THE WESTERN ARCTIC SHELF-BASIN INTERACTIONS (SBI) PROGRAM
Jacqueline M. Grebmeier*
The University of Tennessee, Knoxville, Tennessee 37996, U.S.A.
1. INTRODUCTION
Interactions among Arctic continental shelves and basins are key components to influencing projected global change in Arctic marine ecosystems. Portions of the Arctic shelf/slope have high biological productive, but despite this ecological importance, many physical processes and ecological linkages at the shelf/slope interface are poorly understood. The Western Arctic Shelf-Basin Interactions (SBI) program of the U.S. National Science Foundation's Arctic System Science Program has been developed to elucidate the critical physical and biological shelf and slope processes that influence the structure and functioning of the Arctic Ocean (Grebmeier et al., 1998). The SBI program will have a regional focus on the Chukchi and Beaufort Seas and will combine modeling and observational approaches.
General circulation models (GCMs) indicate that the Arctic will be a focal region for observing early effects of global change. The rationale for the SBI program is premised on major global changes influencing biological and physical linkages between the shelf and basin, with amplification in the Arctic. These changes could influence maintenance of water column stratification, sea ice distribution, renewable resources, and have subsequent impacts on human communities in the Arctic.
2. BACKGROUND
The largely land-locked Arctic Ocean shows the distinct imprint of waters from the Pacific and Atlantic oceans and from rivers draining the surrounding continents (Figure 1; Aagaard, 1989). These inflows are important sources of salt, heat, nutrients, carbon, sediments, and organisms to the central basin. However, with the exception of a portion of the Atlantic contribution, all of these inflows must cross continental shelves where they are modified by benthic and water-column biological processes and by exchanges with the atmosphere, sea ice, and bottom sediments. The modified shelf waters eventually feed the polar mixed layer and/or ventilate the subsurface layers of the interior basin. In this manner, the shelves profoundly influence the thermohaline structure and maintenance of the ice cover of the Arctic Ocean. These same processes must markedly affect biogeochemical cycles and the biological productivity that support the living marine resources of the Arctic Ocean.
*Corresponding author address. Jacqueline M.
Grebmeier, Univ. of Tennessee, Dept. of Ecology and Evol. Biology, Knoxville, TN 37996, U.S.A.;
email: jgreb@unix.cas.utk.edu or jg9@ornl,gov
