the Southern Ocean is 4,000 to 5,000-m deep over most of its extent with only limited areas of shallow water; the Antarctic continental shelf is generally narrow and unusually deep, its edge lying at depths of 400 to 800 m (the global mean is 133 m); the Antarctic icepack grows from an average minimum of 2.6 million sq km in March to about 18.8 million sq km in September, better than a sixfold increase in area

The Southern Ocean is one of the world’s five oceans. The Southern Ocean surrounds the Antarctica. The total volume of the Southern Ocean is 17.2 million mi 3 of water. The Southern Ocean contains 5.4% of all the world’s ocean water. The Southern Ocean is the second smallest of all five oceans.

The Southern Ocean is the second smallest ocean in the world and surrounds the entire land of Antarctica. It is formed by the partition of the drake passage between the continents of Southern America and Antarctica. It is the only ocean that includes a wide range of diverse ecosystems in the entire world.

At approximately 20.3 million square kilometers (7.8 million square miles) and about twice the size of the U.S.A., the new ocean is the world's fourth-largest (following the Pacific, Atlantic, and Indian, but larger than the Arctic Ocean). The Southern Ocean's lowest point is 7,235 meters (23,737 feet) below sea level in the South Sandwich Trench.