ODEN ODEN_SynopticArcticSurvey

In the Arctic, climate change is most obvious. This can be seen, for example, in the sharp decline of sea ice cover in the Arctic Ocean, with implications for the region's heat balance and, indirectly, ocean and atmospheric circulation. An elementary component of ocean circulation is the formation of deep water. It is accompanied by the transport of dissolved gases such as carbon dioxide from the surface to the interior of the ocean. This process is called ventilation and it is disproportionately present in the Arctic Ocean. Because it is an important buffer for greenhouse gas emissions, its knowledge is critical for climate prediction. Over which timescales the ventilation extends and where water masses with dissolved carbon dioxide spread to in which period of time can be determined by using certain trace substances (tracers). During the expedition on the Swedish icebreaker ODEN, samples will be taken in the Central Arctic and analyzed for tracers. This will include the use of the new Atom Trap Trace Analysis (ATTA) method, which now makes it possible to measure the radioisotope 39Ar in seawater, that is useful to understand the older (slower ventilated) deep water with its half-life time of 269 years. The data will be used to improve models for the uptake and distribution of anthropogenic carbon in the ocean. The results will be compared with biogeochemical approaches and used to estimate ocean acidification rates.
Additional tracer data will provide information on the circulation in the North Atlantic region as well as ocean surface processes using a GC-MS technique developed at GEOMAR.

The results of this project will thus provide extensive contributions to a better understanding of Arctic ocean circulation and ventilation, ocean carbon uptake capacity, and the consequences of changing Arctic and global climate.