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Antarctic Ocean,name sometimes given to those parts of the Pacific, Atlantic, and Indian oceans that surround Antarctica S of roughly 60°S. These waters are marked by the Antarctic Circumpolar Current, or West Wind Drift Current, a surface current that flows E around Antarctica and transports more water than any other current in world. North of the current, along a fluctuating, zigzagging line between 48°S and 61°S, lies the Antarctic Convergence, an oceanic boundary, 20–30 mi (30–50 km) wide, where the warm, subtropical waters of the Indian, Pacific, and Atlantic the cold, polar waters off Antarctica. The Antarctic Convergence and the Antarctic Divergence, a region of major oceanic upwelling lying to the S of the former, have a profound effect on climate, marine life, and the ice, and create a unique ecological region rich in marine life. This region was recognized as a fifth ocean by the International Hydrographic Organization in 2000. The ocean includes the Ross, Amundsen, Bellingshausen, and Weddell seas and small gulfs and bays off Antarctica. Its deepest point, 27,119 ft (8,266 m), is in the South Sandwich Trench, E of the South Sandwich Islands.
(also Antarctic Ocean), a conventional designation for the southern parts of the Atlantic, Indian, and Pacific oceans that adjoin Antarctica.
The ocean was first identified by the Dutch geographer B. Varenius (Varen) in 1650, and the term “Southern Ocean” was used in maps and atlases until the first quarter of the 20th century. During this period, geographers in many countries extended the designation to include Antarctica, inasmuch as the ice-covered continent was considered part of the ocean and the antarctic circle was regarded as the ocean’s boundary. Since the second quarter of the 20th century various lines have been proposed for the boundary of the Southern Ocean; they lie between 35° S lat.—a limit based on the circulation of the water and atmosphere—and 60° S lat.—a limit based on the relief of the ocean floor. The Soviet Atlas of the Antarctic (vol. 2, 1969) places the boundary of the Southern Ocean at the northern limit of the Antarctic Convergence, which lies near 55° S lat.
The designation “Southern Ocean” is not used in navigation, because such navigational aids as sailing directions, running lights, signals, and charts do not make use of the concept.