THE INFLUENCE OF THE STRUCTURE AND FUNCTION OF THE MARINE FOOD-WEB ON THE DYNAMICS OF CONTAMINANTS IN ARCTIC-OCEAN ECOSYSTEMS

This paper examines some features of arctic marine ecosystems that may render them vulnerable to airborne pollutants. These features include the seasonal and spatial focus of primary productivity, the allocation of a relatively large proportion of the newly fixed carbon to the benthos, the prevalence of large mammals as apex consumers, and relatively high lipid levels in many arctic species. Sea ice is an important factor, since pollutants falling onto the ice surface during the winter months can be concentrated in epontic particulate matter (at the ice/seawater interface), or, more likely, be released through melting of the ice and enter the planktonic system in spring, reaching the benthos via sedimentation. Two ecosystems are discussed in which these processes are likely to be important - the highly productive Chirikov Basin of the northern Bering Sea and the sea ice-associated community north of Svalbard. There is evidence that pollutants are accumulating in arctic marine ecosystems. However, our predictive ability is constrained by the inability to delineate the sites of deposition.