Arctic Ecosystems

The Arctic lies between North America, Greenland and North Asia beyond the Arctic Circle at 66 degrees North latitude. The geography of this region is complex. The Arctic Ocean is almost completely enclosed and close to, and influenced by, large populations and industrial activities. Surface water enters the Ocean through the shallow Bering Straits and through the eastern part of the Fram Strait. These source waters are modified by river runoff and meltwater in summer and by salt rejection during freezing in winter resulting in its characteristic surface brackish layer (lower salinity). The Arctic is dominated by permanent ice cover which opens significantly during summer only in the coastal seas to the north of Asia, Alaska and the Canadian Northwest Territories. Both the Arctic and the Antarctic have notable year to year variations in ice cover although there is a definite upward trend. This warming trend, if continued, will not only significantly affect global climate but will also change the strategic and economic importance of the Arctic Ocean through its use for commercial shipping routes and increased exploration of natural resources.
Kongvegen Glacier, Norway. Photo: W Block, British Antarctic Survey (BAS)

The Arctic Ocean is classified as a low productivity ecosystem, a consequence of the extensive seasonal ice cover and extreme weather conditions. The Arctic plankton show weak diurnal vertical migrations but pronounced seasonal ones. The Arctic fauna is impoverished and consists mainly of organisms derived from the Atlantic Ocean. The biomass is lower than in the Antarctic; often dominated by one of only a few species. Because of the extensive areas of sediments, the Arctic benthic fauna is mainly an infauna. Specialized endemic fish are not present in the Arctic, in contrast to the Antarctic. In the seas adjacent to, and south of the Arctic Ocean are some of the major cold-water fisheries of the world. The distribution of birds is longitudinal with strong differences between communities at similar latitudes in different parts of the ocean basin. Marine mammals are diverse.
Large male walrus, Greenland. Photo: Mario Acquarone

Pressures on the Arctic marine ecosystem are derived from both global and local sources. Pollutants generated in Europe, Asia and North America are transported very effectively into the Arctic environment by the atmospheric and oceanic circulation processes. These include persistent organic pollutants (POPs) from industrial and agricultural practices (e.g. metal smelters, paper and waste processing plants, pesticides, and herbicides), heavy metals (e.g. lead from petrol) and radionuclides (e.g. emissions from reprocessing plants and accidents). In recent years there has been a perception on the part of some of the Inuit hunters in Nunavut (the eastern Canadian Arctic) that they may be seeing more abnormalities in the marine mammals they harvest for food and income. Some Arctic indigenous groups, which rely heavily on food from species at high trophic levels in both marine and terrestrial ecosystems, show levels of POPs in tissue and breast milk significantly higher than those found in more southerly populations. More.
Polar bear and Norwegian Polar Research Institute Research Vessel Lance, Barents Sea. Photo: Georg Bangjord at [email protected] From Polar Bears at Risk. Reproduced with permission from WWF� 2002 WWF-Norway. All rights reserved.

The marine environment surrounding the Arctic has been highly disturbed by fishing activity, but, in terms of pollution, some areas of the central Arctic remain among the most pristine in the world. The greatest concern for the Arctic is probably the ecological implications of climate change, particularly as sea ice extent and duration are likely to be affected. There are international efforts to protect the Arctic and its marine life through the Program for the Conservation of Arctic Flora and Fauna (CAFF). With a secretariat based in Iceland, this program cooperates with the Program for the Protection of the Arctic Marine Environment (PAME). For management purposes, the Arctic, in a broad sense, contains 12 of the 64 Large Marine Ecosystems:

• 18 West Greenland Shelf
• 19 East Greenland Shelf
• 20 Barents Sea
• 21 Norwegian Shelf
• 53 West Bering Sea
• 54 Chukchi Sea
• 55 Beaufort Sea
• 56 East Siberian Sea
• 57 Laptev Sea
• 58 Kara Sea
• 63 Hudson Bay
• 64 Arctic Ocean

Aerial view of science settlement at Ny-?lesund, Norway showing the newly-constructed jetty (mid-foreground), the disused coal sorting building (middle-right), the road/track system and the air strip (upper right). Photo: W Block, British Antarctic Survey

Based on Nybakken, Longhurst and Clarke and Harris .