II.

Boundaries and Size

The Southern Ocean is generally described as extending from the coast of Antarctica north to latitude 60° south (just south of the southern tip of South America). This latitude approximates the location of the Antarctic Convergence, an ocean zone where cold, northbound Antarctic surface waters sink below warmer sub-Antarctic waters. This zone spans the globe and creates the unique waters and ecosystem of the Southern Ocean.

The Southern Ocean encompasses roughly 20.3 million sq km (7.8 million sq mi) in area, slightly more than twice the size of the United States. Its greatest depth measures 7,235 m (23,737 ft) below sea level in the South Sandwich Trench. The Southern Ocean includes Amundsen Sea, Bellingshausen Sea, Ross Sea, Weddell Sea, and part of Drake Passage.