information which has been commonly used by the scientic community as a proxy for the phytoplankton composition. The feasibility of this methodology has initially been demonstrated using a simulation-based approach, i. e. using a radiative transfer modeling framework for open ocean and shallow coastal environments. In addition, different real open ocean environments corresponding to several stations in the eastern Atlantic Ocean have successfully been classied by applying the cluster analysis to different hyperspectral data sets including absorption and remote-sensing reectance spectra and their second derivative spectra. This classication has served to identify a potential application of the proposed methodology: the establishment of different bio-optical provinces from the analysis of hyperspectral oceanographic observations, leading to examination of its biogeographical relevance by comparison to ecological provinces previously proposed in the literature. This thesis concludes by conrming the main hypothesis that discrimination of phytoplankton community structure and dynamics in the ocean can be enhanced while using hyperspectral oceanographic observations. It is noteworthy that the proposed approach is generally applicable to different data sets, besides in-situ pigment or optical data data also to remotely-sensed, biogeochemical or hydrographic data sets.

Patterns in marine microbial community structure

Autor: T. Lefort
Director/es tesi: J.M. Gasol Pique
Any publicació: 2012
Institució: Universidad de Las Palmas de Gran Canaria
Resum: Veure
Understanding the distribution of the different picoplankton groups represents a central tenet of marine microbial ecology. Centering our study on the three major groups constituting the bulk picoplankton community (size 0.2-3 mm), we sought to analyze the distribution of autotrophic bacteria (Synechococcus and Prochlorococcus), photosynthetic Picoeukaryotes pPeuk, and heterotrophic bacteria. For that objective, two different strategies were used, the first one was based on flow cytometry for determining ataxonomic patterns in picoplankton distribution, and the second a comparative analysis approach for identifying broad patterns in bacterial phylogenetic community structure. Given that conversion factors (CFs) were necessary to translate group cell abundance into carbon biomass, but that large discrepancies for CF values of pPeuk had been reported in the literature, we first (re-) evaluated the CF for small phototrophic picoeukaryotes (<5 mm). On one hand, as the set of cultures of Peuk used for that purpose were maintained in non-axenic conditions, we compared two different methods for correcting errors in biomass estimation due to presence of bacteria. Secondly, a relatively higher CF value for pPeuk than those previously reported to date was found, with implications on the role generally attributed to pPeuk in the carbon cycling and other ecosystem processes. Applying this CF, we could identify patterns of variability in picoplankton group distribution at different spatio-temporal scales during winter in a NW Mediterranean coastal station and during a cruise performed in summer from coast to offshore off the Catalan coast. By focusing on the variability at the short time scale, our work showed not only evidences of coupling between picophytoplankton variability and the single-cell bacterial activities but also highlighted how a relatively small variation in meteorology changed considerably the structure of the microbial community. Different trends of variability were observed between the different picoplankton groups, pPeuk cell numbers exhibiting the highest spatio-temporal variability, and bacterial abundance the lowest. Opposite patterns between picoplankton community structure and chlorophyll a levels were observed not only spatially, but also at both the short-term and large temporal scale, suggesting that picoplankton group distribution are useful indicators of the ecosystem state. Finally, we assessed the biogeography of the bacterial phylogenetic groups along a continuum of environmental parameters such as chlorophyll a, temperature and salinity, and identified different patterns in bacterial community structure as related to phytoplankton biomass among coastal and open ocean ecosystems, suggesting unequal metabolic aptitudes of the different bacterial groups for utilizing algal-derived DOC.

Potential Vorticity Conserving Flows and Vortex-Wave Interaction: The Role of Vertical Velocity and Isopycnal Diffusion on Plankton Heterogeneity

Autor: M. Claret Cortés
Director/es tesi: A. Viúdez (ICM), Y.H. Spitz (CEOAS)
Any publicació: 2012
Institució: Institut de Ciències del Mar - Universidad de las Palmas de Gran Canaria
Resum: Veure
This thesis investigates physical-ecological and vortex-wave interactions through potential vorticity (PV) considering a stratified and oligotrophic ocean. To this end, a NPZ (Nutrients-Phytoplankton-Zooplankton) model is coupled to a physical one that conserves PV explicitly on isopycnals. The physical-ecological coupled model is initialized using stationary NPZ solutions numerically stable with the fluid at rest. These solutions are implemented homogeneous both on horizontal and isopycnals levels to quantify the effect of horizontal and vertical advection caused by mesoscale and submesoscale vortex structures, and isopycnal mixing. At the interior of the vortex separatrix, plankton and PV distributions translate in phase at vortex propagation speed. Within cyclones, isopycnal doming enhances plankton biomass at the vortex center in different trophic conditions. Furthermore, isopycnal mixing associated to small-scale motions maximizes the phytoplankton (P) biomass in cyclones through a resonant response between P and diffusive timescales. This P increase is significant in mesotrophic conditions and occurs where the vertical displacement of isopycnals is maximum, and hence where vertical gradients of PV are large. At the separatrix outer, horizontal and vertical advection are of the same order of magnitude than the ecological forcing and enhance P through different mechanisms. Firstly, vertical velocity w uplifts nutrients and P to better lit levels. P responds with some time lag to this perturbation and the associated increase in biomass occurs far from the upwelling location due to the action of horizontal advection. As a result, P correlates with w, and thus with horizontal gradients of PV, only at initial times. In the particular case of translating cyclones, this mechanism explains the development of a P trail at their wake. And secondly, the horizontal advection of a surface ecosystem patch by subsurface vortices decreases P self-shading at the patch front in benefit of P growth. Finally, interactions between vortex structures and pure inertial and gravity large amplitude waves are investigated. The advection of PV by waves causes vortices to be unsteady and modifies the upper and lower bounds of the wave frequency band. The advection of waves by vortices Doppler shifts the local wave frequency. When inertial waves are involved, a near-inertial right-handed helical wave is developed due to a non-linear interaction. As a result, total w increases one order of magnitude and correlates with horizontal gradients of PV. These results aim to shed further light on the ecological impact of long-lived coherent vortices in the open ocean.

Trophic ecology of small pelagic fish in the northwestern Mediterranean

Autor: D. Costalago Meruelo
Director/es tesi: I. Palomera Laforga
Any publicació: 2012
Institució: Universitat de Barcelona

Wind-driven currents in the coastal and equatorial upwelling regions

Autor: P. Castellanos Ossa
Director/es tesi: J.L. Pelegrí
Any publicació: 2012
Lloc d'edició: Barcelona
Institució: Institut de Ciències del Mar - Universitat Politècnica de Catalunya (UPC)
Resum: Veure
During the last two decades the scientific community has recognized the importance of the tropical Atlantic Ocean and the upwelling regions on the Earth’s climate. This recognition has opened new questions such as: ¿What are the mechanisms for the ocean to adjust to variations in atmospheric forcing?, ¿Is there any indirect relation between the atmospheric seasonal cycle and the response of the surface ocean?, ¿How are the meridional boundary flows connected with the zonal jets in the interior ocean?, ¿What is the relevance of these processes in the redistribution of properties such as water mass, heat and fresh water? [..]

A Boussinesq-type model for wave propagation in deep and shallow waters and boundary layer considerations

Autor: A. Galán Alguacil
Director/es tesi: A. Orfila Förster, G. Simarro Grande
Any publicació: 2011
Lloc d'edició: Ciudad Real
Institució: Universidad de Castilla La-Mancha
Resum: Veure
En esta Tesis se deriva un nuevo conjunto de ecuaciones tipo Boussinesq para la propagación de oleaje en aguas profundas y someras. Se trata de un nuevo conjunto de ecuaciones totalmente no lineal con propiedades dispersivas mejoradas respecto a los sistemas previos. Las nuevas ecuaciones son exactas hasta O(kh)2. Se emplea un método de optimización para determinar el valor de los coeficientes introducidos en las nuevas ecuaciones propuestas con el objetivo de minimizar las diferencias entre el modelo y las teorías de Airy (dispersión lineal y asomeramiento) y de Stokes (transferencia de energía débilmente no lineal). Se muestra que con la adecuada elección de estos coeficientes el modelo es aplicable hasta valores de kh = 20 con un error relativo menor del 1% en dispersión lineal. En esta Tesis se presenta un nuevo esquema numérico explícito de cuarto orden para resolver y verificar el nuevo conjunto de ecuaciones. Además, se ha llevado a cabo un análisis lineal de estabilidad para obtener una condici´on tipo CFL para el paso de tiempo. La integración temporal se lleva a cabo empleando un esquema Runge-Kutta de 4o orden. El oleaje se genera internamente en el dominio por medio de una función fuente. [...]

Culturing bias in the study of marine heterotrophic flagellates diversity

Autor: J. Del Campo García-Ramos
Director/es tesi: R. Massana Molera
Any publicació: 2011
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona
Resum: Veure
Dins dels protozous, és ben sabut que els flagel·lats heterotròfics juguen un paper clau en les xarxes tròfiques marines. Aquests organismes diminuts es distribueixen en ambients planctònics en concentracions entre 10 2 i 10 5 cèl·lules ml-1 , el que representa el 10-30% dels microorganismes eucariotes en aigües marines superficials. Són actors principals en els cicles biogeoquímics globals com a bacterívors, i remineralitzadors de nutrients i constitueixen un conjunt d'espècies diverses, tot sovint mal identificades. Els flagel·latsheterotròfics són principalment fagòtrofs depredadors i controlen l'abundància de procariotes i petits eucariotes, però també poden incloure les etapes de dispersió de paràsits d'altres organismes marins. Aquest paper central en els ecosistemes marins s'ha traduït en un gran interès en el manteniment d'aquests organismes en condicions controlades de laboratori, per tal d'estudiar les taxes de depredació, les taxes de creixement, les preferències de presa, la ultraestructura, la genòmica o la transcriptòmica. Els cultius han estat essencials per a dur a terme estudis fisiològics i filogenètics, però la rellevància ecològica de les soques cultivades no està gaire clara. Els flagel·lats heterotròfics que tenim en cultiu representen els que són dominants en el medi natural?

Dinoflagellates and raphidophytes microalgal groups as feedstock for biodiesel production

Autor: C. Fuentes Grünewald
Director/es tesi: E. Garcés Pieres, S. Rossi Heras
Any publicació: 2011
Institució: Universitat Autònoma de Barcelona

Ecophysiology of marine invertebrate planktonic larvae: species and community level approach

Autor: R. Almeda García
Director/es tesi: M. Alcaraz Medrano, A. Calbet Fabregat
Any publicació: 2011
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona
Resum: Veure
Most marine invertebrates have a complex life history involving stages of planktonic larval development between the egg and the adult form (Thorson 1950; Strathmann 1987, 1993). These larvae may differ from adults in size, form, habitat, mode of nutrition, and/or ability to disperse (Barnes et al. 1988; Young 2002). The environmental conditions experienced during larval development can have profound effects on the subsequent performance of individuals and cohorts (Pechenik et al. 1998, 2002). Survival and growth of marine invertebrate larval stages can influence species recruitment success and population connectivity, distribution and abundance (Roughgarden et al. 1988; Eckert 2003). However, in spite of the obvious importance of larvae in the life cycles of most marine animals, the ecophysiology of larvae of many ecologically relevant invertebrates remains poorly understood in comparison to our knowledge of the adult phases. Additionally, as important components of zooplankton communities, the trophic role of planktonic larvae in marine food webs should not be neglected. [...]

Effects of solar radiation on marine bacterial and phytoplankton heterotrophic activities

Autor: C. Ruiz González
Director/es tesi: J.M. Gasol Pique, R. Simó
Any publicació: 2011
Institució: Universidad de Las Palmas de Gran Canaria
Resum: Veure
Since the discovery, 20 years ago, that solar ultraviolet radiation (UVR, 280-400 nm) penetrates much deeper into the ocean’s water column than previously thought, knowledge on its effects on diverse surface processes and organisms has significantly increased, yet further research is needed for a good understanding of sun-organism interactions. Marine bacteria are considered some of the most susceptible to sunlight damage due to their small size and lack of pigments. Since they are primary consumers of dissolved organic matter (DOM) in seawater, one might expect that any effect on them will ultimately have implications for carbon and nutrient cycling. In this work, we contributed to increase the knowledge on the effects of sunlight on the heterotrophic uptake of DOM by bacteria, although we also devoted some effort to assess its impact on the osmoheterotrophic activity of phytoplankton. For that purpose, we combined bulk activity measurements with a single-cell approach involving microautoradiography for identification of both the responses at the community levels and particular responses and sensitivities to sunlight of different microorganisms. Our work highlights the role of solar radiation as a significant modulator of DOM fluxes through differentially affecting the diverse components of the planktonic food webs. The observed responses were shown to vary not only at different scales depending on changes in the light conditions, but also owing to the previous light-exposure history, the identity of the organisms involved, the substrates considered and the accuracy of our light incubation conditions. Whereas exposure to sunlight often led to a reduction in the amount of leucine incorporated, incubation under photosynthetically active radiation (PAR, 400-700 nm) conditions sometimes stimulated its uptake, and potential photoheterotrophy is discussed among other possibilities. In contrast, bulk assimilation of the organic compound dimethylsulfoniopropionate (DMSP) was often increased upon light exposure, particularly within the non-bacterial fraction. We also found that algal osmoheterotrophy seems to be widespread and more common than previously thought, particularly within the phytoplankton assemblages inhabiting the DMSP-rich summer polar waters, and that this behaviour was highly dependant on the light levels. The present thesis sheds light on the complexity of sun-microbe interactions and provides evidence of the need to afford the study of solar radiation effects on the different compartments of the microbial food webs.

Effets du changement climatique sur les écosystèmes littoraux de la Mer Méditerranée Nord-occidentale: étude de la relation entre les conditions de température et la réponse biologique pendant les événements de mortalité massive

Autor: C. Crisci Karlen
Director/es tesi: J. Garrabou, B.Ghattas, J.-P. Féral
Any publicació: 2011
Lloc d'edició: Aix-Marseille
Institució: Université de la Méditerranée
Resum: Veure
Climate change is an emerging threat affecting marine ecosystems worldwide. In recent years, mass mortality events (MME) of unprecedented extension and severity were observed in the coastal rocky benthic communities of the North-Western Mediterranean (NWM) Sea. The registered MMEs were concomitant with thermal anomalies in the water column. A trait of these events was the great variability in mortality pattern observed at all spatial scale considered (between regions and depths and between populations of same regions and depths). Since a warming trend was addressed for the NWM region, new MME are likely to occur in the future. For this reason, deepening the knowledge on temperature (T)-mortality relationship as well as on the causes of the observed variability in the biological response, will allow to anticipate the occurrence and effects of future thermal anomalies and contribute to develop management and conservations strategies in the face of climate change. [...]

Interactions between physical forcing, water circulation and phytoplankton dynamics in a microtidal estuary

Autor: C. Llebot Lorente
Director/es tesi: M. Estrada Miyares, J. Solé Ollé
Any publicació: 2011
Institució: Universidad de Las Palmas de Gran Canaria
Resum: Veure
This thesis focuses on the interactions between water circulation dynamics, nutrient availability and the structure of the phytoplanktonic community from a mesoscale point of view. To accomplish this aim we studied the micro-tidal estuaries of Alfacs and Fangar, located in the Ebre river Delta, in the Northwestern Mediterranean. The work was developed along three main lines. First, the analysis of the variability of a 14-year long time series of the phytoplankton and environmental data showed a strong seasonality of the phytoplankton communities of both bays, characterized by an autumn diatom assemblage and a winter group of dinoflagellates in Alfacs, and a flagellate-dominated group in winter, and a mixed group of dinoflagellates and diatoms in late spring and summer in Fangar. The phytoplankton dynamics and composition was different in the two bays, a finding that could be attributed to a lower residence time of the water in Fangar, which has a smaller volume than Alfacs but receives comparable inputs of freshwater. No relevant temporal trends were detected in phytoplankton abundance or composition. Second, scale considerations and a three-dimensional circulation model of Alfacs revealed that the principal forcing factors are freshwater inflow and wind, while the tide is not relevant regarding water transport or mixing. The freshwater input is important at a seasonal scale, and is responsible for the stratified situation usually found in Alfacs. The wind is particularly important at time scales of a few days and, above a certain threshold, wind events can mix the estuary and break the stratification. Based on the strength of the stratification relative to the wind speed, as expressed by a Richardson number, and the direction of the wind, three scenarios regarding the coupling between wind forcing and hydrodynamics have been defined, demonstrating the importance of wind in controlling the exchange of water with the exterior. Finally, the third line of research approached the budget of major nutrients (nitrogen N and phosphorus P) in Alfacs. A zero-dimensional ecosystem model incorporating phytoplankton, zooplankton and the concentrations of various (organic and inorganic) N and P pools suggested that the inputs of dissolved organic phosphorus (DOP) through the discharge channels are a crucial source of phosphorus to the system, explaining the draw-down of nitrogen during the summer and the observed high primary production. Two non-exclusive mechanisms could explain DOP availability for phytoplankton: direct uptake and remineralisation to dissolved inorganic phosphorus. Input of phosphorus from sediment resuspension could be important at short time scales, but did not seem to be a substantial contribution to the total P budget from a seasonal perspective. In conclusion, this thesis shows how the physical forcing can influence the composition, timing and abundance of the phytoplanktonic community in two bays that can be taken as an example of microtidal estuarine water bodies.

Multiscale variability in the North Atlantic Ocean

Autor: V. Benitez Barrios
Director/es tesi: Alonso Hernández Guerra (ULPGC), J.L. Pelegrí (ICM-CSIC)
Any publicació: 2011
Lloc d'edició: Las Palmas de Gran Canaria (ES)
Institució: Facultad de Ciencias del Mar, Universidad de Las Palmas De Gran Canaria
Resum: Veure
The world ocean heat content has increased between mid 1950’s and mid 1990’s, highlighting the key role of the ocean in the climate system. A set of ship-based observations have evidenced substantial temperature and salinity changes in the Atlantic thermocline, although they are neither uniform nor monotonic. In this thesis we evaluate the recent variability of the tropical and subtropical North Atlantic Ocean over different spatial scales, and explore the possible controlling mechanisms. […]

Neotectonic and Paleoseismic Onshore-Offshore integrated study of the Carboneras Fault (Eastern Betics, SE Iberia)

Autor: X. Moreno Mota
Director/es tesi: E. Gracia Mont, E. Masana Closa
Any publicació: 2011
Institució: Universitat de Barcelona
Resum: Veure
La paleosismología trata del estudio de los grandes terremotos prehistóricos con el objetivo de extender el catálogo sísmico atrás en el tiempo. Esto es especialmente importante en regiones donde las tasas de deslizamiento son lentas y los periodos de recurrencia largos, regiones en las cuales el catálogo sísmico no llega a abarcar un ciclo sísmico completo (Santanach y Masana, 2001). Además, la incertidumbre en la localización de terremotos históricos suele ser importante, y más aún cuando el epicentro se localiza en mar, lo cual dificulta la relación entre terremotos históricos y estructuras concretas. Si queremos estar preparados para futuros terremotos, es imprescindible detectar y caracterizar todas las posibles fuentes sísmicas de una región, incluyendo aquellas que no hayan roto durante el periodo histórico. [...]

Neuroendocrine control of puberty in vertebrates: Characterization of the Kisspeptin system in flatfish

Autor: A.S. Mechaly García
Director/es tesi: F. Piferrer Circuns, J. Viñas de Puig
Any publicació: 2011
Institució: Universitat Pompeu Fabra
Resum: Veure
The recently discovered decapeptide kisspeptin and its G-protein coupled receptor form a signaling system expressed ubiquitously and are implicated in a variety of still poorly characterized functions. In the brain, kisspeptin is secreted by specific neurons and its receptor is localized in GnRH neurons. Kisspeptin signaling has been fully established in the control of the onset of puberty in vertebrates, from fish to mammals. In this study, we characterized the kisspeptin gene in the Senegalese sole and characterized the kiss-peptin receptor genes in both the Senegalese sole and in the Atlantic halibut. In contrast to other fish species, the two species analyzed here showed only the presence of one ligand and one receptor, probably as a consequence of the genome reduction characteristic of Pleuronectiformes. However, in both cases we found an alternative splicing mechanism based on intron retention that produces also non-functional isoforms, but whether this is part of a mechanism to control abundance of the active gene product is still not known. We document spatial and temporal changes of expression of kisspeptin and its receptor in the brain, pituitary and gonads related to the annual reproductive cycle. Finally, we present the first evidence of a possible link between energy balance and reproduction mediated by kisspeptin signaling in a non-mammalian vertebrate.

Nutrient fluxes in marine sponges: methodology, geographical variability and the role of associated microorganisms

Autor: E. Jiménez Tejero
Director/es tesi: M. Ribes Llordés
Any publicació: 2011
Institució: Universitat Politècnica de Catalunya

Optical properties of the dissolved organic matter as tracers of microbiological and geochemical processes in marine ecosystems

Autor: C. Romera Castillo
Director/es tesi: C. Marrasé Peña, X.A. Álvarez-Salgado
Any publicació: 2011
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona
Resum: Veure
Oceans store 685 Pg of organic carbon, 662 Pg of which are in the dissolved form. The diversity of compounds that comprise the dissolved organic matter (DOM) pool and the low concentration of each individual compound make the chemical characterization of this material a difficult task. For that reason, less than 11% of the oceanic DOM has been identified. A variable fraction of the DOM –between 20% in the open ocean and 70% in coastal areas– absorbs UV and visible radiation and it is known as coloured DOM (CDOM). A sub-fraction of CDOM emits the absorbed radiation as fluorescence with a low quantum yield (around 1%) and it is called fluorescent DOM (FDOM). The study of the CDOM and FDOM pools, combining absorption and fluorescence spectroscopy, allows to gain knowledge on (i) the molecular structure of DOM (e.g. aromaticity and average molecular weigh) and (ii) its biological and photochemical reactivity in a relatively simple, fast and economic mode. This can be done through the study of the production, utilization and/or chemical transformation of the different chromophores and fluorophores in response to the activity of microorganisms and solar radiation in the oceans. [...]

The ecology of deep sublittoral populations of Mediterranean gorgonians

Autor: A. Gori
Director/es tesi: J.M. Gili i Sardà, S. Rossi Heras
Any publicació: 2011
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona
Resum: Veure
The understanding of Mediterranean gorgonian ecology increased significantly in the last decades. However, although Mediterranean sublittoral gorgonians are known to be present from shallow to deep waters, the research focused, up to this date, almost only on the shallow gorgonian populations located from the surface to approximately 40 m depth. Intermediate depths, particularly coastal rocky bottoms in the 40-150 m depth range, has remained mostly unexplored until now. This thesis addressed a first description of the ecology of deep sublittoral populations of Mediterranean gorgonians by means of a multidisciplinary approach combining classical methods, new technologies and modern genetic and biochemical analyses. The first chapter presented the results of applying quantitative analysis to underwater video transects performed with Remotely Operated Vehicles (ROV), in order to address the spatial distribution patterns of gorgonian populations. The second chapter combined the analysis of photographic images obtained by ROV, with scanning electronic microscope (SEM) analysis of gorgonian sclerites and histological and genetic analysis, all in order to investigate the morphological variability of gorgonians along a depth gradient. The third chapter offered a combination of classical methods for population size and spatial structure analysis that have been innovatively applied to ROV video transects to address the study of gorgonian populations over a larger bathymetrical scale. Finally, in the fourth chapter the microscopy and histology techniques for the study of gorgonian reproductive cycle were coupled with biochemical analysis of tissue composition (carbohydrate, protein and lipid) in order to determine the energetic state of gorgonian colonies and its relation to the reproductive cycle, as well as the analyses of the stable isotopes and fatty acids composition to get some insight into the trophic ecology of the gorgonians throughout the year and in a depth comparison. Although scientific research often leads to few answers and to much more new questions, we hope that the results of this thesis may serve as a stimulus for future studies focused on hard-bottom benthic communities located at intermediate depths, which have remained fairly ignored for a long time.

Thophic ecology of hake, anchovy, sardine, round sardinella and bullet tuna larvae of NW Mediterranean. Influence of trophic environment and ontogeny

Autor: E. Morote Córdoba
Director/es tesi: M.P. Olivar Buera, F. Villate Guinea
Any publicació: 2011
Institució: Universitat Politècnica de Catalunya
Resum: Veure
We have analysed the relationship of the ictioplankton community with its fisical and trophic environment in two hydrographical contrasting conditions (summer stratification versusautumn mixed column), and we have characterized the larval diet of five teleost species in the NW Mediterranean: the three clupeiform of the region [anchovy (Engraulis encrasicolus), sardine (Sardina pilchardus) and round sardinella (Sardinella aurita)], a small tuna [bullet tuna (Auxis rochei)] and the most important demersal species of the region [hake (Merluccius merluccius)]. These species have been chosen because they represent two different morphotypes, 1) that of the clupeiforms, which correspond to a stylized larvae with small mouth, long body and digestive tract linked to the tail, and 2) that of bullet tuna and hake, which correspond to a robust larvae with big mouth, robust body and compact digestive tract independent of the tail. Moreover, we have studied the diet variations i) along development, in relation to ii) prey availability and iii) morphology of the feeding-related structures like visual system, mouth and digestive tract. [...]

Upwelling in the Eastern Subtropical North Atlantic Ocean

Autor: M. Pastor Mollà
Director/es tesi: J.L. Pelegrí (ICM-CSIC)
Any publicació: 2011
Lloc d'edició: Las Palmas de Gran Canaria (ES)
Institució: Institut de Ciències del Mar - Facultad de Ciencias del Mar, Universidad de Las Palmas de Gran Canaria
Resum: Veure
Coastal upwelling in the eastern margin and offshore curl-driven upwelling in the southeastern margin, make the subtropical Northeast Atlantic a region of major primary productivity. When examining a broad zonal area, from the coast to 40º W, we find that the upward transport of nutrients due to offshore curl-driven upwelling becomes the main control on productivity. Nevertheless, despite its relatively small zonal extension of about 100 km, coastal upwelling extends its impact towards the open ocean through offshore Ekman transport and convergence of the meridional flow at Cape Blanc (21º N). Analysis of hydrographic data from spring 1973 and fall 1975 shows an export from the coast to the open ocean of 2.9 Sv of water mass and 53 kmol s-1 of nitrate during spring and 0.6 Sv and 3 kmol nitrate s-1 during fall in the area south of Cape Blanc. It is fundamental to improve our understanding of the distribution of the different water masses of the upper thermocline, as they carry the nutrients that will reach the euphotic layer and sustain primary production. In the study region, central waters of northern and southern origin meet at the Cape Verde frontal zone. Northern waters are nutrient-poor and oxygen-rich while local southern waters are nutrient-rich and oxygen-poor. Here, intense double diffusive mixing enhances horizontal heat transfer, thus the front appears as a smooth feature in terms of temperature, but resembles a barrier in terms of other properties such as salt or nutrients. The application of an Optimum Multiparameter analysis to hydrographic data collected during November 2007 and November 2008 shows a sharp front separating the central waters of northern and southern origin. In contrast, at intermediate layers, the transition between Mediterranean Water and Antarctic Intermediate Water is smoother.

Análisis de remolinos mesoescalares oceánicos mediante trayectorias de boyas de deriva y un modelo de velocidad angular

Autor: M. Auladell Mestre
Director/es tesi: J.L. Pelegrí, Antonio García-Olivares
Any publicació: 2010
Lloc d'edició: Barcelona
Institució: Institut de Ciències del Mar - Universitat Politècnica de Catalunya

Biologie de la conservation du corail rouge, Corallium rubrum (Linnaeus, 1758) : Impact du changement global sur l'évolution des populations infralittorales en Méditerranée Nord-Occidentale

Autor: J.-B. Ledoux
Director/es tesi: J.P. Féral, J. Garrabou, D. Aurelle
Any publicació: 2010
Lloc d'edició: Marseille
Institució: Université de la Méditerranée
Resum: Veure
Les pressions anthropiques agissent en synergie du gène à l’écosystème, des régions polaires aux régions tropicales, et induisent une érosion biologique telle, qu\'elle est qualifiée de sixième extinction de masse.Ce constat pose la question de l’évolution de la biodiversité face aux changements environnementaux en cours. C’est dans ce contexte que s’inscrit ce travail de thèse focalisé sur les populations de surface (5 - 60 m) de corail rouge, Corallium rubrum (Linnaeus, 1758), en Méditerranée Nord-Occidentale. [...]

Contribution to the Improvement of the Soil Moisture and Ocean Salinity (SMOS) Mission Sea Surface Salinity Retrieval Algorithm

Autor: M. Talone
Director/es tesi: A. Camps (UPC), C. Gabarró (ICM-CSIC)
Any publicació: 2010
Lloc d'edició: Barcelona
Institució: Dept . Teoria del senyal i comunicacions, Univ. Politècnica de Catalunya (UPC)
Resum: Veure
The European Space Agency\'s Soil Moisture and Ocean Salinity (SMOS) satellite was launched on November, 2, 2009 from the Russian cosmodrome of Plesetsk. Its objective is to globally and regularly collect measurements of Sea Surface Salinity (SSS). To do that, a pioneering instrument has been developed: the Microwave Imaging Radiometer by Aperture Synthesis (MI-RAS), the rst space-borne, 2-D interferometric radiometer ever built; it operates at L-band, with a central frequency of 1.4135 GHz, and consists of 69 antennas arranged in a Y shape array. MIRAS\' output are brightness temperature maps, from which SSS can be derived through an iterative algorithm, and using auxiliary information. For each overpass of the satel-lite an SSS map is produced, with an estimated accuracy of 1 psu (rmse). According to the Global Ocean Data Assimilation Experiment (GODAE) the mission requirement is instead speci ed as 0.1 psu after averaging in a 10-day and 2º x 2º spatio-temporal boxes. In previuos works ((Sabia et al., 2010), or more extensively in Dr. Sabia\'s Ph.D. thesis (Sabia, 2008)) the main error sources in retrieving SSS from SMOS measurements were determined as: 1. Scene-dependent bias in the simulated measurements, 2. L-band forward modeling de nition, 3. Radiometric sensitivity and accuracy, 4. Constraints in the cost function, and 5. Spatio-temporal averaging. This Ph.D. thesis, is an attempt of reducing part of the aforementioned errors (the relative to the one-overpass SSS (1 - 4)) by a more sophisticated data processing. Firstly, quasi-realistic brightness temperatures have been simulated using the SMOS End-to-end Performance Simulator (SEPS) in its full mode and an ocean model, as provider for geophysical parameters. Using this data set the External Brightness Temperature Calibration technique has been tested to mitigate the scene-dependent bias, while the error introduced by inaccuracies in the L-band forward models has been accounted for by the application of the External Sea Surface Salinity Calibration. Apart from simulated brightness temperatures, both External Brightness Temperature Calibration and External Sea Surface Salinity Calibration have been tested using real synthetic-aperture brightness temperatures, collected by the Helsinki University of Technology HUT-2D radiometer during the SMOS Calibration and Valdation Rehearsal Campaign in August 2007 and on one week of data (in Dual polarization mode) acquired by the SMOS satellite between march 3 and 9, 2010. Finally, a study of the cost function used to derive SSS has been performed: The correlation between measurement mis ts has been estimated and the e fect of including it in the processing have been assessed. As an outcome of a 3-month internship at the Laboratoire LOCEAN in Paris, a theoretical review of the e ect of the rain on the very top SSS vertical pro le has been carried out and is presented as Appendix.

Ecología y dinámica de la fase juvenil de la langosta roja Palinurus elephas en el Mediterráneo noroccidental

Autor: D. Díaz Viñolas
Director/es tesi: P. Abelló Sala
Any publicació: 2010
Institució: Universitat de Barcelona
Resum: Veure
Las langostas (Crustacea: Decapoda: Achelata: Palinuridae) constituyen desde siempre y en todos los mares un objetivo de pesca preferencial (Phillips y Sastri, 1980). Como tales, no escapan a las predicciones de los modelos actuales sobre la viabilidad de las pesquerías que vaticinan un colapso general en menos de 50 años Worm et al., 2006). [...]

Feeding behavior of the mussel Mytilus spp: Responses to the natural variability of seston and to toxic phytoplankton ingestion

Autor: E. Galimany Sanromà
Director/es tesi: M. Ramon
Any publicació: 2010
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Impact of viruses on baterial communities in marine ecosystems

Autor: J.A. Boras
Director/es tesi: D. Vaqué Vidal, M.M. Sala
Any publicació: 2010
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona
Resum: Veure
Viruses are a numerous and active element in all marine ecosystems, from coastal waters, through open sea, and to hydrothermal vents and the dark deep ocean layers. With concentrations of approximately 107 viruses per milliliter of seawater and 109 viruses per gram of soil or sediment (Wommack & Colwell 2000), they gain the status of the most abundant biological entities in the biosphere. Assuming that each virus contains roughly 10-17 grams of carbon, and a total number of viral particles in the ocean of 1030 (Suttle 2005), it can be calculated that they constitute the ocean second biomass (ca. 200 Mt) after bacteria (Hambly & Suttle 2005). Viruses also represent the largest reservoir of genetic diversity in the ocean (Rohwer 2003). [...]

Organic matter in sediments of Antarctic continental shelves under the influence of climate change

Autor: E. Sañé Schepisi
Director/es tesi: J.E. Isla Saavedra
Any publicació: 2010
Lloc d'edició: Barcelona
Institució: Universitat Politècnica de Catalunya
Resum: Veure
In the last 60 years air and oceanic temperatures increased in Antarctica above global average (Vaughan et al., 2001; Gille, 2002). As a consequence, the increase of glaciers retreat (Cook et al., 2005) and the thinning of ice shelves (Shepherd et al., 2003; Whingham et al., 2009) have been observed. Furthermore, ice shelf collapses became more frequent in Antarctica, as exemplified by the collapse in 2008 of Wilkins ice shelf and in 2010 of Mertz glacier. In 1995 and 2002, 4200 km2 and 3200 km2 of the sections A and B of the Larsen Ice shelf disintegrated, respectively (Rack and Rott, 2004). [...]

Role of life-cycle stages in dinoflagellate population dynamics

Autor: S. Anglès Calvo
Director/es tesi: E. Garcés Pieres
Any publicació: 2010
Institució: Universitat de Barcelona

Shedding ligth on the role of the prokaryotic assemblage in the biogeochemical cycles of the dark ocean

Autor: F. Baltar González
Director/es tesi: J. Arístegui Ruiz, G. Herndl, J.M. Gasol Piqué
Any publicació: 2010
Institució: Universidad de las Palmas de Gran Canaria
Resum: Veure
Prokaryotes are the cornerstone mediating the oceanic biogeochemical cycles. Due to the typical extreme abiotic conditions (e.g. high pressure, low temperature, low availability of organic matter) found in the dark ocean (> 200 m depth), it was generally assumed to be a site holding negligible, homogeneously-distributed biological activity. That is why most of the research done concerning the ecology ofprokaryotes have been carried out in surface waters, further leaving behind the study of the largest habitat in the biosphere: the dark ocean. In this study we assessed the actual role of the deep-sea prokaryotes in the marine biogeochemical cycles. The distribution of the organic matter pool (dissolved and particulate), the prokaryotic assemblage structure, abundance and metabolism (heterotrophic production, respiration, extracellular enzymatic activity) were analyzed along the water column of the North Atlantic, in six different research cruises. We found that the dark ocean plays a key role in the carbon mineralization processes (sometimes being, on a per-cell level, as active as the epipelagic waters), being far from a homogenously-distributed non-active ecosystem. The heterogeneity found in the dark ocean seemed to be controlled by a “bottom-up” effect, where the suspended particulate organic matter distribution modulates the prokaryotic activity. This stronger association between suspended particles and deepsea prokaryotes than assumed hitherto, would facilitate synergistic interactions in the cycling of matter in the dark ocean. Finally, we also found that the enigmatic imbalance between the organic carbon supply to the dark ocean and the mesopelagic prokaryotic carbon demand could be greatly reduced when taking into account the dissolved inorganic carbon (DIC) fixation. Our numbers indicates that the sinking particulate organic carbon could only account for 4-12% of the daily-required organic carbon, while the mesopelagic dark fixation of DIC can supply 12% to 72% of this prokaryotic carbon demand. Overall, this thesis contributes to shed light on the actual paramount role that dark ocean’s prokaryotes play in the global biogeochemical cycles, suggesting that the deep-sea microbes are principal characters in the material cycling of the biosphere.

Sources of plankton variability in an urbanized coastal ecosystem

Autor: E. Romero Sotoca
Director/es tesi: F. Peters
Any publicació: 2010
Institució: Universitat Politècnica de Catalunya
Resum: Veure
Coastal areas play a fundamental role in the functioning of marine ecosystems. These are strategic areas, transition zones in which terrestrial, atmospheric and oceanic factors come together and whose dynamics determines a wide variety of natural resources. Unlike what happens in vast regions of the ocean, where planktonic organisms exhibit recurring seasonal cycles and a clear synchrony with the physical forcing, coastal planktonic communities show a strong temporal and spatial variability. Seasonal patterns are not always visible and the dynamics of the community is often dependent on specific local processes. In recent decades, the step-up of urban pressure along the coast and the growing impact of human populations have increased the influence of terrestrial factors on coastal waters, pressing the need to understand the singularities and the functioning of coastal ecosystems. In this context, the present thesis addresses the variability of plankton in an urbanized coastal area, placing special emphasis on (1) the various time scales at which physical forcing factors operate and their different effects on the organisms, (2) the divergence between coastal plankton dynamics and the variations observed in open ocean regions, (3) the heterogeneity of coastal waters, which integrate different geomorphological, oceanographic and land use properties that are key to understand the response of the organisms to environmental perturbations. Broadly, the significance of seasonal patterns is examined through a multi-year series of monthly samplings. In Barcelona, as in other parts of the Mediterranean, there is an annual chlorophyll maximum between late winter and early spring. It is a recurrent pattern, although it represents only a small fraction of the annual variability; on the one hand, chlorophyll maxima vary significantly from year to year; on the other, terrestrial inputs can induce chlorophyll peaks of similar magnitude during other periods of the year. The comparison with nearby coastal areas, less exposed to human disturbances but subject to similar climatological and hydrological conditions showed that beyond smoothing the seasonal cycles, the city exerts a continuous pressure which modifies the structure and the response of the planktonic community. We identified two key aspects: first, the composition of urban inflows, particularly enriched in ammonia and organic matter; second, the decoupling between nutrient inputs and turbulence. Both factors seem to sustain a background community where the smallest plankton abounds and the microbial loop is kept very active. Ultimately, the fast growth of small planktonic organisms limits the response of microphytoplankton, whose proliferation appears to be strongly influenced by the availability of nitrate and the concurrence with mixing processes. The influence of turbulence and the composition of nutrients, particularly the nitrogen source, on the structure and dynamics of plankton was also assessed experimentally. In the laboratory, under controlled conditions, it is possible to distinguish more clearly the effects of specific factors; the experimental results were consistent with the observations at sea and stressed the importance on the coast, not only of nutrient loads, but especially of its relative composition and the coupling with turbulence. Finally, we examine the effects of an intense episode of atmospheric deposition. Atmospheric inputs, in particular Saharan dust, are a prominent source of variability in the Mediterranean coast. The study analyzes in detail the increase of nutrients in the water column, the sequence and interactions among organisms and the differences in the biological response depending on the severity of the episodes

Técnicas multidimensionales de procesado de la señal aplicadas a datos sísmicos

Autor: S. Ventosa Rahuet
Director/es tesi: Directora: Carine Simon (UTM), Co-directores: JJ Dañobeitia (UTM) y M. Schimmel (ICTJA-CSIC)
Any publicació: 2010
Lloc d'edició: Barcelona
Institució: Univ. Politécnica de Cataluña y Unid. de Tecnología Marina (CSIC)

A microcanonical cascade formalism for multifractal systems and its application to data inference and forecasting

Autor: O. Pont i Plà
Director/es tesi: C.J. Pérez Vicente, A.Turiel Martínez
Any publicació: 2009
Lloc d'edició: Barcelona
Institució: Institut de Ciències del Mar - Fac. Física, Universitat de Barcelona (UB)
Resum: Veure
Complex systems are abundant in our natural environment. In linear systems, the equations of their dynamics can be very difficult to solve, but if they cannot be described with a single characteristic scale, at least they can be described by a set of few characteristic scales that are totally decoupled from each other. However, this takes on a completely different flavour in non-linear systems, where scales are coupled and appropriate multiscale analysis is in order. This is the case of complex systems and, more particularly, scale invariant systems. In these, the approach to their solution is different, and it usually involves a multiscale basis. In this context, wavelets are one of the most used representation paradigms. The research context of complex systems and, particularly, scale invariant systems and multifractals has been in constant evolution over the last few years. Theoretical advances, either statistical (stochastic processes and probability distributions) or geometrical (function analysis and measure theory), along with fancy signal-processing algorithms suited to scale invariant data (and additionally handling aliasing, discretization and other artefacts of experimental data), have originated new tools for multifractal characterization of systems. While ten years ago the only methods available were statistical, by the start of this thesis project, development of geometrical methods had begun (most notably, the microcanonical multifractal formalism (MMF)). Geometrical methods have a clear advantage over statistical methods: they characterize each point of the system and thus they permit new applications such as reconstruction and prediction of signals, i.e., not only statistical characterization. Additionally, geometrical methods provide statistical characterization with much less need of data than statistical methods. In the present thesis, we have worked on the generalization and improvement of MMF, as well as its applications to the inference and forecasting of systems that follow a cascade process. In particular, we have described applications to two very different systems: stock-market series and ocean turbulence. The representation of the signal as a microcanonical cascade plays a crucial role in these applications. This representation can be achieved with one particular wavelet called optimal wavelet. The most relevant theoretical achievements are the regularization of diverging multifractal measures, the establishment of the bridge between multiplicative variables in microcanonical cascade processes and local singularity exponents, and the design of accurate and robust measure of wavelet optimality for a given dataset. To achieve this, we have introduced a new formalism, that of microcanonical cascades, that marries the cascade formalisms with MMF. Regarding the developed applications, on stock-market time series, we have inferred the distribution of future returns conditioned by the cascade and we have shown that a prediction based on this inference improves that of an ARIMA model. From the distribution of future returns, future volatility and value-at-risk can be reliably forecasted. On ocean data we have characterized dynamical aspects from optimal wavelet cascade analysis. In particular, we have observed that anomalies in the cascade of sea surface temperature show particular points of heat transfer between structures at different scales in the zones of wind-driven currents, also in the gyres. Both understanding -- combined with appropriate modelling -- of dynamics and design of inference/forecasting algorithms have crucial importance for the anticipation of changes in natural phenomena. In this context, the chain formed by the three steps followed during the thesis, namely multifractal characterization first, then obtaining of the optimal wavelet and finally design of inference algorithms, summarizes the direction we have followed to tackle the study of econometric time series and ocean maps.
Paraules clau: statistical physics, nonlinear dynamics, fractals, cascade processes

Effects of small-scale turbulence on dinoflagellate ecophysiology

Autor: G. Llaveria
Any publicació: 2009
Lloc d'edició: Elisa Berdalet i Andrés
Institució: Instituto de Ciencias del Mar / Universidat Politécnica de Catalunya
Resum: Veure
Les proliferacions de dinoflagel·lades semblen estar relacionades sovint amb certa estabilitat de la columna d’aigua. Experiments de laboratori han mostrat que la turbulència de petita escala pot disminuir-ne la taxa de creixement i inhibir-ne la divisió cel·lular, juntament amb un augment de la mida i dels continguts d’ADN i ARN. L’objectiu de la present Tesis Doctoral fou explorar els efectes directes de la turbulència de petita escala en processos fisiològics relacionats amb el cicle cel·lular i de vida, i investigar els mecanismes pels quals aquest factor ambiental interfereix en la biologia de les dinoflagel·lades per contribuir així a la comprensió del desenvolupament de llurs proliferacions. Es va evidenciar que el cicle cel·lular de la dinoflagel·lada Alexandrium minutum es va aturar transitòriament en la fase G2/M. Les investigacions del possible mecanisme d’interferència per part de la turbulència varen considerar la hipòtesis d’una alteració del sistema microtubular implicat en la dinomitosi, la participació dels receptors de rianodina en la via de mecanotransducció activada per aquest estímul, i l’existència d’una expressió gènica diferencial. La turbulència va modular també la concentració cel·lular de toxines i de DMSP, la formació de cists d’ecdisi. i la infecció de l’endoparàsit Parvilucifera sinerae en dinoflagel·lades. La infectivitat va disminuir en condicions d’agitació i l’encistament asexual no va constituir un mecanisme útil per a la seva prevenció. També es va avaluar l’adequació de diversos sistemes experimentals per a generar turbulència en el laboratori. L’agitador orbital és el més idoni per a estudis fisiològics amb dinoflagel·lades, ja que tot el cultiu és exposat a la turbulència i les cèl·lules no se’n poden escapar. La present tesis doctoral conclou que les dinoflagel·lades prefereixen condicions de calma en la columna d’aigua, ja que la seva fisiologia és sensible a les situacions de mescla intensa.

Estudio de los genes implicados en el metabolismo del arsénico en cultivos y en sistemas naturales

Autor: L.V. Escudero González
Director/es tesi: C. Pedrós-Alió, C. Demergasso
Any publicació: 2009
Institució: Universitat Autònoma de Barcelona
Resum: Veure
La presencia de arsénico en aguas potables y de riego es un problema económico, social y ambiental de extrema importancia, especialmente en varios países de América Latina (principalmente en el Norte de Chile y de Argentina). Los microorganismos respiradores que reducen As(V) a arsenito As(III) son diversos y pueden estar implicados en la movilización del arsénico del sedimento a fuentes de agua potable. Para entender cómo contribuye este metabolismo a la biogeoquímica del arsénico la presente tesis explora, por un lado, tanto la diversidad de comunidades microbianas en ambientes naturales salinos con presencia (p. ej. el Salar de Ascotán) o ausencia (Laguna Tebenquiche) de arsénico, como la distribución y diversidad de los genes involucrados en este metabolismo (arsenato reductasa arrA y arsC) y, por el otro, el aislamiento y caracterización de cultivos puros y su implicación en la formación de minerales sulfurosos de arsénico en estos ambientes salinos. [...]

Processos sedimentaris d'edat Holocena al marge sud-oest de la Península Ibèrica: Aplicació a la paleosismologia marina

Autor: A. Vizcaino i Martí
Director/es tesi: E. Gràcia Mont, C. Escutia Dotti
Any publicació: 2009
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Sedimentation on the Cantabrian Continental Margin from Late Oligocene to Quaternary

Autor: J. Iglesias Crespo
Director/es tesi: G. Ercilla Zárraga, S. García-Gil
Any publicació: 2009
Lloc d'edició: Vigo
Institució: Universidade de Vigo
Resum: Veure
The Cantabrian continental margin constitutes a magnificent natural laboratory to investigate submarine sedimentation and the processes of deposition and erosion that operated in a continental margin from the Alpine continental collision up to the recent evolution. More specifically, this research focuses on the sedimentary evolution spanning from the Late Oligocene to the present of the easternmost sector of this margin, that is, from Gijón to Bilbao, comprising also a small sector of the distal Aquitanian continental margin, from Biarritz to Bordeaux. [...]

Sedimentology and Geochemistry of Gas Hydrate-rich sediments from the Oregon Margin (Ocean Drilling Program Leg 204)

Autor: E. Piñero Melgar
Director/es tesi: E. Gràcia i Mont, F. Martínez-Ruiz
Any publicació: 2009
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona
Resum: Veure
Gas hydrates have been recently recognized as a key factor affecting a number of global processes such as the climatic change, sea floor stability, etc. In this thesis we present the multidisciplinary study of gas hydrate rich sediments recovered during ODP Leg 204 “Drilling gas hydrates at Hydrate Ridge”. The main objective of this thesis is to study how the textural characteristics of marine sediments can affect the main pathways and intensity of fluid flow and how fluid flow determines the distribution of gas hydrates in the continental margins, as well as the main geochemical processes that occur during early diagenesis. To reach these objectives, a complete sedimentary and geochemical study of 581 sediment samples from southern Hydrate Ridge was carried out. The methods and techniques that were applied include: complete textural analyses (grain size, granulometric distribution curve, statistical parameters, identification of the coarse-grained particles, carbonate content…), mineralogy (bulk sediment and clay minerals), physical properties (magnetic susceptibility) and geochemistry (major and trace elementary composition, total organic carbon). The southern Hydrate Ridge sediments are mainly made up of four lithofacies defined as: hemipelagites, turbidites, ash layers and debrites. Mass-transport deposits such as turbidites and debrites are more abundant in Lithostratigraphic Unit III and II, as well as in Lithostratigraphic Unit IA in the slope basin of southern Hydrate Ridge. Some increasing trends with depth can be observed in the smectite content in the clay mineral assemblages of southern Hydrate Ridge sediments. These features suggests that the transport in suspension of fine sediments through the California Current was more effective during the Pliocene and early Pleistocene period. Bedload transport of coarse material from local and distal areas was more effective during the middle Pleistocene and Holocene due to the tectonic reactivation of the southern Hydrate Ridge uplift. During the Pleistocene and owing to the pervasive fluctuation of sea-level, gas hydrate dissociation together with the seismic movements in the Oregon margin seems a plausible triggering mechanism for mass-movements. Thus, the results presented here confirm that the sedimentation patterns in the Hydrate Ridge region are controlled by climate and tectonic parameters such as the regional intensity of the California Current or the local tectonic movements that lead to the uplift of the Ridge. These parameters mainly control the clay mineral distribution as well as the sedimentary facies that are produced. [...]

Shoreline and nearshore bar morphodynamics of beaches affected by artificial nourishment

Autor: E. Ojeda Casillas
Director/es tesi: J. Guillén Aranda
Any publicació: 2009
Lloc d'edició: Barcelona
Institució: Universitat Politècnica de Catalunya
Resum: Veure
The coastal system is in incessant change, subject to the constant action of waves and tides (in addition to the wind action) that shape its morphology. The mutual interaction and adjustment of the seafloor topography and the fluid dynamics involving the motion of sediment is known as coastal morphodynamics (Voigt, 1998). This interrelation can be explained as follows: in the nearshore region the water motion is influenced by the seafloor topography and is responsible of sediment transport. Gradients in the sediment transport produce morphological changes in the seafloor. The loop is complete as hydrodynamic processes respond to the modified bathymetry. [...]

Aplicacions de tècniques de fusió de dades per a l'anàlisi d'imatges de satèl·lit en Oceanografia

Autor: R. Reig Bolaño
Any publicació: 2008
Lloc d'edició: V Parisi Baradad, E García Ladona
Institució: Universitat Politècnica de Catalunya
Resum: Veure
Durant dècades s\'ha observat i monitoritzat sistemàticament la Terra i el seu entorn des de l\'espai o a partir de plataformes aerotransportades. Paral·lelament, s\'ha tractat d\'extreure el màxim d\'informació qualitativa i quantitativa de les observacions realitzades. Les tècniques de fusió de dades donen un >ventall de procediments que ens permeten aprofitar les dades heterogènies obtingudes per diferents mitjans i instruments i integrar-les de manera que el resultat final sigui qualitativament superior>. En aquesta tesi s\'han desenvolupat noves tècniques que es poden aplicar a l\'anàlisi de dades multiespectrals que provenen de sensors remots, adreçades a aplicacions oceanogràfiques. Bàsicament s\'han treballat dos aspectes: les tècniques d\'enregistrament o alineament d\'imatges; i la interpolació de dades esparses i multiescalars, focalitzant els resultats als camps vectorials bidimensionals. En moltes aplicacions que utilitzen imatges derivades de satèl·lits és necessari mesclar o comparar imatges adquirides per diferents sensors, o bé comparar les dades d\'un sòl sensor en diferents instants de temps, per exemple en: reconeixement, seguiment i classificació de patrons o en la monitorització mediambiental. Aquestes aplicacions necessiten una etapa prèvia d\'enregistrament geomètric, que alinea els píxels d\'una imatge, la imatge de treball, amb els píxels corresponents d\'una altra imatge, la imatge de referència, de manera que estiguin referides a uns mateixos punts. En aquest treball es proposa una aproximació automàtica a l\'enregistrament geomètric d\'imatges amb els contorns de les imatges; a partir d\'un mètode robust, vàlid per a imatges mutimodals, que a més poden estar afectades de distorsions, rotacions i de, fins i tot, oclusions severes. En síntesi, s\'obté una correspondència punt a punt de la imatge de treball amb el mapa de referència, fent servir tècniques de processament multiresolució. El mètode fa servir les mesures de correlació creuada de les transformades wavelet de les seqüències que codifiquen els contorns de la línia de costa. Un cop s\'estableix la correspondència punt a punt, es calculen els coeficients de la transformació global i finalment es poden aplicar a la imatge de treball per a enregistrar-la respecte la referència. [...]

Caracterización del género Pseudo-nitzschia en la Costa Catalana

Autor: S. Quijano
Director/es tesi: E. Garcés Pieres
Any publicació: 2008
Institució: Universitat Politècnica de Catalunya
Resum: Veure
Las diatomeas son el grupo de microalgas más abundante y diversificado, con más de 200.000 especies reconocidas (Mann, 1999). En el ambiente marino forman parte del fitoplancton con más de 18 mil especies (Fryxell y Hasle, 2003) y son responsables de proliferaciones estacionales recurrentes en zonas costeras (Margalef, 1991; Falkowski et al., 1998). Como todos los organismos autotróficos, contienen clorofila y pigmentos adicionales para capturar la energía del sol, y mediante la fotosíntesis producen compuestos carbonados y oxígeno. Son las mayores fuente de oxígeno en el planeta, produciendo un equivalente al de toda la selva húmeda tropical (Field et al., 1998). Además son responsables de entre el 40% al 45% de la producción primaria global de compuestos orgánicos en el océano (Mann, 1999). Las diatomeas pertenecen taxonómicamente a la división Heterokontophyta, clase Bacillariophyceae. Se caracterizan por tener una cubierta de sílice en forma de caja formada por dos valvas que se denomina la frústula. Se diferencian en cuanto a la morfología de las valvas en dos grandes grupos: las centrales con simetría radial, y las pennadas con simetría bilateral (Round et al., 1990). [...]

Carbon fluxes thorough major phytoplankton groups under contrasting environmental conditions

Autor: A. Gutierrez Rodríguez
Director/es tesi: M. Latasa Arcalis
Any publicació: 2008
Institució: Universitat Politècnica de Catalunya

Effects of different allochthonous carbon sources on marine bacterioplankton diversity and function

Autor: I. Lekunberri García
Director/es tesi: J.M. Gasol Pique
Any publicació: 2008
Institució: Universitat Politècnica de Catalunya
Resum: Veure
Bacteria are the most abundant organisms on Earth and mediate many critical ecosystem processes. This indicates the great importance of the knowledge of the identity and population dynamics of the indigenous microorganisms. Initial studies in aquatic microbiology were carried out by traditional cultivation techniques. Later on, cell counts by epifluorescence techniques demonstrated how abundant bacteria were, and molecular techniques were developed and used to detect the most representatives bacteria in the environment. This is mainly because the culture media have nutrient contents (both organic and inorganic) which are several times more concentrated than those in the natural environment. This makes retrieving dominant organisms from an oligotrophic environment not an easy task, and generates selectivity for particular bacterial types, which are not very representative. A similar selection of bacteria also occurs in the natural environment, at another scale, when different allochthonous inputs take place. These can be due to natural processes, such as river run-offs, aerosol deposition, etc., or may have an anthropogenic origin, such as oil spills. In this thesis we evaluate the effect of several of these additions on bacterial community structure and function. There is an increasing interest in the isolation of naturally dominating organisms since it provides a better information about the metabolic capabilities of the organisms that are growing in the environment. Thus, we decided to evaluate how representative were the isolates obtained in the Mediterrranean Sea as compared to the sequences retrieved by molecular techniques such as cloning and DGGE fingerprinting. Our analysis highlighted the selectivity created by the growth media, but simultaneously allowed to increase our knowledge about the diversity in our study area, and provided a means for looking into the “rare microbial biosphere”, which cannot be analyzed with other techniques. To address the question of how nutrient addition modifies bacterial community structure and affects microbial function, we performed different mesocosm experiments, where we added different types of nutrients to water collected from Blanes Bay (NW Mediterranean Sea). Another mesocosm experiment was carried out to evaluate the effect of the oil spill that took place after the Prestige tanker accident in front of the Galician coast. Mesocosms experiments have been widely used to evaluate addition effects as a means to reproduce of the natural conditions. During these experiments different environmental parameters were measured and also bacterial production and abundance were monitored. Bacterial community structure was determined by the DGGE fingerprinting technique, which allows the comparison of different samples and further analysis of the dominant richness by the Shannon-Weaver index, based on the presence and absence of bands. These analyses showed the influence of grazers on the bacterial selection after the different additions and, for example, explained the effects of Saharan Dust deposition on microbial function and community metabolism, as an effect of the inorganic phosphorus and organic carbon contributed by the dust. In the oil spill mesocosm experiments, effects on bacterial structure, production and abundance were detected only with additions four times higher than the concentration found after the Prestige tanker accident. We also include an experimental study carried out in the North Atlantic during two different cruises, in which using dyalisis bags and transplant experiments we tested whether bottom-up conditions were stronger than top-down factors in determining microbial function and community structure. The results showed differences between experiments, but a general higher effect of bottom-up conditions than the effect of predators. The different experimental work included in this thesis allows for some generalizations, but also show some discrepancies, which we discuss in the last chapter.

Fish sex hormone-binding globulin

Autor: S. Miguel Queralt
Director/es tesi: G.L. Hammond, F. Piferrer Circuns
Any publicació: 2008
Institució: Universitat de Barcelona

Genètica evolutiva en llagostes de l’infraordre Achelata

Autor: F. Palero Pastor
Director/es tesi: M. Pascual Berniola, E. Macpherson Mayol, P. Abelló Sala
Any publicació: 2008
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona
Resum: Veure
Si donem un cop d’ull al nostre voltant, estareu d’acord en què la diversitat dels éssers vius és immensa. Fins i tot si vivim a la ciutat i sols veiem Homo sapiens en el nostre quefer diari, haureu de reconèixer que aquestos també són molt diferents entre ells. Quan mirem amb detall qualsevol grup taxonòmic, ens hi trobem molts tipus de diversitat: diversitat morfològica, ecològica, comportamental, etc. Ara sabem, gràcies al treball de síntesi d’en Charles Darwin, que tota aquesta diversitat no és deguda a l’atzar, sinó que principalment és el resultat d’un procés d’adaptació dels éssers vius a la diversitat de medis que es troben a la natura (Darwin, 1859). Així, la gran varietat d'espècies actuals s'hauria generat per un procés continuu de divergència i separació de llinatges, a partir d'avantpassats comuns, com si tots els éssers vius forméssin una gran família. [...]

Multiscale techniques in turbulence: application to geophysical fluids and operational oceanography

Autor: V.U. Nieves Calatrava
Director/es tesi: A. Turiel
Any publicació: 2008
Lloc d'edició: Barcelona
Institució: Institut de Ciències del Mar - Fac. Fisica, Univ. Politècnica de Catalunya
Resum: Veure
Turbulent ows are of major interest for scientists and engineers, playing an essential role in uid dynamics. Even though a precise de nition of turbulence does not exist,it is generally assumed that turbulence is a ow regime characterized by instabilities at large Reynolds numbers. The Reynolds number is a measure of the ratio of inertial forces to viscous forces. In the ocean, Reynolds number are of the order of 106, and so ocean dynamics is strongly nonlinear involving a large spectra of processes across all space and time scales. However, the ocean seems to be very active at around 30-300 Km, which is known as mesoscale. A schematic diagram of the spatial and temporal scales of various oceanic phenomena is shown in Figure 1.1. Instabilities in the ocean explain the meandering nature of oceanic currents, which can isolate and shed eddies when the meanders reach large amplitudes [3]. Examples of such ows are high- and low-pressure systems that are formed in the Gulf Streamarea (see Figure 1.2). These systems have been related to coherent structures, which are a combination of the geometrical and dynamical properties of the ow, i.e., regions containing most of the surviving vorticity [56, 47]. As it occurs in the ocean, a turbulent ow self-organizes into a collection of coherent structures [91, 141]. The smaller eddiesare exposed to the strain-rate eld of these coherent structures [124]. In recent studies, coherent structures not only have been identi ed with vortices, but also their presence has been connected with non-Gaussian Probability Density Functions (PDFs) of velocity elds from the ocean [17, 40, 54, 51, 140]. In addition to this characteristic, a near Gaussian component is expected for the background ow. These statistical distributions of ocean velocity elds have similar characteristics to the ones of numerical simulations of bidimensional turbulence.

Post-Rift sedimentary evolution of the Central Brandsfield Bassin (Antarctic Peninsula)

Autor: M. García García
Director/es tesi: G. Ercilla Zárraga, B. Alonso Martínez
Any publicació: 2008
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona
Resum: Veure
The Central Bransfield Basin is located at the northernmost tip of the Antarctic Peninsula (West Antarctica). This investigation, focused in the morphology, stratigraphy and near-surface sedimentation, and based on acoustic, seismic and sedimentological methods, reveals the main sedimentary systems and processes involved in the stratigraphic architecture and growth pattern of the basin. Likewise, it provides clues about the interplay of the global and local factors that have controlled the basin sedimentary evolution during the post-rift stage and allows the reconstruction of depositional models. The most striking physiographic characteristic of the Central Bransfield Basin is the presence of slope platforms composing the middle domain of the slope, in both the Antarctic Peninsula and South Shetland Islands margins. This favors the occurrence of glacial and glaciomarine processes on this domain, representing a difference with other high-latitude margins, where these processes are restricted to the continental shelf. The morphologic elements identified on the Central Bransfield Basin may be grouped into four major sedimentary systems (glacial-glaciomarine, slope-basin, seabed fluid outflow and contourite). The development of these systems has occurred during the last glacial cycle and has been controlled by the glacial cyclicity, tectonics, physiography and oceanography. The post-rift seismic stratigraphy of the Antarctic Peninsular margin consists on two seismic sequences, S1 and S2, of glacial and glaciomarine origin, overlying the syn-rift record. S2 was deposited during the post-rift to the Mid-Pleistocene and can be subdivided into four seismic units composed of prograding wedges. S1 was deposited after the Mid-Pleistocene and is composed of prograding/aggrading deposits. This sequence is composed of five seismic units whose distribution was mostly governed by variations in the thermal regimes of the Antarctic Peninsula Ice Sheet. Climate and physiography are interpreted as the major factors controlling the stratigraphic architecture and growth pattern of the margin. The near-surface sedimentary record of the Central Bransfield Basin corresponds to the last glacial cycle and offers a high-resolution definition of sediment sequences, including subglacial diamicton, compound glaciomarine, turbid glacial meltwater, proglacial diamicton, flow-in and contourite sequences, and a characterization of the sedimentary paleoenvironments during the deglaciation and interglacial stage. Likewise, the identification of sedimentary processes allows the establishment of several stratigraphic models (glacial trough, slope platforms, lower slope and basin) in the Central Bransfield Basin, in relation to sedimentary processes that were directly controlled by climatic factors and modulated by the physiography/morphology, sediment source and oceanography. This PhD Thesis has allowed the definition of post-rift sedimentary models by different scale, resolution and temporal approaches. Likewise, the interpretation of the interplay among the different depositional systems has been done considering the margin and deep sea as an entire system, to analyze the inherent sedimentary dynamics and processes that transfer the sediment from the shoreline to the deep basin.

Regulatory mechanisms and effects of temperature during sea bass (Dicentrarchus labrax) sex diferentiation

Autor: L. Navarro Martín
Director/es tesi: F. Piferrer Circuns
Any publicació: 2008
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona
Resum: Veure
This Thesis has been carried out in the Group of Biology of the Reproduction (GBR) of the Department of Renewable Marine Resources at the Institute of Marine Sciences (ICM-CSIC) of Barcelona and under the tuition of the department of Physiology of the University of Barcelona during the period 2003-2008. The results obtained in these studies are not only important in sea bass, but also some of them can be generalized to other fish and vertebrates. The aim of this Thesis was to study sea bass sex differentiation at different levels: at endocrine level, analysing the influence of different steroids and agonists and antagonists compounds of the ovarian and testicular differentiation pathways; at expression level of some genes that are required for the necessities of the gonads to differentiate towards ovaries or testes; and also through mechanisms of epigenetic regulation, such as methylation, that may be responsible for the complex process of developing a bipotential tissue, like the undifferentiated gonad, into a ovary or testis. In non-mammalian vertebrates like some fishes, amphibians and reptiles, the mechanism by which the temperature can affect sex differentiation, and consequently the proportion of sexes, remains unknown. The results obtained in this thesis allow to propose an hypotheses about how temperature can be influencing sex differentiation and which mechanism can be responsible for that. In the present thesis, the sea bass has been used as model specie. However, and although these studies have broadened our knowledge in this field, the obtained results have posed new questions that can be resolved in future experiments. [...]

Sea Surface Salinity Retrieval Error Budget within the ESA Soil Moisture and Ocean Salinity Mision

Autor: R. Sabia
Director/es tesi: A. Camps Carmona, M. Vall-llossera Ferran
Any publicació: 2008
Lloc d'edició: Barcelona
Institució: Universitat Politècnica de Catalunya
Resum: Veure
Satellite oceanography has become a consolidated integration of conventional in situ monitoring of the oceans. Accurate knowledge of the oceanographic processes and their interaction is crucial for the understanding of the climate system. In this framework, routinely-measured salinity fields will directly aid in characterizing the variations of the global ocean circulation. Salinity is used in predictive oceanographic models, but no capability exists to date to measure it directly and globally. The European Space Agency’s Soil Moisture and Ocean Salinity (SMOS) mission aims at filling this gap through the implementation of a satellite that has the potential to provide synoptically and routinely this information. A novel instrument, the Microwave Imaging Radiometer by Aperture Synthesis, has been developed to observe the sea surface salinity (SSS) over the oceans by capturing images of the emitted microwave radiation around the frequency of 1.4 GHz (L-band). SMOS will carry the first-ever, polar-orbiting, space-borne, 2-D interferometric radiometer and will be launched in early 2009. Like whatsoever remotely-sensed geophysical parameter estimation, the retrieval of salinity is an inverse problem that involves the minimization of a cost function. In order to ensure a reliable estimation of this variable, all the other parameters affecting the measured brightness temperature will have to be taken into account, filtered or quantified. The overall retrieved product will thus be salinity maps in a single satellite overpass over the Earth. The proposed accuracy requirement for the mission is specified as 0.1 ‰ after averaging in a 10-day and 2ºx2º spatio-temporal boxes. In this Ph.D. Thesis several studies have been performed towards the determination of an ocean salinity error budget within the SMOS mission. The motivations of the mission, the rationale of the measurements and the basic concepts of microwave radiometry have been described along with the salinity retrieval main features. The salinity retrieval issues whose influence is critical in the inversion procedure are: • Scene-dependent bias in the simulated measurements, • Radiometric sensitivity (thermal noise) and radiometric accuracy, • L-band forward modeling definition, • Auxiliary data, sea surface temperature (SST) and wind speed, uncertainties, • Constraints in the cost function, especially on salinity term, and • Adequate spatio-temporal averaging. A straightforward concept stems from the statement of the salinity retrieval problem: different tuning and setting of the minimization algorithm lead to different results, and complete awareness of that should be assumed. Based on this consideration, the error budget determination has been progressively approached by evaluating the extent of the impact of different variables and parameterizations in terms of salinity error. The impact of several multi-sources auxiliary data on the final SSS error has been addressed. This gives a first feeling of the quantitative error that should be expected in real upcoming measurements, whilst, in another study, the potential use of reflectometry-derived signals to correct for sea state uncertainty in the SMOS context has been investigated. The core of the work concerned the overall SSS Error Budget. The error sources are consistently binned and the corresponding effects in terms of the averaged SSS error have been addressed in different algorithm configurations. Furthermore, the results of a salinity horizontal variability study, performed by using input data at increasingly variable spatial resolution, are shown. This should assess the capability of retrieved SSS to reproduce mesoscale oceanographic features. Main results and insights deriving from these studies will contribute to the definition of the salinity retrieval algorithm baseline.

Effects of commercial trawling activities on benthic communities from the NW Mediterranean Sea

Autor: S. De Juan Mohan
Director/es tesi: M. Demestre Alted
Any publicació: 2007
Institució: Universitat de Barcelona

Fisiología de la reproducción del lenguado senegalés (Solea senegalensis): mecanismos endocrinos y aplicaciones en acuicultura

Autor: M.J. Agulleiro Gozalbo
Director/es tesi: J. Cerdà Luque
Any publicació: 2007
Lloc d'edició: Valencia
Institució: Universitat de Valencia
Resum: Veure
El presente trabajo se puede dividir en tres partes. En la primera parte, o Introducción General, se resume el estado actual de conocimientos sobre los mecanismos endocrinos implicados en la reproducción de teleósteos, y se introduce al lector en los beneficios y problemas de la acuicultura de peces planos, especialmente del lenguado senegalés (Solea senegalensis). En la segunda parte, Capítulos 2 y 3, se describen los cambios estacionales de las principales hormonas, moléculas y receptores que intervienen en el proceso de crecimiento ovárico en el lenguado. Y en la tercera parte, Capítulos 4 y 5, se diseñan y aplican métodos hormonales para controlar la reproducción del lenguado en condiciones de cautividad. El objetivo principal de la presente tesis ha sido profundizar en el conocimiento de la endocrinología de la reproducción en teleósteos, y particularmente en el lenguado senegalés. Esta especie posee actualmente un alto interés comercial para la acuicultura marina mediterránea, pero su fisiología reproductiva es todavía muy desconocida, lo que imposibilita mejorar su producción y calidad a nivel industrial. Por ello, el objetivo final de este trabajo ha sido desarrollar métodos para controlar la reproducción del lenguado en condiciones de cautividad los cuales puedan ser transferidos a la industria

Influence of turbulence variability on osmotrophic plankton dynamics in a coastal area

Autor: O. Guadayol Roig
Director/es tesi: F. Peters, C. Marrasé Peña
Any publicació: 2007
Institució: Universitat Politècnica de Catalunya
Resum: Veure
Why is turbulence so important for plankton? Plankton is at the base of the marine trophic web. It can be defined from a hydrodynamic point of view, as the collection of organisms that live suspended in a body of water with a limited ability to regulate its position. Therefore plankton drifts with currents, tides and other water motions, which become environmental properties inherent to planktonic life. Planktonic organisms range several orders of magnitude in size, from tenths of microns to meters, although most are microscopic. They can feed on other particles (phagotrophs) or acquire dissolved substances (osmotrophs), incorporating them into particulate form. Osmotrophic plankton dominates the flux of carbon within the pelagic ecosystem, through CO2 fixation (primary production) and re-mineralization (respiration). In fact, the majority of primary production in aquatic systems, which accounts for roughly half of the global primary production (Field et al. 1998), is performed by osmotrophic plankton through photosynthesis. Parallely, bacterioplankton is responsible for the majority of organic carbon respired in the ocean (e.g. Rivkin and Legendre 2001). […]

Microbial Evolution: patterns of diversity in aquatic protists

Autor: R. Logares
Any publicació: 2007
Institució: Lunds Universitet

Proteomic approach to flatfish aquaculture. Study of the reproductive biology of Solea senegalensis

Autor: I. Forné Ferrer
Director/es tesi: J. Cerdà Luque
Any publicació: 2007
Institució: Universitat Autònoma de Barcelona
Resum: Veure
The flatfishes represent a group of species with a high biological and economical interest. Due to the decrease in fish hatchings, in the last years different several projects related to the aquaculture of these species were proposed. The project of this doctoral thesis has focused on the Senegal sole (Solea senegalensis), a flatfish specie with a great commercial interest and a candidate with high potential for aquaculture. However, lots of questions about its reproduction haven't been so far … [+]properly addressed, and they should be approached in order to optimize the culture of the Senegal sole. The main problems detected for this specie in captivity are the low spermiation volume and the impaired quality of spermatozoa motility males. This thesis aims to investigate the molecular mechanisms involved in the spermatogenesis and sperm production of S. senegalensis through the analysis of the testis proteome of wild and cultured animals under several conditions, in order to unveil the candidate proteins related to these processes. Initially, the proteome of S. senegalensis has been approached by de novo peptide sequencing based on mass spectrometry. Afterwards, the testis proteome from wild and cultured individuals in several spermatogenic stages was compared using two-dimensional electrophoresis and mass spectrometry. Once this point was performed, a comparative study of testis proteome from individuals cultured with and without hormonal treatment was approached. Both proteomic studies were complemented with mRNA expression analysis using microarrays. Finally, the information related to protein expression obtained during the different parts of the project, the mRNA expression and the histological analysis were integrated in a bioinformatic visual atlas specifically designed for S. senegalensis

Relació entre la distribució de nutrients i oxigen dissolt i la composició elemental del fitoplàncton a la Mar Catalana (N-O Mar Mediterrània)

Autor: M.M. Segura Noguera
Director/es tesi: D. Blasco Font de Rubinat
Any publicació: 2007
Institució: Universitat Politècnica de Catalunya
Resum: Veure
Els organismes vius estan composats d’elements químics, principalment C, H, O, N, P i S. L’estudi d’aquests elements essencials és una eina molt útil que permet moure’ns entre diferents nivells d’organització biològica, estudiant relacions entre elements (estequiometria), així com estimant fluxos i balanços de massa entre i des d’orgànuls i cèl·lules fins a conques senceres o tota la biosfera. L’objectiu d’aquesta tesi consisteix en establir les relacions entre aquests elements tant a l’interior com a l’exterior de les cèl·lules del fitoplàncton de la Mar Catalana (Mar Mediterrània occidental). [...]

Simulation techniques for the bioeconomic analysis of Mediterranean fisheries: Game Theory and effort dynamics. GAMEFISTO model

Autor: G. Merino Cabrera
Director/es tesi: F. Maynou, A. García-Olivares (ICM-CSIC)
Any publicació: 2007
Lloc d'edició: Barcelona
Institució: Universitat Politècnica de Catalunya
Resum: Veure
The words by Herman Melville and Henri Charrière summarize two perspectives about the limits and the vulnerability of natural and marine environments and allow us to introduce some ideas about the sustainability of the human exploitation of natural resources discussed in the present work. [...]

Situacions d'anòxia en zones estuàriques sense forçament mareal: una aproximació als balanços producció/consum d'oxigen

Autor: X. De Pedro Puente
Director/es tesi: J. Romero Martinengo, J. Camp Sancho
Any publicació: 2007
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona
Resum: Veure
Els sistemes estuarians són dominis d’aigua costanera semiconfinada, que tenen una connexió lliure amb el mar, i on l’aigua de mar es dilueix amb l’aigua dolça procedent del desguàs continental (Pritchard 1952, Pritchard 1967, Cameron i Pritchard 1965). En ells existeix confluència de matèria i energia de diferents orígens, que dóna lloc a l’existència de forts gradients i ecotons, així com una alta variabilitat en les condicions ambientals (Ketchum 1983a). Per això presenten característiques afins, en part, a totes dues zones que els limiten geogràficament, a part d’altres peculiaritats pròpies. Algunes d’aquests peculiaritats pròpies són comuns a tots els estuaris arreu del món, com la seva alta producció biològica respecte la majoria d’altres sistemes de la Terra; altres peculiaritats són específiques per les condicions locals d’aquell indret en concret (Ketchum 1983b, Valiela 1995). La Badia dels Alfacs és un sistema estuarià influït per l’absència de marees notables, com passa en alguns altres sistemes estuarians mediterranis del mon. El present treball s\'emmarca en la línia de tota una sèrie de treballs realitzats en aquesta badia, per tal de conèixer millor la seva dinàmica, les similituds i diferències respecte altres sistemes estuarians del món, i molt especialment esbrinar els mecanismes que controlen les concentracions d’oxigen dissolt i les seves fluctuacions.

Trophic relationships in demersal communities of Western Mediterraneo occidentale: case studies from coastal and deep-sea ecosystems

Autor: E. Fanelli
Director/es tesi: J.E. Cartes, F. Badalamenti
Any publicació: 2007
Institució: Università degli studi della Tuscia di Viterbo
Resum: Veure
The present thesis deals with the analysis of the trophic web structure and spatio-temporal variation in trophic levels of prey and predator in two different ecosystems: a coastal environment up to 80 m in the Northern Sicily (Italy) and a deep-sea ecosystem, the middle slope (450-750 m deep) of the Balearic basin (Cabrera Archipelago-Spain). As trophic relationships are fundamental to understand biological interaction, a detailed study of the food and feeding ecology of demersal fish species, in the coast and deep-sea, is attempted. Three fish species from costal ecosystems and three from deep-sea were selected as representative of different trophic guilds (benthophagous, suprabenthic feeder and planktophagous). Moreover to define the trophic structure of coastal and deep-sea communities a complete examination of prey (i.e. zooplankton, suprabenthos and benthos, where possible) and predator based on stable isotope analysis was carried out. Particularly suprabenthic resources were generally ignored or scarcely considered in trophic web studies, thus the role of suprabenthos as a link between benthic and pelagic environments and its importance as forage for juveniles of coastal fish species and for deep-sea fish is explored. [...]

Biogeochemical modelling of upper ocean sulfur dynamics and its impact on cloud forming aerosols

Autor: S.M. Vallina Fernández
Director/es tesi: R. Simó Martorell
Any publicació: 2006
Institució: Universitat Politècnica de Catalunya. Institut de Ciències del Mar
Resum: Veure
The CLAW hypothesis postulates that an increase in solar irradiance or in the heat flux to the ocean can trigger a biogeochemical response to counteract the associated increase in temperature and available sunlight. This natural (negative) feedback mechanism would be based on a multi-step response: first, an increase in seawater dimethylsulfide concentrations (DMSw ) and then its fluxes to the atmosphere (DMSflux ); second, an increase in the atmospheric cloud condensation nuclei (CCN) burden as a consequence of DMS oxidation to form biogenic CCN (CCNbio ); third, an increase in cloud albedo due to higher CCN numbers. Therefore, DMS is suggested to exert a cooling effect on the Earth radiative budget through its involvement in the formation and optical properties of tropospheric clouds over the ocean. Such a feedback has been regarded as a potential natural mechanism that might partly counteract anthropogenic GlobalWarming. This hypothesis, although suggestive, is highly speculative and some of itsmain postulates remain unproved. In this study we sought to contribute to the current knowledge of the oceanic biogenic sulfur cycle and its potential impact on climate by addressing some relevant open questions regarding the CLAW hypothesis. The climatic factor that drives oceanic DMS production, the impact of DMS oxidation on atmospheric CCN, and the potentiality of DMS to counteract Global Warming are investigated in detail based on modeling and data analyses. A new one-dimensional (1D) model of DMS dynamics (DMOS) is developed and coupled to a pre-existing ecological model that explicitly simulates the microbial-loop. The model is applied to the Sargasso Sea in order to explain what drives DMS seasonality. We have conducted a series of modeling experiments where some of the DMOS sulfur paths are turned ’off’ or ’on’, and the results on chlorophyll-a, dimethylsulfoniopropionate (DMSP; the DMS precursor) and DMS concentrations have been compared with the vertical profiles of these same variables measured during the years 1992 through 1993. Solar-induced DMS exudation by phytoplankton outstands as the process without which the model is unable to produce realistic DMS simulations and reproduce the DMS summer-paradox. The analysis of a global DMS database as well as local DMS time-series (Blanes Bay and Sargasso Sea) have revealed that it is the solar radiation dose in the upper mixed layer (or SRD) the climatic factor that seems to drive DMS dynamics. With a spatially resolved perspective, our analysis of globally derived SRD and DMS climatologies shows that the seasonal couplings between SRD and DMS are very tight and widespread over the Global Ocean, irrespective of latitude, temperature, and phytoplankton biomass. From these results, we have been able to obtain a global predictive diagnostic equation that relates DMS concentrations to the SRD. Statistical analyses of satellite and model-derived global data of several oceanic and atmospheric variables suggest that DMS oxidation can indeed be a major source of CCN over oceanic regions far from continental aerosol sources (eg. Southern Ocean, Subtropical South Pacific), especially in summer when the oxidation efficiency of DMS is the highest. Small sea-salt (SS) aerosols, although quantitatively important, do not seem to control CCN seasonality over the Southern Ocean, a region were SS production is amongst the highest of the world due to the constant presence of strong winds. Rather, they appear to conform a fairly constant background of CCN. Differences in the seasonalities of wind speed and the small-mode fraction of aerosols support these conclusions. [...]

Dinámica del material Sedimentario y de los metales pesados asociados en el margen noroccidental del Mar de Alborán

Autor: M. El-Khatab
Director/es tesi: A. Palanques Monteys
Any publicació: 2006
Lloc d'edició: Barcelona
Institució: Universitat Politècnica de Catalunya

Ecology of the marine cladoceran Penilia avirostris

Autor: D. Atienza Ariznavarreta
Director/es tesi: E. Saiz Sendrós, A. Calbet Fabregat
Any publicació: 2006
Institució: Universitat Politècnica de Catalunya

Estudio multitemporal de la clorofila superficial en el mar mediterráneo nor-occidental, evaluada a partir de datos SEAWIFS: septiembre de 1997 a agosto del 2004

Autor: A. Morales Blake
Any publicació: 2006
Lloc d'edició: Barcelona
Institució: CMIMA-CSIC

Links between bacterial divesity and carbon cycling in the sea

Autor: L. Alonso Saez
Director/es tesi: J.M. Gasol Pique
Any publicació: 2006
Institució: Universitat Politècnica de Catalunya
Resum: Veure
Although our knowledge about bacterial diversity in marine waters and that about the role of bacteria in the oceanic carbon cycling have greatly advanced in the last decades, very little is known about the linkage between those important characteristics, particularly under in situ conditions. The study of such relationship is hampered by the difficulties in obtaining pure cultures from representative marine bacteria, which would provide information about their metabolic capacities. The recent development of single-cell techniques has allowed studying the activity of marine populations in situ, allowing advances on this topic. We are starting now to know what is the specific role of specific groups of bacteria in carbon cycling, and the relationship between bacterial community assemblage and the global magnitude and patterns of carbon cycling in the ocean. In this study, we assessed the linkage between bacterial diversity and function along two gradients in marine waters: a temporal gradient (a seasonal study in a coastal Mediterranean station), and a spatial gradient covering different trophic states in oceanic waters (from the Cape Blanc upwelling to the N Atlantic subtropical gyre). We first described exhaustively bacterial assemblage structure at both sites, with the simultaneous use of clone libraries, fluorescence in situ hybridization with specific probes and fingerprinting of genes encoding the 16S rRNA. Since both studies were focused on surface bacterial assemblages, Archaea were minor components and we focused on Bacteria. We also exhaustively described the use of carbon by bacteria at both sites, taking special care in identifying and constraining the limitations in the methodologies used for that purpose. Afterwards, we performed comparative studies in which changes in bacterial assemblage structure were systematically compared to changes in a range of in situ measurements of bacterial carbon processing, including bacterial respiration and production, since this type of comparisons in marine field studies are absent from the literature. Several similarities were found between both systems studied, in terms of bacterial community composition, such as the increasing abundances of the Roseobacter group in high-nutrients waters, and the predominance of SAR11 bacteria in less productive waters. However, and with the use of multivariate statistics and Mantel tests, a tight linkage between bacterial diversity and function could not be proved in neither of the gradients. This lack of pattern could be due to several reasons, including the fact that the bulk measurements that describe carbon function (bacterial biomass production or respiration) are so general and important for ecosystem maintenance that they are redundantly performed by different bacterial groups. However, a more specific study using a single-cell level approach (microautoradiography combined to fluorescent in situ hybridization) showed that different bacterial populations had significantly distinct patterns of carbon use along the seasonal study in Blanes Bay, which suggests that different bacterial groups are not equal in terms of carbon utilization. Finally, we studied the effect of a variable environmental factor, such as UV and PAR radiation, as it inhibited or stimulated the different bacterial groups. Environmental conditions were shown to affect differently the activity of specific bacterial groups and, thus, their role in the processing of carbon in the marine planktonic environment.

Major players in the biogeochemical cycling of dimenthylated sulfur compounds in seawater

Autor: M. Vila Costa
Director/es tesi: R. Simó Martorell
Any publicació: 2006
Institució: Universitat Politècnica de Catalunya

Mesoscale balanced flow, vertical velocity, and spontaneous emission of inertia-gravity waves

Autor: E. Pallàs Sanz
Director/es tesi: A. Viudez (ICM-CSIC)
Any publicació: 2006
Lloc d'edició: Barcelona
Institució: Dept. d'Enginyeria Hidràulica, Marítima y Ambiental, Univ. Politècnica de Catalunya - Inst. Ciencies del Mar - CSIC
Resum: Veure
Aquesta tesi es una investigació de la generació espontània i propagació d’ones inercials-gravitatòries (OIGs) de petita escala en fluxos geofísics inicialment en balanç. La investigació inclou les fonts d’ones (flux en balanç) i les OIGs (flux que no està en balanç). La velocitat vertical de mesoescala w s’obté a partir de dades experimentals en el ‘Western Alboran Gyre’ (WAG) resolent una aproximació de l’equació ω generalitzada (equació ω), i la circulació ageostròfica tridimensional (3D) es simula numèricament en un dipol baroclí ‘quasi en balanç’ a partir d’un model de Bousinessq no-hidrostàtic. Aquests fluxos són inercialment estables amb nombres de Rossby màxims de Rmax≈0.9 i 0.7, respectivament. La velocitat vertical es relaciona, en ambdós fluxos, amb l’advecció de la component vertical de la vorticitat per la cisalla vertical. Les diferències entre w i la velocitat vertical quasigeostròfica en el WAG es deuen a la inclusió de la part ageostròfica del vector Q en l’equació ω. La trajectòria del dipol es relaciona amb el màxim de l’anomalia de vorticitat potencial (VP) i la grandària dels remolins. El flux ageostròfic del dipol depèn de la distància entre els remolins d0. Per a petites d0, la w té una distribució 3D octupolar i el dipol és compacte. Si augmentem d0, la velocitat del dipol i el màxim de |w| disminueixen, i les oscil·lacions internes o ‘heading’ trenquen ocasionalment l’estructura octupolar de w. La velocitat horitzontal ageostròfica s’explica per l’acceleració advectiva, concretament per l’acceleració centrípeta. Les OIGs es detecten en el flux total a partir de sèries temporals i distribucions horitzontals de w i de la seva derivada vertical. La generació espontània d'OIGs es mostra en diferents fluxos geofísics: un anticicló, un corrent de doll, un dipol, un tripol, i una col·isió entre dipols. Les OIGs són extretes, durant la interacció de dos anticiclons baroclins, amb el mètode ‘Optimal potential vorticity balance.’ Els paquets d’OIGs que es propaguen lliurement en el camp llunyà tenen fronts d’ones en forma d’espiral mentre que els quals es propaguen en l’interior del flux vortical poden ser atrapats i els fronts d’ona formar distribucions “frontals” o anulars. L’augment de la VP i de la isotropía del remolí incrementa l’emissió espontània d'OIGs. Es consideren tres indicadors possibles de la generació espontània d’OIGs: (i) la advecció de la VP, (ii) el residu de l’equació del balanç no lineal, i (iii) l’extensió 3D de l’analogia de la generació d'OIGs, en aigües succintes, de la teoria de radiació del so de Lighthill. L’anàlisi numèrica de les OIGs extretes suggereix la coexistència de dos mecanismes de generació. El primer es relaciona amb l’advecció de la VP, i el segon amb la interacció coherent d’OIGs preexistents que, ocasionalment, cooperen per a produir divergència horitzontal de major escala, l’ascens de les isopicnes, i amb això l’emissió d’un nou paquet d'OIGs de major amplitud.

Modelización de flujos tróficos y uso de indicadores ecológicos como aproximación al estudio de las pesquerías mediterráneas

Autor: M. Coll Montón
Director/es tesi: I. Palomera Laforga, S. Tudela Casanova
Any publicació: 2006
Lloc d'edició: Barcelona
Institució: Universitat Autònoma de Barcelona, CMIMA-CSIC
Resum: Veure
El impacto de la actividad pesquera sobre los ecosistemas marinos explotados es ampliamente reconocido. La pesca puede tener impactos de carácter directo e indirecto y modificar el funcionamiento y la estructura de estos ecosistemas. Por lo tanto, es necesario el estudio integrado de esta actividad extractiva en el seno del ecosistema. Desde la comunidad científica se han desarrollado varias aproximaciones metodológicas de carácter multiespecífico o ecosistémicas para estudiar los ecosistemas marinos y sus recursos. En este trabajo se presenta el estudio de las pesquerías mediterráneas mediante la modelización ecológica de flujos tróficos y el uso de indicadores de impacto pesquero. El objetivo final es el caracterizar la estructura y funcionamiento de los ecosistemas explotados mediterráneos para abordar la sostenibilidad de la actividad pesquera por medio de una aproximación ecológica integral del ecosistema. [...]

Molecular and cellular mechanisms during oocyte hydration in marine fish

Autor: M. Fabra
Director/es tesi: J. Cerdà
Any publicació: 2006
Institució: Universitat de Barcelona

Studies into the effects of environmental signals on eel reproduction and chemical communication

Autor: M. Huertas
Director/es tesi: J. Cerdà
Any publicació: 2006
Institució: Universitat de Barcelona

Evaluación de la gamba rosada Aristeus antennatus (Risso, 1816) en el mar Balear

Autor: A. Carbonell Quetglas
Director/es tesi: M. Demestre Alted
Any publicació: 2005
Institució: Universitat de les Illes Balears
Resum: Veure
La especie de crustáceo decápodo Aristeus antennatus, explotado en el talud superior de las Baleares se encuentra explotado desde hace más de 50 años por las flotas de arrastre que operan alrededor de las Islas. La biología de la especie aparece adaptada al medio en que vive, con una composición de las poblaciones similar en todas las zonas, dominada por las hembras y con un patrón de movilidad entre caladeros claramente relacionado con la reproducción y con los procesos de maduración y puesta en zonas concretas. [...]

Inestabilidades submarinas: Caracterización sedimentaria y factores de control

Autor: D. Casas Layola
Director/es tesi: G. Ercilla Zarraga, B. Alónso Martinez
Any publicació: 2005
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona
Resum: Veure
Las inestabilidades submarinas de sedimentos tienen un impacto significativo en la construcción y evolución de los márgenes continentales y en la transferencia de sedimentos hacia las zonas profundas de los océanos. También son un factor de gran importancia económica al poder afectar a estructuras submarinas construidas por el hombre. Todas las provincias fisiográficas del margen continental presentan fenómenos de inestabilidad sedimentaria desde la línea de costa hasta el glacis continental. Pero el número de inestabilidades presentes es significativamente más alto en el talud continental. De entre los diferentes tipos de movimientos de masa submarinos existentes, los deslizamientos, las coladas de derrubios y las corrientes de turbidez son quizás los más abundantes y los que transportan mayores volúmenes de sedimento hacia las zonas más profundas de los océanos. [...]

Sedimentary Dynamics in the Palamós Submarine Canyon

Autor: J. Martín Nascimento
Director/es tesi: A.Palanques Monteys, P. Puig Alenyà
Any publicació: 2005
Lloc d'edició: Barcelona
Institució: Universitat Politècnica de Catalunya
Resum: Veure
The present thesis focuses on the transfer and accumulation of particulate matter in the Palamós Canyon, located in the Northwestern Mediterranean. In the context of the CANYONS project, 7 moorings with a total of 7 sediment traps and 18 current meters (some of them equipped with turbidimeters) were deployed in the Palamós submarine canyon and adjacent slope from March to November 2001, during two consecutive deployments. [...]

The significance of sexuality and cyst formation in the life-cycles of four marine dinoflagellate species

Autor: R.I. Figueroa
Director/es tesi: I. Bravo Portela, Tutelada por E. Garcés Pieres
Any publicació: 2005
Resum: Veure
Phytoplankton is a term coined in 1897 to describe a diverse, polyphyletic group of mostly single-celled photosynthetic organisms that drift with the currents in marine and fresh waters (Falkowski and Raven, 1997). […]

Triploidía y ginogénesis en el rodaballo (Scophthalmus maximus). Inducción, verificación y efectos sobre el crecimiento y la reproducción

Autor: R. Cal
Director/es tesi: F. Piferrer Circuns
Any publicació: 2005
Lloc d'edició: Vigo
Institució: Universidade de Vigo
Resum: Veure
En la acuicultura, el control de la reproducción de las especies en cautividad permite su domesticación y la aplicación de la tecnología adecuada para su mejora genética. En los sistemas actuales de producción del rodaballo (Scophthalmus maximus L.), los métodos utilizados para el control de la reproducción son ya habituales e incluyen la manipulación del fotoperiodo, la criopreservación del esperma, la inducción hormonal a la maduración y la aplicación de técnicas de mejora genética tradicional, tales como la selección fenotípica asistida en programas de cruzamientos. Estos métodos se ejercen sobre individuos adultos y permiten decidir "cuando" y "con quien" ha de efectuarse la reproducción. [...]

A bioeconomic analysis of the coastal fishery of Pernambuco State, North-Eastern Brazil

Autor: S.M.G. de Mattos
Director/es tesi: R. Franquesa, F. Maynou
Any publicació: 2004
Institució: Universitat Politècnica de Catalunya
Resum: Veure
Modern bioeconomic concepts invoke the importance to define the property rights possible to be implemented within a management context. In conducting a fishery research, local expectancies must be achieved, as for fisheries researchers, managers, stakeholders, industries, the concerned public at large, and it need to be devolved down to the level of communities or fishermen. Following this concept, a bioeconomic analysis of the coastal fishery of Pernambuco State, North-eastern Brazil, was conducted, directed to the hand-line and gillnet coastal fisheries management, as part of a regional planning project, in virtue of the found social, economic and cultural peculiarities, the existing low Human Development Index (HDI) of this Region, and the importance of social insertion of the less favoured fishing communities. [...]

Distribution of Liocarcinus depurator along the western Mediterranean Coast

Autor: M.M. Rufino
Director/es tesi: P. Abelló Sala
Any publicació: 2004
Institució: University of Wales
Resum: Veure
The distribution of L. depurator has been analysed through classical statistics, linear models and geostatistics. Density was obtained from a ten-year time series of bottom, otter trawl surveys in eight areas along the Mediterranean coast of Spain. Two peaks of L. depura-tor occurrence were observed. The first (80% occurrence) between 51 and 150 m, and the other (66% occurrence) between 301 and 400 m. Below 500 m, crab occurrence was negligi-ble (<8%) and densities fell sharply. The pattern shown by crab densities closely shadows that of occurrence, although a second abundance peak was barely evident, and was located at 201-300 m. From 200-400 m, crab abundance appeared fairly evenly distributed but showing lower densities than in shallower waters. Analysis through linear modelling showed that L. depurator density decreased signifi-cantly with depth and year, but no effect of sample location was evident. The decrease of L. depurator density was most pronounced at shallower depths (depths < 150 m, declining at ~8±1 % per annum), than in deeper waters (depths > 150 m, declining at ~4±1 % per annum). Geostatistical analysis of L. depurator densities showed that the crabs distributions ex-hibited varying degrees of spatial structure with patch sizes varying between 19 and 75 km among the sampled years. When average densities were low, crabs were most abundant in Ebro River Delta area and Western Alborán Sea, areas showing permanent high-density popu-lations. The virtues and drawbacks of each approach are discussed. On a smaller scale, off the Ebro Delta L. depurator distribution (numbers and biomass) was related to sediment characteristics using geostatistics. Smaller crabs were found preferen-tially in shallower water, whereas larger crabs, in deeper ones. Given the presence of at least two distinctive aggregations (possible populations) of L. depurator on the Spanish coast, a series of morphometric studies were undertaken. A combi-nation of traditional dimension analysis and geometric morphometry (whole shape analysis) was used to compare crab morphology. Differences in carapace shape were identified between genders and geographic location that largely appeared to involve the abdomen width.

Estudi de la dinàmica de poblacions marines: Proliferacions Algals Nocives.

Autor: J. Solé i Ollé
Director/es tesi: M. Estrada, E. García-Ladona (ICM, CSIC)
Any publicació: 2004
Lloc d'edició: Barcelona
Institució: Universitat Politècnica de Catalunya
Resum: Veure
Interest on the study of algal blooms is increasing, especially because some of them (known as harmful algal blooms or HAB) may have deletereous effects for socio-economic activities or for human health. Here, we will refer in general to ”Exceptional algal blooms” or EAB, without assuming noxious effects for human interests, to deal with the rapid proliferation of a phytoplankton population, leading to cell densities above a certain reference level that can be operatively defined. EAB are controlled by both physical (such as advection and dispersion) and biological factors (growth rate, predation and other biological interactions). This thesis examines the potential influence of toxic effects of the alga that causes the bloom towards other organisms of the ecosystem (not necessarily implying effects on human health or interests). Assuming favourable physico-chemical conditions for the success of a bloom, mathematical modelling and numerical simulations have been used to study: (i) the effect of a toxin produced by a microalga towards microalgal competitors (allelopathy) and (ii) the effect of this toxin on potential predators, causing feeding avoidance of the toxin producer and increasing predation pressure on other non-toxic components of the microalgal community (feeding avoidance). The overall objective of this mathematical approach is to open new perspectives in the evaluation of the role of biological interactions on EAB (and HAB) development, within a general ecological context. Chapter 3 presents the adjustment of experimental data to a mathematical model of allelopathy and the estimation of values for the relevant parameters. A mathematical model involving feeding avoidance is examined in chapter 4. The simultaneous effect of both interactions is addressed in chapter 5. Assuming pre-bloom conditions and parameter values similar to those derived from the laboratory experiments, allelopathy does not appear to be a significant cause of HAB initiation, although it must be taken into account when the bloom is already well developed (population density > 100000 cells/l). Therefore, this interaction has been included in the multispecies model (chapter 5) that simulates algal bloom and post-bloom phases. On the other hand, the mathematical model indicates that feeding avoidance of a toxic alga may have an important influence on the development of an EAB of the toxin producer. A relationship involving the degree of feeding avoidance of the toxic alga and other parameters of the algal and predator populations can be used to determine a critical threshold value for the development of a bloom. Based on this relationship, an analogy has been made with critically self-organized systems (such as phase transitions), which can be characterized by internal and control parameters. Examination of the effects of allelopathy and feeding avoidance in a multispecies model indicated that allelopathy was not significant for the concentrations and parameter ranges considered. However, feeding avoidance caused by a predation repellent toxin had important consequences for the behaviour of the system. The effects of this interaction on the functional groups included in the model were both direct and indirect and were more important for microzooplankton than for mesozooplankton predators. Above a certain threshold value for feeding avoidance effects, the behaviour of the system showed notable changes

Influència de les comunitats bentòniques sobre el sediment al litoral del Delta de l'Ebre

Autor: S. Soriano
Director/es tesi: M. Demestre Alted, J. Guillén Aranda
Any publicació: 2004
Lloc d'edició: Barcelona
Institució: Universitat Politècnica de Catalunya
Resum: Veure
El delta de l'Ebre es troba a la Mediterrània occidental, situat a la costa est de la península Ibèrica. El riu Ebre és un dels sistemes fluvials més importants a la Mediterrània occidental, amb 928 Km de llargària, una conca de drenatge de 85835 km2 i ha desenvolupat un delta de 2170 km2, dels quals 325 estan emergits (Maldonado, 1986). Presenta una topografia plana que s'endinsa en el mar uns 25 km a partir d'Amposta, població assenyalada com a inici de la plana deltàica. Les poblacions més importants, a més d'Amposta, són el Deltebre i Sant Jaume d'Enveja, situades a la part central del delta, i l'Ampolla i Sant Carles de la Ràpita, que limiten al delta per la part nord i sud, respectivament. [...]

Paleoclimatic reconstruction from the northeast subtropical atlantic: atmospheric and oceanographic scenarios

Autor: G. Bozzano
Director/es tesi: B. Alonso Martínez
Any publicació: 2004
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona
Resum: Veure
An integrated and comprehensive picture of the climatic and oceanographic changes experienced by the northeast subtropical Atlantic (NW African margin) during the last 220 thousand years is here presented. The study region is characterized by features of local and global relevance. From one hand, it is part of the Atlantic Subtropical Gyre, one of the most effective climatic components of heat and salt transfer from low to high latitudes. From the other hand, local factors (e.g. coastal upwelling and filament proximity, monsoon, trades, coastline shape, bottom topography, etc.) interplay to create a certain degree of complexity in the area, concerning both the oceanographic and the atmospheric realms. [...]

Study of salinity retrieval errors for the SMOS mission

Autor: C. Gabarró i Prats
Director/es tesi: J. Font (ICM-CSIC), A. Camps (UPC)
Any publicació: 2004
Lloc d'edició: Barcelona
Institució: Universitat Politècnica de Catalunya
Resum: Veure
This PhD thesis has been done in the framework of the SMOS (Soil Moisture and Ocean Salinity) mission, from the European Space Agency. This satellite will be launched in February 2007 and will provide global sea surface salinity and soil moisture maps, variables that never have been measured before from space. The payload instrument (MIRAS) is an L-band interferometric radiometer. This will be the first time an instrument with this characteristics is put in orbit. However, there are still a lot of issues that need to be solved. This thesis is focused on some open questions of the salinity retrieval process from SMOS measurements. [...]

Actividad citocromo P450 aromatasa en la lubina (Dicentrarchus labrax L.)

Autor: A. González
Director/es tesi: F. Piferrer
Any publicació: 2003
Lloc d'edició: Barcelona
Institució: Universidad de Barcelona
Resum: Veure
A pesar de que la lubina ha sido objeto de numerosos trabajos sobre su cultivo, desarrollo y reproducción, aún no se conoce bien su mecanismo de determinación y diferenciación sexual. Por ello, y debido a la importancia de la aromatasa en este proceso, así como en la síntesis de neuroestrógenos, el objeto global de esta investigación fue el estudio de la actividad aromatasa en la lubina. [...]

Biología, autoecología y toxinología de las principales especies del género Dinophysis asociadas a episodios de Intoxicación Diarreogénica por Bivalvos (DSP)

Autor: B. Reguera Ramírez
Director/es tesi: Marta Estrada I Miyares, F. G. Figueiras
Any publicació: 2003
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona
Resum: Veure
Floraciones Algales Nocivas es una expresión de carácter más socio-económico que científico con la que se designa cualquier acontecimiento o episodio de proliferación de microorganismos planctónicos, o incluso de microalgas bentónicas, queconlleve un efecto percibido como dañino por el hombre. Las mareas rojas son discoloraciones del agua de mar causadas por elevadas concentraciones (> 10 6 cel · l-1) de microplancton. Muchas mareas rojas son totalmente inocuas si se producen en zonas con buen intercambio de aguas. Por el contrario, existen microalgas planctónicas productoras de toxinas o venenos tan potentes, que bastan unos pocos cientos o miles de células por litro para que conviertan en “no aptos para el consumo humano” a los bivalvos filtradores que se alimentan de ellas. A las proliferaciones de este último tipo de microalgas, que no causan discoloraciones aparentes, las denominaremos episodios de algas tóxicas . Una vez filtradas por los bivalvos y transmitidas a los consumidores, pueden dar lugar a episodios de intoxicación por bivalvos. Los episodios de intoxicación por bivalvo más conocidos y con mayor impacto en Europa son el PSP (Paralytic Shellfish Poisoning = Intoxicación Paralizante por Bivalvo), el DSP (Diarrhetic Shellfish Poisoning = Intoxicación Diarreica por Bivalvo) y el ASP (Amnesic Shellfish Poisoning = Intoxicación Amnésica por Bivalvo). En las Rías Gallegas, que constituyen el segundo productor (después de la R. P. China) y primer exportador mundial de mejillón (25 · 104 t anuales), la ocurrencia crónica de episodios DSP y ASPobliga a establecer prolongados cierres en la extracción de mejillones de batea yotros bivalvos, causando considerables pérdidas al sector maricultor. [...]

Condition Indices and their Relationship with Environmental Factors in Fish Larvae

Autor: I.A. Catalán Alemany
Director/es tesi: M.P. Olivar Buera
Any publicació: 2003
Institució: Universitat de Barcerlona
Resum: Veure
This thesis is organised in four main chapters. The first chapter is devoted to a general introduction and objectives. Number two is devoted to all the work developed in the laboratory. Chapter three embraces all the work that was done with field data. Each of these two central chapters collects a mixture of published and row material. In the sake of clarity, all the thesis has been written in the same format, regardless the state of publication of the information. If the information of a particular section has been published, it is indicated at the beginning of the section. Information which is considered important but which was not included in a particular published section, has been inserted after authors’ approval. A brief introduction and extensive discussion is given in each of the sections conforming chapters two and three. In chapter four, the main conclusions from each part are summarised. Provided that the thesis is organised in a similar way that a compendium of publications, and as a guide to the reader, the repetition of some material at the introduction was unavoidable.

Estadística de vòrtex coherents a la Mediterrània: Anàlisis de la superficie lliure del mar.

Autor: J. Isern Fontanet
Director/es tesi: J. Font, E. García-Ladona (ICM-CSIC)
Any publicació: 2003
Lloc d'edició: Barcelona
Institució: Universitat Politècnica de Catalunya
Resum: Veure
La mar Mediterrània es caracteritza per l'entrada d’aigües poc salades procedents de l'Atlàntic a través de l'estret de Gibraltar. El ux sovint es inestable i genera vòrtex coherents, amb longituds característiques compreses entre els 50 i 150 km i temps de vida de mesos fins i tot anys, que afecten fortament el transport a la conca. L'objectiu principal de la tesi es estudiar i caracteritzar les propietats dels vòrtex coherents a la Mediterrània. Des dels inicis dels anys 90 l’ús intensiu d'alt__metres a proporcionat dades sobre la superfície lliure de l'oceà, que, recentment, han estat assimilades a sistemes de predicció oceànica de la Mediterrània. Aquest fet proporciona un conjunt de dades de la superfície lliure forca gran. La presencia d'estructures coherents fa que les observacions de mesoescala de l'oceà s'assemblin a la turbulència bidimensional. Aquestes similituds suggereixen que els darrers avenços en turbulència bidimensional es podrien fer servir com a punt de partida per investigar els vòrtex Mediterranis. Un vòrtex coherent es defineix com la regió simplement connexa amb valors del paràmetre d'Okubo-Weiss W < 􀀀0:2_W, on _W _es la desviació estàndard espaial de W, i el mateix signe de la vorticitat. Quan un vòrtex es identificat les seves propietats tals com, mida, energia cinètica o amplitud es poden calcular. En aquest estudi, aquesta definició s'ha aplicat als mapes d'anomalies del nivell del mar (SLA) del període octubre 1992-setembre 1999 i a simulacions numèriques de la Mediterrània pel període setembre 1999 a abril 2003. Els resultats de l'altimetria mostren que la Mediterrània es caracteritza per una distribució de vòrtex aproximadament homogènia. De tota manera, algunes de les propietats dels vòrtex com l'energia o l'amplitud tenen distribucions irregulars amb valors més alts en regions on estaven documentada la presència de vòrtex de mesoescala. Aquest fet suggereix que una classificació basada en l'amplitud podria permetre separar aquests vòrtex de les altres estructures. L'anàlisi de la dependència de l'amplitud de la mida mitjana dels vòrtex mostra un comportament asimptòtic que tendeix cap als a radis d'uns 40 km. Aquests resultats suggereixen la classificació heur_stica de les estructures coherents en vòrtex intensos (caracteritzats per valors de l'amplitud menors de 􀀀2_w) que tenen la mida dels vòrtex de mesoescala, i vòrtex febles que es corresponen amb estructures sorolloses i estats poc energètics dels vòrtex de mesoescala. Aquesta separació d'estructures permet seguir amb facilitat de mapa a mapa els vòrtex i, per primera vegada, construir una imatge completa dels Camins preferencials que segueixen. Per altra banda també s'han analitzat les distribucions de probabilitat de la velocitat (PDF) derivades dels mapes de SLA. S'ha dividit la Mediterrània 7 regions depenent de la geometria i la distribució vòrtex intensos. Per cada regió s'han calculat les PDF de la velocitat geostròfica. Les formes de les distribucions observades es caracteritzen per tenir un nucli gaussià amb cues exponencials. De tota manera, la mida del nucli i les cues canvia d'una regió a una altra depenent de la distribució de vòrtex intensos. La descomposició del camp de velocitats en: un camp de fons, un camp induït pels vòrtex febles i un camp induït pels vòrtex intensos mostra que els dos primers es caracteritzen per tenir distribucions semblants a una gaussiana, mentre que el tercer té una distribució propera a una exponencial. L'aplicació a les simulacions numèriques mostra resultats equivalents amb la diferència que conté més estructures petites.

Feeding Strategies and Trophodynamic Requirements of Deep-Sea Demersal Fish in the Eastern Mediterranean

Autor: T. Madurell López
Director/es tesi: J.E. Cartes Rodríguez, B. Morales-Nin
Any publicació: 2003
Institució: Universitat de les Illes Balears

Trophic interactions between micro and mesozooplankton

Autor: E. Broglio
Director/es tesi: E. Saiz Sendrós
Any publicació: 2003
Institució: Universitat Politècnica de Catalunya

Caracterización ecológica de comunidades de microorganismos planctónicos marinos, basada en relaciones entre la distribución de tamaños, composición química y taxonomía

Autor: L. Arín Carrau
Director/es tesi: M. Estrada i Miyares
Any publicació: 2002
Institució: Universitat Autònoma de Barcelona
Resum: Veure
El conocimiento de la estructura de tamaños de las comunidades de microorganismos planctónicos y de su composición química es importante debido, entre otros aspectos, a la implicación que tienen ambos en el flujo de materia y energía entre los distintos eslabones de la cadena trófica. En un ambiente determinado, el desarrollo de un tipo de red trófica depende, fundamentalmente, de los factores físico-químicos del medio. Según el esquema generalmente aceptado, en aguas ricas en nutrientes y con cierta intensidad de mezcla turbulenta, el desarrollo de autótrofos grandes haría que predominase la vía trófica "clásica" (Steele 1974), mientas que en ambientes oligotróficos y estratificados, el desarrollo de autótrofos pequeños favorecería la vía trófica "microbiana" (Azam et al. 1983). La dominancia de una vía trófica u otra determinaría, a su vez, el destino final del carbono fijado fotosintéticamente. [...]

Evolución tectónica del margen continental oeste de México: Fosa Mesoamericana y Golfo de California (CORTES-P96)

Autor: R. Bartolomé
Director/es tesi: J.J. Dañobeitia
Any publicació: 2002
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Fish vision: adaptive mechanisms to different lifestyles

Autor: A. Bozzano
Director/es tesi: F. Sardà Amills
Any publicació: 2002
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

The Norway lobster (Nephrops norvegicus) catchability variations in the Wester Mediterranean and their relationship with behavioural and physiological rhythms

Autor: J. Aguzzi
Director/es tesi: F. Sardà Amills, P. Abelló
Any publicació: 2002
Institució: Universitat Politècnica de Catalunya

Diversidad del picoplancton eucariótico marino mediante métodos moleculares

Autor: B. Díez Moreno
Director/es tesi: C. Pedrós-Alió, R. Massana
Any publicació: 2001
Institució: Universitat de Barcelona

Downward particle fluxes and sediment accumulation rates related to the organic carbon and biogenic silica cycles in the Gerlache and Western Bransfield stratits, Antarctica

Autor: E. Isla
Director/es tesi: A. Palanques Monteys
Any publicació: 2001
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Environmental factors affecting the trophic ecology of benthic suspension feeders

Autor: S. Rossi
Director/es tesi: J.M. Gili Sardà
Any publicació: 2001
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona
Resum: Veure
Scales of variability in both planktonic and benthic marine communities are still poorly understood. In general, the factors that influence variability in a community are placed in one of two categories, environmental (physico-chemical factors affecting the water column) and biological (physiological, genetic, etc.). All water masses are affected by physical processes which in turn affect the structure of both pelagic and benthic communities. In the Mediterranean Sea physical processes follow clear seasonal patterns that result in repeated fluctuations in planktonic production in the water column (Estrada et al. 1985, Estrada 1996). These fluctuations are reflected in the feeding, reproduction, growth, respiration, etc.of benthic communities (Boero 1984, Ballesteros 1989, Sardà et al. 1999, Coma et al. 2000). [...]

Estrutura, Variabilidade e Dinâmica do Fitoplâncton na Costa de Portugal Continental

Autor: M.T. Moita
Director/es tesi: Marta Estrada I Miyares, Fernando M. Catarino
Any publicació: 2001
Lloc d'edició: Lisboa
Institució: Universidad de Lisboa
Resum: Veure
The present dissertation deals with the study of spatial and temporal distribution of phytoplankton off the coast of Portugal. In this area, coastal upwelling is the most significant hydrodynamic process and typically occurs between April and October. This work focus four main subjects: i) Spatio-seasonal patterns of distribution of the phytoplankton biomass and assemblages; ii) Phytoplankton as an indicator of oceanographic processes in the sediment record; iii) Identification of trends and different scales of variability of toxic phytoplankton; iv) Inventory of marine phytoplankton species described for the Portuguese coast. [...]

Estudio paleoceanográfico de los testigos TG-7 (dorsal de Nazca-Pacífico) y MD95-2043 (Mar de Alborán-Mediterráneo)

Autor: A. Plaza García
Director/es tesi: A. Palanques Monteys
Any publicació: 2001
Lloc d'edició: Barcelona
Institució: Universitat Politècnica de Catalunya

Planktonic Coccolithophores of the NW Mediterranean

Autor: M.Ll. Cros i Miguel
Director/es tesi: R. Margalef i López
Any publicació: 2001
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona
Resum: Veure
Este trabajo estudia las algas haptófitas que de una manera continuada, o en algún momento de su ciclo de vida, producen y llevan cocolitos. Los cocolitos son delicadas y muy bellas plaquitas de carbonato cálcico, que no se sabe bien para qué les sirven, pero que tienen un papel muy importante en la translocación del carbonato cálcico y otros elementos, desde la columna de agua hacia los sedimentos. [...]

Proliferacions algals nocives a la costa catalana

Autor: M. Vila-Reig
Director/es tesi: M. Delgado, J. Camp
Any publicació: 2001
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Análisis espacial objetivo de datos oceanográficos: aplicaciones en el Mar de Alborán.

Autor: S. Ruíz Valero
Director/es tesi: J. Font (ICM, CSIC), D. Gomis (UIB)
Any publicació: 2000
Lloc d'edició: Barcelona
Institució: Programa: Ciencias del Mar, Universitat Politècnica de Barcelona
Resum: Veure
El perfilador de corriente por efecto Doppler acoplado a un barco oceanográfico es un instrumento cada vez más utilizado para el estudio de las corrientes en el océano. Sin embargo, también es bien conocido la dificultad que implica el procesado de la señal acústica y los errores asociados que pueden llegar a tener las medidas de la velocidad en función de la metodología del procesado y de la precisión de los instrumentos auxiliares utilizados por el perfilador. En este trabajo se presenta una nueva metodología que permite mejorar notablemente la precisión de las medidas de velocidad gracias al uso de un nuevo sistema de posicionamiento tridimensional (3DF Ashtech) utilizado de forma auxiliar por el perfilador. La reducción del error asociado a las velocidades medidas se ha evaluado en un 25% comparado con el error inducido con otras metodologías anteriores. El esfuerzo en mejorar la precisión de las medidas de velocidad tiene un objetivo principal: Llevar a cabo un análisis multivariante en el que se combinan los datos hidrográficos registrados con un SeaSoar (CTD ondulante) y de velocidad obtenidos con el perfilador de corriente. En primer lugar el análisis multivariante ha mostrado ser muy superior al univariante ya que reduce en un 50% los errores estadísticos del análisis. La limitación principal de esta técnica es que es bidimensional y por tanto no aprovecha la coherencia vertical de los perfiles registrados. Por otro lado, en términos de diagnóstico de variables, tanto básicas (temperatura, salinidad, densidad y altura dinámica) como derivadas (vorticidad relativa y velocidad vertical), los resultados multivariantes son más consistentes que los univariantes. A partir del análisis multivariante se han diagnosticado velocidades verticales del orden de 45 m/día que pueden contribuir a la fertilización (entrada de nutrientes) de la capa superficial, aunque también hay que tener en cuenta que en la zona de estudio (mar de Alborán) se han medido velocidades horizontales muy elevadas (hasta 1.4 m/s en superficie) que inducen una importante advección horizontal. Por último, para aprovechar la coherencia vertical de los perfiles se ha implementado un esquema de análisis basado en funciones empíricas ortogonales (EOFs), donde a diferencia del método clásico, los modos dependen únicamente de la profundidad y las amplitudes de la dimensión horizontal. La principal novedad del método es la posibilidad de incluir en el mismo análisis los datos hidrográficos y de velocidad. El método de EOFs-multivariante ha resultado ser muy eficaz para el caso particular de estudio (remolino anticiclónico del mar de Alborán occidental), ya que el primer modo permite explicar mas del 99% de la varianza del campo de altura dinámica. Los resultados de las diferentes variables estimadas (vorticidad relativa, estabilidad, etc) a partir del análisis de EOFs permiten caracterizar la zona como un una región extremadamente energética, donde existe un importante gradiente vertical de la velocidad en los niveles superiores, pero a la vez también existe una gran estabilidad de la columna de agua que impide la mezcla turbulenta y por tanto la fertilización de la capa superficial del océano por dicho mecanismo de mezcla. Las velocidades verticales antes referidas, se consideran por tanto como el mecanismo principal responsable del transporte de nutrientes desde niveles inferiores (150-175 m) a los más superficiales del océano (0-50 m)

Analysis of Mesoscale structures through digital images techniques

Autor: V. Parisi Varadad
Director/es tesi: J. Cabestany Moncusi (UPC), E. García Ladona (ICM)
Any publicació: 2000
Lloc d'edició: Barcelona
Institució: Universitat Politècnica de Catalunya

Aspectos Biológicos y Ecológicos del Salmonete de Fango Mullus barbatus L., 1758 y del Salmonete de Roca Mullus surmuletus L., 1758, del Mediterráneo Noroccidental

Autor: H. Aguirre Villaseñor
Director/es tesi: M.P. Sánchez Zalacain, A. Lombarte Carrera
Any publicació: 2000
Institució: Universitat Politècnica de Catalunya

Efectes de l’ambient sobre la producció pesquera (Mediterrània nord-occidental i Atlàntic nord)

Autor: J. Lloret
Director/es tesi: J. Lleonart, F. Pereira
Any publicació: 2000
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Nutrientes inorgánicos disueltos en aguas litorales próximas del Mar Catalán

Autor: A. Olivos Ortiz
Director/es tesi: J. Camp, M. Masó
Any publicació: 2000
Lloc d'edició: Barcelona
Institució: Universitat de Barcerlona

Control, por parte de los protozoos, de las comunidades bacterianas en diferentes ecosistemas marinos

Autor: E. Vázquez Domínguez
Director/es tesi: D. Vaqué, J. Flos
Any publicació: 1999
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Estudio lagrangeano de la circulación superficial en la cuenca argelina (Mar Mediterráneo occidental)

Autor: J. J. Salas Peréz
Director/es tesi: J. Font (ICM-CSIC)
Any publicació: 1999
Lloc d'edició: Barcelona
Institució: Programa: Ciencias del Mar, Universitat Politècnica de Catalunya

Geología del margen y cuenca del Mar de Alborán durante el Plio-Cuaternario: Sedimentación y tectónica

Autor: F. Peréz Belzuz
Director/es tesi: B. Alónso Martínez
Any publicació: 1999
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Producción primaria particulada y disuelta en sistemas planctónicos marinos: variabilidad de mesoescala y acoplamiento con la producción bacteriana heterotrófica

Autor: X.A. Gutiérrez Morán
Director/es tesi: Marta Estrada I Miyares
Any publicació: 1999
Institució: Universidad de Oviedo

Aspectos de la ecología, las pesquerías y la biogeografía de los peces costeros de Michoacán y Colima, México.

Autor: J. Madrid
Any publicació: 1998
Lloc d'edició: Barcelona
Institució: Univ. Barcelona

Autosimilaridad Estadística en Imágenes Naturales

Autor: A. Turiel
Director/es tesi: N. Parga Carballeda
Any publicació: 1998
Lloc d'edició: Madrid
Institució: Universidad Autónoma de Madrid

Dinàmica sedimentària i contaminants inorgànics associats en el marge continental de Barcelona

Autor: P. Puig Alenyà
Director/es tesi: A. Palanques Monteys
Any publicació: 1998
Lloc d'edició: Barcelona
Institució: Departament d'Enginyeria Hidràulica. Universitat Politècnica de Catalunya

Estacionalidad reproductiva y producción ovárica de la anchoa europea, engraulis encrasicolus (clupeiformes, engraulidae) en el mar catalán

Autor: R.I. Ochoa Báez
Director/es tesi: I. Palomera Laforga, S. Zanuy Doste
Any publicació: 1998
Institució: Universidad Politécnica de Cataluña

Feeding activity and diet of benthic suspension feeders related to metabolic requirements and seston composition

Autor: M. Ribes
Director/es tesi: J.M. Gili Sardà, M. Zabala Limousin
Any publicació: 1998
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona Barcelona

Influència dels processos i de les estructures hidrogràfics de mesoescala en l’heterogeneïtat espacial i l’ecologia tròfica dels quetògnats

Autor: A. Duró i Sans
Director/es tesi: J.M. Gili
Any publicació: 1998
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Models de distorsió i efectes de fonts no uniformes en els mètodes magnetotel·lúric i de font controlada

Autor: X.G. García Martínez
Director/es tesi: J. Pous
Any publicació: 1998
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Proliferacions de dinoflagel.lades a la Costa Catalana: estudi del creixement in situ i adaptacions per al creixement

Autor: E. Garcés
Director/es tesi: J. Camp, M. Delgado
Any publicació: 1998
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona
Resum: Veure
La caracterització general d'una proliferació d'algues és difícil. Per exemple l'escala i el patró de les proliferacions són molt variables. Algunes són localitzades, ara com en ports, badies i estuaris; mentre que d'altres s'extenen al llarg de molts quilòmetres. Algunes proliferacions són anualment recurrents, mentre que d'altres proliferen d'una manera aparentment arbitrària. La durada és molt variable, algunes duren pocs dies, d'altres duren mesos. Quant a les densitats a què atenyen les proliferacions també són variables, cosa que en condiciona els efectes, l'interés i la mateixa qualificació. D'altra banda, hi ha espècies no tòxiques que poden ser nocives quan s'acumulen en nombre suficient (milions per litre), produeixen discoloracions en l'aigua, provoquen ombra a la vegetació submergida, trenquen la dinàmica de la cadena alimentària i poden produir depleció d'oxigen. A l'altre extrem, hi ha les espècies tòxiques que poden ser una part molt petita de la fracció del fitoplàncton total i ser encara nocives. Per exemple, les concentracions d'organismes associats a la toxicitat de DSP (enverinament diarreic per consum de mol·luscs bivalves) poden ser de cent cèl·lules per litre. [...]

Abundància i dinàmica dels virus en ecosistemes planctònics

Autor: N. Guixa
Any publicació: 1997
Lloc d'edició: Barcelona
Institució: Univ. Barcelona

Comportement migratoire et trophique des mysidacés benthopélagiques Anchialina agilis et Haplostylus lobatus sur la marge continentale en Méditerranée Nord-Occidentale. Incidence sur les transferts de matière.

Autor: E. Ribera Maycas
Director/es tesi: M. Alcaraz
Any publicació: 1997
Institució: Universitaté d’Aix Marseille

Dinámica de poblaciones de la gamba Aristeus antennatus (Crustacea, Decapoda) en las zonas de Murcia, Almería e Ibiza. Análisis global en el Mediterráneo español

Autor: P. Martínez Baños
Director/es tesi: M. Demestre Alted
Any publicació: 1997
Institució: Universidad de Murcia

Ecología de las bacterias heterotróficas en ecosistemas planctónicos

Autor: J.I. Calderón Paz
Director/es tesi: C. Pedrós-Alió
Any publicació: 1997
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

La reproducción de la sardina monterrey Sardinops caeruleus (Girard, 1854) en el noroeste de México y su relación con el ambiente

Autor: J.R. Torres
Director/es tesi: I. Palomera
Any publicació: 1997
Lloc d'edició: Barcelona
Institució: Universitat Politècnica de Catalunya

Producció zooplàntonica marina: efectes de les escales de variabilitat de factors abiòtics i biòtics

Autor: A. Calbet
Any publicació: 1997
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Revisión de la familia bovichtidae (Perciformes, notothenioidei) y aspectos biogeográficos

Autor: R. Bravo
Director/es tesi: D. Lloris, G. Pequeño
Any publicació: 1997
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Revisió taxonòmica mundial de la família Triglidae (Pisces, Scorpaeniformes)

Autor: Ll. Del Cerro
Director/es tesi: D. Lloris i Samo
Any publicació: 1997
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona
Resum: Veure
La conclusió positiva d’una tesi doctoral és la culminació de més o menys anys de treball on hom experimenta una munió de sensacions, algunes plaents i d’altres desagradables. La redacció de la memòria sol ésser, com a mínim, feixuga per l’esforç que representa plasmar en paper allò que hom té en el cap i que no sempre esdevé una tasca fàcil. Com a treball científic que és, una memòria d’aquest tipus té, entre d’altres, un avantatge important davant de les publicacions seriades i és que en capítols com la INTRODUCCIÓ se li permeten a l’autor certes llibertats d’expressió. Em permetran, doncs, que en faci ús per exposar tot seguit alguns punts del meu pensament vital que d’una o altra manera tenen relació amb la Història Natural, demanant perdó d’antuvi a qui aquest capítol pugui semblar-li un pèl extens. Nogensmenys, la lectura d’aquestes pàgines serà d’innegable ajut per comprendre la filosofia del treball que hi ha darrera. [...]

Structure and dynamics of north-western Mediterranean rocky benthic communities along a depth gradient: a geographical information system (GIS) approach

Autor: J. Garrabou
Director/es tesi: M. Zabala, E. Ballesteros
Any publicació: 1997
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Variabilité spatiale et temporelle de la circulation superficielle dans la region du courant Algerien.

Autor: C. Bouzinac
Director/es tesi: J. Font (ICM, CSIC)
Any publicació: 1997
Lloc d'edició: París VI, Francia
Institució: Universite Pierre et Marie Curie

Variación intraespecífica e interespecífica de la morfología y de las pautas del crecimiento del otolito Sagitta en el género Merluccius (Gadiformes: Teleostei)

Autor: G.J. Torres Gadea
Director/es tesi: B. Morales-Nin, A. Lombarte
Any publicació: 1997
Institució: Universitat Politècnica de Catalunya

Aplicaciones del radar de apertura sintética (SAR) del satélite ERS-1 al estudio de la dinámica superficial de mesoescala en el Mediterráneo occidental

Autor: B. Shirasago Germán
Director/es tesi: J. Font (ICM-CSIC)
Any publicació: 1996
Lloc d'edició: Barcelona
Institució: Programa: Ciencias del Mar, Universitat de Barcelona

Reproduction, développement, incubation et dynamique de population de l’ophiure Amphipholis squamata (Echinodermata) en Baie de Seine

Autor: V. Alvà
Director/es tesi: M. Jangoux
Any publicació: 1996
Lloc d'edició: Bruxelles
Institució: Université Libre de Bruxelles

Rifting and seafloor spreading in backarcs. the Bransfield and North Fiji Basins (NW Antarctica and SW Pacific)

Autor: E. Gràcia
Director/es tesi: J.M. Auzende, M. Canals
Any publicació: 1996
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Aplicación de un perfilador acústico por efecto Doppler a la medida de corrientes marinas en el Mediterráneo occidental.

Autor: E. García Górriz
Director/es tesi: J. Candela (Woods Hole Oceanographic Inst.), J. Font (ICM-CSIC).
Any publicació: 1995
Lloc d'edició: Barcelona,
Institució: Universitat Politècnica de Catalunya (UPC)
Resum: Veure
Esta Tesis consta de 4 capítulos. Las áreas de estudio corresponden al Mar catalán y al Mar de Alboran. En el primero se describe el funcionamiento del perfilador acústico por efecto Doppler (ADCP). Las observaciones directas que proporciona de la corriente marina son precisas, frecuentes, de buena resolución vertical en un rango de profundidades que abarca los primeros cientos de metros desde la superficie. El objetivo último del trabajo realizado ha sido convertir el uso de este instrumento, hasta ahora poco utilizado en el Mediterráneo y de forma poco cuantitativa por causas que en la tesis se describen, en una herramienta poderosa en el estudio de la dinámica de mesoescala. En el segundo capítulo se analiza detalladamente los factores que condicionan la calidad de las medidas de la corriente por ADCP, evaluando la imprecisión asociada a las mismas (directamente relacionada con la de la giroscópia del buque y con la del sistema de navegación GPS empleado) y estableciendo un protocolo para su revisión sistemática, como paso previo indispensable para cualquier análisis cuantitativo .

Estudi comparatiu de les estratègies biològiques dels crustacis decàpodes del talús de la Mar Catalana

Autor: J.B. Company i Claret
Director/es tesi: F. Sardà Amills
Any publicació: 1995
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Factors affecting the feeding of planktonic protozoa with special emphasis on small-scale turbulence

Autor: F. Peters
Director/es tesi: L.R. Pomeroy
Any publicació: 1995
Institució: University of Georgia

Modelització espacial de crustacis decàpodes: aspectes ecològics i pesquers

Autor: F. Maynou
Director/es tesi: G.Y. Conan, F. Sardà
Any publicació: 1995
Lloc d'edició: Barcelona
Institució: Universitat Politècnica de Catalunya, Universitat de Barcelona

Evaluación del balance energético de dos especies de cnidarios bentónicos marinos

Autor: R. Coma
Director/es tesi: M. Zabala, J.M. Gili
Any publicació: 1994
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Ingestion et production secondaire des copépodes planctoniques de l’estuaire de la Gironde en relation avec la distribution du phytoplancton et la matière en suspensión

Autor: M.X. Irigoien
Director/es tesi: M. Alcaraz
Any publicació: 1994
Lloc d'edició: Bordeaux
Institució: Université Bordeaux I

La conca nord-oriental de la mar d’Alboran : Evolució morfo-sedimentària i tectònica durant el Pliocè i el Quaternari

Autor: F. Estrada
Director/es tesi: B. Alonso, E. Ramos
Any publicació: 1994
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Estudio de las poblaciones de Chamelea gallina (Linnaeus, 1758) y Donax trunculus Linnaeus, 1758 (Mollusca: Bivalvia) en el Golfo de Valencia (Mediterráneo occidental)

Autor: M. Ramón Herrero
Director/es tesi: J. Lleonart
Any publicació: 1993
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona
Resum: Veure
Los estudios relacionados con las comunidades de sustrato blando asentadas en aguas poco profundas son más bien escasos en el litoral mediterráneo español. Sin embargo, dentro de dichas comunidades se desarrollan especies cuya producción es lo suficientemente elevada como para permitir su explotación. Este es el caso de Chamelea gallina y Donax trunculus, dos especies de bivalvos infralitorales que representan casi la totalidad de bivalvos en el litoral valenciano y la mayor parte de las capturas de este grupo en el litoral catalán. [...]

La xarxa tròfica microbiana en un sistema planctònic estratificat

Autor: R. Massana
Director/es tesi: C. Pedrós-Alió
Any publicació: 1993
Institució: Universitat Autònoma de Barcelona

Ontogenese anatomo-fonctionnelle des centres neuroendocrines pedonculaires chez le Homard Europeen, Homarus gammarus ( L., 1758)

Autor: G. Rotllant
Director/es tesi: M. Charmantier-Duares
Any publicació: 1993
Lloc d'edició: Montpellier
Institució: Université de Montpellier II

Biología pesquera de la anchoa, Engraulis encrasicolus, del litoral catalán

Autor: J.P. Pertierra
Director/es tesi: J. Lleonart
Any publicació: 1992
Institució: Universitat Politècnica de Catalunya

Cephalopods of Namibia: Three life strategies in the Benguela system

Autor: R. Villanueva López
Director/es tesi: P. Sánchez Zalacaín, A. Guerra
Any publicació: 1992
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Diapycnal mixing and mass transfer in Western Boundary currents

Autor: J.Ll. Pelegrí
Director/es tesi: G.T. Csanady
Any publicació: 1992
Institució: Old Dominion University

Dinàmica de poblacions i pesqueria del lluç (Merluccius merluccius) al golf de Lleó i la mar Catalana

Autor: L Recasens Albaladejo
Director/es tesi: J. Lleonart Aliberas
Any publicació: 1992
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Dinámica y balance sedimentario en los ambientes fluvial y litoral del Delta del Ebro

Autor: J. Guillén Aranda
Director/es tesi: A. Maldonado López
Any publicació: 1992
Lloc d'edició: Barcelona
Institució: Universitat Politècnica de Catalunya

Sedimentación en Márgenes Continentales y Cuencas del Mediterráneo Occidental durante el Cuaternario (Península Iberica)

Autor: G. Ercilla Zárraga
Director/es tesi: B. Alonso Martínez, A. Maldonado López
Any publicació: 1992
Lloc d'edició: Barcelona
Institució: Universitat Politècnica de Catalunya

Análisis de las comunidades y estructura trófica de los crustáceos decápodos batiales del mar catalán

Autor: J.E. Cartes
Director/es tesi: F. Sardà Amills
Any publicació: 1991
Institució: Universitat Politècnica de Catalunya

Ecología y sistemática de los cnidarios planctónicos de la corriente de Benguela (Atlántico sudoriental)

Autor: F. Pagès
Director/es tesi: J.M. Gili
Any publicació: 1991
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Effects of environmental factors on physiological parameters of marine phytoplankton populations

Autor: E. Berdalet Andrés
Director/es tesi: M. Estrada i Miyares
Any publicació: 1991
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Estudio numérico de la dinámica de la capa superficial oceánica: Aplicación al Mar Catalán

Autor: E. García-Ladona
Director/es tesi: J. Font (ICM-CSIC), J. Tintoré (Univ. Illes Balears)
Any publicació: 1991
Lloc d'edició: Barcelona
Institució: Facultat de Ciències, Universitat Autónoma de Barcelona

Estudios sobre la dinámica de nutrientes en sistemas estuáricos: Flujos sedimento-agua de nutrientes y oxigeno

Autor: M. Vidal Barcelona
Any publicació: 1991
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Importància de l'energia auxiliar en la dinàmica dels sistemes pelàgics: turbulència i zooplancton

Autor: E. Saiz Sendrós
Director/es tesi: M. Alcaraz
Any publicació: 1991
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Life history strategies of euphausiids in the northern Benguela (Namibia) upwelling system

Autor: M. Barangé Corachan
Director/es tesi: M. Alcaraz
Any publicació: 1991
Institució: Universitat de Barcelona

Variabilidad de la composición pigmentaria de fitoplancton marino en relación con parámetros ambientales

Autor: M. Latasa Arcalís
Director/es tesi: M. Estrada I Miyares
Any publicació: 1991
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Biología Pesquera de la gamba Aristeus antennatus (Risso, 1816) en el Mar Catalán

Autor: M. Demestre
Director/es tesi: F. Sardà Amills
Any publicació: 1990
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Contribución al estudio de la circulación marina mediante el método de los elementos finitos: aplicación al área del Delta del Ebro y el Golfo de Sant Jordi

Autor: Marc A. García López
Director/es tesi: A. Sánchez Arcilla, A. Ballester
Any publicació: 1990
Lloc d'edició: Barcelona
Institució: Universitat Politècnica de Catalunya (UPC)

Efectos ambientales y filogenéticos en la morfología del laberinto auditivo de los peces teleósteos

Autor: A. Lombarte Carrera
Director/es tesi: B. Morales Nin
Any publicació: 1990
Institució: Universitat Autònoma de Barcelona

Los Quetognatos de las costas de la Península Ibérica

Autor: P. Andreu
Director/es tesi: F. Vives
Any publicació: 1990
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Dinámica de la pesquería de arrastre de Cataluña

Autor: P. Martín
Director/es tesi: J. Lleonart
Any publicació: 1989
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Primeras fases del desarrollo de la anchoa (Engraulis encrasicolus) en la costa catalana

Autor: I. Palomera
Director/es tesi: C. Bas, J. Lleonart
Any publicació: 1989
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Procesos de edificación y características geotécnicas del talud continental del Ebro

Autor: J. Baraza
Director/es tesi: A. Maldonado
Any publicació: 1989
Institució: Universitat Politècnica de Catalunya

Relacions entre el fitoplàncton i el baterioplàncton en el mar català: interpretació de les dades de camp mitjantçant l’aproximació experimental

Autor: D. Vaqué i Vidal
Director/es tesi: F. Vallespinós
Any publicació: 1989
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Variabilidad espacio-temporal de las características oceanográficas de la zona costera y su relación con el sistema planctónico

Autor: M. Masó Agustina
Director/es tesi: J. Font (ICM-CSIC)
Any publicació: 1989
Lloc d'edició: Barcelona
Institució: Facultat de Biologia, Universitat de Barcelona
Resum: Veure
Estudio de la variabilidad física de mesoescala en la zona costera, con gran cantidad de datos hidrográficos. Los de la costa catalana cubren la totalidad de la plataforma contienental y además se extienden sobre una gran parte del año. En el área norte de la corriente de Benguela son especialmente valiosos, dada la escasez de estudios sobre esa zona que ofrezcan informaciones de este tipo y en especial de las regiones mas alejadas de la costa. Es el resultado de diversas campañas oceanográficas en las costas catalanas y namibias realizadas con el fin de investigar las dinámica de las masas de aguas costeras y como influencian en el plancton.

Variaciones de capturabilidad de Merluccius spp. en aguas de Namibia

Autor: A.C. Gordoa
Director/es tesi: J. Lleonart
Any publicació: 1989
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Ecologia microbiana a l’estanyol d’en Cisó

Autor: J.M. Gasol
Director/es tesi: C. Pedrós-Alió
Any publicació: 1988
Institució: Universitat Autònoma de Barcelona

Sistemática y distribución espacio-temporal del ictioplancton en la costa catalana

Autor: A. Sabatés
Director/es tesi: J. Flos
Any publicació: 1988
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Dinámica sedimentaria, mineralogía y microcontaminantes inorgánicos de las suspensiones y de los sedimentos superficiales en el margen continental del Ebro

Autor: A. Palanques Monteys
Director/es tesi: A. Maldonado López, F. Plana Llevat
Any publicació: 1987
Lloc d'edició: Barcelona
Institució: Universitat Politècnica de Catalunya

Els crustacis decàpodes del delta de l’Ebre

Autor: X. Fusté Miquela
Director/es tesi: M. Alcaraz
Any publicació: 1987
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Estudio ecológico del zooplancton en un sistema costero-estuarico (el Abra de Bilbao): estructura de la comunidad, dinámica temporal y organización espacial de las poblaciones

Autor: L.F. Villate Guinea
Director/es tesi: M. Alcaraz, E. Orive
Any publicació: 1987
Institució: Universidad del Pais Vasco

Estudi sedimentològic dels dipòsits eòlics del Baix Empordà

Autor: Ll. Cros Miguel
Director/es tesi: J. Serra i Raventós
Any publicació: 1987
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona
Resum: Veure
Aquest treball és un estudi de les dunes de Begur "conegudes ab lo nom de sorres de Begur, que lo vent porta de la platja de Pals y mou d'una banda a l'altre" (BOTET i SISO, CARRERAS CANDI s.d.), però que un cop encetat i per enmarcar-les dins el seu context ens hem sentit obligats a extendre'l a totes les formacions eòliques del Baix Empordà. [...]

Anàlisi de les poblacions de crustacis decàpodes demersals al litoral català: aspectes biològics del Braquiur Liocarcinus Depurator

Autor: P. Abelló
Director/es tesi: C. Bas i Peired
Any publicació: 1986
Institució: Institut de Ciencies del Mar, Universitat de Barcelona
Resum: Veure
L\'estudi de les comunitats animals presents a les zones de plataforma i talús continentals, i sobretot a les àrees sotmeses a un fort esforç de pesca, és fonomental per tal d\'intentar entendre els processos que regulen la dinàmica de la comunitat. La primera tasca a fer en l\'estudi d\'una comunitat consisteix en obtenir una imatge el més fidel possible de la composició específica, nombre i distribuió dels seus components en un moment donat, així com l\'anàlisi de l\'estructuració d\'aquestes poblacions. El present treball ha pogut ser dut a terme gràcies a l\'anàlisi de pesques d\'arrossegament fetes al llarg de tota la costa catalana. Les dades obtingudes com a resultat dels mostreigs han tingut per objecte la caracterització de les \"comunitats\" integrades per crustacis decàpodes, és a dir, de la taxocenosi corresponent als crustacis decàpodes. Totes les espècies interactuen entre sí i amb el seu ambient, i aquesta interacció pot explicar les fluctuacions i canvis observats en l\'estructura i dinàmica de les poblacions. Els crustacis decàpodes de la costa catalana han estat objecte pràcticament només de treballs de caire sistemàtic, entre els què cal destacar l\'obra fonomental de Zariquiey (1968). Molt poques espècies han estat peró estudiades en detall, mancant molta informació sobre la distribució en l\'espai i en el temps de les agrupacions multiespecífiques de la fauna bentònica. Aquesta manca d\'informació no és sorprenent donat l\'esforç necessari per a obtenir dades fiables sobre la distribució batimètrica i canvis en les característiques biològiques i poblacionals de les diferents espècies d\'una zona tal com la plataforma i talús continentals al llarg de tota la costa.

Ecología de Diatomeas Costeras: Relación Plancton-Bentos

Autor: M. Delgado Morán
Director/es tesi: M. Estrada i Miyares
Any publicació: 1986
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

El sistema del abanico profundo del Ebro

Autor: B. Alonso Martínez
Director/es tesi: A. Maldonado López
Any publicació: 1986
Lloc d'edició: Barcelona
Institució: Facultad de Geología. Universitat de Barcelona

Estudio sistemático y faunístico de los cnidarios de la costa catalana

Autor: J.M. Gili
Director/es tesi: J.D. Ros
Any publicació: 1986
Institució: Universitat Autònoma de Barcelona

Estudio y descripción de las puestas, desarrollo larvario y protoconchas de algunos gasterópodos prosobranquios de la costa catalana

Autor: M. Ramón
Director/es tesi: E. Gadea
Any publicació: 1986
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Experimentos multifactoriales con plancton marino en microcosmos

Autor: C. Marrasé Peña
Director/es tesi: R. Margalef
Any publicació: 1986
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

La circulació general a la mar Catalana

Autor: J. Font Ferré
Director/es tesi: M. Puigcerver Zanon
Any publicació: 1986
Lloc d'edició: Barcelona
Institució: Fac. Física, Universitat de Barcelona

Ictioplancton del Atlántico sudoriental

Autor: M.P. Olivar
Director/es tesi: C. Bas (IIP-CSIC)
Any publicació: 1985
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona, Instituto de Investigaciones Pesqueras de Barcelona

The Role of Inertial Oscillations in the Dynamics of Coastal Upwelling

Autor: J.Ll. Pelegrí
Director/es tesi: J.G. Richman
Any publicació: 1985
Institució: Oregon State University

Geoquímica y sedimentología de los sedimentos profundos del Mediterráneo suroccidental: Significado pale-oceanográfico

Autor: M. Farran
Director/es tesi: A. Maldonado
Any publicació: 1984
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Ictiofauna demersal de la costa sudoccidental de África (S.W.A.- Namibia)

Autor: D. Lloris
Director/es tesi: J. Nadal Puigdefabregas
Any publicació: 1984
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

La fosa de Valencia: un sistema deposicional profundo alimentado por aportes longitudinales y transversales

Autor: A. Palanques
Director/es tesi: A. Maldonado
Any publicació: 1984
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Microarquitectura, características y composición de los otolitos de los peces teleósteos

Autor: B. Morales-Nin
Director/es tesi: C. Bas (IIP-CSIC)
Any publicació: 1984
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Características bioecológicas de Illex coindetii (Verany, 1837) en el Mar Catalán

Autor: P. Sanchez Zalacain
Director/es tesi: C. Bas (IIP-CSIC)
Any publicació: 1982
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Distribución y abundancia de larvas de mictófidos y gonostomátidos en el noroeste de África

Autor: A. Sabatés
Director/es tesi: C. Bas (IIP-CSIC)
Any publicació: 1982
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Ictioplancton de la costas gallega : Campaña oceanográfica Galicia IV

Autor: P. Martín
Director/es tesi: J. Nadal Puigdefabregas
Any publicació: 1982
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Microcontaminantes inorgánicos y procesos sedimentarios en la plataforma continental de Tarragona-Castellón (mar Mediterráneo occidental)

Autor: B. Alonso
Director/es tesi: A. Maldonado
Any publicació: 1981
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Contribución al conocimiento de la biología de Nephrops norvegicus (L.) : Estudio del ciclo de intermuda

Autor: F. Sardà
Director/es tesi: C. Bas (IIP-CSIC)
Any publicació: 1980
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Contribución al estudio de los pigmentos porfirínicos como elementos de traducción de energía

Autor: J. Sánchez Pardo
Director/es tesi: A. Ballester Nolla (IIP-CSIC), J.M. Font Cierco
Any publicació: 1980
Lloc d'edició: Barcelona
Institució: Facultad Ciencias, Universidad Autónoma de Barcelona

Estudio sistemático y ecológico de los cnidarios bentónicos de las islas Medes (Girona)

Autor: J.M. Gili
Director/es tesi: J.D. Ros
Any publicació: 1980
Institució: Universitat Autònoma de Barcelona

Balance asimilación-excreción en cultivos convencionales de Phaeodactylum tricornutum (Bohlin)

Autor: M. Martí Viudes
Director/es tesi: A. Ballester (ICM-CSIC)
Any publicació: 1979
Lloc d'edició: Barcelona
Institució: Facultad Ciencias, Universidad Autónoma de Barcelona

Balance asimilación-excreción en cultivos convencionales de Phaeodactylum tricornutum (Bohlin)

Autor: M. Martí Viudes
Director/es tesi: A. Ballester Nolla (IIP-CSIC)
Any publicació: 1979
Institució: Universitat Autònoma de Barcelona

La comunitat epibentònica del banc canario-saharià : tipificació i cartografia mitjançant l’anàlisi de dades i comentaris crítics sobre la metodologia

Autor: J. Lleonart
Director/es tesi: C. Bas (IIP-CSIC)
Any publicació: 1979
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona, Instituto de Investigaciones Pesqueras de Barcelona

Avances en el estudio del otolito de los teleósteos Morales-Nin

Autor: B. Morales
Director/es tesi: J. Nadal Puigdefabregas
Any publicació: 1978
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona, Instituto de Investigaciones Pesqueras de Barcelona

Ecología, competencia y segregación en especies congenéricas de Copépodos (Acartia)

Autor: M. Alcaraz Medrano
Director/es tesi: R. Margalef López
Any publicació: 1977
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Estudio sobre relaciones tróficas en peces bentónicos de la costa catalana

Autor: E. Macpherson
Director/es tesi: C. Bas (IIP-CSIC)
Any publicació: 1977
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Afloramiento costero en el Atllántico nororiental: análisis del ecosistema en sus aspectos de hidrografía y producción primaria

Autor: A. Cruzado Alorda
Director/es tesi: R. Margalef (UB)
Any publicació: 1976
Lloc d'edició: Barcelona
Institució: Dept.. Ecología, Universidad de Barcelona

Aplicación del análisis de Fourier al estudio de la composición de una corriente fluida

Autor: J. Font
Director/es tesi: J. Navarro
Any publicació: 1976
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Contribución al estudio de la maduración sexual de Eledone cirrosa (Lamarck)

Autor: P. Sanchez Zalacain
Director/es tesi: C. Bas
Any publicació: 1976
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Descripción y distribución de huevos y larvas de peces planos (Pisces, Pleuronectiformes) en la plataforma continental sahariana

Autor: I. Palomera
Director/es tesi: J. Nadal Puigdefabregas
Any publicació: 1976
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Estudios sobre poblaciones de organismos acuáticos en medio no uniforme

Autor: M. Estrada
Director/es tesi: R. Margalef
Any publicació: 1976
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona

Contribución al estudio de la reproducción y la alimentación de la bacaladilla (Micromesistius poutassou, Rissa, 1810)

Autor: E. Macpherson
Any publicació: 1975
Lloc d'edició: Barcelona
Institució: Universitat de Barcelona. Instituto de Investigaciones Pesqueras

Contribución al estudio de las proteinas musculares de peces y de sus procesos de degradación enzimática y bacteriana

Autor: E. Arias Serrano
Director/es tesi: J. Planas Mestres
Any publicació: 1972
Lloc d'edició: Barcelona
Institució: Fac. Biolog./Bioq./Fisiol. Universitat de Barcelona

Regularidad y heterogeneidad de los pigmentos fotosintetizadores

Autor: A. Ballester Nolla
Director/es tesi: F. Ponz Piedrafita (UB)
Any publicació: 1971
Lloc d'edició: Barcelona
Institució: Facultad Biología/Bioq.y Fisol.,Universidad Autónoma de Barcelona