Searching for life in extreme environments relevant to Jovian’s Europa: Lessons from subglacial ice studies at Lake Vostok (East Antarctica) |
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Authors: | Sergey A Bulat Irina A Alekhina Dominique Marie Jean Martins Jean Robert Petit |
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Institution: | 1. Petersburg Nuclear Physics Institute, St. Petersburg Gatchina 188300, Russia;2. Station Biologique de Roscoff, Place Georges Teissier, 29682 Roscoff Cedex, France;3. Laboratoire Glaciologie et Géophysique Environnement CNRS-UJF, 38402 St. Martin d’Hères Cedex, France;4. Laboratoire d’étude des Transferts en Hydrologie et Environnement CNRS-UJF, 38041 Grenoble Cedex 9, France |
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Abstract: | The objective was to estimate the genuine microbial content of ice samples from refrozen water (accretion ice) from the subglacial Lake Vostok (Antarctica) buried beneath the 4-km thick East Antarctic ice sheet. The samples were extracted by heavy deep ice drilling from 3659 m below the surface. High pressure, a low carbon and chemical content, isolation, complete darkness and the probable excess of oxygen in water for millions of years characterize this extreme environment. A decontamination protocol was first applied to samples selected for the absence of cracks to remove the outer part contaminated by handling and drilling fluid. Preliminary indications showed the accretion ice samples to be almost gas free with a low impurity content. Flow cytometry showed the very low unevenly distributed biomass while repeated microscopic observations were unsuccessful. |
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Keywords: | Subglacial environments Antarctica Low biomass Forward contamination Astrobiology Icy worlds |
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