Arctic Ocean, body of water variously identified as the smallest of four world oceans or as a virtually landlocked arm of the Atlantic Ocean. The Arctic Ocean extends south from the North Pole to the shores of Europe, Asia, and North America. l8s1sf
I BOUNDARIES AND SIZE The surface waters of the Arctic Ocean mingle with those of the Pacific Ocean through the Bering Strait, by way of a narrow and shallow channel, which has a depth of about 55 m (about 180 ft). More importantly, the Arctic waters mix with those of the Atlantic Ocean across a system of submarine sills (shallow ridges) that span the great distances from Scotland to Greenland and from Greenland to Baffin Island at depths of about 500 to 700 m (about 1640 to 2300 ft). Emptying into the Arctic Ocean are the Ob’, Yenisey, and Lena rivers in Asia and the Mackenzie River in North America. The total surface area of the Arctic Ocean, including its major subdivisions—the North Polar Sea (the main portion), the Norwegian Sea, the North Sea, and the Barents Sea—is about 14 million sq km (about 5.4 million sq mi).

II RESOURCES Fish, in commercially exploitable quantities, are found only in the warmer marginal seas of the Arctic Ocean, notably in the North Sea (herring, cod, and flounder) and the Barents Sea (primarily cod). Sea mammals, including various species of seal and whale, were hunted to near extinction before being protected by quotas set during the 1900s. Tin is actively mined off the coast of eastern Siberia, and petroleum and natural gas are extracted north of Alaska and Canada and in the North Sea.