Microorganisms in the Accreted Ice of Lake Vostok, Antarctica

Abstract

Analysis of a portion of Vostok ice core number 5G, which is thought to contain frozen water derived from Lake Vostok, Antarctica (a body of liquid water located beneath about 4 kilometers of glacial ice), revealed between 2 × 10 2 and 3 × 10 2 bacterial cells per milliliter and low concentrations of potential growth nutrients. Lipopolysaccharide (a Gram-negative bacterial cell biomarker) was also detected at concentrations consistent with the cell enumeration data, which suggests a predominance of Gram-negative bacteria. At least a portion of the microbial assemblage was viable, as determined by the respiration of carbon-14–labeled acetate and glucose substrates during incubations at 3°C and 1 atmosphere. These accreted ice data suggest that Lake Vostok may contain viable microorganisms.