Southern Ocean or 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.