sabato 20 marzo 2010

A Hidden Landscape. VOSTOK, ANTARCTICA

Lake Vostok lies in the heart of the Antarctic continent hidden beneath 4 kilometers of ice. As big as Lake Ontario in North America, Lake Vostok is one of the world's biggest freshwater lakes. Lake Vostok has been covered by the vast Antarctic ice sheet for up to 25 million years. The lake was named for the Russian research station that sits above its southern tip - a place where in 1983 the temperature fell below -129°F (-89°C), the coldest ever recorded temperature on Earth. More than 145 lakes have been identified beneath the thick Antarctic ice sheet. Most of these lakes, covered between 3-4 kilometers of ice, are several kilometers long. One of these lakes, Lake Vostok, is an order of magnitude larger than all other known lakes.
Bacteria found in refrozen lake water at the bottom of the Vostok ice core could be part of an indigenous ecosystem below that's been living in the cold, dark waters for millions of years. Lake Vostok has been isolated from open exchange with the atmosphere for several million years. No one knows how any organism, cut off from air, sunlight or any apparent source of life-sustaining energy, could survive in its frigid waters or under such crushing pressure of more than 360 times the atmospheric pressure at sea level.

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