Life discovered 20m under Antarctic lake

By AAP with AG staff 28 November 2012
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Ancient bacteria found thriving beneath a frozen lake could hold clues to life on other planets.

TWO-THOUSAND-YEAR-OLD bacteria has been discovered thriving beneath a frozen lake in Antarctica, pushing the boundaries of what was thought necessary to sustain life.

Researchers discovered the microbial life 20m below salty Lake Vida, where the community was thriving without light or oxygen, at temperatures of around -13 degrees Celcius.

Ancient bacteria could hold clues for interplanetary life

Lake Vida, in Antarctica’s McMurdo Dry Valleys, has the highest nitrous oxide levels of any natural water-body on Earth. It also has high concentrations of hydrogen gas, nitrate and nitrite. Water beneath the ice layer can be six times saltier than ocean water.

Dr Nathaniel Ostrom, a zoologist from Michigan State University in the USA, who co-authored the report, says the discovery provides insight into other isolated, frozen environments here on Earth, and beyond.

“[The discovery] gives us a potential model for life on other icy planets that harbour saline deposits and subsurface oceans, such as Jupiter’s moon, Europa,” Nathaniel says.

Frozen lake in Antarctica teeming with life

Researchers drilled beneath the ice, uncovering an environment that may have been sealed off for 2,800 years. Because of the lengthy period of isolation, it was assumed that the area would have run out of energy stores. This did not appear to be the case.

“It’s plausible that a life-supporting energy source exists solely from the chemical reaction between anoxic salt water and (iron-rich) rock,” says Dr Christian Fritsen, a systems microbial ecologist based in the United States at the Desert Research Institute (DRI).

Dr Alison Murray, also of the DRI and a leading author on the report, says our knowledge of geochemical and microbial processes in lightless, icy environments – especially at subzero temperatures – has been minimal up until now.

“This work expands our understanding of the types of life that can survive in these isolated, cryoecosystems and how different strategies may be used to exist in such challenging environments,” Alison says.

A report of these findings was published in the Proceedings of the National Academy of Science on Monday.