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Oceans

Polar waters

The icy waters off AntarcticaThe icy waters off Antarctica The North Pole lies not on land but on water: the Arctic Ocean. It is permanently covered by ice, although the size of the ice cap shrinks dramatically in summer months as the ice melts and stretches of water open up. The South Pole lies on the continent of Antarctica, a huge, mountainous landmass, much of it covered by a permanent ice cap almost three kilometres (about 10,000 feet) thick in some places. It is the coldest place in the world. In winter, the waters of the Southern Ocean surrounding the continent are covered with floating pack ice and icebergs.

An icebreaker carving through Arctic pack iceAn icebreaker carving through Arctic pack ice
A map of the Arctic OceanA map of the Arctic Ocean

Arctic Ocean

Much of the Arctic Ocean is covered with a thick layer of floating ice all year round. At its edges, rafts of broken ice, called pack ice, drift in the freezing cold waters. These are pieces of ice that are constantly being broken up and crushed together by the movement of the water. During the summer, some of the ice cracks and melts, forming waterways and large stretches of water.

Ice in the Arctic Ocean thawing in summer
The Southern Ocean surrounds AntarcticaThe Southern Ocean surrounds Antarctica

Southern Ocean

Most Arctic icebergs have broken off glaciers and crashed into the sea: they are usually cone-shaped. Antarctic icebergs break off from the ice shelf and so are often flat-topped.

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