UNIVERSITY OF BRISTOL
Lake Vostok - new research
New research from the vast Lake Vostok which lies beneath 4 km of ice in Antarctica is published this week in Nature [6 December 2001]. In 1999 the world's longest ice core, at Vostok Station, stopped 160 m short of Lake Vostok, to prevent contamination of this pristine environment. To predict environmental conditions within the lake and its potential for supporting life, an international group of scientists has combined available information from remote sensing and ice core research with a new model of how the lake water circulates under the ice.
The new model suggests that microbes found recently in the layer of refrozen lake water (attached to the bottom of the overlying glacier ice) may not be representative of life forms throughout the lake. It is now thought that these microbes, which took at least 500,000 years to migrate through the glacial ice, may spend only a short time in the lake before being trapped in refrozen lake water that accumulates at the base of the ice sheet.
The lake, which is thought to be at least 20 million years old, is subject to high pressure, low temperatures (-3°C) and in permanent darkness, so no photosynthesis occurs. In spite of these extreme conditions a wide diversity of micro-organisms is predicted. Many of these will utilise dissolved organic carbon, released from bedrock, and oxygen that has to migrate through the 4 km ice sheet to reach the lake. The model predicts that oxygen will not be distributed evenly within the lake so creating a range of environmental conditions and opportunities for greater diversity of micro-organisms.
Lead author of the review, Dr Martin Siegert of the University of Bristol, said: 'We have identified the likely physical and chemical environment within which any life forms must function. The conditions we predict for Lake Vostok are also applicable to the other 70 Antarctic subglacial lakes.'
Dr Cynan Ellis-Evans of the British Antarctic Survey said: 'Solving the mystery of Lake Vostok is one of the great scientific prizes for Antarctic research and has generated enormous excitement and speculation. We think the microbes found so far are what you might call 'tourists' in the lake as they appear to be modern microbes, but we expect to find far more ancient micro-organisms in the deep lake water and the lake sediments.'
The ultimate aim of a new international programme is to explore subglacial Antarctic lakes is to penetrate Lake Vostok and obtain sediment and biological samples. Progress so far by the SALE (the Subglacial Antarctic Lake Exploration) Group of Specialists, appointed by the Scientific Committee for Antarctic Research (SCAR) to develop a science plan, can be found at http://salegos-scar.montana.edu
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Email: public-relations@bristol.ac.uk
Copyright: 2001 The University of Bristol, UK
Updated: Friday, 07-Dec-2001 09:46:19 GMT