Geomicrobiology of subglacial ice above Lake Vostok, Antarctica

Data from ice 3590 meters below Vostok Station indicate that the ice was ac creted from liquid water associated with Lake Vostok. Microbes were observe d at concentrations ranging from 2.8 x 10(3) to 3.6 x 10(4) cells per milli liter; no biological incorporation of selected organic substrates or bicarb onate was detected. Bacterial 16S ribosomal DNA genes revealed Low diversit y in the gene population. The phylotypes were closely related to extant mem bers of the alpha- and beta-Proteobacteria and the Actinomycetes. Extrapola tion of the data from accretion ice to Lake Vostok implies that Lake Vostok may support a microbial population, despite more than 10(6) years of isola tion from the atmosphere.