DISTRIBUTION OF ZOOPLANKTON IN THE NORTHEAST WATER POLYNYA DURING SUMMER 1992

The distribution and abundances of zooplankton in the Northeast Water (NEW) Polynya during the summer of 1992 have been determined from samp les collected with Bongo (this study) and MOCNESS (earlier analysis) p lankton net tows. The initial hypothesis was that the troughs of the G reenland Shelf in the region of the NEW polynya would be conduits for the infusion of zooplankton species of Arctic and North Atlantic origi n on to the shelf. Analysis of MOCNESS tows indicated instead that adv ection of zooplankton onto the shelf in the polynya ;region was limite d, resulting in low abundances of the large herbivores in the polynya. The distribution of zooplankton determined from the 43 Bongo tows rep orted here strengthen this finding. Low abundances of the large herbiv orous copepods and of other primarily herbivorous zooplankton taxa wer e observed throughout the ice-free region, in contrast to higher abund ances observed further to the east in Westwind Trough or in the south in Belgica Trough. Cluster analysis was used to identify groups of co- occurring zooplankton taxa and groups of stations with similar relativ e compositions of zooplankton taxa. The community composition of the B elgica Trough was distinctly different from that observed in northern regions, with high abundances of open ocean copepods (Calanus finmarch icus and C. hyperboreus). Two types of communities were identified in the northern regions: one typical of the eastern basin (Westwind Troug h) and one typical of the western basin (Norske Trough) of the norther n trough. The relationship between the different zooplankton communiti es and the water mass characteristics was not conclusive; however, it did appear that zooplankton populations had been advected in the upper water column into the Westwind Trough from north of the study area. T he low abundances of herbivorous taxa in the ice free region supported previous estimates that meso-macro zooplankton may not be significant consumers of primary reduction in the polynya.