ZOOPLANKTON RETAINED IN SEQUENTIAL SEDIMENT TRAPS ALONG THE BEAUFORT SEA SHELF BREAK DURING WINTER

Zooplankton retained in four sediment traps deployed along the shelf break of the eastern Beaufort Sea, from September 1987 to March 1988, were used to investigate temporal and regional variations of the zooplankton community during winter. Despite trap selectivity, the species composition indicated that both the shelf community and Atlantic water community of the deep Arctic Ocean are excluded from the shelf break at this time of year. There was no evidence of off-shelf transport during the study period. Taxa collected, predominantly pteropods (Spiratella helicina) and calanoid copepods, were typical of the community in the upper 200 m of the central Arctic Ocean. The abundance of pteropods was strongly associated with ice cover. The easternmost trap, located at the entrance to Amundsen Gulf, had a distribution of animals distinct from those in the other traps. It lay outside the influence of the Beaufort Gyre and Beaufort Undercurrent, which apparently affected the other locations.