The Arctic Ocean

The Arctic Ocean covers a large area with harsh climatic conditions. x01x02 There are strong seasonal and geographical variations in light, temperature and ice cover. x01x02 The European part of the Arctic Ocean covers only about 8 % of the total area of the Arctic Ocean, but due to its great depth it represents about 25 % of the total volume. x01x02 The system of ocean currents induces an eastu0096west temperature gradient with warmer conditions in the eastern part of the European Arctic Ocean, strongly influenced by the warm Gulf Stream. This keeps the Norwegian Sea and a large part of the Barents Sea ice-free and favourable for the growth of a wide range of open-sea (pelagic) and bottom-living (benthic) species. This biological production sustains huge stocks of pelagic fish in these areas. x01x02 The extreme conditions in the area create unique marine ecosystems, and some species live on the border of their tolerance. x01x02 Generally, the environmental quality of these waters is high, but there are several reasons for concern, and an urgent need for more knowledge about the biological systems in this vulnerable area. x01x02 The main threats to biological diversity in the Arctic are o Extensive fishery is probably the greatest threat to biodiversity today. A better understanding of the effects of these fisheries is needed, especially of the effects of bycatch and effects on benthic habitats. o Effects of climatic changes are not yet unequivocally identified, but global warming can influence hydrographical conditions in the region. The recent possibility of ship passage along the Siberian coast may be an indication of such effects. o Accumulation of micro-contaminants in biota is of great concern, particularly since little is known about the relation between levels of contaminants and biological effects. Discharges from industry in the Russian area of Murmansk are considerable and make up a substantial part of total industrial outputs to the Arctic. Long-distance transport of contaminants from other areas is