Science

Diverse microbial life beneath Antarctic ice sheet

Scientists have found evidence of microbial life at a depth of 800 metres below the West Antarctic ice sheet in the Subglacial Lake Whillans. The depth of the Lake at the drilling site was about 2.2 metres. The results are published today (August 21) in the journal Nature.

The extremophiles (microorganisms that live in extreme environments like very high or low temperature, extreme pressure etc) in the Subglacial Lake Whillans survive at very low temperature of -49 degree C and in a highly alkaline environment (pH of 8.1). The pressure at a depth of 800 metres where the Lake is found is about eight megapascal. The Lake water was not saturated with oxygen.

The Lake supports a rich and diverse microbial community of bacteria and archaea — over 3,900 operational taxonomical units (definition of a species or group of species when only DNA sequence data is available) with average cell density of 1.3 x 10 cells per millilitre.

According to the paper, the carbon biomass estimates are 3-50 fold higher than that observed beneath the Ross Ice Shelf.

Like some other extremophiles, these microbes convert the inorganic compounds found in the rock into food and use carbon dioxide as their source of carbon.

According to the National Oceanic and Atmospheric Administration, “chemosynthesis is at the heart of deep-sea communities, sustaining life in absolute darkness, where sunlight does not penetrate.”

Nitrification may turn out to be “fundamental chemoautotrophic pathway of new organic carbon production,” note the authors.

The presence of large diverse microbial community in the Subglacial Lake Whillans suggests that other microbial life must be present beneath the 10 square kilometres of Antarctic ice sheet.

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Printable version | Jul 13, 2020 5:45:12 PM | https://www.thehindu.com/sci-tech/science/diverse-microbial-life-beneath-antarctic-ice-sheet/article6335337.ece

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