Abstract
Lake Vostok is the largest of the nearly 400 subglacial Antarctic lakes and has been continuously buried by glacial ice for 15 million years. Extreme cold, heat (from possible hydrothermal activity), pressure (from the overriding glacier) and dissolved oxygen (delivered by melting meteoric ice), in addition to limited nutrients and complete darkness, combine to produce one of the most extreme environments on Earth. Metagenomic/metatranscriptomic analyses of ice that accreted over a shallow embayment and over the southern main lake basin indicate the presence of thousands of species of organisms (94% Bacteria, 6% Eukarya, and two Archaea). The predominant bacterial sequences were closest to those from species of Firmicutes, Proteobacteria and Actinobacteria, while the predominant eukaryotic sequences were most similar to those from species of ascomycetous and basidiomycetous Fungi. Based on the sequence data, the lake appears to contain a mixture of autotrophs and heterotrophs capable of performing nitrogen fixation, nitrogen cycling, carbon fixation and nutrient recycling. Sequences closest to those of psychrophiles and thermophiles indicate a cold lake with possible hydrothermal activity. Sequences most similar to those from marine and aquatic species suggest the presence of marine and freshwater regions.
Highlights
Introduction400 subglacial lakes have been discovered in Antarctica, the largest of which is Lake
400 subglacial lakes have been discovered in Antarctica, the largest of which is LakeVostok [1±5]
The lower number of sequences and the shorter average read lengths might indicate that the nucleic acids in this sample were degraded to a greater extent than those in the V5 sample
Summary
400 subglacial lakes have been discovered in Antarctica, the largest of which is Lake. Mesophilic, thermophilic, aerobic, anaerobic thermophilic, mesophilic, psychrophilic, psychrotolerant, aerobic, anaerobic, peizophilic, deep sea, halophilic, polar ice, soil, sediments, permafrost, 33 distinct sequences from species of Psychrobacter, 10 distinct sequences from species of Halomonas (halophilic), some produce intracellular gas vesicles, some are animal associated unknown animal pathogens saprobes and arthropod pathogens/symbionts, anaerobic freshwater, soil, symbionts of protists and nematodes, aerobic Sequences similar to those from uncultured and unidentified species, many from other environmental metagenomic studies deep hydrate-bearing sediment, peizotolerant, psychrotolerant carbon fixation using the reductive TCA cycle nitrogen fixation, nitrate reduction, nitrite respiration, denitrification, sulfur oxidation, chemolithoautotrophs, iron oxidation, mineralization of aromatics, carbon fixation using the reductive pentose phosphate cycle unknown heterotrophic heterotrophic heterotrophic. Sources of information were NCBI descriptions, publications cited in the NCBI descriptions and web sources (see Supplementary Tables S1±S6)
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