Subglacial L ake V ostok

Abstract

Abstract Recent studies have revealed that several subglacial lakes exist beneath the East Antarctic Ice Sheet. The largest of these lakes, Subglacial Lake Vostok, is ∼4 km beneath the ice surface, with a surface area near 14,000 km 2 and a depth exceeding 800 m. A permanent ice sheet covered the lake at least 15 million years ago, which isolated it from the atmosphere. Because of concerns for contaminating this pristine environment, no direct samples of lake water have yet been obtained. The accreted ice retrieved from an ice core drilled at Vostok station, which represents lake water frozen to the bottom of the ice sheet, has provided the only material for microbiological and geochemical investigations. The presence of microorganisms within the accreted ice has been confirmed independently by several laboratories; however, the question remains whether a flourishing microbial ecosystem exists within Lake Vostok. Subglacial lake exploration represents one of the last unexplored frontiers on our planet, and the unusual microbial ecosystems that may exist have much to tell us about the limits of life on Earth and on icy planets and moons in the solar system.