Primary Production, Illumination and Hydrography in Jørgen Brønlund Fjord, North Greenland.

Resumé

The data on temperature, salinity, transparency, ice, illumination and primary production gathered during the Fifth Peary Land Expedition to Jørgen Brønlund Fjord in the summer of 1968 are presented and discussed. The fjord is regarded to be rather unique for the area in being free from ice and open to insolation and wave action in a period during the summer and having a restricted contact across a shallow threshold with neighbouring waters, that are largely ice-bound throughout the year.
The result is slightly higher temperatures and lower salinities and most certainly greater primary production. Estimated gross production was on the basis of 14C experiments found to be 4.7 g C/m2/year. Control experiments performed in Disko Fjord, West Greenland indicate that the technique of using a Secchi disc to set the experimental depths yielded results far too low owing to the occurrence of a shallow layer of turbid surface water during most of the summer. Accordingly a yearly production of 7.4-13.7 g/m2 in Jørgen Brønlund Fjord is rather to be expected.