Sea surface CO2 in the changing Arctic

23 March 2018
Sala d'Actes
Given by: 
Dr. Mike DeGrandpre
Position at: 
University of Montana, Missoula, Montana, United States of America


The carbon cycle in the Arctic Ocean is intimately connected to the loss of sea ice, but it is not clear how CO2 sources and sinks are changing, and if they could affect greenhouse gas accumulation in the atmosphere and oceans. Using a 5-year shipboard time series in the Canada Basin, we show that loss of sea ice leads to rapid and large increases in sea surface pCO2 and ocean acidification. Sea surface partial pressure of CO2 (pCO2) is strongly negatively correlated with ice extent. The relationship indicates that the Arctic Ocean sea surface will soon reach or surpass atmospheric saturation as ice extent continues to decline. Commensurate with the increase in pCO2, mean sea surface pH levels decrease seasonally by >0.1 pH units depending upon seasonal ice extent. This talk will also provide an overview of other documented changes in the Arctic Ocean.


Brief biography

Mike DeGrandpre studied chemical engineering at Montana State University (USA) and then went on to obtain a PhD in analytical chemistry in 1990 at the University of Washington. His post-doc and subsequent research position at Woods Hole Oceanographic Institution focused on the development of a CO2 sensor (the “SAMI”) for marine applications. His key contributions include important breakthroughs in the development of autonomous biogeochemical instrumentation (DeGrandpre et al. 1995; Seidel et al. 2008; Spaulding et al. 2013). This technology was the recipient of the Ocean Health XPRIZEs for pH sensor technology in 2015. He has used these instruments to study carbon cycling in many different marine and freshwater environments with a current focus on the Arctic Ocean.