Climate change accelerates the melting of the Greenland Ice Sheet and terrestrial permafrost which leads to increased freshwater and organic carbon loading of marine waters around Greenland. This carbon may potentially be mineralized to CO₂ resulting in an increased CO₂ content in the marine waters and a decreased CO₂ uptake from the atmosphere.

In the current project we will study the fate of both the particulate and dissolved organic carbon in the fjord. The organic and inorganic particles will be deposited on to the seafloor with a sedimentation rate highest close to the river mouth and decreasing with increasing distance. We will quantify this sedimentation and investigate the effects of this terrestrial particulate matter on sediment and water column biogeochemistry as a function of distance from the source. Furthermore, we will characterize the particulate matter with respect to composition, degradability, age, and particle characteristics such as size distribution and sinking rates. Also the importance of particulate versus dissolved organic matter for especially water column biogeochemistry will be quantified. Organic matter is also produced in the fjord through primary production and we will compare the importance of this with that of the organic loading from terrestrial sources for carbon turnover. Finally, we will try to evaluate how the role of Young Sound as a sink for atmospheric CO₂ is affected by loading of terrestrial organic carbon.

Field Site: Daneborg, NE. Greenland

PI: Mikael Sejr/Tage Dalsgaard