Islands of the Southern Ocean
Sometimes described as the fifth
ocean, or as the Antarctic Ocean, the world-wrapping Southern Ocean comprises the southernmost waters of the
Earth's major oceans — the Atlantic, Indian and Pacific oceans — where they converge to wrap around the
continent of Antarctica.
Technically it has been described as comprising all those waters existing south of the lattitide of 60° South. Although traditional definitions are often loose (and can include waters lapping the southern coasts of Australia), for the purposes of this site the boundaries are extended north of 60° S to include the islands of the far southern Indian and Atlantic oceans — islands which have traditionally been studied by Antarctic researchers and explorers.
At some 20 millon km² in area, the Southern Ocean is the second smallest of the Earth's oceans and is around 6 million km² larger that its northern counterpart, the Arctic Ocean. Its waters typically have depths of between 4,000 and 5,000 m, with a greatest depth of 7,235 m below mean sea level being found at the southern end of the South Sandwich Trench.
Its waters are dominated by the 21,000 km long Antartic Circumpolar Current — the world's lengthiest ocean current. Flowing slowly from east to west around Antarctica, the Antartic Circumpolar Current extends to great depth and can be up to 2,000 km in width — resulting in a greater volume of water transported than any other ocean current.
Major island types of the Southern Ocean. Left to right: (i) Large volcanic shield - Amsterdam Island; (ii) highly eroded mountainous island - Île de l'Est, Crozet Islands; (iii) glaciers and ice caps of the far south - South Georgia.