Artículos

153 documentos.
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López-González N., B. Alonso, C. Juan, G. Ercilla, G. Bozzano, I. Cacho, D.Casas, D. Palomino, J.-T. Vázquez, F. Estrada, P. Bárcenas, E. d’Acremont, C. Gorini, B. El Moumni
Geosciences, 9, 8, 345. DOI: 10.3390/geosciences9080345 (BibTeX: lopezgonzalez.etal.2019a)
Resumen: Ver
The Djibouti Ville Drift is part of a contourite depositional system located on the southern side of the Djibouti Ville Seamount in the Alboran Sea (Western Mediterranean). The sedimentary record of a core located in the drift deposits has been characterized to achieve the possible sediment sources for the Saharan dust supply and the paleocurrent variability related to Mediterranean intermediate waters for the last 133 kyr. Three end-member grain-size distributions characterize the sediment record transported by the bottom current to address the different aeolian populations, i.e., coarse EM1, silty EM2, and fine EM3. For these particles, the most likely source areas are the Saharan sedimentary basins and deserts, as well as the cratonic basins of the Sahara-Sahel Dust Corridor. The prevalence of these main source areas is shown in the core record, where a noticeable change occurs during the MIS 5 to MIS 4 transition. Some punctual sediment inputs from the seamount have been recognized during sea-level lowstand, but there is no evidence of fluvial supply in the drift deposits. The paleocurrent reconstruction allows the characterizing of the stadial and cold periods by large increases in the mean sortable silt fraction and UP10, which point to an enhanced bottom current strength related to intermediate water masses. Conversely, interglacial periods are characterized by weaker bottom current activity, which is associated with denser deep water masses. These proxies also recorded the intensified Saharan wind transport that occurred during interstadial/stadial transitions. All these results point to the importance of combining sediment source areas with major climatic oscillations and paleocurrent variability in palaeoceanographic sedimentary archives, which may help to develop future climate prediction models.
Palabras clave: Contourite drift ;Aeolian sediment sources; Paleocurrent proxies; Mediterranean intermediate water masses; Djibouti ville seamount; Alboran sea
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Ramírez Téllez J.G.,
PhD thesis. Director/es: F. Maynou, M. Coll. Barcelona. (BibTeX: ramireztellez.2019a)
Resumen: Ver
Small-scale fishers are often identified as key players in the recovery of overexploited fish and invertebrate stocks supplying food for rural people and contributing to achieving healthy marine ecosystems. Stocks harvested by small-scale fisheries tend to be largely unassessed, but methods based on the data-limited toolbox exist that help provide information on exploitation status for fished stocks that do not have historical time series of catches, as usually occur in small-scale fisheries. Many of the data-limited methods follow length-based assessment approaches, which assume steady state, use at least length structure derived from fishery and knowledge on the life history parameters of the fished species. Accordingly, this thesis aimed at addressing the reliability of data-poor stock assessment methods in providing advice on the status of small-scale fisheries lacking knowledge of catch history. The data-rich bottom trawl fishery for European hake (Merluccius merluccius) in GSA 06 (Northwest Mediterranean Sea) was assumed as data-limited. This case study allowed me to test the performance of the pseudo-cohort Virtual Population Analysis (VPA) when input data are considered well known and unbiased. The same fishery but held in GSA 01 (Southwest Mediterranean Sea) was used as data-limited case study to introduce the uncertainty derived from parameterizing the length-based spawning potential ratio (LB-SPR) model with two contrasting growth hypotheses. Acknowledging challenges faced by stock assessment of small- scale fisheries around the world, I considered high input-data bias and large outputs uncertainty. The effect of biases in fishery data and uncertainty in life-history parameters on the outputs of the pseudo-cohort VPA model was explored by assessing the small-scale Wayuu fisheries for lane snapper (Lutjanus synagris) and white grunt (Haemulon plumierii) in the northern Colombian Caribbean Sea. An extreme, but common, case of uncertainty in small-scale fisheries was explored through assessing the beach fishery of the Peruvian grunt (Anisotremus scapularis) in the central coast of Peru on the Pacific Ocean, holding poor information on life-history parameters and catches. My findings indicate that the pseudo-cohort VPA may offer useful information regarding the exploitation trend but the absolute values of the indicators do not accurately express the fishing mortality and stock size among years for the European hake. The SPR estimates for this species is not specially linked to the growth hypothesis, and estimates of the ratio of fishing mortality to natural mortality (F/M) and the SPR value depend on the sample size and representation of the stock structure. The contribution of the information derived from the participatory monitoring of small-scale fisheries in Colombia, instead of using only official fishery data, largely demonstrated an improving picture of the exploitation of the lane snapper and white grunt. The uncertainty related to estimates of the von Bertalanffy growth parameters and natural mortality of the Peruvian grunt could be addressed but an accurate definition of SPR was not straightforwardly achieved. This thesis highlights that the data-limited methods assuming a steady state might contribute to defining the status of the small-scale fisheries. However, the stock status is importantly affected by bias in the input data, the available knowledge on the assessed fisheries and how fishery fit the model assumptions.
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Cuesta J.A., J.E. García Raso, P. Abelló, E. Marco-Herrero, L. Silva, P.Drake
Journal of the Marine Biological Association of the United Kingdom, 99, 5, 1141-1152. DOI: 10.1017/S0025315419000018 (BibTeX: cuesta.etal.2019b)
Resumen: Ver
After the recent detection, by both morphology and DNA barcodes, of the larval stages of an unknown species of pea crab (Pinnotheres sp.) in European waters, adults of this crab are herein reported and described as a new species. The current known geographic distribution of the species comprises the Gulf of Cádiz in the eastern Atlantic and the adjacent Mediterranean waters of the south of the Iberian Peninsula (Alboran Sea), where this crab is well-established inside the anomiid bivalve Anomia ephippium. In the Gulf of Cádiz, the species displayed a relatively high prevalence: on average, 55.6–77.7%, in A. ephippium samples. The dominant demographic categories of the new species were soft females (61.8–77.0%) with fewer males (17.7–21.10%). Most of the host bivalves carried only one crab; in bivalves harbouring two crabs, heterosexual pairs were collected more frequently than expected by chance, which suggests that they could be mated pairs. A strong correlation between host size and soft female size was found (r = 0.73, P < 0.01) indicating that space availability within hosts seems to be relevant in determining the size of the sedentary phase of the new crab species.
Palabras clave: Anomia ephippium; Brachyura; Distribution; DNA barcoding; European waters; New species; Pinnotheres bicristatus
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Meléndez A., C.E. Jiménez, V. Sallarès, C.R. Ranero
Solid Earth, 10, 6, 1857-1876. DOI: 10.5194/se-10-1857-2019 (BibTeX: melendez.etal.2019a)
Resumen: Ver
We present the implementation of Thomsen\'s weak anisotropy approximation for vertical transverse isotropy (VTI) media within TOMO3D, our code for 2-D and 3-D joint refraction and reflection travel-time tomographic inversion. In addition to the inversion of seismic P-wave velocity and reflector depth, the code can now retrieve models of Thomsen\'s parameters (δ and ε). Here, we test this new implementation following four different strategies on a canonical synthetic experiment in ideal conditions with the purpose of estimating the maximum capabilities and potential weak points of our modeling tool and strategies. First, we study the sensitivity of travel times to the presence of a 25 % anomaly in each of the parameters. Next, we invert for two combinations of parameters (v, δ, ε and v, δ, v⊥), following two inversion strategies, simultaneous and sequential, and compare the results to study their performance and discuss their advantages and disadvantages. Simultaneous inversion is the preferred strategy and the parameter combination (v, δ, ε) produces the best overall results. The only advantage of the parameter combination (v, δ, v⊥) is a better recovery of the magnitude of v. In each case, we derive the fourth parameter from the equation relating ε, v⊥ and v. Recovery of v, ε and v⊥ is satisfactory, whereas δ proves to be impossible to recover even in the most favorable scenario. However, this does not hinder the recovery of the other parameters, and we show that it is still possible to obtain a rough approximation of the δ distribution in the medium by sampling a reasonable range of homogeneous initial δ models and averaging the final δ models that are satisfactory in terms of data fit.
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Corcione V., G. Grieco, M. Portabella, F. Nunziata, M. Migliaccio
IEEE Transactions on Geoscience and Remote Sensing, 57, 6, 3331-3340. DOI: 10.1109/TGRS.2018.2883364 (BibTeX: corcione.etal.2019)
Resumen: Ver
In this paper, the synthetic aperture radar (SAR) azimuth cutoff method is thoroughly revised and a new and general implementation is proposed. The key roles of the pixel spacing, the size of the image box, and the texture of the SAR scene are analyzed and optimized in terms of azimuth cutoff estimation. The reliability of the azimuth cutoff estimation is analyzed by measuring the distance between the measured and fitted autocorrelation functions. This analysis shows that it is of paramount importance to ilter unfeasible/unreliable azimuth cutoff values. To identify those values in an objective way, a criterion that is based on the \"Chi-squared\" test performed over a large data set of Sentinel-1 SAR imagery is defined and proven to be effective. The new robust implementation of the azimuth cutoff estimation at about 1-km grid spacing is then used to produce averaged azimuth cutoff at about 10-km grid spacing. The performance of the new estimation procedure, analyzed using a azimuth cutoff-to-wind-speed forward model, is shown to provide improved wind speed retrievals, with a root-mean-square error of 1.8–2 m/s when verified against independent numerical weather prediction model output and scatterometer winds.
Palabras clave: Cutoff frequency, sea surface, spectral analysis, synthetic aperture radar.
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Lin W., X. Dong, M. Portabella, S. Lang, Y. He, R. Yun, Z. Wang, X. Xu, D. Zhu, J. Liu
IEEE Transactions on Geoscience and Remote Sensing, 57, 2, 627-639. DOI: 10.1109/TGRS.2018.2858852 (BibTeX: lin.etal.2019c)
Resumen: Ver
The China-France Oceanography Satellite (CFOSAT) to be launched in October 2018 will carry two innovative payloads, i.e., the surface wave investigation and monitoring instrument and the rotating fan-beam scatterometer [CFOSAT scatterometer (CFOSCAT)]. Both instruments, operated in Ku-band microwave frequency, are dedicated to the measurement of sea surface wave spectra and wind vectors, respectively. This paper provides an overview of the system definition and characteristics of the CFOSCAT instrument. A prelaunch analysis is carried out to estimate the scatterometer backscatter and wind quality based on the developed CFOSCAT simulator prototype. The overall simulation includes two parts: first, a forward model is developed to simulate the ocean backscatter signals, accounting for both instrument and geophysical noise. Second, a wind inversion processor is used to retrieve wind vectors from the outputs of the forward model. The benefits and challenges of the novel observing geometries are addressed in terms of the CFOSCAT wind retrieval. The simulations show that the backscatter accuracy and the retrieved wind quality of CFOSCAT are quite promising and meet the CFOSAT mission requirements.
Palabras clave: Backscatter; Inversion; Measurement errors; Remote sensing; Rotating fan-beam scatterometer; Simulation; Wind.
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Zattara E.E., F.A. Fernández-Álvarez, T.C. Hiebert, A.E. Bely, J.L. Norenburg
Proceedings of the Royal Society. Biological Sciences, 286, 1898, 20182524. DOI: 10.1098/rspb.2018.2524 (BibTeX: zattara.etal.2019b)
Resumen: Ver
Animals vary widely in their ability to regenerate, suggesting that regenerative ability has a rich evolutionary history. However, our understanding of this history remains limited because regenerative ability has only been evaluated in a tiny fraction of species. Available comparative regeneration studies have identified losses of regenerative ability, yet clear documentation of gains is lacking. We assessed ability to regenerate heads and tails either through our own experiments or from literature reports for 35 species of Nemertea spanning the diversity of the phylum, including representatives of 10 families and all three orders. We generated a phylogenetic framework using sequence data to reconstruct the evolutionary history of head and tail regenerative ability across the phylum and found that all evaluated species can remake a posterior end but surprisingly few could regenerate a complete head. Our analysis reconstructs a nemertean ancestor unable to regenerate a head and indicates independent gains of head regenerative ability in at least four separate lineages, with one of these gains taking place as recently as the last 10–15 Myr. Our study highlights nemerteans as a valuable group for studying evolution of regeneration and identifying mechanisms associated with repeated gains of regenerative ability.
Palabras clave: Nemertea; Evolution of regeneration; Phylogenetics; Ancestral state reconstruction
Park J., M. Dall’Osto, K. Park, J, -H, Kim, J. Park, K.-T. Park, C. Yeon Hwang, G. Il Jang, Y. Gim, S. Kang, S. Park, Y. Keun Jin, S. Soo Yum, R. Simó, Y. Jun Yoon
Environmental Science and Technology, 53, 15, 8621-8630. DOI: 10.1021/acs.est.9b03399 (BibTeX: park.etal.2019a)
Resumen: Ver
The sources of primary and secondary aerosols in the Arctic are still poorly known. A number of surface seawater samples -with varying degrees of Arctic riverine and sea ice influences- were used in a sea spray generation chamber to test them for their potential to produce sea spray aerosols (SSA) and cloud condensation nuclei (CCN). Our interdisciplinary data showed that both sea salt and organic matter (OM) significantly influenced the SSA production. The number concentration of SSA in the coastal samples was negatively correlated with salinity and positively correlated with a number of OM tracers, including dissolved and chromophoric organic carbon (DOC, CDOM), marine microgels and chlorophyll a (Chl-a) but not for viral and bacterial abundances; indicating that OM of riverine origin enhances primary aerosol production. When all samples were considered, transparent exopolymer particles (TEP) were found to be the best indicator correlating positively with the ratio number concentration of SSA/salinity. CCN efficiency was not observed to differ between the SSA from the various samples, despite differences in organic characteristics. It is suggested that the large amount of freshwater from river runoff have a substantial impact on primary aerosols production mechanisms, possibly affecting the cloud radiative forcing.
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Strieder Philippsen J.,C.V. Minte-Vera, M. Coll, R. Angelini
Reviews in Fish biology and Fisheries, 29, 1, 125–146. DOI: 10.1007/s11160-018-9539-9 (BibTeX: striederphilippsen.etal.2019)
Resumen: Ver
Ecological models are useful for evaluating fishery management scenarios, as they allow researchers to investigate alternative fishing effort, as well as varying environmental and trophic interaction scenarios. Through an ecosystem modeling approach (Ecopath with Ecosim), we addressed the possible impacts of small-scale fisheries on the structure and functioning of a tropical ecosystem (Itaipu Reservoir, Brazil). We found that fishing effects and predator–prey interactions were the main drivers explaining catch trends in the Itaipu Reservoir fisheries. The mean trophic level of catch did not change throughout the analyzed time period and no losses in secondary production from exploitation (L index) were observed, indicating that Itaipu fisheries are sustainable regarding ecosystem effects. The negative impacts of introduced species on native species seem to be greater than the fishing impacts. Fishing simulations from the ecosystem Maximum Sustainable Yield (MSY) reduced the biomass of some important species in the local fishery. Regarding management advice, our results indicate that fishing efforts should not be increased for curimba (Prochilodus lineatus), pintado (Pseudoplatystoma corruscans), and jaú (Zungaro jahu). Additionally, participative management methods are important measures for local fisheries. Finally, additional research is needed to investigate how fishery management can promote the use of multispecific methods (e.g., gillnets) to control introduced species
Palabras clave: Ecopath with Ecosim; Ecosystem-based management; Inland fisheries; L index; Maximum sustainable yield
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del Campo J., T. Heger, R. Rodríguez-Martínez, A.Z. Worden, T.A. Richards, R. Massana, P.J. Keeling
Frontiers in Microbiology, 10, 2373, 1-15. DOI: 10.3389/fmicb.2019.02373 (BibTeX: delcampo.etal.2019)
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Castillo Y.M., J.‐F. Mangot, L.F. Benites, R. Logares, M. Kuronishi, H. Ogata, O. Jaillon, R. Massana, M. Sebastián, D. Vaqué
Molecular ecology, 28, 18, 4272-4289. DOI: 10.1111/mec.15210 (BibTeX: castillo.etal.2019b)
Resumen: Ver
Viruses are the most abundant biological entities on Earth and have fundamental ecological roles in controlling microbial communities. Yet, although their diversity is being increasingly explored, little is known about the extent of viral interactions with their protist hosts as most studies are limited to a few cultivated species. Here, we exploit the potential of single‐cell genomics to unveil viral associations in 65 individual cells of 11 essentially uncultured stramenopiles lineages sampled during the Tara Oceans expedition. We identified viral signals in 57% of the cells, covering nearly every lineage and with narrow host specificity signal. Only seven out of the 64 detected viruses displayed homologies to known viral sequences. A search for our viral sequences in global ocean metagenomes showed that they were preferentially found at the DCM and within the 0.2–3 µm size fraction. Some of the viral signals were widely distributed, while others geographically constrained. Among the viral signals we detected an endogenous mavirus virophage potentially integrated within the nuclear genome of two distant uncultured stramenopiles. Virophages have been previously reported as a cell\'s defence mechanism against other viruses, and may therefore play an important ecological role in regulating protist populations. Our results point to single‐cell genomics as a powerful tool to investigate viral associations in uncultured protists, suggesting a wide distribution of these relationships, and providing new insights into the global viral diversity.
Palabras clave: Protists; Single‐cell genomics; Uncultured stramenopiles; Viral associations; Virophages; Viruses
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Tilves U., A. Sabatés, M. Blázquez, V. Raya, V.L. Fuentes
Marine Biology, 165, 127, 1-14. DOI: 10.1007/s00227-018-3381-4 (BibTeX: tilves.etal.2019)
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Viúdez A.,
Journal of Fluid Mechanics, 878, R5, 1-11. DOI: 10.1017/jfm.2019.730 (BibTeX: viudez.2019c)
Resumen: Ver
An exact solution of a stable vortex tripole in two-dimensional (2-D) Euler flows is provided. The stable tripole is composed of an inner elliptical vortex and two small-amplitude lateral vortices. The non-vanishing vorticity field of this tripole, referred to as here as an embedded tripole because of the closeness of its vortices, is given in elliptical coordinates .; / by the even radial and angular order-0 Mathieu functions Je0./ce0./ truncated at the external branch of the vorticity isoline passing through the two critical points closest to the vortex centre. This tripole mode has a rigid vorticity field which rotates with constant angular velocity equal to 0Je0.1/ce0.0/=2, where 1 is the first zero of Je0 0./ and 0 is a constant modal amplitude. It is argued that embedded 2-D tripoles may be conceptually regarded as the superposition of two asymmetric Chaplygin–Lamb dipoles, separated a distance equal to 2R, as long as their individual trajectory curvature radius R is much shorter than their dipole extent radius.
Palabras clave: vortex dynamics, vortex instability, vortex interactions
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Marín-Beltrán I., J.B. Logue, A.F. Andersson, F. Peters
Frontiers in Microbiology, 10, 858, 1-14. DOI: 10.3389/fmicb.2019.00858 (BibTeX: marinbeltran.etal.2019)
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Viúdez A.,
Journal of Fluid Mechanics, 859, R1, DOI: 10.1017/jfm.2018.892 (BibTeX: viudez.2019a)
Resumen: Ver
Exact solutions for multipolar azimuthal-mode vortices in two-dimensional Euler flows are presented. Flow solutions with non-vanishing far-field velocity are provided for any set of azimuthal wavenumbers m and arbitrary number n of vorticity shells. For azimuthal wavenumbers mD0 and mD1, the far-field velocity is a rigid motion and unsteady flow solutions with vanishing far-field velocity are obtained by means of a time-dependent change of reference frame. Addition of these first two modes, in the case of n = 1, results in a particular Chaplygin–Lamb (C–L) dipole, with continuous and vanishing vorticity at the vortex boundary. Numerical simulations suggest that this particular C–L dipole is stable.
Palabras clave: Vortex dynamics; Vortex flows
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Guerrero Sánchez Q.,
PhD thesis. Director/es: J. Guillén Aranda. (BibTeX: guerrerosanchez.2019b)
Resumen: Ver
This Thesis conducts the study of bedform development and dynamics in the inner shelf integrating observations at different spatial and temporal scales. An initial assumption is that different scales of sedimentary processes strongly interact between them and small-scale sedimentary processes intended to foster those of larger scale. The potential contribution of small-scale bedforms to the sediment transport is particularly addressed. The study includes the monitoring and analysis of sand ridges, ripples and near-bottom suspended sediment variations at the Ebro Delta (NW Mediterranean Sea) and Perranporth (Atlantic Ocean) inner shelves. A sand ridge field with maximum ridges heights of 2.5 m and 400 m spaced is located over a retreating lobe in the Ebro Delta. Ridges are mostly symmetric arranging obliquely to the shoreline. The change of the main Ebro River channel led to the progressive abandonment of the former river mouth and to the severe coastal retreatment, providing large amount of sediment available in the coastal zone. NW winds induce strong near-bottom currents flowing towards the SE, which are able to transport sediment and produce ridge formation and migration towards the SE at ~10 m/y. The characteristics of the Ebro sand ridges match well with those of shoreface-connected sand ridges and, particularly, with the initial stages of sand ridge development on storm-dominated continental shelves. Time-scales related to their genesis can be within a few decades. The presence of ripples on the different inner shelves is the most usual situation under low- to moderate-energetic conditions. In the wave-dominated and tideless coast (Ebro Delta) ripples were observed superimposed on sand ridges. Four types were identified: small undulations that were the precursor ripples, 2D wave-ripples, current-dominated 2D-3D-ripples, and combined wave-current 3D-ripples. The wave-ripples were static while the current-dominated ripples migrated. In a macro-tidal sandy beach exposed to high-energetic Atlantic storms (Perranporth), only wave-ripples were developed arranging orthogonal to wave approach and they were static. The size of ripples changed from larger (developed in equilibrium conditions) to smaller ripples, the latter interpreted as degraded ripples in wash-out conditions. The ripple prediction did not well-adjust to neither ripple appearance nor dimension. However, if the observed thresholds of seabed states are applied the model improves ripple appearance forecast. The near-bottom suspended sediment variability from seconds to months in the Ebro Delta is described distinguishing between waves, currents, and combined wave-currents conditions. In general, waves dominated the sediment resuspensions although strong currents also have an important contribution in the suspended sediment concentration (SSC) increases. The time-averaged SSC usually showed redundant structure by forming three layers with different patterns. In the lower and intermediate layers the SSC oscillated at gravity and infragravity wave frequencies. Time-varying and instantaneous profiles exhibit sediment patterns potentially related to ripples. The potential role of ripple migration as an additional long-term mechanism of sediment transport was analysed. In Perranporth, wave ripples are stationary and did not contribute to beach recovery because of wave orbital symmetry. The sediment transport is alongshore during low-energetic regimes and cross-shore during more energetic regimes when ripples are washed-out. In the Ebro Delta, 3D-ripples migration agrees with sand ridges migration direction towards the SE. The respective migration rates and their differences in size, support that a subordinate part of sand ridge migration can be the result of ripple migration contribution under low-, moderate-regimes, suggesting that in specific environments, dynamics of small-scale bedforms can play a subordinate but not negligible role in the evolution of larger bedforms.
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Galimany E., E. Marco-Herrero, S. Soto, L. Recasens, A. Lombarte, J. Lleonart, P. Abelló, M. Ramón
Waste Management, 95, 620-627. DOI: 10.1016/j.wasman.2019.07.004 (BibTeX: galimany.etal.2019a)
Resumen: Ver
Fisheries are one of the main economic sectors affected by marine litter, which can damage gear, reduce catch, and require time to repair or clean nets. This study aims to evaluate the type and density of marine litter in two shallow fishing grounds in the NW Mediterranean Sea, both belonging to the Natura 2000 network. Moreover, it quantifies the fraction of marine litter within the total catch to help understand the potential influence of marine litter on fisheries. Two study areas were selected, one in the vicinity of urban populated areas and high navigational traffic and one in a rural site off an agricultural area. The urban area had more benthic marine litter (393 to 198 kg km−2) including clinker (residue from coal-burning steamships), fabric, plastics, and processed wood and accounting for up to 38% of the total catch. The rural area had far less marine litter (34–56 kg km−2), accounting for only 5% of the total catch. Marine litter may have potential negative effects on fisheries; thus we propose that government credit trading programs could be promoted to help recover litter from fishing catches, to reduce fishing costs and hazards to marine ecosystems
Palabras clave: Catalan coast; Fishery; Marine debris; Pollution; Plastic; Dredge
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Tilves U.,
PhD thesis. Director/es: A. Sabatés, V. Fuentes. (BibTeX: tilves.2019b)
Resumen: Ver
Jellyfish are important components of marine ecosystems, being a key link between lower and higher trophic levels. Jellyfish blooms occur sporadically and unpredictably in coastal areas and often have important socio-economic consequences for fisheries and tourism. This PhD thesis addresses some questions regarding the potential impact, positive and/or negative, that jellyfish have on fish populations in the Catalan coast (NW Mediterranean). [...]
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Bravo A.G., C. Cosio
Limnology and Oceanography, DOI: 10.1002/lno.11366 (BibTeX: bravo.cosio.2019a)
Resumen: Ver
Mercury (Hg) is a natural and widespread trace metal, but is considered a priority pollutant, particularly its organic form methylmercury (MMHg), because of human\'s exposure to MMHg through fish consumption. Pioneering studies showed the methylation of divalent Hg (HgII) to MMHg to occur under oxygen‐limited conditions and to depend on the activity of anaerobic microorganisms. Recent studies identified the hgcAB gene cluster in microorganisms with the capacity to methylate HgII and unveiled a much wider range of species and environmental conditions producing MMHg than previously expected. Here, we review the recent knowledge and approaches used to understand HgII‐methylation, microbial biodiversity and activity involved in these processes, and we highlight the current limits for predicting MMHg concentrations in the environment. The available data unveil the fact that HgII methylation is a bio‐physico‐chemical conundrum in which the efficiency of biological HgII methylation appears to depend chiefly on HgII and nutrients availability, the abundance of electron acceptors such as sulfate or iron, the abundance and composition of organic matter as well as the activity and structure of the microbial community. An increased knowledge of the relationship between microbial community composition, physico‐chemical conditions, MMHg production, and demethylation is necessary to predict variability in MMHg concentrations across environments.
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Ercilla G., T. Schwenk, G. Bozzano, V. Spiess, R. Violante, F. Estrada, F. Ianniccheri, D.V. Spoltore, B. Alonso
Marine Geology, 417, 106028. DOI: 10.1016/j.margeo.2019.106028 (BibTeX: ercilla.etal.2019c)
Resumen: Ver
New insights into the Cenozoic depositional architecture based on the seismic stratigraphy of the northern Argentine continental slope, off Bahia Blanca, allow us to reconstruct its sedimentary evolution. Five major seismic boundaries, B1 to B5 (from oldest to youngest) represent the main discontinuities bounding six seismic units: I (Eocene), II (Oligocene to early Miocene), III (middle Miocene), IV (late Miocene), V (Pliocene), and VI (Quaternary). These units comprise deposits and features (mass-flow deposits, (hemi)pelagites and/or low-density turbidites, contourite drifts and moats, sediment waves, and canyon deposits), of which, through time, the contourites are ubiquitous. The depositional stratigraphic architecture reflects the expansion and relocation of the contourites, which are used to divide the sedimentation history into three major periods: Eocene to Early Miocene; Middle Miocene; and Late Miocene to Recent. Each period is interpreted as having occurred in response to palaeoceanographic changes in the Southern Component Deep Water (SCDW). These changes were regulated by palaeogeodynamic variations, regionally related to the Andean orogeny and remotely related to the opening stages of the Drake Passage and Central American Seaway, as well as the consequent increases in deep-water flux to the southern Atlantic. Additionally, we also consider their interplay with local and global sea-level changes. These three main periods reveal changes in the alongslope dynamics of the SCDW on the Argentine continental slope.
Palabras clave: Seismic stratigraphy; Contourites; Cenozoic sedimentary history; Argentine continental margin; Ewing Terrace
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Rossi S., E. Isla, M. Bosch-Belmar, G. Galli, A. Gori, M. Gristina, G. Ingrosso, G. Milisenda, S. Piraino, L. Rizzo, N. Schubert, M. Soares, C. Solidoro, R.H. Thurstan, N. Viladrich, T.J. Willis, P. Ziveri
ICES Journal of Marine Science, 76, 7, 2008-2019. DOI: 10.1093/icesjms/fsz147 (BibTeX: rossi.etal.2019b)
Resumen: Ver
Climate change is already transforming the seascapes of our oceans by changing the energy availability and the metabolic rates of the organisms. Among the ecosystem-engineering species that structure the seascape, marine animal forests (MAFs) are the most widespread. These habitats, mainly composed of suspension feeding organisms, provide structural complexity to the sea floor, analogous to terrestrial forests. Because primary and secondary productivity is responding to different impacts, in particular to the rapid ongoing environmental changes driven by climate change, this paper presents some directions about what could happen to different MAFs depending on these fast changes. Climate change could modify the resistance or resilience of MAFs, potentially making them more sensitive to impacts from anthropic activities (i.e. fisheries and coastal management), and vice versa, direct impacts may amplify climate change constraints in MAFs. Such changes will have knock-on effects on the energy budgets of active and passive suspension feeding organisms, as well as on their phenology, larval nutritional condition, and population viability. How the future seascape will be shaped by the new energy fluxes is a crucial question that has to be urgently addressed to mitigate and adapt to the diverse impacts on natural systems.
Palabras clave: Benthic-pelagic coupling; Benthic suspension feeders; Climate change; Energy fluxes; Heterotrophy; Ocean warming; Primary productivity; Secondary productivity; Seston availability; Water stratification
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Olmedo E., V. González-Gambau, J. Martínez, C. González-Haro, A. Turiel, M. Portabella, M. Arias, R. Sabia, R. Oliva, I. Corbella
Proc. of the International Geoscience and Remote Sensing Symposium (IGARSS), Yokohama, Japan, 28 July - 2 August, . DOI: 10.1109/IGARSS.2019.8900562 ISBN: 978-1-5386-9154-0 (BibTeX: olmedo.etal.2019b)
Resumen: Ver
The quality of the Soil Moisture and Ocean Salinity (SMOS) Sea Surface Salinity (SSS) maps has been noticeably improved in the last two years, in particular those produced at the Barcelona Expert Center (BEC). However, the BEC SSS maps are still affected by a latitudinal and seasonal bias. In this work, we comprehensively characterize the residual latitudinal and seasonal biases, which are used to correct de retrieved SSS, leading to a new generation of higher-quality SSS maps. The shape and regularity of this bias suggests that the effect, which produces this error, is not a poor characterization of the galaxy, some residual Total Electron Content (TEC) effect, or a poor characterization of the systematic Sea Surface Temperature (SST) effects on the SSS retrieval. It appears to be related to a geometrical effect associated to the relative position between the SMOS antenna, the Sun and the Earth.
Palabras clave: SMOS; Sea Surface Salinity; Latitudinal bias; Seasonal bias.
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Caputi L., Q. Carradec, D. Eveillard, A. Kirilovsky, E. Pelletier, J.J. Pierella Karlusich, F. Rocha Jimenez Vieira, E. Villar, S. Chaffron, S. Malviya, E. Scalco, S.G. Acinas, A. Alberti, J.M. Aury, A.S. Benoiston, A. Bertrand, T. Biard, L. Bittner, M. Boccara, J.R. Brum, C. Brunet, G. Busseni, A. Carratalà, H. Claustre, L.P. Coelho, S. Colin, S. D\'Aniello, C. Da Silva, M. Del Core, H. Doré, S. Gasparini, F. Kokoszka, J.L. Jamet, C. Lejeusne, C. Lepoivre, M. Lescot, G. Lima-Mendez, F. Lombard, J. Lukes, N. Maillet, M.A. Madoui, E. Martinez, M.G. Mazzocchi, M.B. Néou, J. Paz-Yepes, J. Poulain, S. Ramondenc, J.B. Romagnan, S. Roux, D. Salvagio Manta, R. Sanges, S. Speich, M. Sprovieri, S. Sunagawa, V. Taillandier, A. Tanaka, L: Tirichine, C. Trottier, J. Uitz, A. Veluchamy, J. Veselá, F. Vincent, S. Yau, S. Kandels-Lewis, S. Searson, C. Dimier, M. Pichera, P. Bork, E. Boss, C. de Vargas, M.J. Follows, N. Grimsley, L. Guidi, P. Hingamp, E. Karsenti, P. Sordino, L. Stemmann, M.B. Sullivan, A. Tagliabue, A. Zingone, L. Garczarek, F. d\'Ortenzio, P. Testor, F. Not, M. Ribera d\'Alcalà, P. Wincker, C. Bowler, D. Iudicone
Global Biogeochemical Cycles, 33, 3, 391-419. DOI: 10.1029/2018GB006022 (BibTeX: l..etal.2019)
Resumen: Ver
Predicting responses of plankton to variations in essential nutrients is hampered by limited in situ measurements, a poor understanding of community composition, and the lack of reference gene catalogs for key taxa. Iron is a key driver of plankton dynamics and, therefore, of global biogeochemical cycles and climate. To assess the impact of iron availability on plankton communities, we explored the comprehensive bio‐oceanographic and bio‐omics data sets from Tara Oceans in the context of the iron products from two state‐of‐the‐art global scale biogeochemical models. We obtained novel information about adaptation and acclimation toward iron in a range of phytoplankton, including picocyanobacteria and diatoms, and identified whole subcommunities covarying with iron. Many of the observed global patterns were recapitulated in the Marquesas archipelago, where frequent plankton blooms are believed to be caused by natural iron fertilization, although they are not captured in large‐scale biogeochemical models. This work provides a proof of concept that integrative analyses, spanning from genes to ecosystems and viruses to zooplankton, can disentangle the complexity of plankton communities and can lead to more accurate formulations of resource bioavailability in biogeochemical models, thus improving our understanding of plankton resilience in a changing environment.
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Giakoumi S., V. Hermoso, S.B. Carvalho, V. Markantonatou, M. Dagys, T. Iwamura, W.N. Probst, R.J. Smith, K.L. Yates, V.i Almpanidou, T. Novak, N. Ben‐Moshe, S. Katsanevakis, J. Claudet, M. Coll, A. Deidun, F. Essl, J.A. García‐Charton, C. Jimenez, S. Kark, M. Mandić, A.D. Mazaris, W. Rabitsch, V. Stelzenmüller, E. Tricarico, I.N. Vogiatzakis
Conservation Letters, 12, 1, e12586. DOI: 10.1111/conl.12586 (BibTeX: giakoumi.etal.2019)
Resumen: Ver
Terrestrial, freshwater, and marine ecosystems are connected via multiple biophysical and ecological processes. Identifying and quantifying links among ecosystems is necessary for the uptake of integrated conservation actions across realms. Such actions are particularly important for species using habitats in more than one realm during their daily or life cycle. We reviewed information on the habitats of 2,408 species of European conservation concern and found that 30% of the species use habitats in multiple realms. Transportation and service corridors, which fragment species habitats, were identified as the most important threat impacting ∼70% of the species. We examined information on 1,567 European Union (EU) conservation projects funded over the past 25 years, to assess the adequacy of efforts toward the conservation of “multi‐realm” species at a continental scale. We discovered that less than a third of multi‐realm species benefited from projects that included conservation actions across multiple realms. To achieve the EU\'s conservation target of halting biodiversity loss by 2020 and effectively protect multi‐realm species, integrated conservation efforts across realms should be reinforced by: (1) recognizing the need for integrated management at a policy level, (2) revising conservation funding priorities across realms, and (3) implementing integrated land‐freshwater‐sea conservation planning and management.
Palabras clave: Birds Directive; Conservation planning; EU Biodiversity Strategy; Funding priorities; Habitats Directive; Integrated management; Multi-realm species; Red List; Threats
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Uttieri M., A. Nihongi, P. Hinow, J. Motschman, H. Jiang, M. Alcaraz, J.R. Strickler
Scientific Reports, 9, 547. DOI: 10.1038/s41598-018-37020-9 (BibTeX: uttieri.etal.2019a)
Resumen: Ver
Oil spills are one of the most dangerous sources of pollution in aquatic ecosystems. Owing to their pivotal position in the food web, pelagic copepods can provide crucial intermediary transferring oil between trophic levels. In this study we show that the calanoid Paracartia grani can actively modify the size-spectrum of oil droplets. Direct manipulation through the movement of the feeding appendages and egestion work in concert, splitting larger droplets (Ø = 16 µm) into smaller ones (Ø = 4–8 µm). The copepod-driven change in droplet size distribution can increase the availability of oil droplets to organisms feeding on smaller particles, sustaining the transfer of petrochemical compounds among different compartments. These results raise the curtain on complex small-scale interactions which can promote the understanding of oil spills fate in aquatic ecosystems.
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Maynou F.,
Fisheries Management and Ecology, 26, 4, 345-353. DOI: 10.1111/fme.12365 (BibTeX: maynou.2019b)
Resumen: Ver
The joint viability, or co‐viability, of a Mediterranean Sea mixed demersal fishery was examined by applying a bioeconomic fisheries model to the main seven target stocks of the fishery under biological, social and economic constraints. The stocks of interest were hake, black‐bellied angler, deep‐water rose shrimp, red mullet, blue and red shrimp, Norway lobster and blue whiting, all of which were assessed as overexploited. Their combined production corresponds to 34% by volume and 52% by value of the landings of the demersal fishery studied. Simulation scenarios based on effort reduction, changes in the selectivity pattern and implementing a fisheries restricted area were compared over the simulation horizon of 2015–2030. The latter two scenarios were also examined in terms of full or partial compliance. The effect of a discard ban on the economy of the fleet was also analysed. The results show that the fishery is not co‐viable because some stocks are not viable in the projection period, but social and economic viability was ensured in all cases. As is often the case for mixed fisheries, a unique management measure is unlikely to improve the situation of all stocks simultaneously, but all the management measures tested are better than the status quo.
Palabras clave: Bioeconomic model; Co‐viability analysis; Demersal fisheries; Landing obligation; Western Mediterranean
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Flores E., S. Arévalo, M. Burnat
Algal Research-Biomass Biofuels and Bioproducts, 42, 101577. DOI: 10.1016/j.algal.2019.101577 (BibTeX: flores.etal.2019b)
Resumen: Ver
mospheric nitrogen and some amino acids such as arginine as nitrogen source. Under unbalanced growth in the presence of sufficient nitrogen, many cyanobacteria accumulate cyanophycin, a co-polymer of aspartate and arginine that serves as a nitrogen reservoir. Cyanophycin metabolism enzymes include cyanophycin synthetases, cyanophycinase and isoaspartyl dipeptidase. The latter splits β‑aspartyl arginine released from cyanophycin by cyanophycinase into aspartate and arginine. The arginine catabolic pathway of cyanobacteria has been recently elucidated and consists of two bifunctional enzymes, arginine-guanidine removing enzyme (AgrE) and proline oxidase (PutA). This pathway makes available to metabolism the four nitrogen atoms of arginine, three as ammonia and one as glutamate. A variant of the pathway cycles ornithine (an intermediate in the AgrE-catalyzed reactions) back to arginine incorporating aspartate and, hence, recovering its nitrogen atom for metabolism. Many cyanobacteria also make use of this pathway to utilize arginine taken up from the outer medium through a high-affinity ABC transporter. An analysis of co-occurrence in cyanobacteria of genes encoding cyanophycin metabolism and arginine catabolism enzymes and arginine and aspartate transporters indicates a strong correlation between the presence of cyanophycin and the AgrE/PutA pathway.
Palabras clave: Anabaena; Nostoc; Nitrogen metabolism; Nitrogen mobilization; Nitrogen storage; Synechocystis
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Orué-Echevarría D., J.L. Pelegrí, I.J. Alonso-González, V.M. Benítez-Barrios, P. De La Fuente, M. Emelianov, M. Gasser, C. Herrero, J. Isern-Fontanet, J. Peña-Izquierdo, S. Ramírez-Garrido, M. Rosell-Fieschi, J. Salvador, M. Saraceno, D. Valla, M. Vidal
Data in Brief, 22, 185–194. DOI: 10.1016/j.dib.2018.12.004 (BibTeX: orueechevarria.etal.2019b)
Resumen: Ver
This oceanographic dataset was gathered during the TIC-MOC cruise, which was designed to characterize the dynamics of the Brazil-Malvinas Confluence. The cruise was carried on board the R/V Hespérides ,with departure from Ushuaia and arrival to Salvador de Bahía. A total of 66 conductivity-temperature-depth (CTD) stations were completed between 8 and 22 March 2015, offshore from the continental platform and within 45°S-35°S and 61°W-50°W. At each station, water samples were collected, which were used to calibrate the CTD salinity-oxygen sensors and to determine inorganic nutrient concentrations, and the horizontal current was measured. Along its track, the vessel recorded surface temperature and salinity, as well as the horizontal flow down to about 700 m. Lastly, eight position-transmitting drifters were launched and two profiling
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Díez-Vives C., S. Nielsen, P. Sánchez, O. Palenzuela, I. Ferrera, M. Sebastián, C. Pedrós-Alió, J.M. Gasol, S.G. Acinas
Molecular ecology, 0, 1-14. DOI: 10.1111/mec.15068 (BibTeX: diezvives.etal.2019)
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Zamanillo Campos M.,
PhD thesis. Director/es: R. Simó, E. Ortega-Retuerta. (BibTeX: zamanillocampos.2019a)
Resumen: Ver
Transparent exopolymer particles (TEP) and Coomassie stainable particles (CSP) are operationally defined as organic particles > 0.4 µm that are stainable with the dyes Alcian Blue (specific for acidic polysaccharides) and Coomassie Brilliant Blue (specific for proteins), respectively. They are ubiquitous in the ocean, where they play important roles in biogeochemical processes such as the carbon cycle and sea-air gas and particle exchanges. However, there is a lack of large-scale studies of TEP and CSP distributions in the ocean, particularly in the open ocean, as well as temporal studies following their dynamics over more than one complete seasonal cycle. In addition, it is not clear yet whether these particles represent independent particle fractions or not and which are their main drivers, with a particular lack of information on CSP. In this thesis, TEP and CSP distributions were characterized, combining the horizontal and vertical scales whenever possible, in distinct regions of the ocean: Atlantic Ocean (October-November 2014), Southern Ocean (January 2015 and January-March 2017) and the NW Mediterranean Sea (October 2015). Besides, a time series study was conducted in two coastal stations in the NW Mediterranean Sea for two complete seasonal cycles (2015-2017). In all cases, a number of physical, chemical and biological variables were determined in parallel in order to explore the main drivers of TEP and CSP distributions. TEP concentrations ranged from below detection limit to 446 µg XG eq L-1, whereas CSP concentrations ranged between 0.3 and 52.2 µg BSA eq L-1. The highest TEP concentrations were found in the edge of the Canary Coastal Upwelling, the Southwestern Atlantic Shelf and some regions of the Southern Ocean, whereas the highest CSP concentrations were found in the Southern Ocean. Phytoplankton biomass, and not heterotrophic prokaryotic biomass or activity, is the best predictor of the concentration of both particle types, yet no single taxonomic group of phytoplankton stand as the universally dominant producer. Other variables that play important roles are the daily solar radiation dose in the mixed layer, surface irradiance, sea ice melt, nutrients and phytoplankton mortality in the case of TEP, and phytoplankton mortality for CSP. Our results suggest that TEP and CSP are independent particles, since they follow different dynamics in the temporal and spatial scales. The estimated contribution of TEP to the particulate organic carbon (POC) pool varies widely among regions and exceeds that of living phytoplankton biomass in some areas (Atlantic Ocean) and seasons (Mediterranean sea during summer)
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Zamanillo M., E. Ortega-Retuerta, S. Nunes, M. Estrada, M.M. Sala, S.-J. Royer, D.C. López-Sandoval, M. Emelianov, D. Vaqué, C. Marrasé, R. Simó
Science of The Total Environment, 691, 736-748. DOI: 10.1016/j.scitotenv.2019.06.524 (BibTeX: zamanillo.etal.2019f)
Resumen: Ver
Transparent exopolymer particles (TEP) are an abundant class of suspended organic particles, mainly formed by polysaccharides, which play important roles in biogeochemical and ecological processes in the ocean. In this study we investigated horizontal and vertical TEP distributions (within the euphotic layer, including the upper surface) and their short-term variability along with a suite of environmental and biological variables in four distinct regions of the Southern Ocean. TEP concentrations in the surface (4 m) averaged 102.3 ± 40.4 μg XG eq. L−1 and typically decreased with depth. Chlorophyll a (Chl a) concentration was a better predictor of TEP variability across the horizontal (R2 = 0.66, p < 0.001) and vertical (R2 = 0.74, p < 0.001) scales than prokaryotic heterotrophic abundance and production. Incubation experiments further confirmed the main role of phytoplankton as TEP producers. The highest surface TEP concentrations were found north of the South Orkney Islands (144.4 ± 21.7 μg XG eq. L−1), where the phytoplankton was dominated by cryptophytes and haptophytes; however, the highest TEP:Chl a ratios were found south of these islands (153.4 ± 29.8 μg XG eq (μg Chl a)−1, compared to a mean of 79.3 ± 54.9 μg XG eq (μg Chl a)−1 in the whole cruise, in association with haptophyte dominance, proximity of sea ice and high exposure to solar radiation. TEP were generally enriched in the upper surface (10 cm) respect to 4 m, despite a lack of biomass enrichment, suggesting either upward transport by positive buoyancy or bubble scavenging, or higher production at the upper surface by light stress or aggregation. TEP concentrations did not present any significant cyclic diel pattern. Altogether, our results suggest that photobiological stress, sea ice melt and turbulence add to phytoplankton productivity in driving TEP distribution across the Antarctic Peninsula area and Atlantic sector of the Southern Ocean.
Palabras clave: Transparent exopolymer particles; Phytoplankton; Prokaryotes; Solar radiation dose; Southern Ocean
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Santín A., J. Grinyó, S. Ambroso, M.J. Uriz, C. Dominguez-Carrió, J.M. Gili
Progress in Oceanography, 173, 9-25. DOI: 10.1016/j.pocean.2019.02.002 (BibTeX: santin.etal.2019b)
Resumen: Ver
Nowadays, there is still a huge lack of knowledge regarding the morphology and size structure of sponge populations and their possible ecological implications. This study assesses, by means of quantitative analyses of video transects and morphometric analyses on still photographs, the geographical, bathymetrical and size-structure distribution of the most relevant habitat-forming sponge species on the continental shelf and the upper slope of the Menorca Channel, an area soon to be declared a Marine Protected Area (MPA) as part of the Natura 2000 Network. Additionally, the influence of seafloor variables on the observed distribution patterns was evaluated. Highest sponge densities and abundances were concentrated in areas of high hydrodynamism, namely the rocky shoals offshore Cap Formentor and the Menorca Canyon’s head. Most of the studied species were dominated by small to medium size classes, suggesting pulse recruitment events. A clear depth-zonation pattern has been observed, going from the inner continental shelf to the upper slope. At the same time, the continental shelf harbored the presence of diverse and contrasting growth morphologies, yet the biggest forms occurred at the shelf edge and the upper slope. This study highlights the presence of dense, well-preserved sponge populations in the Menorca Channel, and provides a baseline for their future monitoring once the MPA is declared, potentially serving as reference for other areas across the Atlanto-Mediterranean region.
Palabras clave: Sponges; Geographical distribution; Size distribution; ROVs; Marine protected areas; Benthos; Mediterranean Sea; Balearic Archipelago; Menorca Channel
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Piles M., J. Ballabrera-Poy, J. Muñoz-Sabater
Remote Sensing, 11, 95, DOI: 10.3390/rs11010095 (BibTeX: piles.etal.2019a)
Resumen: Ver
Soil moisture observations are expected to play an important role in monitoring global climate trends. However, measuring soil moisture is challenging because of its high spatial and temporal variability. Point-scale in-situ measurements are scarce and, excluding model-based estimates, remote sensing remains the only practical way to observe soil moisture at a global scale. The ESA-led Soil Moisture and Ocean Salinity (SMOS) mission, launched in 2009, measures the Earth’s surface natural emissivity at L-band and provides highly accurate soil moisture information with a 3-day revisiting time. Using the first six full annual cycles of SMOS measurements (June 2010–June 2016), this study investigates the temporal variability of global surface soil moisture. The soil moisture time series are decomposed into a linear trend, interannual, seasonal, and high-frequency residual (i.e., subseasonal) components. The relative distribution of soil moisture variance among its temporal components is first illustrated at selected target sites representative of terrestrial biomes with distinct vegetation type and seasonality. A comparison with GLDAS-Noah and ERA5 modeled soil moisture at these sites shows general agreement in terms of temporal phase except in areas with limited temporal coverage in winter season due to snow. A comparison with ground-based estimates at one of the sites shows good agreement of both temporal phase and absolute magnitude. A global asseSMent of the dominant features and spatial distribution of soil moisture variability is then provided. Results show that, despite still being a relatively short data set, SMOS data provides coherent and reliable variability patterns at both seasonal and interannual scales. Subseasonal components are characterized as white noise. The observed linear trends, based upon one strong El Niño event in 2016, are consistent with the known El Niño Southern Oscillation (ENSO) teleconnections. This work provides new insight into recent changes in surface soil moisture and can help further our understanding of the terrestrial branch of the water cycle and of global patterns of climate anomalies. Also, it is an important support to multi-decadal soil moisture observational data records, hydrological studies and land data assimilation projects using remotely sensed observations.
Palabras clave: SMOS; Soil moisture; Climatology; Trends; Signal decomposition
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de la Fuente P.,
PhD thesis. Director/es: J.L. Pelegrí, C. Marrasé. 1-124. (BibTeX: delafuente.2019)
Resumen: Ver
The Global Ocean is the largest Earth compartment holding carbon and nutrients that reaches the upper-ocean at temporal scales ranging from months to 10 kyr. The availability of these nutrients is fundamental to sustain primary production and the concentration of dissolved inorganic carbon (DIC) in surface waters controls the glacial-interglacial changes in atmospheric. One process that influences both nutrients and carbon availability is the Microbial Carbon Pump (MCP), which refers to the production of refractory dissolved organic carbon (RDOC) compounds via heterotrophic microbial activity. Variations in the RDOC pool affect long-term carbon storage in the ocean, hence influencing the carbon cycle and climate. The general objective of this thesis is to expand our understanding of the connections between RDOC production by MCP and the ocean metabolism (understood as the upper-ocean net autotrophic community production), paying special attention to the role of the marine microbial processes in the glacial-interglacial transitions of the Earth system. The RDOC production by MCP is inferred through the lineal dependence of fluorescent dissolved organic matter (FDOM) with apparent oxygen utilization (AOU) and nutrients. This relationship, however, depends on the preformed content in the water masses. In this thesis, a valuable dataset, obtained from a high-resolution spatial sampling along 7.5ºN in the equatorial Atlantic Ocean, is used to distinguish the variability of FDOM distribution associated with in situ production from that related to the water properties at origin. A simple objective nonlinear-global methodology for resolving the non-conservative fraction of biogeochemical variables distribution is presented. The approach focuses on fitting high-order polynomial models over the entire temperature-salinity space. The differences between the modelled values and the observations are identified as biogeochemical anomalies. The goodness of the method is compared, for each water stratum, with the traditional approach, which is based on the local linear mixing of a maximum of three source water masses. The new methodology has good skill at distinguishing between the conservative and non-conservative contributions to biogeochemical variables, lending information about biogeochemical processes, stoichiometric ratios and patterns of connectivity within a certain region. For the first time, a general relationship between humic-like FDOM and AOU in the dark equatorial Atlantic Ocean is formulated, irrespective of the water masses. The results endorse the idea that FDOM is mostly produced in situ in the dark ocean. In the second part of the thesis, the role of RDOC pool in quaternary climate transitions is explored. The glacial-interglacial transitions are considered as functional states of the complex Earth system, with different energetic conditions in terms of solar energy conversion through marine photosynthesis. However, the oceanic system capacity to capture and transform the incident solar radiation depends on the availability of DIC and nutrients to the productive upper ocean. The supply of DIC and nutrients by the Meridional Overturning Circulation (MOC) and the DOM pool are evaluated through a simple two-box and two-state relaxation-type model for the DIC and nutrients in the upper ocean. The model, inspired on physiological concepts, considers the upper ocean to switch between basal (glacial) and enhanced (interglacial) metabolic states. The model reproduces well the atmospheric time series for the last 420 kyr, providing a solution for the size and temporal dependence of the MOC and setting global constraints on primary production and remineralization in the upper ocean. The RDOC accumulates during the glacial period and its availability at the end of this cycle sets the metabolic intensity of the subsequent interglacial, in what constitutes a central component of the Earth’s pulsating homeostatic organization
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Gràcia E., I. Grevemeyer, R. Bartolomé, H. Perea, S. Martínez-Loriente, L. Gómez de la Peña, A. Villaseñor, Y. Klinger, C. Lo Iacono, S. Diez, A.e Calahorrano, M. Camafort, S. Costa, E. d’Acremont, A. Rabaute, C.R. Ranero
Nature Communications, 10, 3482. DOI: 10.1038/s41467-019-11064-5 (BibTeX: gracia.etal.2019a)
Resumen: Ver
Large continental faults extend for thousands of kilometres to form boundaries between rigid tectonic blocks. These faults are associated with prominent topographic features and can produce large earthquakes. Here we show the first evidence of a major tectonic structure in its initial-stage, the Al-Idrissi Fault System (AIFS), in the Alboran Sea. Combining bathymetric and seismic reflection data, together with seismological analyses of the 2016 Mw 6.4 earthquake offshore Morocco – the largest event ever recorded in the area – we unveil a 3D geometry for the AIFS. We report evidence of left-lateral strike-slip displacement, characterise the fault segmentation and demonstrate that AIFS is the source of the 2016 events. The occurrence of the Mw 6.4 earthquake together with historical and instrumental events supports that the AIFS is currently growing through propagation and linkage of its segments. Thus, the AIFS provides a unique model of the inception and growth of a young plate boundary fault system.
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Contreras Fuentes T.A.,
PhD thesis. Director/es: P. Olivar. Barcelona. (BibTeX: contrerasfuentes.2019a)
Resumen: Ver
The studies that determine the trophic biology of the species and the knowledge of their food patterns provide basic and necessary information to understand the biological and ecological role of an organism within the ecosystem. Food is one of the most important factors in the biology of organisms because it regulates or affects growth and reproduction, as well as the way in which their life cycle develops. Likewise, the knowledge of the feeding habits of the species allows to evaluate their status in the community, i.e., their trophic level, relationships with other species or groups and to provide an approximate idea of their environment. This thesis provides information about the distribution patterns and the trophic ecology of early life stages of mesopelagic fishes in the western Mediterranean Sea and the equatorial and tropical Atlantic Ocean. We studied the vertical distribution and feeding patterns of some of the most abundant and most frequent mesopelagic fish species of these regions. Changes in the diet are described throughout its ontogenetic development. These aspects have been studied mainly in juveniles and adults of mesopelagic fish; however they are much scarcer for the early stages of development of these species. The importance of mesopelagic fishes is due to their high biomass in all the oceans. They are key elements in marine trophic networks, as they are part of the diet of pelagic fish, birds and marine mammals. Migratory mesopelagic species, such as myctophids, make extensive daily vertical migrations, between the mesopelagic zone (daytime habitat) andepipelagic zone (where they feed at night); thus contributing to the transport of carbon from the photic zone to deeper waters. […]
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Albo-Puigserver M.,
PhD thesis. Director/es: M. Coll, J. Navarro. (BibTeX: albopuigserver.2019a)
Resumen: Ver
Mediterranean marine ecosystems are fundamentally driven by their pelagic communities and small and medium-size pelagic fish (SMPF) play crucial ecological roles. Although fluctuations of the populations of these organisms have been mainly attributed to environmental variability and overfishing, there is still a lack of understanding on specific mechanisms that drive their population changes. In recent decades a decline in landings, biomass and body condition of sardine and anchovy in the northwestern Mediterranean Sea has been observed and several hypotheses to explain these changes have been formulated. Therefore, accurate scientific data at species and community level is needed in order to understand the most likely causes of these declines. Within this context, this PhD thesis aims to improve the knowledge of the seasonal dynamics and functioning of the pelagic compartment focusing in the trophic relationships and energy dynamics of SMPF in the northwestern Mediterranean Sea. [...]
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Corrales Ribas X.,
PhD thesis. Director/es: M. Coll, G. Gal. (BibTeX: corralesribas.2019a)
Resumen: Ver
Modelización ecológica en el Mediterráneo oriental: el impacto acumulado de las especies invasoras, la pesca y el cambio climático en el ecosistema marino de Israel. The ecosystems of the Eastern Mediterranean Sea have undergone significant ecological changes caused by multiple human stressors, including the impact of invasive alien species (IAS), overfishing and sea warming. Firstly, I reviewed modelling approaches that have been used to assess the impact of IAS in aquatic ecosystems. According to the review, multispecies/ecosystem mechanistic models dominated the applications, with dynamic and non-spatial models being the most prevalent. Most of the models included an additional human stressor, mainly fisheries, climate change and/or nutrient loading. In the review, I summarised the main features of these applications and analysed their capabilities and limitations. Based on my conclusions, I reflected on future directions of development and applications of suitable modelling tools. In the review, I found that the Ecopath with Ecosim (EwE) approach had been frequently used to assess the impacts of already established IAS. In addition, the review highlighted EwE capabilities to forecast existing, emerging and potential new IAS. Other available literature reviews had shown EwE capabilities in assessing impacts of fishing and climate change, the other two stressors included in this thesis. Therefore, as a second step in the thesis, I first developed two static Ecopath ecosystem models from EwE approach representing the food web of the Israeli Mediterranean coast in 1990s and 2010s to characterize the structure and functioning of the ecosystem and assess past and current impacts of IAS and fishing. I then used the time-dynamic Ecosim module of EwE to fit the 1990s model to available time series of observations between both periods and to explore the historical dynamics of the ecosystem considering the effects of IAS, fishing dynamics and sea warming. Finally, the time-dynamic ecosystem model was used to perform future simulations of ecosystem change. Particularly, and after interacting with key stakeholders, I assessed the effects of a new set of fishing regulations currently being implemented in Israel, future changes in sea temperature following IPCC (Intergovernmental Panel on Climate Change) scenario projections and the potential increases in IAS biomass in the future. Firstly, I investigated the impacts of the stressors separately, and then I combined them to evaluate their cumulative effects. Results from the static Ecopath models highlighted that the Israeli marine ecosystem, despite productivity differences, shared some structural and functional traits with other Mediterranean ecosystems such as the dominance of the pelagic domain in term of flows, the important role of detritus through low trophic levels and the importance of the benthic-pelagic coupling. In both time periods investigated, the same keystone groups were identified with the exception of hake in 2010s, which showed a decline in its keystone role, and may indicate that hake had lost its ecological role due to population declines. Most of the functional groups identified as keystone species had been previously identified as keystones in other Mediterranean ecosystems, such as dolphins, large pelagic fishes, sharks and squids. The temporal dynamic Ecosim model indicated that trophic interactions, ocean warming and fishing were important drivers of the ecosystem dynamics. In general, temporal biomass trends revealed that native demersal predators (e.g. hake) and native medium trophic level fishes (e.g. mullets) largely declined over time, while an increase over time of alien species was observed. Results from selected ecological indicators suggested a degradation pattern of the ecosystem over time. Future scenarios using the temporal dynamic Ecosim model showed overall potential benefits of fishing effort reductions, and detrimental impacts of increasing sea temperature and increasing biomass of alien species. Cumulative scenarios highlighted that the beneficial effects of fisheries reduction could be dampened by the impact of increasing sea temperature and alien species when acting together. These results support the need for reducing local and regional stressors, such as fishing and biological invasions, to retain marine ecosystems within a “safe operating space (SOS)” and ensure ecosystem resilience in an ongoing warming and impacted sea.
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Sala M.M., J. Piontek, S. Endres, A.M. Romani, S. Dyhrman, A.D. Steen
Frontiers in Microbiology, 10, 1463. DOI: 10.3389/fmicb.2019.01463 (BibTeX: sala.etal.2019a)
Resumen: Ver
Microbes drive the Earth\'s biogeochemical cycles, exerting profound control over the global cycling of carbon and other elements (Falkowski et al., 2008). In aquatic systems, the importance of microbial extracellular enzymes to the mobilization, transformation, and turnover of organic and inorganic compounds in aquatic environments has been proved since the 80\'s (Hoppe, 1983; Chróst, 1989) and was summarized in the book “Microbial enzymes in aquatic environments” (Chróst, 1991). Since then, the field has advanced considerably, with new observations, assay methods, and molecular-level studies (Arnosti et al., 2014) and the measurement of extracellular enzyme activities has become standard in many labs. We now have rates of enzymatic activities in a wide variety of freshwater and marine environments, from polar to tropical and from surface to deep ocean, and from isolates obtained even from extreme environments. Additionally, in recent years measurement of enzyme activities has become an important tool to assess the impact of anthropogenic changes on microbial communities and biogeochemical cycles, such as in the events of oil spills, acidification, or global warming (e.g., Piontek et al., 2010; Sala et al., 2016; Ziervogel et al., 2016; Freixa et al., 2017). [...]
Palabras clave: Enzymes; Microorganisms; Aquatic environment; Degradation; Bacterial activity
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Uria N., I. Ferrera, J. Mas
BMC Microbiology, 17, 208, 1-12. DOI: 10.1186/s12866-017-1115-2 (BibTeX: uria.etal.2019)
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Pelegrí J.L., H. Marotta, S.A. Navarrete, A. Pascual
In: Cambio global. Una mirada desde Iberoamérica, ACCI. Chap. 7. 129-152. ISBN: 978-84-17519-33-9 (BibTeX: pelegri.etal.2019)
Resumen: Ver
Aproximadamente el 71% de la superficie del planeta está cubierta por océanos y mares que se encuentran interconectados. A pesar de su importancia, aún desconocemos muchos de los procesos físicos y biogeoquímicos de los océanos y su papel regulador sobre los ecosistemas marinos y terrestres. El objetivo de este capítulo es proporcionar una introducción muchos de los procesos físicos y biogeoquímicos de los océanos, con el énfasis puesto en su capacidad reguladora del ecosistema planetario, en lo que acostumbramos a llamar el estado termodinámico, o clima, de nuestro Planeta. En primer lugar describiremos las principales características de las variables físicas y biogeoquímicas que caracterizan al medio marino, con especial atención a la circulación oceánica y nivel medio del mar, así como a su temperatura, salinidad y nutrientes inorgánicos. A continuación nos centraremos en una de estas propiedades, el carbono, de interés muy especial para comprender el estado actual y posible evolución futura del clima de la Tierra. Concluiremos con unas reflexiones generales sobre la relevancia planetaria de los flujos y transformaciones de masa, energía y vida, y cómo estos flujos están siendo afectados por la actividad humana.
Piferrer F.,
In: Sex Control in Aquaculture, Ed. H. Wang, F. Piferrer, S.L Chen, Z.-G.Shen. Wiley-Blackwell. Chap. 3. 65-83. DOI: 10.1002/9781119127291.ch3 ISBN: 978-1-119-12726-0 (BibTeX: piferrer.2019a)
Resumen: Ver
The current knowledge on epigenetics and gene expression regulation during sexual development in fish is reviewed. Gonochoristic species with different types of sex determining mechanisms and different types of hermaphrodites are considered. Most research has targeted only a few genes involved in ovarian differentiation – mainly the gonadal aromatase, cyp19a1a, and foxl2, and genes related to testicular differentiation, mainly dmrt1. However, two whole genome studies have shown species‐specific variation in global methylation differences between sexes. Based on this information, a testable model is proposed for the epigenetic regulation of sexual development in fish – the conserved model of epigenetic regulation of sex, which deals with the relationship between gene silencing and gene expression levels. This model is based on the assumption that there are “pro‐male” and “pro‐female” genes, and on the canonical inverse relationship between gene silencing and gene expression levels emerging from the available data. Importantly, it also postulates that a given set of epigenetic and gene expression patterns are more associated with a particular gonadal phenotype (e.g., males) than the means by which this phenotype is obtained (e.g., natural vs. induced masculinization). Finally, the application of epigenetics in breeding programs to favor the appearance of a desired phenotype and, in particular, to control sex, is briefly explored. To that aim, it will be necessary first to identify what are defined as the essential epigenetic marks (EEMs) – the number and identity of informative epigenetic marks that are strictly necessary, although perhaps not sufficient, to bring about a specific and measurable phenotype of interest.
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López E., F.A. Fernández-Álvarez, I. Rojo
In: Especies exóticas invasoras. Cátedra Parques Nacionales, Ed. J. Junoy. Servicio de Publicaciones de la Universidad de Alcalá. Chap. 3. 51-65. ISBN: 978-84-17729-30-1 (BibTeX: lopez.etal.2019a)
Resumen: Ver
Las especies exóticas invasoras (EEI) marinas más dañinas desplazan a las especies nativas, reduciendo la biodiversidad, y modifican la estructura de las comunidades y las redes tróficas, alterando procesos ecológicos fundamentales, sin olvidar los perjuicios económicos derivados de la reducción de pesquerías o los daños producidos en embarcaciones, conducciones de agua y estructuras portuarias por organismos incrustantes (Molnar et al., 2008). Aunque es posible mencionar algunas excepciones, como se ha mencionado en los artículos previos los mecanismos más frecuentes de introducción de EEI marinas son el transporte de organismos incrustantes en la obra viva o el agua de lastre de embarcaciones comerciales, las actividades de maricultura, la conexión artificial de masas de agua mediante obras públicas y la liberación de especies asociadas con el uso de cebo vivo y la industria de animales de compañía. [...]
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Ramón M., G. Simarro, E. Galimany, J. Lleonart
Regional Studies in Marine Science, 31, 100763. DOI: 10.1016/j.rsma.2019.100763 (BibTeX: ramon.etal.2019b)
Resumen: Ver
Parastichopus regalis is an epibenthic holothurian common in the Mediterranean Sea and the NE Atlantic, which feeds on the upper layer of the sediment playing a significant role on soft-bottom dynamics. Whether or not P. regalis is able to select the sediment ingested by size is the question of this study. For this purpose, a comparison between grain size distributions of the seabed sediments and the digestive contents of sea cucumbers were carried out. We performed the comparisons among sediment distributions through the median diameter and the granulometric dispersion . The results showed that the size of the sediment within the holothurians was significantly smaller and more uniform than the ones in the seabed. Evidence showed that P. regalis select sediment by particle size during feeding, choosing the smaller particles. This finding reports novel information on the feeding behavior of this species, a fishery resource of local interest and importance in the Western Mediterranean region
Palabras clave: Holothurian; Feeding; Grain size selection; Mediterranean Sea
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Ortuño M., O. Corominas, P. Villamor, R.F. Zúñiga, P. Lacan, G. Aguirre-Díaz, H. Perea, P. Štěpančíková, M.T. Ramírez-Herrera
Geomorphology, 326, 17-37. DOI: 10.1016/j.geomorph.2018.07.010 (BibTeX: ortuno.etal.2019)
Resumen: Ver
The Acambay Graben, within the central part of the Trans-Mexican Volcanic Belt, is one of the major sources of continental earthquakes in Mexico. To date, the activity and paleoseismological history of the axial faults of the graben are not well constrained. We provide morphological, structural and sedimentological evidence of the seismogenic nature of two of the axial structures, the Temascalcingo and the Tepuxtepec fault systems. Faults consist of multiple parallel scarps with en echelon and horse-splay patterns. Fault systems extend for 60 km and displace Quaternary to Upper Miocene volcanic edifices and volcano-sedimentary materials. Surface lengths of individual fault traces range between 3 and 25 km, and observed throws reach a minimum of 150–200 m. The long-term and short-term slip rate of the Temascalcingo fault system in the studied section presents similar values, ranging from 0.06 ± 0.02 (minimum long term) to 0.12 ± 0.02 mm y−1 (maximum value of average short-term). Only the long-term slip rate of the Tepuxtepec system could be constrained in 0.01–0.02 mm/y, being a minimum estimate. The Holocene fault rupture history at two sites provided evidence of six ruptures since 12,500–11,195 BCE, among which three ruptures should have occurred between 11,847 ± 652 BCE and 11,425 ± 465 BCE Variable single event displacements (SEDs, between 6 and 77) are interpreted as the result of fault interdependences and/or the interaction with the latest volcanic activity. Also, small displacements triggered by activity on other faults probably contributed to slip variability, i.e., faults display primary and secondary behavior
Palabras clave: Temascalcingo fault system; Tepuxtepec fault system; Paleoseismology; Fault complexity
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Pla Quirante S.,
PhD thesis. Director/es: F. Piferrer, Ll. Tort. (BibTeX: plaquirante.2019a)
Resumen: Ver
A sexual system defines the pattern of distribution of male and female function that exists in a given species, which can occur in separate individuals (gonochorism) or in the same individual (hermaphroditism). In hermaphrodites, male and female function can happen simultaneously or sequentially: male first (protandry) or female first (protogyny). Understanding the evolutionary transitions among the different sexual systems as well as the biotic and abiotic correlates that explain their distribution among taxa is a major challenge in evolutionary biology. The incidence, distribution and evolutionary transitions among the different sexual systems were studied in actinopterygian (ray-finned) fishes, the only group of vertebrates where hermaphroditism is present. To this end, information was compiled on the sexual system, environmental correlates and life-history traits of 10,875 ray-finned fishes. Then, modern phylogenetic methods were applied to reconstruct the ancestral sexual state. [...]
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Viúdez A.,
Journal of Fluid Mechanics, 868, R1, 1-13. DOI: 10.1017/jfm.2019.234 (BibTeX: viudez.2019b)
Resumen: Ver
An exact solution of a baroclinic three-dimensional vortex dipole in geophysical flows with constant background rotation and constant background stratification is provided under the quasi-geostrophic (QG) approximation. The motion of the dipole is unsteady but the potential vorticity contours move rigidly. The vortex comprises three potential vorticity anomaly modes, with a radial dependence given by the spherical Bessel functions and with azimuthal and polar dependences given by the spherical harmonics. The first mode, or spherical mode, accounts for the horizontal asymmetry of the vortex dipole and curvature of the dipole’s horizontal trajectory. The second mode, or dipolar mode, accounts for the speed of displacement of the vortex dipole. A third mode, or vertical tilting mode, accounts for the dipole’s vertical asymmetry. The QG vertical velocity field has two contributions: the first one is octupolar and depends entirely on the dipolar mode, and the second one is dipolar and depends on the nonlinear interaction between dipolar and vertical tilting modes.
Palabras clave: baroclinic flows, quasi-geostrophic flows, vortex dynamics
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Portabella M., W. Lin, A. Stoffelen, A. Verhoef, Z. Wang
Resumen: Ver
Recent developments on the wind geophysical model function (GMF) of Ku-band scatterometers include a sea surface temperature (SST) dependent term. It has been found that the SST effects on the radar backscatter are wind speed dependent and more pronounced in vertical polarization (VV) than in horizontal polarisation (HH) at higher incidence angles, and are mainly relevant at Ku radar wavelengths rather than at C-band. The new Ku-band GMF, NSCAT-5, was initially based on a physical model and RapidScat radar backscatter measurements, which are only available at two incidence angles, i.e., 48.8⁰ and 55.2⁰, for HH and VV beams, respectively. A more recent CDOP-2 AS study (OSI_AVS_17_01) confirms only small differences when verifying the NSCAT-5 GMF at similar incidence angles, using data from the recently-launched Indian SCATSat-1, which operates at 49.1⁰ (HH) and 57.9⁰ (VV) incidence angle. In order to further consolidate the NSCAT-5 GMF, the current study looks for quality control (QC) dependencies. It is found that indeed, the developed GMF is not particularly sensitive to different QC thresholds. Finally, an improved QC method, based on the successful experience with previous Ku-band rotating pencil-beam scatterometers, is developed for SCATSat-1 data.
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Sala M.M., J. Piontek, S. Endres, A.M. Romaní, S. Dyhrman, A.D. Steen
Ed. M.M. Sala, J. Piontek, S. Endres, A.M. Romaní, S. Dyhrman, A.D. Steen. Frontiers Media. ISBN: 978-2-88963-004-2 (BibTeX: sala.etal.2019e)
Resumen: Ver
Microbial extracellular enzymes are fundamental to the cycling of elements in aquatic systems. The regulation of these enzymatic reactions in oceans, lakes and streams is under complex multiple control by environmental factors and the metabolic capacities of different taxa and communities. While the environmental control of enzyme-mediated processes has been investigated for over 100 years, in recent years tremendous progress in techniques to characterize the metabolic potential of microbial communities (“omics” techniques) has been made, such as high-throughput sequencing and new analytical algorithms. This book explores the controls, activities, and biogeochemical consequences of enzymes in aquatic environments. It brings together experimental studies and fieldwork conducted with natural microbial communities in marine and freshwater ecosystems as well as physiological, biochemical and molecular studies o microbial communities in these environments, or species isolated from them. Additionally, the book contributes to the ongoing debate on the impact of anthropogenic climate change and pollution on microbes, extracellular enzymes and substrate turnover.
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Castejón D., G. Rotllant, G. Guerao
Aquaculture, 501, 374-381. DOI: 10.1016/j.aquaculture.2018.11.053 (BibTeX: castejon.etal.2019c)
Resumen: Ver
The common spider crab Maja brachydactyla is an important wild marine resource in many countries in the NE Atlantic region that also has potential in aquaculture. The larval cycle has been replicated successfully in captivity, with highest mortality evident during larval settlement and metamorphosis to first juvenile stage. As an approximation to understanding natural settlement requirements of this species, we examined the need for individual culture to produce first juveniles in the hatchery. In addition, we assessed whether presence of adult exudates and/or a number of different settlement substrates (natural and artificial) influenced larval settlement and metamorphosis under laboratory conditions. Our data demonstrate that M. brachydactyla megalopae reared in communal culture showed similar survival and shorter developmental duration into juvenile crab when compared to individual culture. Presence of adult exudates did not influence the larval survival or development duration to metamorphosis. Survival was not different between control conditions (absence of substrate), artificial substrata (100 to 1000 μm nylon mesh) or natural substrates except for “mud” substrate where no larvae survived to first juvenile stage in this treatment. Duration of the megalopa stage was also not influenced by type of substrate added (natural or artificial) or to a control (no substrate). Results in the present study indicate that M. brachydactyla culture will not require provision of special requirements since communal larval rearing is an efficient and low cost viable strategy and specific exudates or substrates are not required to produce juveniles
Palabras clave: Maja brachydactyla; Megalopae; Communal culture; Chemical odours; Environmental complexity
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Contreras T., M.P. Olivar, P.A. Hulley, M.L. Fernández de Puelles
ICES Journal of Marine Science, 76, 3, 673–689. DOI: 10.1093/icesjms/fsy070 (BibTeX: contreras.etal.2019)
Resumen: Ver
We analysed the trophic ecology of the early ontogenetic stages of six mesopelagic fish species (Bathylagoides argyrogaster, Argyropelecus sladeni, Sternoptyx diaphana, Diaphus vanhoeffeni, Hygophum macrochir, and Myctophum affine), which have different morphologies, vertical distributions, and taxonomic affiliations. The larvae and transforming stages of the sternoptychids fed both during the day and at night. However, larvae of the other species fed during the day, as they apparently rely on light for prey capture. The transforming stages of myctophids showed a similar daylight feeding pattern to their larvae, but in D. vanhoeffeni both day and night feeding was evident, thereby indicating the progressive change toward the adult nocturnal feeding pattern. The number of prey and their maximum sizes were linked to predator gut morphology and gape size. Although the maximum prey size increased with predator development, postflexion larvae and transforming stages also preyed on small items, so that the trophic niche breath did not show evidence of specialization. In all the species, copepods dominated the larval diet, but the transforming stages were characterized by increasing diet diversity. Despite the poor development of these early stages, Chesson’s selectivity index calculated for larvae and transforming stages showed positive selection for particular prey.
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Salat J., J. Pascual, M. Flexas, T.M. Chin, J. Vazquez-Cuervo
Ocean Dynamics, 69, 1067–1084. DOI: 0.1007/s10236-019-01285-z (BibTeX: salat.etal.2019)
Resumen: Ver
Marine and atmospheric parameters, including temperature observations from surface to 80 m (at 6 depths) are measured sinceSeptember 1973 on a higher-than-weekly frequency, at a coastal station 4 km offshore L’Estartit (Costa Brava; NWMediterranean). This constitutes the longest available uninterrupted oceanographic time series in the Mediterranean Sea. Thepresent contribution focuses on observed climatic trends in temperature (°C/year) of air (AT; 0.05), sea surface (SST; 0.03), sea at80 m depth (S80T; 0.02) and sea level (SL; 3.1 mm/year) as well as comparison with trends estimated from coincident high-resolution satellite data. The trending evolution is not uniform across seasons, being significantly higher in spring for both ATandSST, while in autumn for S80T. Other climatological results are a stratification increase (0.02 °C/year in summer temperaturedifference between 20 m (S20T) and S80T), trends in summer conditions at sea (when S20T > 18 °C), estimated as 0.5 and0.9 days/year for the starting day and period respectively, and a decreasing trend of nearly 2 days/year in the period of conditionsfavourable for marine evaporation (when AT < SST). This last trend may be related to the observed decrease of coastalprecipitation in spring. The long-term consistency in the in situ SST measurements presents an opportunity to validate themulti-decadal trends. The good agreement for 2013–2018 (RMS 0.5–0.6, bias−0.1 to−0.2; trends of 0.09 °C/year in situ vs.0.06 to 0.08 °C/year from satellite) allows considering this observational site as ground truth for satellite observations and amonitoring site for climate change
Palabras clave: Oceanographic time series.Climate trends.Satellite ground truth.Stratification.Seasonality.Mediterranean Sea
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Gras C., D. Dagnino, C.E. Jiménez-Tejero, A. Meléndez, V. Sallarès, C.R. Ranero
Solid Earth, 10, 6, 1833-1855. DOI: 10.5194/se-10-1833-2019 (BibTeX: gras.etal.2019a)
Resumen: Ver
We present a high-resolution P-wave velocity model of the sedimentary cover and the uppermost basement to ∼3 km depth obtained by full-waveform inversion of multichannel seismic data acquired with a 6 km long streamer in the Alboran Sea (SE Iberia). The inherent non-linearity of the method, especially for short-offset, band-limited seismic data as this one, is circumvented by applying a data processing or modelling sequence consisting of three steps: (1) data re-datuming by back-propagation of the recorded seismograms to the seafloor; (2) joint refraction and reflection travel-time tomography combining the original and the re-datumed shot gathers; and (3) full-waveform inversion of the original shot gathers using the model obtained by travel-time tomography as initial reference. The final velocity model shows a number of geological structures that cannot be identified in the travel-time tomography models or easily interpreted from seismic reflection images alone. A sharp strong velocity contrast accurately defines the geometry of the top of the basement. Several low-velocity zones that may correspond to the abrupt velocity change across steeply dipping normal faults are observed at the flanks of the basin. A 200–300 m thick, high-velocity layer embedded within lower-velocity sediment may correspond to evaporites deposited during the Messinian crisis. The results confirm that the combination of data re-datuming and joint refraction and reflection travel-time inversion provides reference models that are accurate enough to apply full-waveform inversion to relatively short offset streamer data in deep-water settings starting at a field-data standard low-frequency content of 6 Hz.
Vandeputte M., F. Piferrer
In: Sex Control in Aquaculture, Ed. H. Wang, F. Piferrer, S.L Chen, Z.-G.Shen. Wiley-Blackwell. Chap. 14. 305-325. DOI: 10.1002/9781119127291.ch14 ISBN: 978-1-119-12726-0 (BibTeX: vandeputte.piferrer.2019a)
Resumen: Ver
The European sea bass (Dicentrarchus labrax) is a major species for Mediterranean aquaculture, with more than 160 000 tons produced yearly. It has a haploid genome size of 675 Mb, distributed in 24 chromosome pairs, without sex chromosomes. The sex ratio of wild populations is mildly, but significantly, biased towards females. However, under the farming environment, sex ratios are highly male‐biased. This, along with the fact that males grow about 30% slower than females and mature earlier, has prompted interest in the control of its sex ratio and the elucidation of its sex determining mechanism. European sea bass is a gonochoristic species with polygenic sex determination (>3 sex ratio associated QTLs), in which the contribution of genetics and the environment to sex ratio variance is approximately equal. However, the identity of the sex determining factor(s) remains unknown. There is a strong influence of the parental genotypes on the offspring sex ratio, which can vary from < 10% to ≈ 90% females. The heritability estimate of sex tendency is high (h 2 = 0.62). Sex determination is thought to occur when fish are 3–4 cm in length, and sex related growth is apparent early, before the morphological sex differentiation of the gonads takes place. Temperatures higher than 17 °C during the thermosensitive period (0–60 days post‐fertilization) have a masculinizing effect. Manipulating growth through feeding during the sex differentiation period does not alter sex ratios. Combining selective breeding and environmental control is expected to lead to the production of female‐biased populations with superior growth.
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Lotze H.K., D.P. Tittensor, A. Bryndum-Buchholz, T.D. Eddy, W.W. L. Cheung, E.D. Galbraith, M.l Barange, N. Barrier, D. Bianchi, J.L. Blanchard, L. Bopp, M. Büchner, C.M. Bulman, D.A. Carozza, V. Christensen, M. Coll, J.P. Dunne, E.A. Fulton, S. Jennings, M.C. Jones, S. Mackinson, O. Maury, S. Niiranen, R. Oliveros-Ramos, T. Roy, J.A. Fernandes, J. Schewe, Y.-J. Shin, T.A.M. Silva, J. Steenbeek, C.A. Stock, P. Verley, J. Volkholz, N.D. Walker, B. Worm
Proceedings of the National Academy of Sciences of the United States of America, 116, 26, 1207-12912. DOI: 10.1073/pnas.1900194116 (BibTeX: lotze.etal.2019b)
Resumen: Ver
Climate change can affect the distribution and abundance of marine life, with consequences for goods and services provided to people. Because different models can lead to divergent conclusions about marine futures, we present an integrated global ocean assessment of climate change impacts using an ensemble of multiple climate and ecosystem models. It reveals that global marine animal biomass will decline under all emission scenarios, driven by increasing temperature and decreasing primary production. Notably, climate change impacts are amplified at higher food web levels compared with phytoplankton. Our ensemble projections provide the most comprehensive outlook on potential climate-driven ecological changes in the global ocean to date and can inform adaptive management and conservation of marine resources under climate change
Palabras clave: Climate change impacts; Marine food webs; Global ecosystem modeling; Model intercomparison; Uncertainty
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Rosa R., V. Pissarra, F.O. Borges, J. Xavier, I.G. Gleadall, A. Golikov, G. Bello, L. Morais, F. Lishchenko, A. Roura, H. Judkins, C.M. Ibáñez, U. Piatkowski, M. Vecchione, R. Villanueva
, 6, 469. DOI: 10.3389/fmars.2019.00469 (BibTeX: rosa.etal.2019a)
Resumen: Ver
Within the context of global climate change and overfishing of fish stocks, there is some evidence that cephalopod populations are benefiting from this changing setting. These invertebrates show enhanced phenotypic flexibility and are found from polar regions to the tropics. Yet, the global patterns of species richness in coastal cephalopods are not known. Here, among the 370 identified-species, 164 are octopuses, 96 are cuttlefishes, 54 are bobtails and bottletails, 48 are inshore squids and 8 are pygmy squids. The most diverse ocean is the Pacific (with 213 cephalopod species), followed by the Indian (146 species) and Atlantic (95 species). The least diverse are the Southern (15 species) and the Arctic (12 species) Oceans. Endemism is higher in the Southern Ocean (87%) and lower in the Arctic (25%), which reflects the younger age and the “Atlantification” of the latter. The former is associated with an old lineage of octopuses that diverged around 33 Mya. Within the 232 ecoregions considered, the highest values of octopus and cuttlefish richness are observed in the Central Kuroshio Current ecoregion (with a total of 64 species), followed by the East China Sea (59 species). This pattern suggests dispersal in the Central Indo-Pacific (CIP) associated with the highly productive Oyashio/Kuroshio current system. In contrast, inshore squid hotspots are found within the CIP, namely in the Sunda Shelf Province, which may be linked to the occurrence of an ancient intermittent biogeographic barrier: a land bridge formed during the Pleistocene which severely restricted water flow between the Pacific and Indian Oceans, thereby facilitating squid fauna differentiation. Another marked pattern is a longitudinal richness cline from the Central (CIP) toward the Eastern Indo-Pacific (EIP) realm, with central Pacific archipelagos as evolutionary dead ends. In the Atlantic Ocean, closure of the Atrato Seaway (at the Isthmus of Panama) and Straits of Gibraltar (Mediterranean Sea) are historical processes that may explain the contemporary Caribbean octopus richness and Mediterranean sepiolid endemism, respectively. Last, we discuss how the life cycles and strategies of cephalopods may allow them to adapt quickly to future climate change and extend the borealization of their distribution.
Palabras clave: Biogeography; Mollusk; Cephalopod; Cuttlefish; Squid; Octopus; Species richness
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Bosch-Belmar M., A. Escurriola, G. Milisenda, V.L. Fuentes, S. Piraino
Journal of Marine Science and Engineering, 7, 288, 1-18. DOI: 10.3390/jmse7090288 (BibTeX: boschbelmar.etal.2019)
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Colmenero A.I., C. Barría, P. Abelló
Cahiers de Biologie Marine, 60, 201-204. DOI: 10.21411/CBM.A.132E04E9 (BibTeX: colmenero.etal.2019a)
Resumen: Ver
The crucifix crab Charybdis feriata (Linnaeus, 1758) is reported for the third time in the Mediterranean Sea. An adult male was captured on 6th November 2017 with a trammel net in the fishing grounds off Tarragona at 22 m depth on sandy-muddy bottoms. The record from this study confirms the spreading of C. feriata throughout the northwestern Mediterranean Sea, and allows inferring the occurrence of an established population in the area, although so far at a low settlement level.
Palabras clave: Charybdis feriata; Portunid swimming crab; Invasive species; Range extension; Mediterranean Sea
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Ruiz-González C., R. Logares, M. Sebastián, M. Mestre, R. Rodríguez-Martínez, M. Galí, M.M. Sala, S.G. Acinas, C.M. Duarte, J.M. Gasol
Molecular ecology, 28, 1930-1945. DOI: 10.1111/mec.15026 (BibTeX: ruizgonzalez.etal.2019a)
Resumen: Ver
Microbial taxa range from being ubiquitous and abundant across space to extremely rare and endemic, depending on their ecophysiology and on different processes acting locally or regionally. However, little is known about how cosmopolitan or rare taxa combine to constitute communities and whether environmental variations promote changes in their relative abundances. Here we identified the Spatial Abundance Distribution (SpAD) of individual prokaryotic taxa (16S rDNA‐defined Operational Taxonomic Units, OTUs) across 108 globally‐distributed surface ocean stations. We grouped taxa based on their SpAD shape (“normal‐like”‐ abundant and ubiquitous; “logistic”‐ globally rare, present in few sites; and “bimodal”‐ abundant only in certain oceanic regions), and investigated how the abundance of these three categories relates to environmental gradients. Most surface assemblages were numerically dominated by a few cosmopolitan “normal‐like” OTUs, yet there was a gradual shift towards assemblages dominated by “logistic” taxa in specific areas with productivity and temperature differing the most from the average conditions in the sampled stations. When we performed the SpAD categorization including additional habitats (deeper layers and particles of varying sizes), the SpAD of many OTUs changed towards fewer “normal‐like” shapes, and OTUs categorized as globally rare in the surface ocean became abundant. This suggests that understanding the mechanisms behind microbial rarity and dominance requires expanding the context of study beyond local communities and single habitats. We show that marine bacterial communities comprise taxa displaying a continuum of SpADs, and that variations in their abundances can be linked to habitat transitions or barriers that delimit the distribution of community members.
Palabras clave: dispersal environmental transitions global surface ocean Malaspina expedition marine prokaryotic communities rare bacteria spatial abundance distribution
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Sebastián M., M. Estrany, C. Ruiz-González, I. Forn, M.M. Sala, J.M. Gasol, C. Marrasé
Frontiers in Microbiology, 10, 760, 1-12. DOI: 10.3389/fmicb.2019.00760 (BibTeX: sebastian.etal.2019a)
Resumen: Ver
Experiments with bacteria in culture have shown that they often display “feast and famine” strategies that allow them to respond with fast growth upon pulses in resource availability, and enter a growth-arrest state when resources are limiting. Although feast responses have been observed in natural communities upon enrichment, it is unknown whether this blooming ability is maintained after long periods of starvation, particularly in systems that are energy limited like the bathypelagic ocean. Here we combined bulk and single-cell activity measurements with 16S rRNA gene amplicon sequencing to explore the response of a bathypelagic community, that had been starved for 1.6 years, to a sudden organic carbon supply. We observed a dramatic change in activity within 30 h, with leucine incorporation rates increasing over two orders of magnitude and the number of translationally active cells (mostly Gammaproteobacteria) increasing 4-fold. The feast response was driven by a single operational taxonomic unit (OTU) affiliated with the Marinobacter genus, which had remained rare during 7 months of starvation. Our work suggests that bathypelagic communities harbor a seed bank of highly persistent and resourceful “feast and famine” strategists that might disproportionally contribute to carbon fluxes through fast responses to occasional pulses of organic matter.
Palabras clave: Long-term starvation; Microbial seed bank; Prokaryotes; Bathypelagic; Deep ocean; Bacteria
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Hackert E.C., R.M. Kovach, A.J. Busalacchi, J. Ballabrera-Poy
Journal of Geophysical Research: Oceans, 124, 7, 4546-4556. DOI: http://dx.doi.org/10.1029/2019JC015130 (BibTeX: hackert.etal.2019)
Resumen: Ver
This study demonstrates the positive impact of including gridded Aquarius and Soil Moisture, Active/Passive (SMAP) sea surface salinity (SSS) into initialization of intermediate complexity coupled model forecasts for the tropical Indo‐Pacific. An experiment that assimilates conventional ocean observations serves as the control. In a separate experiment, Aquarius and SMAP satellite SSS are additionally assimilated into the coupled model initialization. Analysis of the initialization differences with the control indicates that SSS assimilation causes a freshening and shallowing of the mixed layer depth near the equator and enhanced Kelvin wave amplitude. For each month from September 2011 to September 2017, 12‐month‐coupled ENSO forecasts are initialized from both the control and satellite SSS assimilation experiments. The experiment assimilating Aquarius and SMAP SSS significantly outperforms the control relative to observed NINO3.4 sea surface temperature anomalies. This work highlights the potential importance of inclusion of satellite SSS for improving the initialization of operational ENSO coupled forecasts.
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Grieco G., A. Stoffelen, M. Portabella
Proc. of the International Geoscience and Remote Sensing Symposium (IGARSS), Yokohama, Japan, 28 July - 2 August, . (BibTeX: grieco.etal.2019b)
Resumen: Ver
This paper presents an assessment of the effects of specular point (SP) estimation inaccuracies on the Signal to Noise Ratio peak (SNRPEAK) used for ocean wind speed retrievals from TechDemoSat-1 (TDS-1) Delay Doppler Maps (DDMs). Results show that the more inaccurate the estimated Doppler frequency at the SP, the lower the intensity of the SNRPEAK. Differences may be up to 2 dB.
Palabras clave: GNSS-R, SNR peak, Doppler frequency, specular point.
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Ortega A., N.R. Geraldi, I. Alam, A.A. Kamau, S.G. Acinas, R. Logares, J.M. Gasol, R. Massana, D. Krause-Jensen, C.M. Duarte
Nature Geoscience, 12, 748-754. DOI: 10.1038/s41561-019-0421-8 (BibTeX: ortega.etal.2019a)
Resumen: Ver
The role of macroalgae in Blue Carbon assessments has been controversial, partially due to uncertainties about the fate of exported macroalgae. Available evidence suggests that macroalgae are exported to reach the open ocean and the deep sea. Nevertheless, this evidence lacks systematic assessment. Here, we provide robust evidence of macroalgal export beyond coastal habitats. We used metagenomes and metabarcodes from the global expeditions Tara Oceans and Malaspina 2010 Circumnavigation. We discovered macroalgae worldwide at up to 5,000 km from coastal areas. We found 24 orders, most of which belong to the phylum Rhodophyta. The diversity of macroalgae was similar across oceanic regions, although the assem-blage composition differed. The South Atlantic Ocean presented the highest macroalgal diversity, whereas the Red Sea was the least diverse region. The abundance of macroalgae sequences attenuated exponentially with depth at a rate of 37.3% km−1, and only 24% of macroalgae available at the surface were expected to reach the seafloor at a depth of 4,000 m. Our findings indicate that macroalgae are exported across the open and the deep ocean, suggesting that macroalgae may be an important source of allochthonous carbon, and their contribution should be considered in Blue Carbon assessments.
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Ercilla G., C. Juana, R. Periáñez, B. Alonso, J.M. Abril, F. Estrada, D. Casas, J.T. Vázquez, E. d’Acremont, C. Gorini, B. El Moumni, D. Do Couto, J. Valencia
Deep-Sea Research. Part I: Oceanographic Research Papers, 144, 1-16. DOI: 10.1016/j.dsr.2018.12.002 (BibTeX: ercilla.etal.2019a)
Resumen: Ver
This is an interdisciplinary study that combines morphoseismics, sedimentology and numerical modelling to elucidate at different scales of resolution the influence of alongslope processes on the turbidite systems (TSs) and canyons in the Alboran Sea (southwestern Mediterranean). Nine TSs are mapped in the Spanish margin (La Linea, Guadiaro, Baños, Torrenueva, Fuengirola, Salobreña, Sacratif, Calahonda and Almeria) and two in the Alboran Ridge (Piedra Escuela and Al-Borani). In the Moroccan margin, there are only two canyons (Ceuta and Nekor). Distinctive morphoseismic and sedimentological signatures from TSs and canyons have enabled three regional models of alongslope influence to be distinguished: a) Alongslope processes are dominant. This scenario characterizes the canyons of the Moroccan margin. The diagnostic signature is the lack of leveed channels and lobes at the Ceuta and Nekor Canyon mouths. b) Different degrees of interplay exist between alongslope and downslope processes. This scenario occurs in the TSs of the western Spanish margin. Here, the alongslope influence on TSs (La Linea, Guadiaro, Baños, Torrenueva and Fuengirola) is evidenced by the lack of overbank deposits in the La Linea and Guadiaro Canyons and an alongslope trend in the morpho-architecture of the channelized lobes and in the textural distribution of canyon/channel deposits (mass-flow deposits and turbidites). Both signatures indicate sandier TSs as well as Bouma turbidite sequences lacking the finest levels towards the Strait of Gibraltar. Local intercalations of contourites are also present in the Guadiaro lobe deposits. c) Downslope processes are dominant. This scenario characterizes the TSs of the eastern and central Spanish margin and Alboran Ridge. There, TSs seem to be controlled solely by the characteristics of the downslope gravity flows that transport sediment. The hydrodynamic and sediment dispersion models confirm that the main oceanographic factors governing the variable alongslope influence in TSs and canyons are the following: a vigorous WMDW flow along the Moroccan margin and the energetic Atlantic Jet, western Atlantic anticyclonic gyre and general acceleration of the Mediterranean waters towards the Strait of Gibraltar, along the western Spanish margin. This study demonstrates the pivotal role that alongslope processes can play in the onset and formation of TSs and canyons at continental margins.
Palabras clave: Turbidite system; Morphoseismic; Sediments; Alongslope processes; Downslope processes; Alboran Sea
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Salvadó J., J.O. Grimalt, J.F. López, A. Palanques, M. Canals
Science of The Total Environment, 647, 597-605. DOI: 10.1016/j.scitotenv.2018.07.458 (BibTeX: salvado.etal.2019b)
Resumen: Ver
The significance of the offshore vertical convection currents in the transport and sinking of water-soluble organic pollutants into marine deep basins has been evaluated. For this purpose, sediment cores were collected in the Gulf of Lion (GoL) at sites between 26 and 2330 m water depth. The top core layers were analyzed for aromatic and aliphatic hydrocarbons and organochlorine compounds. Organic compounds with logKAW (air water partition coefficient) between −2 and −4, e.g. lindane, PCB 28, PCB 52, phenanthrene, methylphenanthrenes, dimethylphenanthrenes, C14–C23n-alkanes, are found in higher concentrations or exhibit relative concentration increases in the sediments deposited in the continental rise as consequence of the open-sea convection processes associated with the formation of Western Mediterranean Deep Water (WMDW). In contrast, the organic pollutants with intermediate air-water distribution coefficients, logKAW between −2 and 0, and high octanol water distribution coefficients (logKow > 6), e.g. highly chlorinated PCBs, DDTs, DDEs, DDDs, C25–C35n-alkanes, and polycyclic aromatic hydrocarbons with molecular weight higher than 200, occur in association to sediment particles, which are mainly transported by the Northern current along the continental shelf forming the mud belt. The Rhône prodelta is therefore the area of the GoL showing the highest concentrations of this group of organic compounds, which are preferentially associated with water particles. Overall, the results show that vertical open-sea convection processes related with offshore formation of WMDW may have an important role in the transport and accumulation of water soluble pollutants to deep marine environments of the GoL (>2000 m water depth).
Palabras clave: Organochlorine compounds; Aliphatic hydrocarbons; Polycyclic aromatic hydrocarbons; Marine sediments; Western Mediterranean; Deep water formation
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Martínez‐Loriente S., V. Sallarès, C.R. Ranero, J.B. Ruh, U. Barckhausen, I. Grevemeyer, N. Bangs
Tectonics, 38, 12, 4360-4377. DOI: 10.1029/2019TC005586 (BibTeX: martinezloriente.etal.2019a)
Resumen: Ver
We present a 2‐D P wave velocity model and a coincident multichannel seismic reflection profile characterizing the structure of the southern Costa Rica margin and incoming Cocos Ridge. The seismic profiles image the ocean and overriding plates from the trench across the entire offshore margin, including the structures involved in the 2002 Osa earthquake. The overriding plate consists of three domains: Domain I displays thin‐skinned deformation of an imbricate thrust system composed of fractured rocks. Domain II shows ~15‐km‐long landward dipping reflection packages and active deformation of the shelf sediment. Domain III is little fractured and appears to be dominated by elastic deformation, overlain by ~2‐km‐thick landward dipping strata. The velocity structure supports the argument that the bulk of the margin is highly consolidated rock. Thick‐skinned tectonics probably causes the uplift of Domains II and III. The oceanic plate shows crustal thickness variations from ~14 km at the trench (Cocos Ridge) to 6–7 km beneath the shelf. We combine (1) interplate geometry and fracturing degree, (2) tectonic stresses and brittle strain, and (3) earthquake locations, to investigate relationships between structure and earthquake generation. The 2002 Osa sequence nucleated at the leading flank of subducting seamounts in the area of highest tectonic overpressure. Both estimated rock fracturing and modeled brittle strain steadily increase from the leading flank of the subducting seamounts to their top, reflecting the progressive damage caused by the seamount. Therefore, the seismicity and structural‐mechanical evolution of the upper plate reflect the downward propagation of the leading edge of seamounts.
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Teixeira M., P. Terrinha, C. Roque, M. Rosa, G. Ercilla, D. Casas
Marine Geology, 410, 88-108. DOI: 10.1016/j.margeo.2018.12.011 (BibTeX: teixeira.etal.2019b)
Resumen: Ver
An integrated analysis of multibeam bathymetry and single- and multichannel seismic records were used to image the morpho-stratigraphy of the Alentejo Margin (Southwest Portuguese Continental Margin). The complex interaction of several alongslope and downslope processes in the area leads to the formation of various bottom current driven depositional and erosive features (moat) as well as gravity-driven features (gullies and landslides) in the Alentejo Margin. These processes feed each other contributing for the active sedimentary pattern on the area. Sines Contourite Drift (SCD) is a ~2311 km2 sedimentary feature with a perimeter of 303.9 km, 98 km length and 35 km width. Landslides occur either on steep and on gentle slopes between ~200 and 3200 mwd (meters water depth) in the study area, which has a total extent of ~85 km × 82 km. Scar concentration is higher in the middle- and lower-slope, whereas the thickest debris deposits are found in the slope basin area - Lebre Basin (LB). Translational landslides, with planar failure planes parallel to the slope surface are the main landslide typology verified in the study area. Several triggering and pre-conditioning factors, resulting from the interaction of alongslope and downslope processes, contribute for varied landslides scar concentration. Steep-slope and high sedimentation rates favour sediments under-consolidation, promoting excess pore water pressure and weak layers formation. In this paper, we show that the interaction of bottom currents with pre-existing tectonic structures promotes the complex interaction of both alongslope and downslope processes thus promoting an active and diversified geomorphological evolution and generalised slope instability.
Palabras clave: Sedimentary processes; Morphosedimentary features; Contourite drift; Bottom currents; Slope instability; Submarine landslides; Triggering and pre-conditioning factors
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Castillo de la Peña Y.M.,
PhD thesis. Director/es: D. Vaqué, M. Sebastián. Barcelona. 1-203. (BibTeX: castillodelapena.2019a)
Resumen: Ver
Marine viruses are key components of marine microbial communities, as they influence the cellular abundances and the community structure of microbes, participate in their genetic exchange, and intervene in the ocean biogeochemical cycles. Moststudies dealing with the role of viruses in the marine environment have been done from abulk community point of view, but going from thebulk community perspective to specific virus-host relationships is essential in order to understand the role of viruses in shapinga determined host community, in modifying host genomes, and ultimately in the release of organic compounds from the lysed cells. For this reason, in this thesis we implemented and applied different methodologies that are able to detect, visualize and quantify virus-host interactions in marine eukaryotes at the single cell level. We focused on picoeukaryotes (cells <3μm) because they play crucial roles in marine food webs and biogeochemical cycles, and virus─host interactions in natural populations of these minute eukaryotes are largely unknown. [...]
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Orué-Echevarría D., J.L. Pelegrí, F. Machín, A. Hernández-Guerra, M. Emelianov
Journal of Geophysical Research: Oceans, 124, 1, 527-554. DOI: 10.1029/2018JC014733 (BibTeX: orueechevarria.etal.2019d)
Resumen: Ver
The Brazil‐Malvinas Confluence arises from the frontal encountering of the subtropical Brazil Current and subantarctic Malvinas Current. It displays a complex regional circulation that is accompanied by mesoscale features and thermohaline intrusions. Here we combine altimetry and cruise data to describe the circulation pattern in the upper 2,000 m at two spatial scales encircling the frontal system. The major regional features appear south of the confluence latitude at 39–40°S: (a) a relatively weak Malvinas Current near 41°S, 56°W (28.3 ± 1.4 Sv), followed by its cyclonic retroflection; (b) an intense subtropical anticyclone (59.3 ± 10.7 Sv) that replaces the Brazil Current overshoot; and (c) a very intense subantarctic inflow (78.9 ± 13.7 Sv) near 53°W that is maintained through both an upstream (near 42°S) earlier diversion of the Malvinas Current and the cyclonic recirculation of the flow exiting east along the confluence. North of the confluence, the Brazil Current provides a net input of 30.8 ± 12.0 Sv (29.1 ± 8.3 Sv along the slope). The southern inflow splits nearly equal between barotropic and baroclinic contributions while the entire northern flow is essentially baroclinic. These northern and southern inputs add to an eastward along‐front transport of 109.7 ± 15.1 Sv, with significant contribution of highly oxygenated, relatively fresh Subantarctic Mode and Antarctic Intermediate Waters (58.7 ± 5.6 Sv). The regional circulation experiences substantial temporal variability, with southern waters flowing into the Brazil‐Malvinas Confluence through along‐slope and interior pathways and partly recirculating within the subtropical South Atlantic gyre.
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Gras Andreu C.,
PhD thesis. Director/es: V. Sallarès, C. Rodríguez Ranero. Barcelona. 1-223. (BibTeX: grasandreu.2019a)
Resumen: Ver
This thesis presents the implementation and application of a procedure combining different geophysical techniques to extract high-resolution information that helps characterizing the structure and properties (p-wave velocity, Vp) of the subsurface by using marine multichannel seismic (MCS) data alone. The challenge is overcoming the inherent non-linearity and non-uniqueness of inverse methods, in general, and of fullwaveform inversion (FWI), in particular, which are especially critical for short-offset, band-limited seismic data. I have applied an in-house modelling workflow consisting of three steps: (1) data re-datuming or downward continuation (DC) by back-propagation of the recorded seismograms to the seafloor; (2) travel-time tomography (TTT) using the first arrivals of the re-datumed shot gathers (synthetic data), combined with those of a reflecting boundary in the original data (field data); and (3) FWI of the original shot gathers using the model obtained by TTT as initial reference. This workflow is first tested with synthetic data, and then applied to field data acquired in the Alboran Sea Basin (SE of Iberia). [...]
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Vilas D., M. Coll, T. Pedersen, X. Corrales, K. Filbee-Dexter, M. Foldager Pedersen, K.M. Norderhaug, S. Fredriksen, T. Wernberg, E. Ramírez-Llodra
Journal of Marine Systems, 203, 103268. DOI: 10.1016/j.jmarsys.2019.103268 (BibTeX: vilas.etal.2019a)
Resumen: Ver
The flow of non-living carbon (detritus) is considered an important process because it connects ecosystems and fuels benthic communities. In Norwegian kelp forests, 90% of the kelp production is exported to adjacent ecosystems where it can play a significant role in shaping benthic communities. We quantified the major structural and functional traits of an Arctic deep-sea ecosystem associated with kelp exports and assessed the ecological role of kelp export into the deep-sea system. We first developed a food-web model using the Ecopath with Ecosim (EwE) approach to represent the state of the deep (450 m) ecosystem of the Malangen fjord (Northern Norway) in 2017. Subsequently, we used the temporal dynamic model Ecosim to explore the structure and functioning traits of a theoretical deep-sea ecosystem projecting a decrease of kelp detritus biomass reaching the deep-sea ecosystem. Overall, our findings reveal that kelp detritus from shallow coastal areas has a small but noticeable role structuring the deep-sea ecosystem of Malangen. The temporal simulations show important differences depending on the application of mediating effects, which allow considering the detritus as a mediating group in prey-predator interaction, in addition to its direct role in trophic relationships. When mediating effects are applied, biomass increases for benthopelagic shrimps and suprabenthos groups and decreases for rays and skates, velvet belly, rabbitfish and other commercial demersal fishes under the low kelp detritus scenarios. Biomass-based and trophic-based indicators reveal a noticeable impact on the deep-sea ecosystem structure due to depletion of kelp detritus. To further assess future changes of the Arctic deep-sea ecosystems, dependencies with adjacent ecosystems, such as kelp detritus production, should be included.
Palabras clave: Kelp detritus; Particulate organic matter; Arctic ecosystem; Ecosystem structure; Mediation effect; Ecopath with Ecosim
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Flo E., E. Garcés, J. Camp
, 6, 18. DOI: 10.3389/fmars.2019.00018 (BibTeX: flo.etal.2019a)
Resumen: Ver
Human activities on land result in the high-level production of nutrients. When these nutrients reach coastal waters, they could drive the eutrophication process. Here we present the Land Uses Simplified Index (LUSI), an easy-to-use tool for assessing continental pressures on coastal waters. This assessment is done by indirectly estimating continental nutrient loads and concentrations, and their influence on coastal waters. LUSI is based on systematic information describing both the land uses that influence coastal waters by providing nutrient-rich freshwater inflows (urban, industrial, agricultural, and riverine) and the coastline morphology, which can modify this influence, as it determines the degree of coastal water confinement and therefore the likelihood that these inflows will be diluted. A low LUSI value indicates that coastal waters are not or only slightly influenced by continental pressures and/or that these pressures are diluted. On the contrary, a high LUSI value indicates that coastal waters are strongly influenced by continental pressures and/or that these pressures are not diluted. LUSI fulfills a methodological gap, as a simple method to assess coastal pressures when there is a lack of information. Furthermore, it fulfills the requirement of the Water Framework Directive for a true pressure assessment (i.e., not confounded with impact), which for coastal waters imply using pressure data from land. An additional and important feature of LUSI is that it allows the establishment of pressure-impact relationships with impact indicators, such as those related to the Biological Quality Elements of the above Directive. For example, a relationship based on LUSI, as a proxy of pressure, and on the chlorophyll-a concentration, as a proxy of phytoplanktonic biomass and, thus, of the eutrophication impact. By providing insights into the land uses that trigger eutrophication in coastal waters, LUSI aids in the design of measures aimed at remediating anthropogenic damage caused to the environment.
Palabras clave: Land uses; Pressure assessment; Coastal waters; Pressure-impact relationship; Chlorophyll-A; Dissolved inorganic nutrients; Water Framework Directive
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Salazar Guiral G.,
PhD thesis. Director/es: S.G. Acinas, J.M. Gasol. (BibTeX: salazarguiral.2019b)
Resumen: Ver
The dark ocean contains about 70% of the ocean’s microbial cells and 60% of its het- erotrophic activity, which is mainly fueled by the flux of organic particles produced in the surface ocean and exported to the bathypelagic ocean (1,000 – 4,000 m depth). The bathypelagic ocean represents a nonhomogeneous environment and contains a variety of particles that are considered as the main supply of organic carbon to this environment. The microorganisms inhabiting this realm play a pivotal regulatory role in the biogeo- chemical cycles at a planetary scale. Accordingly, the study of these microorganisms is an essential step to decipher the ecological functioning of the deep ocean. Chapters 1 to 3 in this Thesis are dedicated to the description of the prokaryotic com- munity composition in the bathypelagic ocean at a global scale through the sequencing of ribosomal DNA and RNA fragments using data collected during the Malaspina 2010 expedition. Chapter 1 identifies the dominant prokaryotes in the deep ocean and reveals a high proportion (~50%) of previously undescribed prokaryotes. The water masses and the structure of the deep ocean’s floor, organized into basins, are identified as the main drivers of their biogeography. Chapter 2 addresses the differences between free-living and par- ticle-attached bathypelagic prokaryotic communities. This is shown to be a phylogeneti- cally conserved trait, indicating that the bathypelagic particles and the water surrounding them constitute two distinct niches and that transitions from one to the other have been rare at an evolutionary timescale. Finally, in Chapter 3 we identify a linear relationship between the 16S RNA/DNA ratio and particle attachment preference, suggesting a global relationship between the prokaryote’s preference for a particle-attached lifestyle and their growth rate. While the deep ocean is a highly unexplored environment, a more complete knowledge exists for the epipelagic ocean (0 – 200 m depth). Steep gradients of light intensity and quality, temperature and nutrient availability characterize the oceans and impact on the distribution of species. However, different processes, such as the sinking of particles and the vertical movement of water masses, have been described as mechanisms capable of connecting the surface and deep layers of the ocean. These same processes could trans- port entire prokaryotic communities, a process theoretically proposed but never tested. In Chapter 4 we develop a tool (mtagger) for the extraction of short 16S ribosomal reads from metagenomes to describe the taxonomical composition of microbial communities. We propose and evaluate technical improvements compared to previous versions as a benchmark for its use in the last chapter. Chapter 5 is dedicated to the development of a modeling tool (disperflux) for the analysis of prokaryotic communities’ connectivity using data collected during the Tara Oceans expedition. We observe and describe a fast- decay relationship between community similarity and depth, which is consistently fitted by a power-law across the whole dataset, with the exception of 5 stations that are compat- ible with events of whole community export from the photic ocean to the mesopelagic. In summary, this Thesis significantly contributes to the knowledge on the ecological functioning of marine prokaryotes by describing the structure of prokaryotic communi- ties along the bathypelagic realm and the vertical gradient of the ocean and by the devel- opment of original methodological tools that may be applied to a variety of environments.
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Guallar C., J. Flos
Progress in Oceanography, 176, (BibTeX: guallar.flos.2019)
Resumen: Ver
The link between phytoplankton primary production (PPP) and chromophoric dissolved organic matter (CDOM) has been demonstrated indirectly in the laboratory, but not directly in the sea. Here, for the first time, we report a strong link between PPP and CDOM in a study carried out in coastal marine waters around Barcelona (NW Mediterranean) in contrasting seasons. We measured relevant correlations between a254 CDOM concentration and both PPP (r=0.89, p < 0.001, n=16; r=0.76, p < 0.01, n=10; and r=0.68, p < 0.001, n=26; for summer, winter–spring and both seasons together, respectively) and the specific production rate at optimal light intensity (Pm B; r=0.77, p < 0.001, n=16; r=0.86, p < 0.01, n=10; and r=0.85, p < 0.001, n=26; for the same seasons). Based on our findings, we design a model that predicts PPP very well, using a254 CDOM, water temperature and photosynthetically active radiation (PAR) (R2=0.84, p < 0.001, n=26). Relationships between CDOM concentration parameters (measured at wavelengths of 280, 300, 340, 355, 375, 412 and 460 nm) and variables associated to CDOM processes (chlorophyll-a, bacterial abundance, turbidity related to sediment resuspension and PAR) were also evaluated. Bacterial abundance is significantly correlated with CDOM concentration measured at higher wavelengths when all samples are considered (e.g., r=0.82, p < 0.001, n=26, for a355 CDOM). However, in seasonal data analysis, the correlations decrease slightly (summer season: e.g., r=0.79, p < 0.001, n=16, for a355 CDOM) or become non-significant (winter– spring season: e.g., r=-0.02, p=0.95, n=10, for a355 CDOM). Sunlight photobleaching and sediment resuspension processes significantly influence CDOM dynamics in the summer (for a300 CDOM: r=-0.72, p < 0.001, n=16; and r=0.67, p < 0.01, n=16, respectively).
Palabras clave: Phytoplankton primary production Carbon uptake CDOM production Bacteria Photodegradation Sediment resuspension
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Garcia X., J. Julià, A.M. Nemocón, M. Neukirch
Gondwana Research, 68, 174-184. DOI: 10.1016/j.gr.2018.11.013 (BibTeX: garcia.etal.2019b)
Resumen: Ver
The lithospheric architecture of the western Borborema Province and northern São Francisco craton of NE Brazil has been investigated through analysis of long-period magnetotelluric data acquired along a 700 km long survey, using 12 instruments. The survey samples several tectonic terrains in the Province and penetrates into the adjacent São Francisco craton after crossing the Araripe Basin, an aborted rift basin filled with Mesozoic sediments that peak at ∼1000 m above mean sea level. High conductivities are observed at shallow depths under the main Precambrian shear zones that pervade the Province – consistent with tectonic reactivation – and as a small patch embedded within the high resistivities that characterize the São Francisco craton. High conductivities (∼25 Ωm) are also observed below 120 km depth between the Patos and Pernambuco lineaments – right under the Araripe Basin – flanked by resistive (>120 Ωm) material immediately to the north and south. This deep, highly conductive body is found consistent with the presence of melt and aqueous fluids, and is interpreted as shallow asthenospheric mantle bounded by thicker lithosphere. We propose that extensional stresses in the Mesozoic stretched and thinned the lithosphere under the Araripe Basin, causing passive upwelling of asthenospheric material and lateral flow of the overlying lithosphere, and resulting in thickening of the lithosphere under the flanks and uplift of the Araripe Basin. We also hypothesize that thermal weakening of the lithospheric mantle – perhaps sustained by channeling of asthenospheric flows under the basin – would have caused regional stresses to concentrate in the brittle upper crust and contribute to basin inversion. We thus propose that a combination of localized horizontal stresses and vertical buoyancy from underlying asthenospheric material are ultimately responsible for the actual topography of the Araripe Basin.
Palabras clave: Araripe Basin; Borborema Province; Magnetotellurics; Conductivity; Lithosphere; Asthenosphere; Basin inversion; Partial melt
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Auladell A., P. Sánchez, O. Sánchez, J.M. Gasol, I. Ferrera
ISME Journal, 1-13. DOI: 10.1038/s41396-019-0401-4 (BibTeX: auladell.etal.2019)
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Zamanillo M., E. Ortega–Retuerta, S. Nunes, P. Rodríguez–Ros, M. Dall’Osto, M. Estrada, M.M. Sala, R. Simó
Biogeosciences, 16, 733-749. DOI: 10.5194/bg-16-733-2019 (BibTeX: zamanillo.etal.2019c)
Resumen: Ver
Transparent exopolymer particles (TEPs) are a class of gel particles, produced mainly by microorganisms, which play important roles in biogeochemical processes such as carbon cycling and export. TEPs (a) are colonized bycarbon-consuming microbes; (b) mediate aggregation and sinking of organic matter and organisms, thereby contributing to the biological carbon pump; and (c) accumulate in the surface microlayer (SML) and affect air–sea gas exchange. The first step to evaluate the global influence of TEPs in these processes is the prediction of TEP occurrence in the ocean. Yet, little is known about the physical and biological variables that drive their abundance, particularly in the open ocean. Here we describe the horizontal TEP distribution, along with physical and biological variables, in surface waters along a north–south transect in the Atlantic Ocean during October–November 2014. Two main regions were separated due to remarkable differences: the open Atlantic Ocean (OAO, n=30), and the Southwestern Atlantic Shelf (SWAS, n=10). TEP concentration in the entire transect ranged 18.3–446.8 μg XG eq L−1and averaged117.1±119.8 μg XG eq L−1, with the maximum concentrations in the SWAS and in a station located at the edge of the Canary Coastal Upwelling (CU), and the highest TEP to chlorophylla (TEP:Chla) ratios in the OAO (183±56) and CU (1760). TEPs were significantly and positively related to Chla and phytoplankton biomass, expressed in terms of C, along the entire transect. In the OAO, TEPs were positively related to some phytoplankton groups, mainly Synechococcus. They were negatively related to the previous 24 h averaged solar irradiance, suggesting that sunlight, particularly UV radiation, is more a sink than a source for TEP. Muliple regression analyses showed the combined positive effect of phytoplankton and heterotrophic prokaryotes (HPs)on TEP distribution in the OAO. In the SWAS, TEPs were positively related to high nucleic acid-containing prokaryotic cells and total phytoplankton biomass, but not to any particular phytoplankton group. Estimated TEP–carbon constituted an important portion of the particulate organic carbon pool in the entire transect (28 %–110 %), generally higher than the phytoplankton and HP carbon shares, which highlights the importance of TEPs in the cycling of organic matter in the ocean.
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Carnicer O., P. De La Fuente, A. Canepa, I. Keith, E. Rebolledo-Monsalve, J. Diogène, M. Fernández-Tejedor
, 6, 235, DOI: 10.3389/fmars.2019.00235 (BibTeX: carnicer.etal.2019)
Resumen: Ver
It is likely that harmful algal blooms have increased in frequency, intensity, and geographic distribution in the last decades in response to anthropogenic activities. The Galápagos Islands are renowned for their exceptional biological diversity; however, marine dinoflagellate communities have not been represented in biodiversity assessments. Therefore, this study aims to provide key information about dinoflagellate diversity and abundances, with special attention to harmful species, during a weak La Niña event in the Galápagos Marine Reserve (GMR). The study was performed during March–April 2017 and four transects were conducted at four Islands (Santa Cruz, Santa Fé, Seymour, and Pinzón) representing the southern region of the GMR. Water net samples were collected at 2, 5, and 10 nautical miles (nm) from the coast, at a total of 48 sampling sites. The presence of toxic species, and their cell abundance was estimated in seven transects at 0, 15, and 30 m of depth. A total of 152 taxa belonging to 7 orders, 22 families, and 38 genera were registered. The number of taxa found is almost three times higher than the maximum observed in previous studies. Dinoflagellate species richness among stations ranged between 53 and 23 taxa and was higher in northern sites. From the applied cluster analysis, five dinoflagellate assemblages were identified as a discrete community structure, one was found only in Santa Fé Island, which is probably related to the presence of the Equatorial Undercurrent (EUC). Regarding cell abundance estimations, low abundances were registered throughout the sampling sites and no blooms were detected. Higher abundances were registered in the northern transects coinciding with one of the most productive areas of the archipelago, situated north of Santa Cruz. Among the identified taxa, 19 of them were potentially toxic, including epiphytic species, allowing the possibility of blooms in benthic areas. This study presents the first record of several dinoflagellate species in the area (both nontoxic and harmful species) and thus, emphasizing the need for the implementation of phytoplankton monitoring programs by the government to prevent potential ecological, sanitary and economic impacts in the GMR.
Palabras clave: harmful algal blooms, dinoflagellate assemblages, richness, spatial variability, CCA, Generalized Additive Models, environmental parameters
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Gregory A.C., S.G. Acinas, et al.
Cell, 177, 5, 1109-1123. DOI: 10.1016/j.cell.2019.03.040 (BibTeX: .etal.2019c)
Resumen: Ver
Microbes drive most ecosystems and are modulated by viruses that impact their lifespan, gene flow, and metabolic outputs. However, ecosystem-level impacts of viral community diversity remain difficult to assess due to classification issues and few reference genomes. Here, we establish an ∼12-fold expanded global ocean DNA virome dataset of 195,728 viral populations, now including the Arctic Ocean, and validate that these populations form discrete genotypic clusters. Meta-community analyses revealed five ecological zones throughout the global ocean, including two distinct Arctic regions. Across the zones, local and global patterns and drivers in viral community diversity were established for both macrodiversity (inter-population diversity) and microdiversity (intra-population genetic variation). These patterns sometimes, but not always, paralleled those from macro-organisms and revealed temperate and tropical surface waters and the Arctic as biodiversity hotspots and mechanistic hypotheses to explain them. Such further understanding of ocean viruses is critical for broader inclusion in ecosystem models.
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Giner C.R., M.C. Pernice, V. Balagué, C.M. Duarte, J.M. Gasol, R. Logares, R. Massana
ISME Journal, 14, 437-449. DOI: 10.1038/s41396-019-0506-9 (BibTeX: giner.etal.2019e)
Resumen: Ver
Microbial eukaryotes are key components of the ocean plankton. Yet, our understanding of their community composition and activity in different water layers of the ocean is limited, particularly for picoeukaryotes (0.2–3 µm cell size). Here, we examined the picoeukaryotic communities inhabiting different vertical zones of the tropical and subtropical global ocean: surface, deep chlorophyll maximum, mesopelagic (including the deep scattering layer and oxygen minimum zones), and bathypelagic. Communities were analysed by high-tthroughput sequencing of the 18S rRNA gene (V4 region) as represented by DNA (community structure) and RNA (metabolism), followed by delineation of Operational Taxonomic Units (OTUs) at 99% similarity. We found a stratification of the picoeukaryotic communities along the water column, with assemblages corresponding to the sunlit and dark ocean. Specific taxonomic groups either increased (e.g., Chrysophyceae or Bicosoecida) or decreased (e.g., Dinoflagellata or MAST-3) in abundance with depth. We used the rRNA:rDNA ratio of each OTU as a proxy of metabolic activity. The highest relative activity was found in the mesopelagic layer for most taxonomic groups, and the lowest in the bathypelagic. Altogether, we characterize the change in community structure and metabolic activity of picoeukaryotes with depth in the global ocean, suggesting a hotspot of activity in the mesopelagic.
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Grinyó J., A. Gori, M. Greenacre, S. Requena, A. Canepa, C. Lo Iacono, S. Ambroso, A. Purroy, J.M. Gili
Progress in Oceanography, 161, 40-51. DOI: 10.1016/j.pocean.2018.02.002 (BibTeX: grinyo.etal.2019)
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Flynn K.J., A. Mitra, K. Anestis, A.A. Anschütz, A. Calbet, G. Duarte Ferreira, N. Gypens, P.J. Hansen, U. John, J. Lapeyra Martin, J.S. Mansour, M. Maselli, N. Medić, A. Norlin, F. Not, P. Pitta, F. Romano, E. Saiz, L.K. Schneider, W. Stolte, C. Traboni
Journal of Plankton Research, 41, 4, 375-391. DOI: 10.1093/plankt/fbz026 (BibTeX: flynn.etal.2019b)
Resumen: Ver
Many protist plankton are mixotrophs, combining phototrophy and phagotrophy. Their role in freshwater and marine ecology has emerged as a major developing feature of plankton research over recent decades. To better aid discussions, we suggest these organisms are termed “mixoplankton”, as “planktonic protist organisms that express, or have potential to express, phototrophy and phagotrophy”. The term “phytoplankton” then describes phototrophic organisms incapable of phagotrophy. “Protozooplankton” describes phagotrophic protists that do not engage in acquired phototrophy. The complexity of the changes to the conceptual base of the plankton trophic web caused by inclusion of mixoplanktonic activities are such that we suggest that the restructured description is termed the “mixoplankton paradigm”. Implications and opportunities for revision of survey and fieldwork, of laboratory experiments and of simulation modelling are considered. The main challenges are not only with taxonomic and functional identifications, and with measuring rates of potentially competing processes within single cells, but with decades of inertia built around the traditional paradigm that assumes a separation of trophic processes between different organisms. In keeping with the synergistic nature of cooperative photo- and phagotrophy in mixoplankton, a comprehensive multidisciplinary approach will be required to tackle the task ahead.
Palabras clave: Mixotrophy; Protist; Mixoplankton; Phytoplankton; Protozooplankton; Microbial loop; Allometry
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Cerro-Gálvez E., M.M. Sala, C. Marrasé, J.M. Gasol, J. Dachs, M. Vila-Costa
Science of The Total Environment, 678, 486-498. DOI: 10.1016/j.scitotenv.2019.04.361 (BibTeX: cerrogalvez.etal.2019d)
Resumen: Ver
Organic pollutants are continuously being introduced in seawater with uncharacterized impacts on the engines of the marine biogeochemical cycles, the microorganisms. The effects on marine microbial communities were assessed for perfluoroalkyl substances, organophosphate esters flame retardants and plasticizers, polycyclic aromatic hydrocarbons, and n-alkanes. Dose-response experiments were performed at three stations and at three depths in the NW Mediterranean with contrasted nutrient and pollutant concentrations. In these experiments, the microbial growth rates, the abundances of the main bacterial groups, measured by Catalyzed Reporter Deposition Fluorescence In Situ Hybridization (CARD-FISH), and extracellular enzymatic activities, were quantified. Increasing concentrations of organic pollutants (OPs) promoted different responses in the communities that were compound, organism and nutrient availability (trophic status). The largest differences between OP treatments and controls in the growth rates of both heterotrophic and phototrophic microbial groups were observed in seawater from the deep chlorophyll maxima. Furthermore, there was a compound specific stimulation of different extracellular enzymatic activities after the exposure to OPs. Our results revealed that marine microbial communities reacted not only to hydrocarbons, known to be used as a carbon source, but also to low concentrations of organic pollutants of emerging concern in a complex manner, reflecting the variability of various environmental variables. Multiple linear regressions suggested that organic pollutants modulated the bacterial growth and extracellular enzymatic activities, but this modulation was of lower magnitude than the observed pronounced response of the microbial community to nutrient availability
Palabras clave: Marine microbial communities; Perfluoroalkyl substances; Organophosphate ester flame retardants and plasticizers; Polycyclic aromatic hydrocarbons; N-alkanes
Blázquez M., E. Saillant
In: Sex Control in Aquaculture, Ed. H. Wang, F. Piferrer, S.L Chen, Z.-G.Shen. Wiley-Blackwell. Chap. 15. 327-346. DOI: 10.1002/9781119127291.ch15 ISBN: 978-1-119-12726-0 (BibTeX: blazquez.saillant.2019a)
Resumen: Ver
The process of sex differentiation in the European sea bass (Dicentrarchus labrax) has been studied in the context of programs aiming to develop methods for sex control in aquaculture. European sea bass gonads remain histologically undifferentiated for about four months after hatching. Ovarian differentiation takes place in fish of 80–90 mm standard length (SL), at the same time as a small proportion of males engage in testicular differentiation and initiate spermatogenesis. The remaining males remain undifferentiated for longer periods, during the first year. Intratesticular oocytes are commonly observed in cultured and wild males, and appear to reflect the masculinization of putative females due to environmental conditions. The labile period of sex differentiation seems to correspond to the end of metamorphosis and the weeks following this developmental phase. Protocols for the complete masculinization and feminization of stocks by the oral administration of sex steroids are available. Because sex differentiation in European sea bass is influenced by environmental factors, and evidence for major sex determinants is lacking in this species, potential approaches to control the sex ratio currently under investigation involve manipulations of the rearing temperature during the labile period of sex differentiation and selective breeding. Several genes have been shown to display sex‐ and/or temperature‐specific expression and methylation patterns in developing gonads before histological sex differentiation is completed. Further studies of the gonadal transcriptome and methylome, employing current genomic approaches, are warranted in order to further understand the physiological mechanisms involved in sex differentiation of the European sea bass.
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Liu S., D. Van Rooij, T. Vandorpe, C. González-Pola, G. Ercilla, F.J. Hernández-Molina
Deep-Sea Research. Part I: Oceanographic Research Papers, 149, 103054. DOI: 10.1016/j.dsr.2019.05.014 (BibTeX: liu.etal.2019a)
Resumen: Ver
The present-day morphology of the Le Danois Bank region has been investigated based on bathymetric and high to ultra-high resolution seismic reflection data. The involved bottom-current processes are associated with the Eastern North Atlantic Central Water, the Atlantic Mediterranean Water and the Labrador Sea Water. Sediments originating from various canyon systems along the Cantabrian Margin and the Asturias continental shelf are transported by downslope and alongslope processes towards the Le Danois intraslope basin. The background flow velocities of bottom currents are all below the threshold (8–10 cm/s) of generating plastered and mounded geometries of contourite drifts. However, bottom currents are locally accelerated (up to 25 cm/s) due to the presence of the Le Danois Bank and the Vizco High, creating a furrow and three moats and generating six plastered drifts, three elongated mounded and separated drifts at different depth intervals. The extension and distribution of the drifts are controlled by slope morphology and/or bottom current velocities. Unlike contourite drifts along other continental slopes, a single contourite drift (the Gijón Drift) with a lateral variation in drift geometry and internal structure indicates the interaction of bottom currents with different flow dynamics. Additionally, scouring of active bottom currents and rapid sedimentation rate of contourite drifts may be at the origin of slope instability events. Besides contourite drifts, internal waves may have induced the formation of sediment waves. In the Le Danois intraslope basin, multiple sedimentary processes work together and shape the present-day seafloor. Bottom currents are focused due to deflection on complex topographical obstacles within a relatively small basin setting, and create a wide variety of sedimentary features, including contourite drifts. The resulting sedimentary features thus have more frequent lateral variations, a feature typical for topographically constrained small basins.
Palabras clave: Bottom currents; Contourites; Southern Bay of Biscay; Small basin
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Carreton​ M., J.B. Company, L. Planella, S. Heras, J.-L. García-Marín, M. Agulló, M. Clavel-Henry, G. Rotllant, A. dos Santos, M.I. Roldán
PeerJ , 7, e6063. DOI: 10.7717/peerj.6063 (BibTeX: carreton.etal.2019a)
Resumen: Ver
The early life stages of the blue and red shrimp Aristeus antennatus (Decapoda: Dendrobranchiata: Penaeoidea: Aristeidae) were described by Heldt in 1955 based on plankton samples, larval rearing and assumptions of species habitat. Even with adequate keys, identification of its first larval stages remained a difficult task due to the lack of specific morphological characters which would differentiate them from other Penaeoidea species. Larvae of Aristeus antennatus were collected in the continental slope off the Spanish Mediterranean coast in August 2016 with a neuston net and preserved in ethanol 96%. DNA from the larvae was extracted and the molecular markers Cytochrome Oxidase I and 16S rDNA were sequenced and compared to that of adults with the objective of confirming the previous morphological description. Then, we present additional information to the morphological description of Aristeus antennatus larval stages through scanning electron microscopy and molecular analysis. This represents the first documented occurrence of Aristeus antennatus larvae off the Catalan coast and sets the grounds for further work on larval ecology and population connectivity of the species, which is an important contribution to a more sustainable fishery.
Palabras clave: Aristeus antennatus; Molecular identification; SEM; Blue and red shrimp; Larvae
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Strand M., J. Norenburg, J.E. Alfaya, F.A. Fernández‐Álvarez, H.S. Andersson, S.C.S. Andrade, T. Bartolomaeus, P. Beckers, G. Bigatti, I. Cherneva, A. Chernyshev, B.M. Chung, J. von Döhren, G. Giribet, J. Gonzalez‐Cueto, A. Herrera‐Bachiller, T. Hiebert, N. Hookabe, J. Junoy, H. Kajihara, D. Krämer, S. Kvist, T.Y. Magarlamov, S. Maslakova, C.B. Mendes, R. Okazaki, C. Sagorny, M. Schwartz, S.‐C. Sun, P. Sundberg, J.M. Turbeville, C.‐M. Xu
Zoologica Scripta, 48, 1, 118-119. DOI: 10.1111/zsc.12317 (BibTeX: strand.etal.2019)
Resumen: Ver
Dear Editor, Nemertean classification has closely followed Stiasny‐Wijnhoff's scheme (1936) that was based on Schultze's (1851) division of the taxon into the two classes Anopla and Enopla. In August 2018, the 9th International Conference of Nemertean Biology took place in the Wadden Sea Station of the Alfred Wegener Institute in List auf Sylt, Germany. At this meeting, the community reached consensus to revise nemertean taxonomy at the class level, based on the compiled evidence from studies on nemertean systematics published in the last 15 years (Andrade et al., 2012, 2014 ; Thollesson & Norenburg, 2003). Previous classifications (e.g., Stiasny‐Wijnhoff, 1936) are not based on phylogenetic grounds, and the use of these names is therefore nowadays not wholly informative. With the purpose of facilitating the practical use of the nemertean taxonomy and also making nemertean taxonomy reflect a wealth of more recent information, we conclude that the ranks Anopla and Enopla should be eliminated with the following argumentation: “Enopla” has for long held no more information than the name “Hoplonemertea”. “Anopla” is paraphyletic and the name usually corresponds to the following traits: (a) not bearing stylet; and (b) mouth and proboscis having separate openings. This information is equally well presented in a system that also bears information on natural groups.
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Romera-Castillo C., M. Álvarez, J.L. Pelegrí, D.A. Hansell, X.A. Álvarez-Salgado
Global Biogeochemical Cycles, 33, 9, 1162-1173. DOI: 10.1029/2018GB006162 (BibTeX: romeracastillo.etal.2019)
Resumen: Ver
Most dissolved organic carbon (DOC) sequestered in the deep ocean has residence times of decades to thousands of years, with clear implications for climate regulation, though some net removal is typically observed with increasing water mass age. Here, a high‐quality‐high‐resolution data set has allowed us to identify net additions of recalcitrant DOC in specific water masses of the deep South Atlantic. Overall, the South Atlantic is a net source of recalcitrant DOC, adding 0.027 ± 0.019 Pg C/year, while the North Atlantic is a net sink that removes 0.298 ± 0.141 Pg C/year. We find that the balance of addition/removal of recalcitrant DOC depends not only on the origin but also on the temperature, age, and depth of the water masses that circulate and mix in the Atlantic Ocean. Future changes in the water mass composition and circulation patterns due to climate change would eventually affect that balance, altering the carbon cycle.
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Jaspers C., B. Huwer, E. Antajan, A. Hosia, H.H. Hinrichsen, A. Biastoch, D. Angel, R. Asmus, C. Augustin, S. Bagheri, S.E. Beggs, T.J.S. Balsby, M. Boersma, D. Bonnet, J.T. Christensen, A. Dänhardt, F. Delpy, T. Falkenhaug, G. Finenko, N.E.C. Fleming, V. Fuentes, B. Galil, A. Gittenberger, D.C. Griffin, H. Haslob, J. Javidpour, L. Kamburska, . Kube, V.T. Langenberg, M. Lehtiniemi, F. Lombard, A. Malzahn, M. Marambio, V. Mihneva, L.F. Møller, Okyar Niermann, Ozdemir M.I., Pitois Z.B., Reusch S., Robbens T.B.H., Stefanova J., Thibault K., van der Veer D., Vansteenbrugge H.W., van Walraven L., Wozniczka L.
Global Ecology and Biogeography, 27, 814-827. DOI: 10.1111/geb.12742 (BibTeX: jaspers.etal.2019)
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Isla E., D. Gerdes
Progress in Oceanography, 178, 102180. DOI: 10.1016/j.pocean.2019.102180 (BibTeX: isla.gerdes.2019a)
Resumen: Ver
Global warming is heating the Antarctic circumpolar deep water (CDW), which comes into direct contact with the diverse and abundant macrobenthic communities thriving on the continental shelf of the Weddell Sea (WS). A set of 16 current meters deployed along more than 3000 km coastline revealed that tidal currents drive CDW intrusions onto the WS continental shelf and they can increase the temperature near the seabed by ~2.7 °C. The ongoing ocean warming trend may expose macrobenthic assemblages to ambient temperatures >2 °C by the end of the century with dramatic consequences for communities which have evolved during millions of years in near geophysical isolation under rather constant environmental conditions with temperatures <0 °C. These stenothermal communities have long generation times (therefore, reduced opportunity to mutate) and require hundreds of years for adaptation. Results from 135 benthic stations along the study area showed that macrobenthic communities in the southeastern section of the WS are the most vulnerable to the increase of temperature near the seabed given their high component of sessile organisms. Besides a dramatic marine biodiversity loss, the eventual demise of these communities, which provide habitat structure for a large number of species that can build up >87 g C m−2, will cause the liberation of thousands of tons of carbon to the environment. Macrobenthic communities colonizing the recently opened shelf in the Larsen A and B bays may not have the chance to reach the type of mature assemblage inhabiting the eastern WS shelf. The highest temperatures derived from CDW intrusions were recorded in the Filchner-Ronne region, suggesting that the consequences of the thermal impact could develop faster here than in the rest of the WS. Thus, these macrobenthic communities may show the effects of warming earlier than those thriving in other regions of the WS shelf. Global warming seriously threats the abundant and highly diverse macrobenthic communities of the Antarctic continental shelf
Palabras clave: Continental shelf; Antarctica; Global warming; Tides; Climate change; Benthic ecosystem; Weddell Sea
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Lin W., M. Portabella, S. Lang, X. Dong, X. Xu, Z. Wang, Y. He
Proc. of the International Geoscience and Remote Sensing Symposium (IGARSS), Yokohama, Japan, 28 July - 2 August, . (BibTeX: lin.etal.2019d)
Resumen: Ver
The sea surface winds from the CFOSAT scatterometer (CFOSCAT) are retrieved using the maximum likelihood estimator, and the inversion residual is used to sort the good-quality winds from the poor-quality ones. A twodimensional variational analysis ambiguity removal (2DVAR) scheme is then applied over the CFOSCAT swath such that a unique wind field is selected from the available local scatterometer wind vector ambiguities. The preliminary results of CFOSCAT Level 2 (L2) processing show that the retrieved wind speed is overestimated under low-wind conditions (w < 4 m/s), and is underestimated at high wind conditions (w > 15 m/s). Moreover, the inversion residual for the sweet swath (where there are more than 10 views) is generally higher than that for the nadir/outer swath. These imply that observations with different geometries (views) at the same WVC are inconsistent with respect to the geophysical model function, and thus a comprehensive calibration is highly demanded. A more detailed assessment of the CFOSCAT wind quality will be carried out after calibration and validation campaign.
Palabras clave: CFOSAT, scatterometer, wind, quality control, calibration
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Gupta M., C. Gabarro, A. Turiel, M. Portabella, J. Martinez
Journal of Glaciology, 65, (251), 481-493. DOI: 10.1017/jog.2019.26 (BibTeX: gupta.etal.2019a)
Resumen: Ver
Arctic sea ice is going through a dramatic change in its extent and volume at an unprecedented rate. Sea-ice thickness (SIT) is a controlling geophysical variable that needs to be understood with greater accuracy. For the first time, a SIT-retrieval method that exclusively uses only airborne SIT data for training the empirical algorithm to retrieve SIT from Soil Moisture Ocean Salinity (SMOS) brightness temperature (TB) at different polarization is presented. A large amount of airborne SIT data has been used from various field campaigns in the Arctic conducted by different countries during 2011–15. The algorithm attempts to circumvent the issue related to discrimination between TB signatures of thin SIT versus low sea-ice concentration. The computed SIT has a rms error of 0.10 m, which seems reasonably good (as compared to the existing algorithms) for analysis at the used 25 km grid. This new SIT retrieval product is designed for direct operational application in ice prediction/climate models.
Palabras clave: Remote sensing; Sea ice; Laser altimetry; Electromagnetic induction; Ice thickness measurements
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Olivares M., E. Saiz, A. Calbet
Marine Ecology Progress Series, 616, 25-35. DOI: 10.3354/meps12928 (BibTeX: olivares.etal.2019a)
Resumen: Ver
The feeding activity of copepods is crucial for the structure and functioning of marine ecosystems. Quantification of feeding rates of different copepod life stages across a range of prey densities (functional response) is essential knowledge for improvement of plankton dynamic models. In this study, we conducted experiments to compare the feeding functional responses of nauplii, copepodites, and adults of the marine copepod Paracartia grani (formerly Acartia grani) when grazing on the flagellate Rhodomonas salina. We found that all copepod stages followed a sigmoid curve in their functional responses (Holling Type III model), indicating a metabolic threshold constraining foraging effort at low prey densities. Maximum clearance rates of nauplii and copepodites increased with body mass with a power scaling factor of 1, but maximum clearance rates of adults did not follow the pattern observed for juvenile stages, likely because of the relatively small prey size used in the experiments. Copepod maximum ingestion rates, however, showed allometric scaling along ontogeny that was closer to the typical 0.75 power law and seemed to not be so dependent on prey size. The insights obtained from our study highlight stage-specific differences in copepod feeding activity, and can help improve our capability to estimate the energy flow through copepods in marine food webs
Palabras clave: Zooplankton; Acartia; Nauplii; Development; Grazing; Ingestion; Clearance rate; Functional trait
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Siliprandi C.C., V.M. Tuset, A. Lombarte, M. Farré, C.L.D.B. Rossi-Wongtschowski
Neotropical Ichthyology, 17, 1, e170168. DOI: 10.1590/1982-0224-20170168 (BibTeX: siliprandi.etal.2019a)
Resumen: Ver
Morphological characters of species are essential for assessing the functional structure of a fish assemblage, since differences between them, for example in body shape, are related to many functional and ecological traits (e.g., swimming, search for food, striking and capturing prey, evading predators, spawning). Globally, tidal flats are relevant to fish assemblages by offering feeding, refuge, and reproduction grounds. To analyze the morphofunctional structure of the fish assemblage from a tidal flat on the Brazilian coast, we conducted standardized sampling using nine different fishing gears. The geometric morphometric method was applied to describe the fish shapes and verify the morphological structure of the assemblage. Here, we present the influence/susceptibility of each gear type on the morphological diversity of the fish assemblage. The results indicated that beach seine, otter trawl, marginal encircling gillnet, and fish traps, together, were the most effective gears to represent the maximum morphological variability of fish inhabiting that tidal flat. Moreover, the assemblage showed high morphological redundancy considered as a resistance of the ecosystem for avoiding functional diversity loss, emphasizing the importance of complementary gear use when determining fish assemblages in a conservation context.
Palabras clave: Ichthyofauna; Geometric morphometrics; Morphological diversity; Multiple fishing gears; Morphological redundance; Ictiofauna; Diversidade morfológica; Morfometria geométrica; Múltiplos petrechos de pesca; Redundância morfológica
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Bostock H.C., J.G. Prebble, G. Cortese, B. Hayward, E. Calvo, L. Quirós‐Collazos, M. Kienast, K. Kim
Paleoceanography, 34, 4, 580-599. DOI: 10.1029/2019PA003574 (BibTeX: bostock.etal.2019b)
Resumen: Ver
The oceans are warming, but it is unclear how marine productivity will be affected under future climate change. In this study we examined a wide range of paleoproductivity proxies along a latitudinal transect (36–58°S) in the SW Pacific during the early Holocene climatic optimum, to explore regional patterns of productivity in a slightly warmer‐than‐present world. During the early Holocene there is a small increase in productivity in the subtropical waters, no change at the subtropical frontal zone, and conflicting evidence in records immediately south of the subtropical front, where an increase is inferred from one core site, but not at the other. Evidence for an increase in productivity in Antarctic Surface Waters, south of the polar front, is also equivocal. We infer a small increase in productivity in subtropical waters, and the ocean just south of the subtropical front was associated with changes in the ocean circulation of the SW Pacific, driven by changes in the Southern Hemisphere Westerly Winds split‐jet structure in this region. The relatively modest warming during the early Holocene climatic optimum in the SW Pacific indicates that this time period may provide an analog for future productivity for the midcentury (2055) under Intergovernmental Panel on Climate Change Representative Concentration Pathway 8.5 or for the end of the century (2100) under Representative Concentration Pathway 4.5. However, higher‐resolution, downscaled models, with realistic Southern Hemisphere Westerly Winds, will be necessary to forecast future productivity for this oceanographically complex region.
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Shiganova T.A., U. Sommer, J. Javidpour, J.C. Molinero, A. Malej, A.S. Kazmin, M. Isinibilir, E. Christou, I. Siokou-Frangou, M. Marambio, V. Fuentes, Z.A. Mirsoyan, N. Gülsahin, F. Lombard, M.K.S. Lilley, D.L. Angel, B.S. Galil, D. Bonnet, F. Delpy
Marine Environmental Research, 152, 104791, 1-23. DOI: 10.1016/j.marenvres.2019.104791 (BibTeX: shiganova.etal.2019)
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Armengol L., A. Calbet, G. Franchy, A. Rodríguez-Santos, S. Hernández-León
Scientific Reports, 9, 2044. DOI: 10.1038/s41598-019-38507-9 (BibTeX: armengol.etal.2019a)
Resumen: Ver
Oligotrophic and productive areas of the ocean differ in plankton community composition and biomass transfer efficiency. Here, we describe the plankton community along a latitudinal transect in the tropical and subtropical Atlantic Ocean. Prochlorococcus dominated the autotrophic community at the surface and mixed layer of oligotrophic stations, replaced by phototrophic picoeukaryotes and Synechococcus in productive waters. Depth-integrated biomass of microzooplankton was higher than mesozooplankton at oligotrophic stations, showing similar biomasses in productive waters. Dinoflagellates dominated in oligotrophic waters but ciliates dominated upwelling regions. In oligotrophic areas, microzooplankton consumed ca. 80% of the production, but ca. 66% in upwelling zones. Differences in microzooplankton and phytoplankton communities explain microzooplankton diel feeding rhythms: higher grazing rates during daylight in oligotrophic areas and diffuse grazing patterns in productive waters. Oligotrophic areas were more efficient at recycling and using nutrients through phytoplankton, while the energy transfer efficiency from nutrients to mesozooplankton appeared more efficient in productive waters. Our results support the classic paradigm of a shorter food web, and more efficient energy transfer towards upper food web levels in productive regions, but a microbially dominated, and very efficient, food web in oligotrophic regions. Remarkably, both models of food web exist under very high microzooplankton herbivory.
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O’Reilly B.M., M. Prada, F. Lavoué, S. Lebedev
Geophysical Journal International, 219, 2, 1421-1430. DOI: 10.1093/gji/ggz378 (BibTeX: oreilly.etal.2019a)
Resumen: Ver
Gravitational compaction of thick (2–10 km) sediment accumulations in sedimentary basins is controlled by the interplay of mechanical and chemical processes that operate over many orders of magnitude in spatial scale. The compaction of sediments into rock typically involves a density increase of ≈500 to 1000 kg m−3, occurring over a depth-scale of several kilometres. The volume decrease in the compacting sediments releases vast volumes of water, which plays an important part in the global hydrological cycle and also in tectonic and geochemical processes; including the formation of hydrocarbon and mineral deposits. This study utilizes recently developed tomographic seismic images from the Porcupine Basin, which lies in the deep-water North Atlantic Ocean. A generic method for predicting fluid pressure variations that are driven by gravitational compaction is developed over the scale of the entire sedimentary basin. The methodology is grounded upon both observational evidence and empirically based theories, relying on geophysical measurements and relationships between sediment porosities and densities. The method is based upon physical concepts that are widely used in the petroleum industry and applied extensively in models of overpressure development in sedimentary basins. Geological and geophysical data from exploration wells are used to test the predictions of the method at two locations within the basin and are found to be in good agreement with the theory.
Palabras clave: Permeability and porosity; Europe; Seismic tomography; Sedimentary basin processes
Preface (2019)
Wang H., F.Piferrer, S.L. Chen
In: Sex Control in Aquaculture, Ed. H. Wang, F.Piferrer, S. Chen, Z.-G.Shen. Wiley-Blackwell. XVII-XVIII. DOI: 10.1002/9781119127291.fmatter1 ISBN: 978-1-119-12726-0 (BibTeX: wang.etal.2019c)
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Dallarés S., N. Montemurro, S. Pérez, N. Rodríguez-Sanchez , M. Solé
Journal of Toxicology and Environmental Health - Part A, DOI: 10.1080/15287394.2018.1562393 (BibTeX: dallares.etal.2019a)
Resumen: Ver
Tamiflu® (oseltamivir phosphate, OST) is an antiviral drug used for the pandemic treatment of avian influenza but few data are available regarding its toxicity. It should be noted that acute adverse responses are not likely to occur due to low environmental presence of this drug. Nonetheless, water concentration levels of this compound may reach the µg/L range under influenza episodes. Bivalves are reliable sentinels of chemical exposure due to their low metabolism; however, biotransformation of drugs does occur in these aquatic invertebrates. Two species of bivalves, namely mussels Mytilus galloprovincialis and clams Ruditapes philippinarum, were exposed for 48 h to 100 µg/L OST. Hemolymph from control and treated bivalves was withdrawn and the presence of OST and its metabolite oseltamivir carboxylate (OST-C) determined by LC-MS/MS. Gills and digestive gland were excised from control and exposed bivalves and carboxylesterase (CE) activities measured using different substrates. In addition, antioxidant defences and lipid peroxidation levels were determined. Higher metabolism of OST seemed to occur in mussels, since both OST and OST-C were found in hemolymph, whereas in clams only the parent compound was detected. In contrast, biomarker responses were more evident in exposed clams which indicate that this species may be considered as more sensitive to OST exposure. CE-related activities successfully reflected OST exposure, with substrates 1-naphthyl acetate (1NA) and 1-naphthyl butyrate (1NB) displaying the highest sensitivity in the two bivalve species. Data thus indicate the usefulness of CE-related activities as biomarkers for OST exposure in bivalves.
Palabras clave: Bivalves; Antiviral drug; Oseltamivir carboxylate; Carboxylesterases; Oxidative stress
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Reñé A., M. Hoppenrath
Harmful Algae, 84, 161-171. DOI: 10.1016/j.hal.2019.04.001 (BibTeX: rene.hoppenrath.2019)
Resumen: Ver
The heterotrophic sand-dwelling dinoflagellate Thecadinium inclinatum has been re-examined by light and scanning electron microscopy in order to resolve the discrepancies on its plate pattern from the literature, and to obtain its phylogenetic information single-cell PCR technique has been used. The comparison of morphological and molecular information available for other Thecadinium species confirms the genus is polyphyletic and T. inclinatum seems not related to other representatives of the genus sensu lato. Thus, a new genus and combination for the species, Psammodinium inclinatum gen. nov., comb. nov. is proposed. Cells are heterotrophic and strongly laterally flattened, with sulcal pocket. The revised tabulation is: APC 3' 7” 7c 7s? 5”' 1p 2”” with a long-shank fishhook-shaped apical pore and descending cingulum. The cingulum inclines ventrally and declines on the right lateral side producing an asymmetrical epitheca. The epitheca is much smaller than the hypotheca. The phylogenetic results showed a strong relationship with the autotrophic epiphytic genera Gambierdiscus and Fukuyoa, being closely related with the latter. The Gambierdiscus species typically have a tropical and sub-tropical distribution and produce ciguatoxins, causing thousands of intoxications every year by consumption of contaminated fish. Fukuyoa representatives have a wider distribution including warm and temperate waters, and it has been demonstrated that they are also able to produce ciguatoxins, even though at lower amounts. P. inclinatum, which potential toxicity remains to be determined, represents an interesting independent evolutionary branch that resulted in the loss of chloroplasts, the strong lateral compression and the adaptation to sandy habitats in temperate and cold waters.
Palabras clave: Benthic; Sand-dwelling; Dinoflagellate; Phylogeny; Taxonomy
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Grieco G., A. Stoffelen, M. Portabella, M. Belmonte, W. Lin, F. Fabra
IEEE Transactions on Geoscience and Remote Sensing, 57, 5, 2990-3000. DOI: 10.1109/TGRS.2018.2879059 (BibTeX: grieco.etal.2019)
Resumen: Ver
A quality control scheme for TechDemoSat 1 (TDS-1) and Cyclone Global Navigation Satellite System (GNSS) delay-Doppler maps (DDMs) is presented and the results of its application to a data set of more than 700 000 DDMs are discussed. This scheme is proven to be effective for such purpose and its output indices can be successfully used as quality indicators of the DDM. This paper shows that most of the TDS-1 DDMs are affected by some distortions that are attributable to an insufficiently accurate estimation of the specular point location. The errors, moreover, can severely alter the symmetry of the isodelay lines with respect to the iso-Doppler lines leading to an asymmetry in the arrival time of the waveforms. Furthermore, these errors may affect the convolution of the GNSS reflected signal with the Woodward ambiguity function, leading to an unwanted redistribution of the incoming echo energy among the DDM bins. Such distortions may, in turn, affect the accuracy of the wind field retrieval using either the stare processing approach or the more consolidated methods of inverting a Geophysical Model Function based on the DDM peak and/or leading edge slope.
Palabras clave: Accuracy, error, quality control (QC), reflected Global Navigation Satellite System (GNSS-R), stare processing, wind.
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Giner C.R., V. Balagué, A.K. Krabberød, I. Ferrera, A. Reñé, E. Garcés, J.M. Gasol, R. Logares, R. Massana
Molecular ecology, 28, 923-935. DOI: 10.1111/mec.14929 (BibTeX: giner.etal.2019c)
Resumen: Ver
How much temporal recurrence is present in microbial assemblages is still an unan‐swered ecological question. Even though marked seasonal changes have been re‐ported for whole microbial communities, less is known on the dynamics and seasonality of individual taxa. Here, we aim at understanding microbial recurrence at three different levels: community, taxonomic group and operational taxonomic units (OTUs). For that, we focused on a model microbial eukaryotic community populating a long -term marine microbial observatory using 18S rRNA gene data from two organ‐ismal size fractions: the picoplankton (0.2–3 μm) and the nanoplankton (3–20 μm). We have developed an index to quantify recurrence in particular taxa. We found that community structure oscillated systematically between two main configurations cor‐responding to winter and summer over the 10 years studied. A few taxonomic groups such as Mamiellophyceae or MALV -III presented clear recurrence (i.e., seasonality), whereas 13%–19% of the OTUs in both size fractions, accounting for ~40% of the relative abundance, featured recurrent dynamics. Altogether, our work links long -term whole community dynamics with that of individual OTUs and taxonomic groups, indicating that recurrent and non‐recurrent changes characterize the dynamics of microbial assemblages
Palabras clave: community assembly, diversity, marine protists, recurrence, seasonality, temporal patterns
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Vandorpe T., T. Collart, V. Cnudde, S. Lebreiro, F.J. Hernández-Molina, B. Alonso, A. Mena, L. Antón, D. Van Rooij
Marine Geology, 417, 106003. DOI: 10.1016/j.margeo.2019.106003 (BibTeX: vandorpe.etal.2019b)
Resumen: Ver
Five sediment cores, retrieved from four different depositional contouritic morphological settings (a sheeted drift, a confined mounded drift, a mounded elongated drift and a plastered drift) from the Northern Gulf of Cadiz and the Alboran Sea have been analysed using medical X-ray computed tomography (medical CT). A quantitative approach has been used, resulting in a workflow that delineates several radio-density ranges based on the Hounsfield Unit (HU) histogram of each core and tracks these ranges throughout the cores. In order to derive the geological significance, the radio-density ranges of all cores have been compared to non-destructive, continuous chemical and physical proxies as well as grain size measurements. The highest correlations occurred between high HU and proxies indicating elevated bottom currents, such as Zr/Al and sortable silt. Additionally, a continuous increase in average HU and inferred bottom current velocities, needed for the creation of the specific contourite setting, could be observed throughout the five cores. Despite imperfections and the requirement of additional research, promising results have been obtained which could improve the detection of diagnostic criteria for contourites. Moreover, the CT data can give more conclusive evidence on the nature of the (contourite) sedimentary sequence boundaries.
Palabras clave: Medical Computed Tomography (CT); Contourites; Grain size; Bottom currents; Gulf of Cadiz; Alboran Sea
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Grieco G., A. Stoffelen, M. Portabella
IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 1-11. DOI: 10.1109/JSTARS.2019.2938327 (BibTeX: grieco.etal.2019a)
Resumen: Ver
Global navigation satellite system reflectometry (GNSS-R)-derived winds from the cyclone GNSS (CYGNSS) satellite constellation are expected to significantly improve weather forecasts in the tropical region. Delay–Doppler maps (DDMs) acquired by the TechDemosat-1 (TDS-1) GNSS-R satellite mission suffer from distortions that are highly correlated to on-board specular point estimation inaccuracies. Such distortions may affect wind retrievals, especially when multilook approaches aiming at exploiting the ambiguity-free area of the DDM are applied. This article demonstrates: that CYGNSS DDMs are also affected by such distortions; the rationale ofDDMshape asymmetries induced by specular point location inaccuracies; and a simple strategy for reducing such induced distortions.Two different datasets have been used, consisting of both regular and raw intermediate frequency CYGNSS measurements. The results show that, similar to TDS-1, the CYGNSS DDM distortions are correlated to specular point location inaccuracies. Furthermore, such inaccuracies are significantly reduced if more accurate specular point related parameters are used to recompress the raw GNSS-R echo, highlighting some sampling issues that are common to both TDS-1 and CYGNSS missions. These results suggest that multilook wind retrieval approaches aiming at exploiting also the peripheral parts of theDDM may be seriously compromised by such distortions. The latter may be substantially reduced by oversampling the outcomingDDMand by a posteriori choosing the proper DDM subsample. For future upcoming GNSS-R missions, it is strongly recommended to store the raw data for eventual reprocessing in case of miscalibration or processing issues such as those shown in this article.
Palabras clave: Delay–Doppler map (DDM) distortions, global navigation satellite system (GNSS), reflectometry.
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Lago-Barcia D., F.A. Fernández-Álvarez, F. Brusa, I. Rojo, C. Damborenea, L. Negrete, C. Grande, C. Noreña
Biological Invasions, 21, 2, 289-302. DOI: 10.1007/s10530-018-1834-9 (BibTeX: lagobarcia.etal.2019)
Resumen: Ver
Among other factors, globalization has promoted the spread of alien organisms, posing a great risk to Earth’s biodiversity. Land planarians of the family Geoplanidae especially benefit from human-mediated transport. Many species become established in new areas, where they represent threats to the native soil fauna. Obama nungara is a species described from Brazil, but with many well-established populations in Europe. In this study, specimens from Argentina, Brazil, Portugal and Spain were morphologically and molecularly studied to establish the potential origin of the invasive events within the Iberian Peninsula. Analyses of the mitochondrial lineages (haplotype networks) of these populations revealed previously unknown relationships and biogeographical patterns that suggest an Argentine origin for the Iberian populations. Furthermore, comparative analysis of Argentine, Iberian and Brazilian populations revealed three well-defined and distinct O. nungara clades. Our findings suggest two independent introductions of different populations from Argentina that gave rise to the different Iberian populations. This population diversity suggests hidden biodiversity of alien land planarians in invaded areas and their invasive and adaptive potential.
Palabras clave: Biodiversity; Biological invasions; Distribution; Haplotype networks; Neotropical land planarian
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Dubois M., D. Gascuel, M. Coll, J. Claudet
Ecosystems, 22, 3, 658-676. DOI: 10.1007/s10021-018-0294-5 (BibTeX: dubois.etal.2019)
Resumen: Ver
Ecosystems are increasingly disturbed by natural disturbances and human stressors. Understanding how a disturbance can propagate through an entire ecosystem and how induced changes can last after apparent recovery is key to guide management and ecosystem restoration strategies. Monitoring programs and impact assessment studies rely mostly on indicators based only on species relative abundance and biomass, potentially misinforming management efforts. Impacts on ecosystem structure and functioning, and subsequent delivery of ecosystem services, are too often overlooked. Here we use an ecosystem network approach to assess the recovery pathway and potential recovery debts of a coral reef ecosystem, following a pulse disturbance. We show that although species abundance and biomass indicators recovered in a decade after the perturbation, the ecosystem as a whole presented a recovery debt. The ecosystem structure lost complexity (became “food chain like”) and lost about 29% of its overall cycling efficiency and 9% of its transfer efficiency. Although the ecosystem trophic network in the fore reef may have maintained its general functioning, the ecosystem network in the lagoon, not directly exposed to the disturbance, presented a stronger recovery debt. Our results give new insights on how ecosystem network approaches can help identify ecosystem impacts and recovery pathways.
Palabras clave: Ecological disturbance; Coral reef; Network analysis; Trophic modelling; Ecopath
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Bourassa M.A., T. Meissner, I. Cerovecki, P.S. Chang, X. Dong, G. De Chiara, C. Donlon, D.S. Dukhovskoy, J. Elya, A. Fore, M.R. Fewings, R.C. Foster, S.T. Guille, B.K. Haus, S. Hristova-Veleva, H.M. Holbach, Z. Jelenak, J.A. Knaff, S.A. Kranz, A. Manaster, M. Mazloff, C. Mears, A. Mouche, M. Portabella, N. Reul, L. Ricciardulli, E. Rodríguez, C. Sampson, D. Solis, A. Stoffelen, M.R. Stukel, B. Stiles, D. Weissman, F. Wentz
Frontiers in Marine Science, 6, 443, DOI: https://doi.org/10.3389/fmars.2019.00443 (BibTeX: bourassa.etal.2019)
Resumen: Ver
Strengths and weakness of remotely sensed winds are discussed, along with the current capabilities for remotely sensing winds and stress. Future missions are briefly mentioned. The observational needs for a wide range of wind and stress applications are provided. These needs strongly support a short list of desired capabilities of future missions and constellations.
Palabras clave: satellite, wind, stress, ocean, requirements
Taboada X., D. Robledo, C. Bouza, F. Piferrer, A.M, Viñas, P. Martínez
In: Sex Control in Aquaculture, Ed. H. Wang, F. Piferrer, S.L Chen, Z.-G.Shen. Wiley-Blackwell. Chap. 28. 547-563. DOI: 10.1002/9781119127291.ch28 ISBN: 978-1-119-12726-0 (BibTeX: taboada.etal.2019a)
Resumen: Ver
Turbot (Scophthalmus maximus) is a flatfish with increasing aquaculture value in Europe and China. This species shows extreme sexual growth dimorphism, with females growing faster and achieving sexual maturity later than males – hence the interest of industry in producing all‐female populations. Sex determination (SD) of turbot shows a major genetic component, the main quantitative trait loci (QTL) being located at linkage group (LG) 5. A microsatellite marker (SmaUSC‐E30) at this region shows a high sexing efficiency and is used by industry for precocious sex identification. Minor secondary QTLs and some temperature influence have also been reported. Available data support a ZZ/ZW system of recent evolutionary origin in turbot. The first signs of sex differentiation are detected at 90 days post‐fertilization, when the genes amh, cyp19a1a and vasa show differential expression between sexes. From this stage, female gonads undergo quick differentiation, while future male gonads remain more similar to undifferentiated gonads. Different approaches have been evaluated to increase the proportion of females in turbot, including hormone treatments and chromosome set manipulation (triploids, gynogenetics), but the most efficient and safe strategy involves a cross between ZZ males and WW superfemales, obtained through a two‐generation pedigree involving sex reversal assisted by the SmaUSC‐E30 marker. Triploids represent an interesting product for turbot aquaculture, because of their functional sterility, female‐biased sex ratio and null impact of escapees on wild populations. Genomic strategies will be likely key to identify the SD master gene, as essential information for efficient sex monitoring and brood stock management at turbot farms.
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Grinyó J., N. Viladrich, D. Díaz, A. Muñoz, S. Mallol, . Salazar , R. Castillo, J.M. Gili, A. Gori
Plos One. Open acces, 13, e0203308, 1-23. DOI: 10.1371/journal.pone.0203308 (BibTeX: grinyo.etal.2019a)
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Medina Henríquez P.J.,
PhD thesis. Director/es: M. Blázquez Peinado. (BibTeX: medinahenriquez.2019)
Resumen: Ver
European sea bass (Dicentrarchus labrax) aquaculture is a thriving industry in Spain where it reached about 23,500 t and a market value of approximately 133 million euros. However, most of the sea bass farms produce a high percentage of males (70-90%) since the rearing temperature is increased during the initial stages of development to speed up development and growth. This is a problem because in this species, generally, females exhibit higher growth rates than males. This situation is aggravated as nearly 30% of these males reach puberty precociously during the first year of life, before attaining commercial size. Puberty is accompanied by a decrease in growth rates as energy diverts towards gonadal growth instead of somatic growth. In addition, it comes along with muscle waste and losses in the organoleptic properties of the meat. Because of these biological responses to captive breeding, there is a great need to understand the reproductive process and its control under intensive production conditions. The main objective of this thesis is to increase the knowledge of European sea bass reproduction. It is focussed on the role of the retinoic acid (RA) signaling pathway during early development and puberty. [...]
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Adl S.M., D. Bass, C.E. Lane, J. Lukes, C.L. Schoch, A. Smirnov, S. Agatha, C. Berney, M.W. Brown, F. Burki, P. Cárdenas, I. Cepicka, L. Chistyakova, J. del Campo, M. Dunthorn, B. Edvardsen, Y. Eglit, L. Guillou, V. Hampl, A.A. Heiss, M. Hoppenrath, T.Y. James, A. Karnkowska, S. Karpov, E. Kim, M. Kolisko, A. Kudryavtsev, D.J.G. Lahr, E. Lara, L. Le Gall, D.H. Lynn, D.G. Mann, R. Massana, E.A.D. Mitchell, C. Morrow, J. Soo Park, J.W. Pawlowski, M.J. Powell, D.J. Richter, S. Rueckert, L. Shadwick, S. Shimano, F.W. Spiegel, G. Torruella, N. Youssef, V. Zlatogursky, Q. Zhang.
Journal of Eukaryotic Microbiology, 66, 4 - 119. DOI: 10.1111/jeu.12691 (BibTeX: adl.etal.2019b)
Resumen: Ver
This revision of the classification of eukaryotes follows that of Adl et al., 2012 [J. Euk. Microbiol. 59(5)] and retains an emphasis on protists. Changes since have improved the resolution of many nodes in phylogenetic analyses. For some clades even families are being clearly resolved. As we had predicted, environmental sampling in the intervening years has massively increased the genetic information at hand. Consequently, we have discovered novel clades, exciting new genera and uncovered a massive species level diversity beyond the morphological species descriptions. Several clades known from environmental samples only have now found their home. Sampling soils, deeper marine waters and the deep sea will continue to fill us with surprises. The main changes in this revision are the confirmation that eukaryotes form at least two domains, the loss of monophyly in the Excavata, robust support for the Haptista and Cryptista. We provide suggested primer sets for DNA sequences from environmental samples that are effective for each clade. We have provided a guide to trophic functional guilds in an appendix, to facilitate the interpretation of environmental samples, and a standardized taxonomic guide for East Asian users.
Palabras clave: Algae; Amoebae; Biodiversity; Ciliate; Ecology; Flagellate; Fungus; Microbiology; Parasite; Plankton; Protozoa; Systematics; Taxonomy
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Alurralde G., V.L. Fuentes, T. Maggioni, J. Movilla, A. Olariaga, C. Orejas, I.R. Schloss, M. Tatián
Marine Environmental Research, 152, 104790, 1-15. DOI: 10.1016/j.marenvres.2019.104790 (BibTeX: alurralde.etal.2019)
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Hoving H.-J.T., F.Á. Fernández-Álvarez, E.J. Portner, W.F. Gilly
Marine Biology, 166, 33. DOI: 10.1007/s00227-019-3476-6 (BibTeX: hoving.etal.2019b)
Resumen: Ver
Dosidicus gigas (the Humboldt squid) is a widely distributed and ecologically important predator in the eastern Pacific Ocean, but its mating behaviour is poorly understood. Individuals of this species have undergone a drastic change in size at maturity in the last years. We investigated mating activity of Humboldt squid in the Gulf of California in 2013, 2014, and 2015 by quantifying spermatangia deposited in the tissue of the buccal area. In 2015, we encountered the smallest mean mantle length of mature specimens recorded to date in the Gulf of California. In all years, numerous males were encountered that had been mated by other males. Spermatangia in males were deposited on the tissue in similar numbers and in the same location as normally occurs in females (the buccal area), suggesting that male-to-male mating behaviour is similar to male-to-female. This behaviour is referred to as same-sex sexual behaviour and has been described for various taxa, including other cephalopods. Overall similarity in mating frequency between males and females and in body size of mated individuals (in 2015) suggests non-discriminative and brief encounters with body size being a cue for mating. This mating strategy may be beneficial for males, as Humboldt squid live in groups where competition for mates is likely high. The energetic costs of male-to-male mating events may be counterbalanced by the fitness profits of indiscriminate mating behaviour.
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Anderson C.R., E. Berdalet, R.M. Kudela, C.K. Cusack, J. Silke, E. O’Rourke, D. Dugan, M. McCammon, J.A. Newton, S.K. Moore, K. Paige, S. Ruberg, J.R. Morrison, B. Kirkpatrick, K. Hubbard, J. Morell
, 6, 250. DOI: 10.3389/fmars.2019.00250 (BibTeX: anderson.etal.2019a)
Resumen: Ver
Harmful algal blooms (HABs) produce local impacts in nearly all freshwater and marine systems. They are a problem that occurs globally requiring an integrated and coordinated scientific understanding, leading to regional responses and solutions. Given that these natural phenomena will never be completely eliminated, an improved scientific understanding of HAB dynamics coupled with monitoring and ocean observations, facilitates new prediction and prevention strategies. Regional efforts are underway worldwide to create state-of-the-art HAB monitoring and forecasting tools, vulnerability assessments, and observing networks. In the United States, these include Alaska, Pacific Northwest, California, Gulf of Mexico, Gulf of Maine, Great Lakes, and the United States Caribbean islands. This paper examines several regional programs in the United States, European Union, and Asia and concludes that there is no one-size-fits-all approach. At the same time, successful programs require strong coordination with stakeholders and institutional sustainability to maintain and reinforce them with new automating technologies, wherever possible, ensuring integration of modeling efforts with multiple regional to national programs. Recommendations for scaling up to a global observing system for HABs can be summarized as follows: (1) advance and improve cost-effective and sustainable HAB forecast systems that address the HAB-risk warning requirements of key end-users at global and regional levels; (2) design programs that leverage and expand regional HAB observing systems to evaluate emerging technologies for Essential Ocean Variables (EOVs) and Essential Biodiversity Variables (EBVs) in order to support interregional technology comparisons and regional networks of observing capabilities; (3) fill the essential need for sustained, preferably automated, near real-time information from nearshore and offshore sites situated in HAB transport pathways to provide improved, advanced HAB warnings; (4) merge ecological knowledge and models with existing Earth System Modeling Frameworks to enhance end-to-end capabilities in forecasting and scenario-building; (5) provide seasonal to decadal forecasts to allow governments to plan, adapt to a changing marine environment, and ensure coastal industries are supported and sustained in the years ahead; and (6) support implementation of the recent calls for action by the United Nations Decade 2010 Sustainable Development Goals (SDGs) to develop indicators that are relevant to an effective and global HAB early warning system.
Palabras clave: Biodiversity; Phytoplankton; Biotoxin; Phycotoxin; Ecological Forecasting; Early warning system; Stakeholder engagement; Earth system science
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Herndl P.A. Steiner; E. Sintes; R. Simó; D. De Corte; D.M. Pfannkuchen; I. Ivančić; M. Najdek; G.J.,
Environmental Microbiology Reports, 11, 5, 699-707. DOI: 10.1111/1758-2229.12783 (BibTeX: steinere.sintesr.simod.decorted.m.pfannkucheni.ivanim.najdekg.j.herndl.2019b)
Resumen: Ver
The extent of DMSP demethylation has been hypothesized to depend on DMSP availability and bacterial sulfur demand, which might lead to niche differentiation of the demethylating bacterial community. In this study, we determined DMSP concentrations in marine snow and the ambient water over a seasonal cycle and linked DMSP concentrations to the abundance of bacteria harbouring the demethylation dmdA gene in the Adriatic Sea. In marine snow, DMSP concentrations were up to four times higher than in the ambient water and three times higher in marine snow in summer than in winter. The average dmdA:recA gene ratio over the sampling period was 0.40 ± 0.24 in marine snow and 0.48 ± 0.21 in the ambient water. However, at the subclade level, differences in the demethylating bacterial community of marine snow and the ambient water were apparent. Seasonal patterns of potentially demethylating bacteria were best visible at the oligotype level. In the ambient water, the SAR116 and the OM60/NOR5 clade were composed of oligotypes that correlated to high DMSP concentrations, while oligotypes of the Rhodospirillales correlated to low DMSP concentrations. Our results revealed a pronounced seasonal variability and spatial heterogeneity in DMSP concentrations and the associated demethylating bacterial community.
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Castellanos P., E. Olmedo, J.L. Pelegrí, A. Turiel, E.J.D. Campos
Remote Sensing, 11(7), 802, 1-17. DOI: 10.3390/rs11070802 (BibTeX: castellanos.etal.2019)
Resumen: Ver
Three of the world’s most energetic regions are in the tropical and South Atlantic: the North Brazil Current Retroflection, the Brazil-Malvinas Confluence, and the Agulhas Current Retroflection. All three regions display offshore diversions of major boundary currents, which define the intensity of the returning limb of the Atlantic meridional overturning circulation. In this work, we use a sea-surface salinity (SSS) satellite product, combined with a high-resolution numerical model and in situ measurements, in order to explore the seasonal variation of the surface currents and transports in these three regions. The analysis of the model output shows that the SSS patterns reflect the surface velocity structure, with the largest horizontal SSS gradients coinciding with those areas of highest velocity and the most predominant velocity vector being 90º anticlockwise (clockwise) from the horizontal SSS gradient in the northern (southern) hemisphere. This information is then applied to the SSS satellite product to obtain maps of water velocity and salt transports, leading to a quantitative tool to estimate both water and salt transports in key regions of the world ocean.
Palabras clave: sea surface salinity; SMOS; retroflections; surface velocity; water transport; salt transport
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Ugalde A., B. Gaite, M. Ruiz, A. Villaseñor, C.R. Ranero
Seismological Research Letters, 90, 4, 1565-1576. DOI: 10.1785/0220180353 (BibTeX: ugalde.etal.2019a)
Resumen: Ver
In November 2014, a temporary land and marine seismic network was deployed to monitor the drilling of an exploratory well in the Canary Channel (eastern Canary Islands). This region is characterized by low‐seismic activity; however, because of the increased awareness of the potential seismic hazard caused by hydrocarbon exploitation activities, the drilling operations were monitored with an unprecedented level of detail for an activity of this kind. According to the reported earthquakes, there was not a measurable increase in seismicity in the vicinity of the well. Overall seismic activity was low, which is consistent with the historical seismicity records. Harmonic tremor, explained here as resonances of the instrument‐seafloor system generated by bottom water currents in the area, was commonly detected on the ocean‐bottom seismometer (OBS) recordings. The marine network data also revealed dozens of nonseismic short‐duration signals per day that appear similar to other events on OBS recordings throughout the world. We suggest that they may be caused by direct perturbations on the OBS, mostly induced by ocean currents in the Canary Channel.
Wang H., F. Piferrer, S.L Chen, Z.-G.Shen
Ed. H. Wang, F. Piferrer, S.L Chen, Z.-G.Shen. Wiley-Blackwell. 1-888. ISBN: 978-1-119-12726-0 (BibTeX: wang.etal.2019d)
Resumen: Ver
A comprehensive resource that covers all the aspects of sex control in aquaculture written by internationally-acclaimed scientists Comprehensive in scope, Sex Control in Aquaculture first explains the concepts and rationale for sex control in aquaculture, which serves different purposes. The most important are: to produce monosex stocks to rear only the fastest-growing sex in some species, to prevent precocious or uncontrolled reproduction in other species and to aid in broodstock management. The application of sex ratio manipulation for population control and invasive species management is also included. Next, this book provides detailed and updated information on the underlying genetic, epigenetic, endocrine and environmental mechanisms responsible for the establishment of the sexes, and explains chromosome set manipulation techniques, hybridization and the latest gene knockout approaches. Furthermore, the book offers detailed protocols and key summarizing information on how sex control is practiced worldwide in 35 major aquaculture species or groups, including fish and crustaceans, and puts the focus on its application in the aquaculture industry. With contributions from an international panel of leading scientists, Sex Control in Aquaculture will appeal to a large audience: aquaculture/fisheries professionals and students, scientists or biologists working with basic aspects of fish/shrimp biology, growth and reproductive endocrinology, genetics, molecular biology, evolutionary biology, and R&D managers and administrators. This text explores sex control technologies and monosex production of commercially-farmed fish and crustacean species that are highly in demand for aquaculture, to improve feed utilization efficiency, reduce energy consumption for reproduction and eliminate a series of problems caused by mixed sex rearing. Thus, this book: Contains contributions from an international panel of leading scientists and professionals in the field Provides comprehensive coverage of both established and new technologies to control sex ratios that are becoming more necessary to increase productivity in aquaculture Includes detailed coverage of the most effective sex control techniques used in the world\'s most important commercially-farmed species Sex Control in Aquaculture is the comprehensive resource for understanding the biological rationale, scientific principles and real-world practices in this exciting and expanding field.
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Richards T.A., R. Massana, S. Pagliara, N. Hall
Philosophical Transactions of the Royal Society B-Biological Sciences, 374, 1786, 20190076. DOI: 10.1098/rstb.2019.0076 (BibTeX: richards.etal.2019a)
Resumen: Ver
Cells are the building blocks of life, from single-celled microbes through to multi-cellular organisms. To understand a multitude of biological processes we need to understand how cells behave, how they interact with each other and how they respond to their environment. The use of new methodologies is changing the way we study cells allowing us to study them on minute scales and in unprecedented detail. These same methods are allowing researchers to begin to sample the vast diversity of microbes that dominate natural environments. The aim of this special issue is to bring together research and perspectives on the application of new approaches to understand the biological properties of cells, including how they interact with other biological entities.
Palabras clave: Microbe; Interactions; Methodology; Symbiosis; Protist; Archaea
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Sieracki M.E., N.J. Poulton, O. Jaillon, P. Wincker, C. de Vargas, L. Rubinat-Ripoll, R. Stepanauskas, R. Logares, R. Massana
Scientific Reports, 9, 6025, 1-11. DOI: 10.1038/s41598-019-42487-1 (BibTeX: sieracki.etal.2019a)
Resumen: Ver
Marine planktonic protists are critical components of ocean ecosystems and are highly diverse. Molecular sequencing methods are being used to describe this diversity and reveal new associations and metabolisms that are important to how these ecosystems function. We describe here the use of the single cell genomics approach to sample and interrogate the diversity of the smaller (pico- and nano-sized) protists from a range of oceanic samples. We created over 900 single amplified genomes (SAGs) from 8 Taraocean samples across the Indian ocean and the Mediterranean sea. We show that flow cytometric sorting of single cells effectively distinguishes plastidic and aplastidic cell types that agree with our understanding of protist phylogeny. Yields of genomic DNA with PCR-identifiable 18S rRNA gene sequence from single cells was low (15% of aplastidic cell sorts, and 7% of plastidic sorts) and tests with alternate primers and comparisons to metabarcoding did not reveal phylogenetic bias in the major protist groups. There was little evidence of significant bias against or in favor of any phylogenetic group expected or known to be present. the four open ocean stations in the Indian ocean had similar communities, despite ranging from 14°N to 20°S latitude, and they differed from the Mediterranean station. single cell genomics of protists suggests that the taxonomic diversity of the dominant taxa found in only several hundreds of microliters of surface seawater is similar to that found in molecular surveys where liters of sample are filtered
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D’Ambrosio M., A.L. Primo, M.A. Pardal, F. Martinho, E. Guerrero, S.C. Marques
Estuarine, Coastal and Shelf Science, 218, 179 - 187. DOI: 10.1016/j.ecss.2018.12.018 (BibTeX: dambrosio.etal.2019)
Resumen: Ver
This study analysed the distribution and abundance of both polygastric (asexual) and gonophores of the calycophoran siphonophores Muggiaea atlantica and Muggiaea kochii in the Mondego estuary (Portugal), as well as the influence of local environment and prey availability on the observed patterns. Samples were collected in three different zones of the estuary, from December 2013 to November 2015. In general, both species nectophores and total gonophores followed a similar trend, with higher abundances during spring-summer periods and increased densities in the downstream areas of the estuary, where the marine influence is stronger. Inter-annual differences occurred mainly for M. atlantica nectophores, which showed higher abundances in 2015, particularly in the upstream areas. Both species displayed a shift in the annual peak abundance, from bimodal in 2014 to unimodal in 2015. Patterns observed were not only strongly related with an increase of the marine influence in the estuary, but also with the presence of zooplanktonic prey, such as cirripede cypris, calanoid nauplius, Poecilostomatoida, and copepodites of Cyclopoida. This study represents a step towards a better knowledge of the biology and ecology of siphonophores.
Palabras clave: Gelatinous zooplankton; Siphonophorae; Calycophorae; Northwestern Atlantic Ocean; Mondego estuary
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Torres G., O. Carnicer, A. Canepa, P. De La Fuente, S. Recalde, R. Narea, E. Pinto, M.J. Borbor-Córdova
Frontiers in Marine Science, 6, 145, DOI: 10.3389/fmars.2019.00145 (BibTeX: torres.etal.2019)
Resumen: Ver
Among marine phytoplankton, dinoflagellates are a key component in marine ecosystems as primary producers. Some species synthesize toxins, associated with human seafood poisoning, and mortality in marine organisms. Thus, there is a large necessity to understand the role of environmental variables in dinoflagellates spatialtemporal patterns in response to future climate scenarios. In that sense, a monthly four-year (2013–2017) monitoring was taken to evaluate dinoflagellates abundances and physical-chemical parameters in the water column at different depths. Sampling sites were established at 10 miles in four locations within the Ecuadorian coast. A total of 102 taxa were identified, corresponding to 8 orders, 22 families, and 31 genera. Eight potentially harmful genera were registered but no massive blooms were detected. The most frequent dinoflagellates were Gymnodinium sp. and Gyrodinium sp. Environmental variables showed different mixing layer thickness and a conspicuous and deepening thermocline/oxycline/halocline and nutricline depending on annual and seasonal oceanographic fluctuations. This study confirms that seasonal and spatial distribution of the environmental variables are linked to the main current systems on the Eastern Tropical Pacific, thus the warm Panama current lead to a less dinoflagellates abundance in the north of Ecuador (Esmeraldas), while the Equatorial Upwelling and the cold nutrient-rich Humboldt Current influence dinoflagellates abundance at the central (Manta, La Libertad) and South of Ecuador (Puerto Bolivar), respectively. Interannual variability of dinoflagellates abundance is associated with ENSO and upwelling conditions. Climate change scenarios predict an increase in water surface temperature and extreme events frequency in tropical areas, so it is crucial to involve policy-makers and stakeholders in the implementation of future laws involving long-term monitoring and sanitary programs, not covered at present.
Palabras clave: dinoflagellates, HABs, ENSO, tropical Eastern Pacific, nutrients, upwelling, humboldt current
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Rodríguez-Flores P.C., A. Machordom, P. Abelló, J.A. Cuesta, E. Macpherson
Marine Biodiversity, 49, 4, 1751-1773. DOI: 10.1007/s12526-019-00941-3 (BibTeX: rodriguezflores.etal.2019b)
Resumen: Ver
The taxonomy of Munida Leach, 1820 from the north-eastern Atlantic and Mediterranean Sea was studied using a comparative analysis of morphological characters and molecular markers (mitochondrial and nuclear). Generalized Mixed Yule Coalescence and the Poisson tree process models were used to delimit two groups of closely related species associated with uncertain nomenclature and taxonomic status: (1) Munida intermedia A. Milne Edwards & Bouvier, 1899, M. rugosa (Fabricius, 1775), M. sarsi Huus, 1935 and M. tenuimana Sars, 1872 and (2) M. rutllanti Zariquiey-Álvarez, 1952 and M. speciosa von Martens, 1878. We found that M. tenuimana is restricted to northern Atlantic waters (north of approx. 48° N), while Mediterranean and Bay of Biscay specimens previously assigned to this taxon actually belong to a different species, indicating that the name Munida perarmata A. Milne Edwards & Bouvier, 1894 should be resurrected. Furthermore, M. rutllanti is shown to be a junior synonym of M. speciosa, a species that has thus far only been reported along western Africa. In addition, three species are re-described and a key to European Munida is provided. The validity of the morphological characters used to distinguish the different species is discussed. Phylogenetic analyses revealed three independent lineages with unsolved relationships among them, including high genetic distances for some species. These findings indicate highly divergent lineages of the European Munida and several events of colonization along the eastern Atlantic.
Palabras clave: Anomura; Munididae; European Munida; Phylogeny; Mitochondrial markers; Nuclear markers; Morphology
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Maldonado M., M. López-Acosta, C. Sitjà, M.G.-Puig, C. Galobart, G. Ercilla, A. Leynaert
Nature Geoscience, 12, 815-822. DOI: 10.1038/s41561-019-0430-7 (BibTeX: maldonado.etal.2019b)
Resumen: Ver
Silicon (Si) is a pivotal element in the biogeochemical and ecological functioning of the ocean. The marine Si cycle is thought to be in internal equilibrium, but the recent discovery of Si entries through groundwater and glacial melting have increased the known Si inputs relative to the outputs in the global oceans. Known outputs are due to the burying of diatom skeletons or their conversion into authigenic clay by reverse weathering. Here we show that non-phototrophic organisms, such as sponges and radiolarians, also facilitate significant Si burial through their siliceous skeletons. Microscopic examination and digestion of sediments revealed that most burial occurs through sponge skeletons, which, being unusually resistant to dissolution, had passed unnoticed in the biogeochemical inventories of sediments. The preservation of sponge spicules in sediments was 45.2 ± 27.4%, but only 6.8 ± 10.1% for radiolarian testa and 8% for diatom frustules. Sponges lead to a global burial flux of 1.71 ± 1.61 TmolSi yr−1 and only 0.09 ± 0.05 TmolSi yr−1 occurs through radiolarians. Collectively, these two non-phototrophically produced silicas increase the Si output of the ocean to 12.8 TmolSi yr−1, which accounts for a previously ignored sink that is necessary to adequately assess the global balance of the marine Si cycle.
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Rotllant D. CastejónG., E. Ribes, M. Durfort, G. Guerao
Journal of Morphology, 280, 3, 370-380. DOI: 10.1002/jmor.20949 (BibTeX: castejong.rotllant.etal.2019b)
Resumen: Ver
The stomach of decapods is a complex organ with specialized structures that are delimited by a cuticle. The morphology and ontogeny of the stomach are largely described, but few studies have focused on the morphology of its cuticle. This study examined the morphology of the stomach cuticle of cardiac sacs, gastric mill ossicles, cardio‐pyloric valve and pyloric filters, and during various stages (zoea I and II, megalopa, first juvenile, and adult) of the common spider crab Maja brachydactyla using dissection, histology and transmission electron microscopy. The results show that cuticle morphology varies among structures (e.g., cardiac sacs, urocardiac ossicle, cardio‐pyloric valve, pyloric filters), within a single structure (e.g., different sides of the urocardiac ossicle) and among different life stages. The cuticle during the larval stages is very thin and the different layers (epicuticle, exocuticle, and endocuticle) are infrequently distinguishable by histology. Major changes during larval development regarding cuticle morphology are observed after the molt to megalopa, including the increment in thickness in the gastric mill ossicles and cardio‐pyloric valve, and the disappearance of the long thickened setae of the cardio‐pyloric valve. The cuticle of all the stomach structures in the adults is thicker than in larval and juvenile stages. The cuticle varies in thickness, differential staining affinity and morphology of the cuticle layers. The structure–function relationship of the cuticle morphology is discussed.
Palabras clave: Foregut; Histology; Larval development; Malacostraca; Transmission electron microscopy
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Beckley L.E., D. Holliday, A.L. Sutton, E. Weller, M.P. Olivar, P.A. Thompson
Deep-Sea Research Part II: Topical Studies in Oceanography, 161, 105-119. DOI: 10.1016/j.dsr2.2018.03.008 (BibTeX: beckley.etal.2019)
Resumen: Ver
In the eastern Indian Ocean, the Kimberley region off north-western Australia is characterised by a wide continental shelf, complex coastal topography and very large tides (>10 m). Diversity of fishes is high although little is known about the distribution of their larvae in this dynamic region. This study investigated spatial variation in ichthyoplankton assemblages along four coastal-oceanic transects and related the results to tidal cycles and other environmental variables. Larvae representing 92 neritic and 21 mesopelagic teleost families were collected; this far exceeds the diversity described for other comparable tropical continental shelf and oceanic systems. Distinct ichthyoplankton assemblages characterised inner shelf (Engraulidae and Gobiidae were dominant families), outer shelf / slope (mixed neritic and mesopelagic taxa) and oceanic waters (mesopelagic taxa, particularly Myctophidae, Gonostomatidae and Phosichthyidae), and were correlated with changes in environmental variables (water depth, seawater density, mixed layer depth and zooplankton). The spring-neap tidal cycle and subsequent tides (same stations sampled 12 h apart) had no significant influence on larval fish assemblages. Coastal waters were delineated by a density front and larval fish assemblages were significantly different from offshore assemblages. This study provides new insights into the pelagic ecosystem in the tropical eastern Indian Ocean and contributes to the understanding of the role of environmental variables and physical forcing in the structuring of larval fish assemblages.
Palabras clave: Kimberley; Coastal-oceanic gradient; Oceanography; Ichthyoplankton; Mesopelagic; Neritic
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Cabré A., J.L. Pelegrí, I. Vallès-Casanova
Journal of Geophysical Research: Oceans, 124, 7, 4820-4837. DOI: 10.1029/2019JC015160 (BibTeX: cabre.etal.2019)
Resumen: Ver
Here we explore the water transfer between the subtropical and tropical gyres of the South Atlantic Ocean to better understand its unique equatorward heat delivery. A Lagrangian technique is applied to the reanalysis product GLORYS2V4 in order to trace back the western boundary flow in the tropical (North Brazil Undercurrent, NBUC) and subtropical (Brazil Current) gyres. Most of the northward NBUC core transport (14.9 Sv at 8°S) arrives from the eastern boundary subtropical current (Benguela Current) via the zonal South Equatorial Current. This subtropical‐tropical transfer represents the core of the returning limb of the Atlantic meridional overturning circulation and accounts for most of the observed increase in heat and salt‐volume transports (0.18 PW and 0.19 Sv from 30°S to 8°S, respectively) across the South Atlantic. The NBUC also includes Antarctic Intermediate Water below 400 m (7.4 Sv at 8°S) coming from the interior subtropical gyre, as well as water from the current\'s surface and peripheral components coming from the tropical gyre (13.3 Sv at 8°S). The Brazil Current (9.9 Sv at 29°S) is mostly composed of subtropical water originating in the upper 800mwest of the eastern boundary current at 30°S (8.5 Sv), with a minor contribution of surface tropical water that transfers to the subtropics (1.4 Sv).
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Orué-Echevarría D., P. Castellanos, J. Sans, M. Emelianov, I. Vallès-Casanova, J.L. Pelegrí
Geophysical Research Letters, 46, 22, 13234-13243. DOI: 10.1029/2019GL084246 (BibTeX: orueechevarria.etal.2019e)
Resumen: Ver
Ocean frontal systems may act both as barriers and mixers between different water masses, the latter thanks to very energetic structures with relatively short temporal and spatial scales. Here, we explore the high‐frequency temperature variability in the Brazil‐Malvinas Confluence through the joint analysis of novel high‐resolution SeaSoar measurements and sea surface temperature imagery. Surface spatiotemporal correlation scales range between 1.5 and 6 days and between 20 and 50 km, with the shortest scales along the shelf‐break path of the Brazil Current and over the confluence and the longest ones along the Malvinas Current. The spatial scales display minima along the front, at the surface because of the presence of brackish shelf waters and at the subsurface due to both mesoscale and submesoscale thermohaline intrusions. The smallest cross‐frontal vertical correlations, in the 5‐ to 10‐m range, are associated with submesoscale processes. Overall, temperature variability is enhanced at depth in the frontal system.
Terrinha P., A. Ramos, M. Neres, V. Valadares, J. Duarte, S. Martínez-Loriente, S. Silva, J. Mata, J.C. Kullberg, A. Casas-Sainz, L. Matias, O. Fernández, J.A.Muñoz, C. Ribeiro, E. Font, C. Neves, C. Roque, F. Rosas, L. Pinheiro, R. Bartolomé, V. Sallarès, V. Magalhães, T. Medialdea, L. Somoza, E. Gràcia, C. Hensen, M.-A. Gutscher, A. Ribeiro, N. Zitellini
In: The Geology of Iberia: A Geodynamic Approach, Regional Geology Reviews 2364-6438. Vol. 3. Ed. C. Quesada, J.T. Oliveira. Springer. Chap. 11. 487-505. DOI: 10.1007%2F978-3-030-11295-0_11 ISBN: 978-3-030-11295-0 (BibTeX: terrinha.etal.2019a)
Resumen: Ver
The Alpine orogeny is well recorded onshore and offshore by tectonic inversion of the Mesozoic rift basins. Large scale linear seamounts (more than 250 km long and with up to 5 km of uplift) involving oceanic and continental lithosphere were carried on top of thrusts, such as the Gorringe seamount and the Estremadura Spur in the SouthWest and West Iberia Margin, respectively. The SouthWest Iberia Margin also recorded the westward migration of the Gibraltar Oceanic slab as the westwards propagation of the Neo-Tethys subduction. Rotation of the tectonic compression from NW-SE to WNW-ESE in Pliocene times caused the development of large scale dextral wrench faults as the present day Africa-Iberia plate boundary. Neotectonics of this plate boundary caused large to mega-scale destructive earthquakes and tsunamis.
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Neukirch M., D. Rudolf, X. Garcia, S. Galiana
Geophysics, 84, 5, B299-V302. DOI: 10.1190/geo2018-0352.1 (BibTeX: neukirch.etal.2019b)
Resumen: Ver
The introduction of the Phase Tensor marked a breakthrough in the understanding and analysis of electric galvanic distortion effects. It has been used for (distortion free) dimensionality analysis, distortion analysis, mapping and subsurface model inversion. However, the Phase Tensor can only represent half of the information contained in a complete impedance data set. Nevertheless, to avoid uncertainty due to galvanic distortion effects, practitioners often choose to discard half of the measured data and concentrate interpretation efforts on the Phase Tensor part. This work assesses the information loss due to pure Phase Tensor interpretation of a complete impedance data set. To achieve this, a new MT impedance tensor decomposition into the known Phase Tensor and a newly defined Amplitude Tensor is motivated and established. Additionally, the existence and uniqueness of the Amplitude Tensor is proven. Synthetic data is used to illustrate the Amplitude Tensor information content compared to the Phase Tensor. While the Phase Tensor only describes the inductive effects within the subsurface, the Amplitude Tensor holds information about inductive and galvanic effects that can help to identify conductivity or thickness of (conductive) anomalies more accurately than the Phase Tensor. Furthermore, the Amplitude and Phase Tensors sense anomalies at different periods and thus the combination of both provides means to evaluate and differentiate anomaly top depths in the event of data unavailability at extended period ranges, e.g. due to severe noise
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Raj R.P., S. Chatterjee, L. Bertino, A. Turiel, M. Portabella
Ocean Science, 15, 1729-1744. DOI: 10.5194/os-15-1729-2019 (BibTeX: raj.etal.2019)
Resumen: Ver
The Arctic Front (AF) in the Norwegian Sea is an important biologically productive region which is wellknown for its large feeding schools of pelagic fish. A suite of satellite data, a regional coupled ocean–sea ice data assimilation system (the TOPAZ reanalysis) and atmospheric reanalysis data are used to investigate the variability in the lateral and vertical structure of the AF. A method, known as “singularity analysis”, is applied on the satellite and reanalysis data for 2-D spatial analysis of the front, whereas for the vertical structure, a horizontal gradient method is used. We present new evidence of active air–sea interaction along the AF due to enhanced momentum mixing near the frontal region. The frontal structure of the AF is found to be most distinct near the Faroe Current in the south-west Norwegian Sea and along the Mohn Ridge. Coincidentally, these are the two locations along the AF where the air–sea interactions are most intense. This study investigates in particular the frontal structure and its variability along the Mohn Ridge. The seasonal variability in the strength of the AF is found to be limited to the surface. The study also provides new insights into the influence of the three dominant modes of the Norwegian Sea atmospheric circulation on the AF along the Mohn Ridge. The analyses show a weakened AF during the negative phase of the North Atlantic Oscillation (NAO-), even though the geographical location of the front does not vary. The weakening of AF during NAO- is attributed to the variability in the strength of the Norwegian Atlantic Front Current over the Mohn Ridge associated with the changes in the wind field.
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Orúe-Echevarría Iglesias D.,
PhD thesis. Director/es: J.Ll. Pelegrí. (BibTeX: orueechevarriaiglesias.2019a)
Resumen: Ver
The Southwest Atlantic Ocean is a key component of the global climate system. It holds the Confluence of the Brazil and Malvinas Currents (BMC), one of the highest frontal systems of the world ocean. The BMC is the encounter point of subtropical origin warm and salty waters, transported southward within the Brazil Current, and subantarctic waters flowing equa- torward along the Malvinas Current. The intense mixing and cross-frontal exchanges highly transform the water masses at this region, which will finally flow southward, eastward or will be subducted into the subtropical thermocline. This PhD dissertation aims at extending our knowledge on the circulation and dynamics in the BMC, placing these results in perspective from the small to the global scales. The intense property contrast found in this region resemble the intense temperature gradients between low and high latitudes. We first analyse the changes in the heat content of the atmosphere and upper ocean compartments for the last 450 kyr and analyse the sensitivity of the system to changes in albedo, cloud cover and atmospheric and oceanic heat transports. We then describe the hydrographic conditions found at the BMC during and early fall cruise (TIC-MOC cruise). These reveal the presence of brackish river water on top the frontal system. The salinity anomaly at the surface correlates with the presence of large ageostrophic velocities along the frontal jet. In addition, the rapid evolution of these waters impinges on the ther-mohaline variability in the proximity of the front. The comparison of surface overview during the cruise is well represented by the high-resolution reanalysis, although at depth it misses the thermohaline intrusions developed both sides the front. On the other hand, climatological data, as it shows the monthly fields, is not able to reproduce the numerous mesoscale features. [...]
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Hernández-Becerril D.U., N. Sampedro, E. Garcés
, 148, 1-10. (BibTeX: hernandezbecerril.etal.2019)
Felip A., F. Piferrer
In: Sex Control in Aquaculture, Ed. H. Wang, F. Piferrer, S.L Chen, Z.-G.Shen. Wiley-Blackwell. Chap. 16. 347-358. DOI: 10.1002/9781119127291.ch16 ISBN: 978-1-119-12726-0 (BibTeX: felip.piferrer.2019a)
Resumen: Ver
Precocious sexual maturation affects approximately one‐third of farmed European sea bass males which, in turn, constitute most of the farmed fish of this species. To prevent sexual maturation, and to contribute to the production of monosex stocks, chromosome set manipulation procedures have been subject to intense investigation over the last 20 years. These include the induction of poliploidy (triploidy and tetraploidy) and the production of individuals with uniparental inheritance (mito‐ and meiogynogens and androgenetics). Several studies have examined different experimental conditions in order to establish optimized protocols based on the application of pressure and temperature shocks, to retain a full set of chromosomes, thus suppressing the extrusion of the second polar body, or the first cleavage in the zygote. The use of UV irradiation has also been evaluated to inactivate the DNA of exposed gametes for the application of induced gynogenesis and androgenesis. Triploidy in the European sea bass results in gonadal sterility in both sexes, which can be of advantage for its production in aquaculture although, only in larger fish, it may represent a superior growth. On the other hand, the maintenance of gynogenetic and androgenetic clonal founders can contribute to a better understanding of the genetic basis of many complex traits of interest for fish farming. Although the performance of fish after ploidy manipulation, concerning the growth, reproductive activity, and proportion of sexes, has been well documented, further evaluations are still required before these fish can achieve societal acceptance and be considered for their applicability to the industry. Finally, benefits, considerations and future work are under discussion.
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Freitas R., F. Coppola, S. Costa, C. Pretti, L. Intorre, V. Meucci, A.M.V.M. Soares, M. Solé
Science of The Total Environment, 663, 992-999. DOI: 10.1016/j.scitotenv.2019.01.189 (BibTeX: freitas.etal.2019b)
Resumen: Ver
Little is known about the consequences of exposure to pharmaceuticals and personal care products (PPCPs) in elevated temperatures associated with climate change. To increase the knowledge on this topic, Mytilus galloprovincialis mussels were exposed to 1.0 μg/L of either the antimicrobial Triclosan (TCS) or the anti-inflammatory drug Diclofenac (DIC), at control (17 °C) and 4 °C raised (21 °C) temperatures for 28 days. Triclosan and DIC concentrations in the water and tissues were subsequently measured and related to biomarker responses including: energy metabolism (electron transport system (ETS) activity, glycogen and protein reserves), oxidative stress markers, glutathione balance between the reduced and the oxidised form (GSH/GSSG), and damage to proteins and lipids. Mussels responded to the increase in temperature and drug exposure by lowering their metabolic rate (decreased ETS), increasing their endogenous reserves and antioxidant defences, thus preventing oxidative stress damage, with the exception of DIC exposure at the higher temperature. In all cases, GSH/GSSG ratio was reduced in detriment of the antioxidant form at both PPCPs exposures and elevated temperature with no additive effect due to combined stressors. Overall, either drug exposure or increased temperature could compromise the ability of mussels to withstand further insults.
Palabras clave: Climate change; Pharmaceuticals; Personal care products; Biomarkers; Bivalves; Mytilus galloprovincialis
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Figuerola B., C. Avila
Marine Drugs, 17, 8, 477. DOI: 10.3390/md17080477 (BibTeX: figuerola.avila.2019a)
Resumen: Ver
Recent advances in sampling and novel techniques in drug synthesis and isolation have promoted the discovery of anticancer agents from marine organisms to combat this major threat to public health worldwide. Bryozoans, which are filter-feeding, aquatic invertebrates often characterized by a calcified skeleton, are an excellent source of pharmacologically interesting compounds including well-known chemical classes such as alkaloids and polyketides. This review covers the literature for secondary metabolites isolated from marine cheilostome and ctenostome bryozoans that have shown potential as cancer drugs. Moreover, we highlight examples such as bryostatins, the most known class of marine-derived compounds from this animal phylum, which are advancing through anticancer clinical trials due to their low toxicity and antineoplastic activity. The bryozoan antitumor compounds discovered until now show a wide range of chemical diversity and biological activities. Therefore, more research focusing on the isolation of secondary metabolites with potential anticancer properties from bryozoans and other overlooked taxa covering wider geographic areas is needed for an efficient bioprospecting of natural products.
Palabras clave: Antitumor compounds; Marine natural products (MNPs); Bioactivity; Cytotoxicity; Marine invertebrates
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Hernández-Guerra A., L.D. Talley, J.L. Pelegrí, P. Vélez-Belchí, M.O. Baringer, A.M. Macdonald, E.L. McDonagh
Progress in Oceanography, 176, DOI: 10.1016/j.pocean.2019.102136 (BibTeX: hernandezguerra.etal.2019)
Resumen: Ver
Mass transports for the thermocline, intermediate, deep and abyssal layers in the Atlantic Ocean, at 30°S and for 2003 and 2011, have been estimated using data from GO-SHIP hydrographic transoceanic sections and applying three inverse models with different constraints. The uppermost layers comprise South Atlantic Central Water (SACW) and Antarctic Intermediate Water (AAIW), with a net northward transport in the range of 12.1–14.7 Sv in 2003 and 11.7–17.7 Sv in 2011, which can be considered as the northward returning limb of the Meridional Overturning Circulation (MOC). The western boundary Brazil Current transports twice as much SACW in 2003 (−20.2 ± 0.7 Sv) than in 2011 (−9.7 ± 0.7 Sv). A poleward current consisting of AAIW and Upper Circumpolar Deep Water (UCDW) flows beneath the Brazil Current. The eastern boundary Benguela Current, characterized by a high mesoscale eddy activity, transports 15.6 ± 0.9 Sv in 2003 and 11.2 ± 0.8 Sv in 2011, east of the Walvis Ridge. In the ocean interior, the northward flow is mainly located east of the Mid Atlantic Ridge (MAR) where Agulhas Rings (ARs), observed in both 2003 and 2011, transport warm and salty water from the Indian to the Atlantic Ocean. For the deep layers, the southward transport of North Atlantic Deep Water (NADW) occurs as the Deep Western Boundary Current and also in the eastern basin. The western and eastern basins transport similar amounts of NADW to the south during both years, although the eastern pathway changes substantially between both years. The total NADW transport, which is also considered the MOC, is in the range 16.3–24.5 Sv in 2003 and 17.1–29.6 Sv in 2011, hence with no significant change.
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Evans R.L., M.H. Benoit, M.D. Long, J. Elsenbeck, H.A. Ford, J. Zhu, X. Garcia
Earth and Planetary Science Letters, 519, 308-316. DOI: 10.1016/j.epsl.2019.04.046 (BibTeX: evans.etal.2019b)
Resumen: Ver
A joint analysis of magnetotelluric and Sp receiver function data, collected along a profile across the central Appalachians, highlights variations in regional lithospheric structure. While the interpretation of each data set by itself is non-unique, we identify three distinct features that are consistent with both the resistivity model and the receiver function image: 1) thin lithosphere beneath the Appalachian Mountains, 2) somewhat thicker lithosphere to the east of the mountains beneath the Coastal Plain, and 3) a lithosphere-asthenosphere boundary that deepens to the west of the mountains. In some regions, the correspondence between seismic velocity discontinuities and resistivity mark the base of the lithosphere, while in other locations we see seismic discontinuities that are contained within the lithosphere. At the western end of our profile a transition from highly resistive lithosphere to more conductive mantle represents the transition across the Grenville front. The thickness of lithosphere beneath the Grenville terrain is ∼140 km. Lithosphere at the eastern end of the profile has a thickness that is not well constrained by our coverage, but is at least 110 km thick. This lithosphere can be associated with a broader region of high resistivity material seen to extend further south. Directly beneath the Appalachian Mountains, lithospheric thickness is inferred to be as thin as ∼80 km, based on observations of elevated mantle conductivities and a westward-dipping seismic converter. Electrical conductivities in the uppermost asthenospheric mantle are sufficiently high (>0.1 S/m) to require the presence of a small volume of partial melt. The location of these elevated conductivities is close (offset ∼50 km to the west) to Eocene volcanic outcrops in and around Harrisonburg, VA. Our observations speak to mechanisms of intraplate volcanism where there is no divergent or convergent plate motion to trigger mantle upwelling or obvious fluid release, either of which can facilitate melting. Instead, we suggest that small scale mantle convection related either to pre-existing lithospheric thickness variations, or to lithospheric loss through delamination, coupled with relative plate motion with respect to the underlying asthenosphere, can trigger small amounts of melting. This melt migrates upslope, along the base of the lithosphere, potentially thermally eroding the lithosphere resulting in further thinning
Palabras clave: Magnetotellurics; Seismic; Receiver function; Lithosphere
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Lin W., M. Portabella, G. Foti, A. Stoffelen, C. Gommenginger, Y. He
IEEE Transactions on Geoscience and Remote Sensing, 57, 2, 655-666. DOI: 10.1109/TGRS.2018.2859191 (BibTeX: lin.etal.2019b)
Resumen: Ver
This paper presents a comprehensive procedure to improve the wind geophysical model function (GMF) for the Global Navigation Satellite System Reflectometry (GNSS-R) instrument onboard the TechDemoSat-1 satellite. The observable used to define the GMF is extracted from the measured delay- Doppler maps (DDMs) by correcting for the nongeophysical effects within the measurements. Besides the instrument and the geometric effects as provided in the bistatic radar equation, a calibration term that accounts for the uncalibrated receiver antenna gain and the unknown transmitter antenna gain is proposed to optimize the calculation of GNSS-R observables. Such calibration term is presented as a function of observing elevation and azimuth angles and is shown to remarkably reduce the measurement uncertainties. First, an empirical wind-only GMF is developed using the collocated Advanced Scatterometer (ASCAT) winds and European Centre for Medium-Range Weather Forecasts (ECMWF) model wind output. This empirical GMF agrees well with the model output. Then, the sensitivity of the observable to waves is analyzed using the collocated ECMWF wave parameters. The results show that it is difficult to include mean square slope (MSS) in the development of an empirical GMF, since the difference between ECMWF MSS and the MSS sensed by GNSS-R varies with incidence angle and wind speed. However, it is relevant to take significant wave height (Hs) in account, particularly for low wind conditions. Consequently, a wind/Hs approach is proposed for improved wind retrievals.
Palabras clave: Advanced Scatterometer (ASCAT); Calibration; Global Navigation Satellite System Reflectometry (GNSS-R); Wave; Winds
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Mir-Arguimbau J., A. Sabatés, U. Tilves
Journal of Sea Research, 147, 28-36. DOI: 10.1016/j.seares.2019.02.004 (BibTeX: mirarguimbau.etal.2019b)
Resumen: Ver
This study analyses the trophic ecology of the horse mackerel (Trachurus mediterraneus) juveniles associated with two jellyfish species, Rhizostoma pulmo and Cotylorhiza tuberculata, in the NW Mediterranean. The aim was to know whether the natural diet composition of the hosted fish could be influenced by the jellyfish species and to explore if the fish could feed on the host jellyfish. Samplings were carried out off the coast of Barcelona in summer 2011 at depths of up to 10 m. Juveniles associated with C. tuberculata showed a higher feeding incidence and number of ingested prey than those associated with R. pulmo. The relative importance of the different prey varied depending on the jellyfish species with which fish were associated. In juveniles associated with C. tuberculata, the diet was similar to the composition of the ambient zooplankton, with the cladocera Evadne spp. and Calanoida copepods as the most important prey. However, juveniles associated with R. pulmo fed mainly on Calanoida and Harpacticoida copepods. These differences could be related to the depth-associated behaviour of each jellyfish species, with R. pulmo particularly making deeper living plankton accessible to the horse mackerel juveniles. The presence of nematocyst cells in the juvenile gut contents suggests that they fed on the host jellyfish, either directly on the jellyfish tissue or accidentally when they remove the prey captured by the jellyfish oral arms. Our results provide a better understanding of the associations between jellyfish and juvenile fish which can have important effects on fish population dynamics.
Palabras clave: Symbiosis; Commensalism; Horse mackerel juvenile; Diet; Nematocyst; NW Mediterranean
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Olivar M.P., A. Bode, C. López-Pérez, P. Alexander Hulley, S. Hernández-León Handling
ICES Journal of Marine Science, 76, 3, 649-661. DOI: 10.1093/icesjms/fsx243 (BibTeX: olivar.etal.2019)
Resumen: Ver
Lanternfishes (Myctophidae) constitute the most important component of the daily vertically migrating mesopelagic fish community. This research addresses the estimation of the trophic position and diet of myctophids using stable isotope analyses. Fishes were collected across the central Atlantic, from a very productive zone influenced by the Mauritanian upwelling to the western oligotrophic equatorial waters. The survey also encompassed a zone of low oxygen concentration in the mesopelagic layers. Determinations of δ13C and δ15N values were made on the 20 most frequent and abundant myctophids, from small-sized species (e.g. Notolychnus valdivae) to larger ones (e.g. Myctophum punctatum). Isotope analyses on the seston and several plankton groups were also performed to assess the influence of zonal differences in trophic position (TP) calculations, and to use as food sources in diet estimations. Myctophids displayed a narrow range of trophic positions, being greater than 2 and less than 4, except for N. valdiviae (TP = 1.7). Comparisons of diets estimated through an isotopic mixing model differentiated the smallest species, with a strong seston signature (Diogenichthys atlanticus and N. valdiviae), from the Diaphus species of medium sizes, (D. brachycephalus, D. holti, and D. rafinesquii), which feed on prey of higher TP values.
Palabras clave: Diet; Mesopelagic fish; Trophic relationships; δ 13C; δ 15N
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Bryndum‐Buchholz A., D.P. Tittensor, J.L. Blanchard, W.W. L. Cheung, M. Coll, E.D. Galbraith, S. Jennings, O. Maury, H.K. Lotze
Global Change Biology, 25, 2, 459-472. DOI: 10.1111/gcb.14512 (BibTeX: bryndumbuchholz.etal.2019a)
Resumen: Ver
Climate change effects on marine ecosystems include impacts on primary production, ocean temperature, species distributions, and abundance at local to global scales. These changes will significantly alter marine ecosystem structure and function with associated socio‐economic impacts on ecosystem services, marine fisheries, and fishery‐dependent societies. Yet how these changes may play out among ocean basins over the 21st century remains unclear, with most projections coming from single ecosystem models that do not adequately capture the range of model uncertainty. We address this by using six marine ecosystem models within the Fisheries and Marine Ecosystem Model Intercomparison Project (Fish‐MIP) to analyze responses of marine animal biomass in all major ocean basins to contrasting climate change scenarios. Under a high emissions scenario (RCP8.5), total marine animal biomass declined by an ensemble mean of 15%–30% (±12%–17%) in the North and South Atlantic and Pacific, and the Indian Ocean by 2100, whereas polar ocean basins experienced a 20%–80% (±35%–200%) increase. Uncertainty and model disagreement were greatest in the Arctic and smallest in the South Pacific Ocean. Projected changes were reduced under a low (RCP2.6) emissions scenario. Under RCP2.6 and RCP8.5, biomass projections were highly correlated with changes in net primary production and negatively correlated with projected sea surface temperature increases across all ocean basins except the polar oceans. Ecosystem structure was projected to shift as animal biomass concentrated in different size‐classes across ocean basins and emissions scenarios. We highlight that climate change mitigation measures could moderate the impacts on marine animal biomass by reducing biomass declines in the Pacific, Atlantic, and Indian Ocean basins. The range of individual model projections emphasizes the importance of using an ensemble approach in assessing uncertainty of future change
Palabras clave: Climate change; Ensemble modeling; Future projection; Marine animal biomass; Marine ecosystem models; Model intercomparison; Ocean basins; Uncertainty
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Cornejo‐Castillo F.M., M.C. Muñoz‐Marín, K.A. Turk‐Kubo, M. Royo‐Llonch, H. Farnelid, S.G. Acinas, J.P. Zehr
Environmental Microbiology, 21, 1, 111-124. DOI: 10.1111/1462-2920.14429 (BibTeX: cornejocastillo.etal.2019a)
Resumen: Ver
The symbiotic unicellular cyanobacterium Candidatus Atelocyanobacterium thalassa (UCYN‐A) is one of the most abundant and widespread nitrogen (N2)‐fixing cyanobacteria in the ocean. Although it remains uncultivated, multiple sublineages have been detected based on partial nitrogenase (nifH) gene sequences, including the four most commonly detected sublineages UCYN‐A1, UCYN‐A2, UCYN‐A3 and UCYN‐A4. However, very little is known about UCYN‐A3 beyond the nifH sequences from nifH gene diversity surveys. In this study, single cell sorting, DNA sequencing, qPCR and CARD‐FISH assays revealed discrepancies involving the identification of sublineages, which led to new information on the diversity of the UCYN‐A symbiosis. 16S rRNA and nifH gene sequencing on single sorted cells allowed us to identify the 16S rRNA gene of the uncharacterized UCYN‐A3 sublineage. We designed new CARD‐FISH probes that allowed us to distinguish and observe UCYN‐A2 in a coastal location (SIO Pier; San Diego) and UCYN‐A3 in an open ocean location (Station ALOHA; Hawaii). Moreover, we reconstructed about 13% of the UCYN‐A3 genome from Tara Oceans metagenomic data. Finally, our findings unveil the UCYN‐A3 symbiosis in open ocean waters suggesting that the different UCYN‐A sublineages are distributed along different size fractions of the plankton defined by the cell‐size ranges of their prymnesiophyte hosts.
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Sallarès V., C.R. Ranero
Nature, 576, 96-101. DOI: 10.1038/s41586-019-1784-0 (BibTeX: sallares.ranero.2019)
Resumen: Ver
Seismological data provide evidence of a depth-dependent rupture behaviour of earthquakes occurring at the megathrust fault of subduction zones, also known as megathrust earthquakes1. Relative to deeper events of similar magnitude, shallow earthquake ruptures have larger slip and longer duration, radiate energy that is depleted in high frequencies and have a larger discrepancy between their surface-wave and moment magnitudes1,2,3. These source properties make them prone to generating devastating tsunamis without clear warning signs. The depth-dependent rupture behaviour is usually attributed to variations in fault mechanics4,5,6,7. Conceptual models, however, have so far failed to identify the fundamental physical causes of the contrasting observations and do not provide a quantitative framework with which to predict and link them. Here we demonstrate that the observed differences do not require changes in fault mechanics. We use compressional-wave velocity models from worldwide subduction zones to show that their common underlying cause is a systematic depth variation of the rigidity at the lower part of the upper plate - the rock body overriding the megathrust fault, which deforms by dynamic stress transfer during co-seismic slip. Combining realistic elastic properties with accurate estimates of earthquake focal depth enables us to predict the amount of co-seismic slip (the fault motion at the instant of the earthquake), provides unambiguous estimations of magnitude and offers the potential for early tsunami warnings.
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Saha M., E. Berdalet, Y. Carotenuto, P. Fink, T. Harder, U. John, F. Not, G. Pohnert, P. Potin, E. Selander, W. Vyverman, T. Wichard, V. Zupo, M. Steinke
Frontiers in ecology and the environment, 17, 9, 530-537. DOI: 10.1002/fee.2113 (BibTeX: saha.etal.2019a)
Resumen: Ver
“Infochemicals” (information‐conveying chemicals) dominate much of the underwater communication in biological systems. They influence the movement and behavior of organisms, the ecological interactions between and across populations, and the trophic structure of marine food webs. However, relative to their terrestrial equivalents, the wider ecological and economic importance of marine infochemicals remains understudied and a concerted, cross‐disciplinary effort is needed to reveal the full potential of marine chemical ecology. We highlight current challenges with specific examples and suggest how research on the chemical ecology of marine organisms could provide opportunities for implementing new management solutions for future “blue growth” (the sustainable use of ocean resources) and maintaining healthy marine ecosystems.
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Hoareau N.,
PhD thesis. Director/es: J. Ballabrera, M. Portabella. (BibTeX: hoareau.2019a)
Resumen: Ver
In January 1969, Jack F. Paris published a comprehensive review of all the knowledge about microwave physics, engineering and its applications to meteorology and oceanography. In this 241 pages-long review, he pointed out that radiometers operating between 1.0 GHz and 5.4 GHz could be used to survey remotely both temperature and salinit along coastal and river regions in the world. [...]
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Carbajal A., O. Tallo-Parra, L. Monclús, D. Vinyoles, M. Solé, S. Lacorte, M. Lopez-Bejar
General and Comparative Endocrinology, 275, 44-50. DOI: 10.1016/j.ygcen.2019.01.015 (BibTeX: carbajal.etal.2019b)
Resumen: Ver
A significant body of literature suggests that aquatic pollutants can interfere with the physiological function of the fish hypothalamic-pituitary-interrenal (HPI) axis, and eventually impair the ability to cope with subsequent stressors. For this reason, development of accurate techniques to assess fish stress responses have become of growing interest. Fish scales have been recently recognized as a biomaterial that accumulates cortisol, hence it can be potentially used to assess chronic stress in laboratory conditions. We, therefore, aimed to evaluate the applicability of this novel method for cortisol assessment in fish within their natural environment. Catalan chub (Squalius laietanus) were sampled from two sites; a highly polluted and a less polluted (reference) site, in order to examine if habitat quality could potentially influence the cortisol deposition in scales. We also evaluated the seasonal variation in scale cortisol levels by sampling fish at three different time points during spring-summer 2014. In each sampling, blood was collected to complement the information provided by the scales. Our results demonstrated that blood and scale cortisol levels from individuals inhabiting the reference site were significantly correlated, therefore increasing the applicability of the method as a sensitive-individual measure of fish HPI axis activity, at least in non-polluted habitats. Since different environmental conditions could potentially alter the usefulness of the technique, results highlight that further validation is required to better interpret hormone fluctuations in fish scales. Scale cortisol concentrations were unaffected by habitat quality although fish from the polluted environment presented lower circulating cortisol levels. We detected a seasonal increase in scale cortisol values concurring with an energetically costly period for the species, supporting the idea that the analysis of cortisol in scales reveals changes in the HPI axis activity. Taken together, the present study suggests that cortisol levels in scales are more likely to be influenced by mid-term, intense energetically demanding periods rather than by long-term stressors. Measurement of cortisol in fish scales can open the possibility to study novel spatio-temporal contexts of interest, yet further research is required to better understand its biological relevance.
Palabras clave: Scales cortisol; Bioindicator; Habitat quality; Pollution; Stress; Seasonality
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Lavergne T., A.M. Sorensen, S. Kern, R. Tonboe, D. Notz, S. Aaboe, L. Bell, G. Dybkjaer, S. Eastwood, C. Gabarró, G. Heygster, M.A. Killie, M.B. Kreiner, J. Lavelle, R. Saldo, S. Sandven, LT. Pedersen
The Cryosphere, 13, 49-78. DOI: 10.5194/tc-13-49-2019 (BibTeX: lavergne.etal.2019a)
Resumen: Ver
We introduce the OSI-450, the SICCI-25km and the SICCI-50km climate data records of gridded global seaice concentration. These three records are derived from passive microwave satellite data and offer three distinct advantages compared to existing records: first, all three records provide quantitative information on uncertainty and possibly applied filtering at every grid point and every time step. Second, they are based on dynamic tie points, which capture the time evolution of surface characteristics of the ice cover and accommodate potential calibration differences between satellite missions. Third, they are produced in the context of sustained services offering committed extension, documentation, traceability, and user support. The three records differ in the underlying satellite data (SMMR & SSM/I & SSMIS or AMSR-E & AMSR2), in the imaging frequency channels (37 GHz and either 6 or 19 GHz), in their horizontal resolution (25 or 50 km), and in the time period they cover. We introduce the underlying algorithms and provide an evaluation. We find that all three records compare well with independent estimates of sea-ice concentration both in regions with very high sea-ice concentration and in regions with very low sea-ice concentration. We hence trust that these records will prove helpful for a better understanding of the evolution of the Earth’s sea-ice cover.
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Vaqué D., E. Lara, J.M. Arrieta, J. Holding, E.L. Sà, I.E. Hendriks, A. Coello-Camba, M. Alvarez, S. Agustí, P.F. Wassmann, C.M. Duarte
Frontiers in Microbiology, 10, 494. DOI: 10.3389/fmicb.2019.00494 (BibTeX: vaque.etal.2019a)
Resumen: Ver
Ocean acidification and warming are two main consequences of climate change that can directly affect biological and ecosystem processes in marine habitats. The Arctic Ocean is the region of the world experiencing climate change at the steepest rate compared with other latitudes. Since marine planktonic microorganisms play a key role in the biogeochemical cycles in the ocean it is crucial to simultaneously evaluate the effect of warming and increasing CO2 on marine microbial communities. In 20 L experimental microcosms filled with water from a high-Arctic fjord (Svalbard), we examined changes in phototrophic and heterotrophic microbial abundances and processes [bacterial production (BP) and mortality], and viral activity (lytic and lysogenic) in relation to warming and elevated CO2. The summer microbial plankton community living at 1.4°C in situ temperature, was exposed to increased CO2 concentrations (135–2,318 μatm) in three controlled temperature treatments (1, 6, and 10°C) at the UNIS installations in Longyearbyen (Svalbard), in summer 2010. Results showed that chlorophyll a concentration decreased at increasing temperatures, while BP significantly increased with pCO2 at 6 and 10°C. Lytic viral production was not affected by changes in pCO2 and temperature, while lysogeny increased significantly at increasing levels of pCO2, especially at 10°C (R2 = 0.858, p = 0.02). Moreover, protistan grazing rates showed a positive interaction between pCO2 and temperature. The averaged percentage of bacteria grazed per day was higher (19.56 ± 2.77% d-1) than the averaged percentage of lysed bacteria by virus (7.18 ± 1.50% d-1) for all treatments. Furthermore, the relationship among microbial abundances and processes showed that BP was significantly related to phototrophic pico/nanoflagellate abundance in the 1°C and the 6°C treatments, and BP triggered viral activity, mainly lysogeny at 6 and 10°C, while bacterial mortality rates was significantly related to bacterial abundances at 6°C. Consequently, our experimental results suggested that future increases in water temperature and pCO2 in Arctic waters will produce a decrease of phytoplankton biomass, enhancement of BP and changes in the carbon fluxes within the microbial food web. All these heterotrophic processes will contribute to weakening the CO2 sink capacity of the Arctic plankton community.
Palabras clave: pCO2; Temperature; Microbial food-webs; Viral life cycle; Arctic Ocean
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Coll M., M. Albo-Puigserver, J. Navarro, I. Palomera, J.M. Dambacher
Marine Ecology Progress Series, 617-618, 277-294. DOI: 10.3354/meps12591 (BibTeX: coll.etal.2019a)
Resumen: Ver
Important changes have been observed in recent decades in small pelagic fish (SPF) populations of the NW Mediterranean Sea: declines in biomass and landings of European anchovy and sardine, and a geographical expansion of round sardinella. These changes have been linked to environmental factors directly influencing annual recruitment and growth. The role of climate change in affecting the composition of plankton has also been suggested to explain declines in SPF, while other causes could be the recovery of predators, competition with other pelagic organisms that prey on early life phases of SPF (i.e. gelatinous zooplankton), interspecific competition for food, or impacts from fisheries harvest. To test the role of these potential pressures, we developed qualitative mathematical models of a NW Mediterranean pelagic food web. We used analyses of sign directed graphs and Bayesian belief networks to compare alternative hypotheses about how SPF species may have responded to combinations of different pressures. Data documenting changes in SPF populations were used to test predicted directions of change from signed digraph models. An increase in sea surface temperature (SST) that had either a positive impact on round sardinella or on gelatinous zooplankton abundance was the pressure that alone provided the most plausible insights into observed changes. A combination of various pressures, including an increase in SST, an increase of exploitation and changes to zooplankton also delivered results matching current observations. Predators of SPF were identified as the most informative monitoring variable to discern between likely causes of perturbations to populations of SPF.
Palabras clave: Small pelagic fish; Population change; Food web; Qualitative model; Pressures; Cumulative impacts; Mediterranean Sea
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Sauer W.H.H., I.G. Gleadall, N. Downey-Breedt, Z. Doubleday, G. Gillespie, M. Haimovici, C.M. Ibáñez, O.N. Katugin, S. Leporati, M.R. Lipinski, U. Markaida, J.E. Ramos, R. Rosa, R. Villanueva, J. Arguelles, F.A. Briceño, S.A. Carrasco, L.J. Che, C. Chen, R. Cisneros, E. Conners, A.C. Crespi-Abril, V.V. Kulik, E.N. Drobyazin, T. Emery, F.A. Fernández-Álvarez, H. Furuya, L.W. González, C. Gough, P. Krishnan, B. Kumar, T. Leite, C. Lu, K.S. Mohamed, J. Nabhitabhata, K. Noro, J.Petchkamnerd, D. Putra, S. Rocliffe, K.K. Sajikumar, H. Sakaguchi, D. Samuel, G. Sasikumar, T. Wada, X. Zheng, . Tian, Y. Pang, A. Yamrungrueng, G. Pecl
Reviews in Fisheries Science & Aquaculture, DOI: 10.1080/23308249.2019.1680603 (BibTeX: sauer.etal.2019a)
Resumen: Ver
Recent studies have shown that coastal and shelf cephalopod populations have increased globally over the last six decades. Although cephalopod landings are dominated by the squid fishery, which represents nearly 80% of the worldwide cephalopod catches, octopuses and cuttlefishes represent ∼10% each. Total reported global production of octopuses over the past three decades indicates a relatively steady increase in catch, almost doubling from 179,042 t in 1980 to 355,239 t in 2014. Octopus fisheries are likely to continue to grow in importance and magnitude as many finfish stocks are either fully or over-exploited. More than twenty described octopus species are harvested from some 90 countries worldwide. The current review describes the major octopus fisheries around the globe, providing an overview of species targeted, ecological and biological features of exploited stocks, catches and the key aspects of management.
Palabras clave: Octopus; Fisheries; Review; Global
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Durán R., J. Guillén, G. Simarro
, Ed. R. Durán, J. Guillén, G. Simarro. ISBN: 978-84-09-12002-4 (BibTeX: duran.etal.2019b)
Resumen: Ver
Desde el año 2000 y con carácter bienal, la comunidad científica dedicada a la Geomorfología Litoral viene reuniéndose con el objetivo de compartir sus avances y dar a conocer de primera mano (mediante charlas, pósteres y salidas de campo) los últimos resultados de su investigación, nuevos casos de estudio, avances técnicos y experiencias de gestión litoral. Alcanzar la décima edición de las Jornadas demuestra que somos una comunidad muy activa y consolidada, consciente de que nuestra aportación es relevante para afrontar los retos que nuestra sociedad tiene que abordar para facilitar una adecuada transformación de la zona costera durante las próximas décadas. [...]