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" Biogeochemical study of subglacial
Lake Vostok accretion ice: searching for
alien life in extreme conditions
". Sergey Bulat (Division of Molecular and
Radiation Biophysics, Petersburg Nuclear Physics Institute, St.
Petersburg-Gatchina, Russia) Abstract: The objective was
to perform complex biogeochemical study of accretion ice of the subglacial
Lake Vostok, East Antarctica with the ultimate goal to discover hidden life
in this extreme icy environment. Principal analyses included gas content,
dissolved organic carbon (DOC), major ion chemistry, mineralogy of sediments,
microbial cell enumeration and 16S rRNA genes sequencing. As a result, total
gas content proved to be 2-3 orders of magnitude lower than in glacier ice.
Meanwhile a giant mica-clay sediment inclusion showed an unusual content of
oxygen, carbon dioxide and methane. Mean DOC levels were found to be less
than 20 pbb. Major ion chemistry showed enrichment of magnesium and calcium
sulfates along with sulfides in ice with sediment inclusions only. Amongst
the latter sulfide minerals like pyrite were also identified. Accordingly the
possible redox couples are rather limited in supporting chemolithoautotrophic
life forms. The molecular microbiology study constrained by Ancient DNA
research criteria showed that the ice until depth |
