Cold-loving microbes that are able to withstand extreme pressures and survive without oxygen or sunlight might exist in veins of liquid more than 3.5 kilometres beneath Antarctica according to a physicist at the University of California at Berkeley. Buford Price is assembling an international and interdisciplinary team to investigate the possibility that life can survive in such harsh conditions.
Antarctica is full of submerged lakes that have been trapped under kilometres of ice for millions of years. The most famous – and largest – of these hidden lakes is Lake Vostok. Price has studied samples taken from 100 metres above the lake’s surface and believes that the nutrients trapped in cracks in the ice could be rich enough to nourish life (Proc. Nat. Acad. Sci. 97 1247).
The freshwater lake has been covered by ice for more than 14 million years. During that time any life forms that exist in the lake have been cut off from the rest of the world. However, when scientists drilled to within 100 metres of the lake’s surface, they noticed two different types of ice. The first 3500 metres of ice was frozen seawater, while the next 1000 metres was frozen freshwater from the lake. Scientists are reluctant to drill directly into Lake Vostok because they do not want to contaminate it.
The samples from the freshwater ice contained salts and dissolved organic material. Price proposes that liquid veins in the ice could concentrate acidic nutrients by a factor of one million above their ‘background’ level, providing a natural habitat for tough forms of bacteria. Price now hopes to examine the samples from 3500 metres with a technique called epifluorescence microscopy. He has also applied to the US National Science Foundation for funding. “I guess it will take a couple of years before I get the ice core samples, set up epifluorescence microscopy, and carry out the search,” he says.
