STUDIES OF PELAGIC BENTHIC COUPLING EXTENDED ONTO THE SOVIET CONTINENTAL-SHELF IN THE NORTHERN BERING AND CHUKCHI SEAS

Studies of pelagic-benthic coupling and benthic carbon cycling in the northern Bering and Chukchi seas were extended onto the Soviet continental shelf as part of the third U.S.A.-U.S.S.R. Oceanographic Expedition to the Bering and Chukchi seas in 1988. High sediment oxygen uptake rates (an indicator of food supply to the benthos) and benthic biomass were observed in the western shelf regions of the Gulf of Anadyr, Chirikov Basin and southern Chukchi Sea. Low sediment respiration and faunal biomass were observed in the central and slope areas of the Gulf of Anadyr and near the Alaska coastline. Both high sediment respiration and benthic biomass were related to regions of high carbon deposition to the benthos and sediment organic carbon content. Preliminary studies of sediment accumulation, measured using organic carbon content and atmospherically-derived Pb-210 loop values in surface sediments, were low in the sandy regions of the northern Bering Sea, with higher sediment accumulation zones occurring in the silt and clay regions in the central Gulf of Anadyr and southern Chukchi Sea. Hydrodynamics have a major influence on organic carbon loading and sediment composition, which in turn influences benthic community structure, biomass and sediment respiration in this Arctic region.