(46) Physical changes—including rising air and seawater temperatures and decreasing seasonal ice cover—appear to be the cause of a series of biological changes in the northern Bering Sea ecosystem that could have long-range and irreversible effects on the animals that live there and on the people who depend on them for their livelihoods. In a paper published March 10 in the journal Science, a team of U.S. and Canadian researchers use data from long-term observations of physical properties and biological communities to conclude that previously documented physical changes in the Arctic in recent years are profoundly affecting Arctic life.The northern Bering Sea provides critical habitat for large populations of such as sea ducks, gray whales, bearded seals and walruses, and all of these mammals depend on small bottom-dwelling creatures for sustenance. These bottom-dwellers, in turn, are accustomed to colder water temperatures and long periods of extensive sea ice cover. (47) However, "a change from arctic to sub-arctic conditions is under way in the northern Bering Sea," according to the researchers, and is causing a shift toward conditions favoring both water-column and bottom-feeding fish and other animals that until now have stayed in more southerly, warmer sea water.(48) As a result, the ranges of region’s typical inhabitants can be expected to move northward and away from the small, isolated Native communities on the Bering Sea coast that subsist on the animals. "We’re seeing that a change in the physical conditions is driving a change in the ecosystems," said JackieGrebmeier, a researcher at the University of Tennessee.Grebmeier said the new report is unusual in that it looks at the potential effects of changing climate in the Arctic primarily through a life-sciences lens, rather than an analysis of the physics of climate change. "It’s a biology driven, integrated look at what’s going," Grebmeier said. Grebmeier is chief scientist for the Western Shelf-Basin Interactions (SBI) research project, which conducted a series of research cruises to observe changes in the carbon balance of the offshore areas of the Alaskan Arctic and their effects on the food chain. The cruises included a number of researchers supported by the National Oceanic and Atmospheric Administration (NOAA), and other federal agencies. (49) NSF and NOAA also funded U.S. researchers who contributed data collected by the Bering Strait Environmental Observatory, which annually samples waters in the northern Bering Sea to assess the biological status of productive animal communities on the sea floor.(50) Those highly productive waters currently act as sponges for carbon dioxide, absorbing quantities of the gas that otherwise would remain in the atmosphere where it would be expected to contribute to warming. But, the researchers say, if the biological trends they observe in the northern Bering Sea persist and are not reversible, the accompanying shift in species and ecosystem structure could have important implications for the role of the sea as a "carbon sink". 50