PERACARID FAUNA (CRUSTACEA, MALACOSTRACA) OF THE NORTHEAST WATER POLYNYA OFF GREENLAND - DOCUMENTING CLOSE BENTHIC-PELAGIC COUPLING IN THE WESTWIND TROUGH

Composition, abundance, and diversity of peracarids (Crustacea) were investigated over a period of 3 mo in the Northeast Water Polynya (NEW), off Greenland. Samples were collected from May to July 1993 during expeditions ARK IX/2 and 3 using an epibenthic sledge on RV 'Polarstern'. Within the macrobenthic community peracarids were an important component of the shelf fauna and occurred in high abundance in this area together with polychaetes, molluscs and brittle stars. A total of 38322 specimens were sampled from 22 stations. Cumacea attained the highest total abundance and Amphipoda the highest diversity. Isopoda were of medium abundance, Mysidacea less abundant, and Tanaidacea least abundant. In total 229 species were found. Differences in composition, abundance and diversity do not reflect bathymetric gradients, but mainly the availability of food (phytoplankton and especially ice algae) and, hence, the temporal and spatial opening of the polynya. Thus primary production and hydrographic conditions (lateral advection due to the anticyclonic gyre around Belgica Bank) are the main biological and physical parameters influencing the peracarida crustacean community, documenting a close coupling between primary production and the benthic community in the eastern Westwind Trough. The high abundance of Peracarida, which are also capable of burrowing in the upper sediment layers, indicates their importance for benthic carbon cycling.