Benthic Ecosystem Response to Changing Ice Cover in the Bering Sea

Funds are provided to support a benthic-focused measurements program in the northern Bering Sea that extends and expands a twenty-year effort in that region. The northern benthic biological communities are known to provide food resources for benthic-feeding apex predators that include gray whales, bearded seals, walruses, and diving sea-ducks, all of which are used by subsistence-based communities along the Bering Sea coast. Previous work indicates that climate warming may change the present benthic-dominated northern Bering Sea ecosystem to one that is more pelagic and similar to the southern Bering Sea food web.

The principal investigators will document benthic infaunal community composition and biomass as a means to determine key indicator species that should be monitored to evaluate climate change impacts on the Bering Sea ecosystem. In addition, they will undertake analyses of sediment indicators of status and trends in ecosystem health, including sediment grain size, oxygen demand, chlorophyll inventories, organic carbon content and stable carbon isotope ratios of sediment organic carbon, and inventories of atmospherically-derived, particle-reactive radionuclides (7Be) and clay-associated radionuclides (137Cs). All of these can be used as ecosystem indicators of recent particle deposition, sediment processing, and the overall fertility of overlying waters. They will integrate these new data with the extensive record for the region. These data will help interpret data collected by collaborators, with other funding, concerning marine mammals. It will also serve a important constraints on the models being developed for the region, both within the BEST and BSIERP programs.