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What lies beneath?

By Rose Layton

Photo credit: Wikimedia Commons

While it may be starting to hot up here in England, Lake Vostok remains under several miles of Antarctic ice. Spanning 150 miles, it boasts an impressive 5,400 km3 water volume, making it the largest subglacial lake of the Antarctic. Its seclusion means that any resident life forms evolved there independently of the external world, providing a unique opportunity for study.

Despite its isolation, for the best part of 15 million years, a Russian team of researchers were able to reach the surface of Lake Vostokís waters by drilling a hole ~3770m in length in 2012. Excitement grew as the team isolated DNA from the water samples, which appeared to be unlike any other known bacteria [1]. However, doubt was soon cast on these findings, as samples were found to be contaminated with fluid used during aid drilling.

Photo credit: Wikimedia

In the face of adversity, a second attempt saw the team reach the lake in early 2015. After careful planning and strict adherence to controls, researchers are confident that the latest samples are of pristine lake water.

Although we are still waiting on the first publication to announce any potential findings, results from similar studies hold promise. Lake Whillans is a large sub-glacial lake lying far beneath the icy surface of Antarctica. Clean exploration of the site revealed honey-coloured contents with extraordinarily high mineral content. Within hours researchers had identified cells and within days these cells were confirmed as being alive.

It turns out that the waters of Lake Whillans are teeming with microbial life, with approximately 1000 bacteria per cubic millimetre. It is impenetrable to sunlight and hence carbon dioxide fixation for photosynthesis is not possible. Ongoing research has identified nearly 4000 microbes, many of which are related to marine species and derive energy through oxidation of iron and sulfur compounds [2].

Only in April this year, the announcement of another giant sub-glacial lake surfaced adding to the vast treasure trove of potential discovery. These systems of rivers and lakes, separated from the surrounding world for hundreds of thousands of years (or longer!) represent an exclusive opportunity for exploring new forms of life in the absence of gene flow from external biota, resulting in unique microbial networks with the possibility of providing new insights into microbial evolution. Itís amazing to think that we didnít know these lakes existed until recently and we are only at the beginning of their discovery. These are exciting times for what lies beneath!


References

  1. Russian scientist defends Lake Vostok life claims, available from http://www.nature.com/news/russian-scientist-defends-lake-vostok-life-claims-1.12578 [Accessed 14/06/2016]
  2. B.C. Christner et al., Nature, 2014, 512, 310-313

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