CarbEx · Tracing carbon exchanges/fluxes between Arctic and Atlantic basins

Dissolved organic matter (DOM) consists of a complex mixture of molecules generated from the degradation of living organisms. Surface waters of the Arctic Ocean (AO) have high concentrations of DOM and freshwater (FW) due to the massive supply from large rivers. Great part of it is exported to the Atlantic Ocean through the Fram Strait (FS). Climate change is expected to increase riverine FW and terrestrial DOM supply, with consequences to the hydrological and carbon cycles. However, such changes remain poorly understood and CarbEx will contribute to rectifying this. The three central goals are to (1) estimate the DOM and FW fluxes from the Arctic to the Atlantic Ocean through the FS, (2) assess their variability and (3) develop an approach to assess the amount of both terrestrial DOM and FW, from optical measurements of DOM. A major challenge is to obtain sufficient data from the region and CarbEx will apply three complementary approaches: oceanographic expeditions (OE), ocean color remote sensing (OCRS, satellite-based Earth Observation) and numerical modelling (NM). Riverine FW and DOC fluxes will be estimated using a combination of observations and NM. Hydrographic and biogeochemical data acquired during a series of OE conducted annually in the FS (Summer 2009–2018) is available. The in situ data will be complemented with OCRS and NM to develop a continuous time series, filling the temporal coverage gaps from OE, to analyse possible trends and links to climate change in the Arctic. CarbEx also has a non-academic character and will provide the necessary foundation to develop new technologies to monitor the FW and carbon dynamics in the AO and aquaculture sites, i.e. in situ multi-channel fluorometers. This aligns with the host’s strategy to develop observational technology and Arctic research, and with the EU’s goal for the IF programme about stimulating the creative and innovative potential through advanced training and international and intersectoral mobility.