Chesapeake Bay Seminar Series 2009

The continental shelf and slope regions in the Pacific Arctic sector are extremely productive due to the input of nutrient-rich Pacific water on the northern Bering and Chukchi Sea shelves and into the Arctic Ocean. Benthic-dominated regions on these shallow shelves have high benthic infaunal biomass and sediment carbon cycling. Bivalves, polychaetes and amphipods dominate the infaunal organisms and this region serves as a major prey area for benthic-feeding marine mammals and seabirds, including walrus, gray whales and diving seaducks. Past studies in the region indicate food supply is the major factor influencing benthic carbon cycling, with colder water regions having some of the highest benthic carbon cycling rates, indicative of higher organic carbon export to the benthos. However, with the increasing influence of warmer, lower nutrient water transiting northward from the Bering Sea, a continued reduced seasonal sea ice coverage, and corresponding increases in seawater temperatures, it is likely that the changes being seen in the biological ecosystem will continue and possibly accelerate. A large-scale impact might well be a transitional change from a benthic-dominated northern Bering and Chukchi shelf region to a more pelagic-dominated system. Data will be presented on key biological factors influencing benthic carbon cycling at various time and space scales in the western Arctic region in order to evaluate both present impacts and possible future changes in benthic processes in this highly productive system.