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Lake under Antarctica mapped

August 02, 2004 19:43 IST
A massive lake buried under four kilometers of ice in the middle of Antarctica has been mapped by scientists using ice-penetrating radar.

'The lake is called Vostok, and for the first time, scientists using airborne radar and other high-tech instruments have probed its depths from far above and discovered intriguing signs that two distinct biological environments may exist there side by side,' says a report in the San Francisco Chronicle.

'To planetary scientists, the hidden lake may be an earthly model for conditions they believe exist on some of the moons of Jupiter -- in particular, the warm-water ocean that is thought to lie beneath the thick and fractured icy crust of Europa, the intriguing moon that the Galileo spacecraft first explored as it flew past four years ago,' says the article by Chronicle Science Editor David Perlman.

'Scientists at Columbia University's Lamont-Doherty Earth Observatory, headed by physicist Michael Studinger, report in the current issue of the journal Geophysical Research Letters that they have now mapped the underwater features of Lake Vostok in unprecedented detail,' the article says.

Vostok, among the largest of 70 such lakes buried under the Antarctic ice, was identified in 1996 by Russian and British scientists, who integrated data ranging from down-hole seismics, star observations and airborne ice-penetrating radar to new spaceborne altimetric observations, says a website maintained by Studinger.

'Their results show that the lake is actually divided by a high ridge of underwater rock into two separate basins that, in effect, could be two huge storage tanks for organisms that may have long thrived in extreme environments not unlike those of other bodies in the solar system,' says the Chronicle.

"Vostok is the closest analogue we have on Earth to what might well exist elsewhere in our solar system," Studinger is quoted as saying. "And because the ridge we have found could limit the exchange of water between the two basins, both the chemical and biological systems could be quite different."

According to the Chronicle, an international treaty bars the entire Antarctic continent from mineral exploitation, but separate regions have been assigned to various countries for scientific research. 'More than 50 years ago, the Soviet Union created its Vostok Station on the ice of East Antarctica at what is known as the "Pole of Inaccessibility," where the coldest temperature ever known on Earth -- 129 degrees below zero Fahrenheit -- was recorded in 1983.'

Russian and American scientists had previously drilled more than two miles into the accreted ice above the lake and recovered core samples at least 420,000 years old that are filled with an amazing variety of bacteria and other microorganisms, the article says.

'Sampling those unknown organisms and understanding the ecology of Lake Vostok's deep and impenetrable waters presents formidable challenges for technology, and no one yet knows how to build a device that can probe the lake and recover living samples without contamination,' said the article.

It goes on to add that scientists and engineers at NASA's Jet Propulsion Laboratory have already developed a unique device they call a "Cryobot," which was primarily intended to probe Europa's putative sea with a camera, instruments and sterilized collecting equipment.

'The device is essentially a heat-tipped probe that would melt its way down through the ice and into the ocean below where it could then recover water samples and any microorganisms that might conceivably exist there,' it said.

In early tests, a full-scale Cryobot model has already successfully melted its way down some 75 feet into a glacier on the Norwegian Arctic island of Spitzbergen, but more elaborate tests of its instruments and their ability to avoid contaminating their targets are still to come, the Chronicle said.

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