GCP-GEOTARCTIC · Geochemical-physical coupled study of the modern Arctic Ocean: GEOTRACES-ARCTIC

Geochemical-physical coupled study of the modern Arctic Ocean: GEOTRACES-ARCTIC

At present, our ability to evaluate the full impact of climate-driven alterations of the Arctic Ocean (sea ice cover, hydrography, circulation) and predict their future trajectory is limited by a poor understanding of the interacting chemical, physical and biological processes that shape the functional characteristics and resiliency of Arctic waters. To bridge this critical knowledge gap, a pan-Arctic field study (Arctic-GEOTRACES, http://www.geotraces.org) has been coordinated between Canada, US, Germany and France to generate a quasi-synoptic database of biogeochemical tracers of circulation, ecosystem structure and productivity, and sea ice state. The Canadian program involves 28 investigators including biological, chemical and physical oceanographers, experimentalists and modellers. Fully integrated in the Canadian Arctic program, the proposed research focused on trace elements (Rare Earth Elements; REEs) and isotopes (ɛNd, 230Th and 231Pa) that provide powerful tracers of ocean circulation and land/ocean chemical exchanges, both impacted by climate change in the Arctic. It was conducted on the Canadian section, itself connected to the US Arctic GEOTRACES section and the French GEOVIDE section by common cross-over intercalibration stations. The proposed study consisted of a three-step approach: i) Initial modelling study of Arctic Ocean dynamics, including off-line Lagrangian analyses to refine the sampling strategy for the tracers mentioned above; ii) Measurements of these tracers on the Canadian section to specifically investigate land-ocean exchanges and circulation in the Arctic Ocean; iii) Integration of these data into a fine resolution model coupling circulation, sea ice dynamics and biogeochemical processes to refine our understanding of circulation and to quantify land-ocean margin chemical exchanges of bioactive or water mass fingerprinting chemical elements. Modelling and observational results notably allowed to evidence, in the sea-ice retreat enhancement context of the studied areas, important changes in the Arctic over the last decades, in terms of intermediate and deep circulation and of fluxes of biologic and lithogenic particles. Estimations of land-ocean flux budgets in the shallow Canadian Arctic Archipelago are ongoing and will allow to characterize the chemical contribution of this area to the crossing waters.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз