Microorganisms in the accreted ice of Lake Vostok, Antarctica

Analysis of a portion of Vostok ice core number 5G, which is thought to con tain frozen water derived from Lake Vostok, Antarctica (a body of liquid wa ter located beneath about 4 kilometers of glacial ice), revealed between 2 x 10(2) and 3 x 10(2) bacterial cells per milliliter and Low concentrations of potential growth nutrients, Lipopolysaccharide (a Gram-negative bacteri al cell biomarker) was also detected at concentrations consistent with the cell enumeration data, which suggests a predominance of Gram-negative bacte ria. At Least a portion of the microbial assemblage was viable, as determin ed by the respiration of carbon-14-labeled acetate and glutose substrates d uring incubations at 3 degrees C and 1 atmosphere. These accreted ice data suggest that Lake Vostok may contain viable microorganisms.