Melting of Greenland Ice Sheet and its impact on Greenland coastal region

The Greenland Ice Sheet is melting at an unprecedented rate, and as a result, fjords and continental shelves around Greenland are exposed to an increasing freshwater runoff. Yet the impact of high meltwater input on the physical functioning and biogeochemistry remains largely unquantified. To resolve the effect on Greenland's fjord and coastal region, sampling was conducted in several fjords impacted by melting glaciers in Greenland and physical, chemical and biological gradients were studied from close to the glaciers towards the open sea. Hydrographic and biogeochemical data from several fjord systems adjacent to the Greenland ice sheet, suggest that impact of either land-terminating or marine-terminating glaciers on the coastal region is very different. Rising subsurface meltwater plumes originating from marine-terminating glaciers entrain large volumes of ambient deep water to the surface. The resulting upwelling of nutrient-rich deep water sustains a high phytoplankton productivity throughout summer in the fjord with marine-terminating glaciers. In contrast, fjords with only land-terminating glaciers lack this upwelling mechanism, and are characterized by lower productivity. These results suggest that a switch from marine-terminating to land-terminating glaciers can substantially alter the productivity in the coastal zone around Greenland with potentially large ecological and socio-economic implications.