CAMBRIDGE, U.K.--Scientists have discovered tantalizing evidence that microbes are living under nearly 4 kilometers of antarctic ice, leaving teams more eager than ever to explore a vast lake beneath the ice sheet. But a host of issues--from how best to probe for life to who should pay for the big-science project--may delay any plunge into one of the world's most isolated ecosystems.
At a meeting here this week, 70 researchers from 14 countries argued for the exploration of Lake Vostok--a body of water in East Antarctica that has been sealed from the rest of the world for millions of years. "It's one of the most high-profile and interesting projects of the next decade," says Chris Rapley, director of the British Antarctic Survey.
Scientists hope that new data pointing to microbial life at Vostok will help convince their governments of the mission's importance. Microbiologist John Priscu of Montana State University in Bozeman, for example, unveiled electron micrographs of what appear to be rod-shaped bacteria isolated from core samples of refrozen lake water, sampled from about 120 meters above the lake. He's now analyzing DNA to try to classify the microbes.
Working on another piece of the same core, David Karl of the University of Hawaii, Manoa, ran a battery of tests to affirm life, such as measuring levels of ATP, an energy molecule vital to all known organisms, and tracing the incorporation of radiolabeled acetate into biomolecules. The sluggish biochemistry that his team saw, Karl says, "is consistent with a population growing very slowly." Sabit Abyzov of the Institute of Microbiology in Moscow and Richard Hoover of NASA's Marshall Space Flight Center in Huntsville, Alabama, who were not at the meeting, have also imaged what appear to be bacterial filaments and other microbes just above the lake.
With their appetites whetted, scientists want to know just how these and other life-forms--if they are alive--can survive. But while further ice-core studies may give clues to which bacteria may colonize the ice-water interface, lake samples are needed to reveal what organisms, if any, live deeper in the water column or in thick sediments that seem to coat the bottom. Seismic mapping surveys to pick a prime drilling spot for accessing Vostok could get off the ground within the next couple of years, but it may be 2004 or later before instruments reach the lake. Officials of NASA and the National Science Foundation plan to meet next month to hash out a possible U.S. role.