Hydrographic Work of the INGOLF Expedition (1895 and 1896) to Icelandic and West Greenland Waters

Abstract

The Danish expedition in the summers of 1895 and 1896 on board the cruiser Ingolf to Icelandic and West Greenland waters mainly had zoological tasks, the results of which are treated in the present issue by Wolff. However, the expedition also obtained significant results in physical oceanography. The existence of a vast subsurface ridge, the Reykjanes Ridge, was proved. On the basis of the hydrographic stations worked, the expedition's physicist and chemist Martin Knudsen was able to describe the hydrographic situation of the area. He proved the division of the Irminger Current into an easterly and westerly branch northwest of Iceland, and the extent and magnitude of the East Icelandic Polar Current were established. The existence of an overflow over the Iceland-Faroe Ridge of cold, low-salinity bottom water from the Norwegian Sea into the Atlantic was demonstrated. Knudsen designed a new, reliable reversing thermometer for use on the expedition, and he constructed an instrument that made it possible to measure aboard the ship the content of oxygen and nitrogen dissolved in the water. He showed that the supersaturation of surface water with oxygen might be explained from the photosynthetic processes of phytoplankton.