Physical Conditions, Carbon Transport, and Climate Change Impacts in a Northeast Greenland Fjord
Søren Rysgaard, Torben Vang, Michael Stjernholm, Bjarke Rasmussen, Anders Windelin, Sissi Kiilsholm
This paper presents data on physical conditions and carbon transport in a typical northeast Greenland fjord along with predictions of expected changes in the area due to climate change. The fjord has an average depth of 100 m; the maximum depth is 360 m, and a sill at a depth of 45 m is found at its entrance. Sea ice covers the fjord from early October to late July. The freshwater input to the fjord, occurring from June to September, is 1063 × 106 m3 from the catchment area (3109 km2) and 440 × 106 m3 from melting of sea ice. During the ice-free period this buoyancy input and mixing by wind and tides results in an estuarine circulation in which lighter low-salinity water is moved seaward above denser water from the Greenland Sea. The tidal amplitude is 0.8 to 1.5 m, and the transport of tides from the outer parts of the fjord to the inner parts is delayed less than 15 min due to low friction in the fjord system. During the ice-free period, a net carbon input of 15-50 t C d-1 occurs in the outer region of the fjord due to transport from land and the adjacent Greenland Sea. A regional atmosphere-ocean model predicts a temperature increase of 6-8°C at the end of this century (2071-2100) that will lead to increase in freshwater runoff, thinning of the sea ice, and an increase in ice-free conditions from 2.5 mo to 4.7-5.3 mo in Young Sound. The increased freshwater input will greatly enhance the estuarine circulation and nutrient input to the fjord and is expected to increase biological productivity.