Coastal and marine areas: the Polar Regions

THE ARCTIC

The global ocean circulation

When warm, salty North Atlantic water reaches the cold Arctic, it becomes denser as it cools, and therefore sinks to deeper layers of the ocean. This process of forming deep water is slow but takes place over a huge area. Every winter, several million cubic kilometres of water sink to deeper layers, which move water slowly south along the bottom of the Atlantic Ocean Source: AMAP 1997

The Arctic marine environment covers approximately 20 million km² and includes the Arctic Ocean and several adjacent water bodies. Nearly half of the ocean floor is continental shelf, the highest percentage among all oceans. Movements of Arctic waters play a significant role in the global ocean regime (AMAP 1997), and in regulating the global climate (see figure).

The Arctic marine environment is rich in fish biodiversity and abundance. The commercial fisheries of the Barents and the Bering systems are among the most productive in the world (Kelleher, Bleakly and Wells 1995), with the Bering Sea accounting for 2-5 per cent of the world's fisheries catches (CAFF 2001, Bernes 1996). Resident and migratory marine mammals include whales, seals and sea lions. The polar bear is also often classified as a marine mammal because it frequents sea ice in search of prey. Many of the indigenous communities of the Arctic have traditionally depended on these marine resources for their livelihood. Other natural resources include vast oil and gas reserves along the continental shelves as well as important mineral deposits. However, there are growing concerns about the negative impacts of development activities on the ecology of the Arctic especially in ice-prone areas and critical habitats.