By Andrew McDonald, The Space Reporter
Tuesday, July 09, 2013
Under more than 3,700 meters (12,130 feet) of Antarctic glacial ice rests a vast body of liquid water known as Lake Vostok. With a volume of 1,800 cubic kilometers and an average depth of 125 meters, Lake Vostok is the seventh largest and fourth deepest lake on Earth, and the largest subglacial lake on the planet. Vostok’s water remains liquid thanks to a geothermal heat source in the continental crust beneath the lake and the pressure of the overlying ice, and now it is providing scientists with an idea of just how life can adapt to nearly any environment, including space.
A team from Bowling Green State University, led by Yury M. Shtarkman, has analyzed genetic material contained in an ice core recently drilled by Russian researchers. The samples come from the accretion ice, a layer of relatively pristine ice that forms between the liquid water of the lake and the overlying glacier.
Shtarkman and his colleagues contend that the genetic material is not outside contamination, based upon the results of several previous studies: a higher concentration and diversity of cells is present in the accretion ice layer than in the glacier; unique bacterial and fungal sequences have been identified in the same sections of the accretion ice core; and all the genetic sequences are most closely related to species that inhabit similar environments, such as lake/ocean sediment and frigid, polar, and/or deep-sea settings.
In their current study, reported in PLoS ONE, Shtarkman and colleagues were able to identify 1,623 genetic sequences to their species. Ninety-six percent of the sequences came from bacteria and six percent from eukaryotes (mostly fungi). Some of the bacteria identified are normally associated with more complex organisms, including anemones, worms, and fish. These results suggest that a complex ecosystem might be thriving under the ice in Lake Vostok.
Although the lake has been isolated from Earth’s atmosphere for 14 million years, it was once exposed to the outside world; over 35 million years ago, Antarctica was far more hospitable and Vostok was free of ice, allowing organisms ample time to migrate in. Since becoming sealed under the glacier, Vostok’s organisms would have followed their own evolutionary course, possibly sustained by nutrients from hydrothermal vents fed by the geothermal activity in the underlying crust.
According to SETI astrobiologist Dale Andersen in an interview with Discovery News, research on Lake Vostok “helps us learn how to explore these kinds of environments better.” Vostok is a dry run, so to speak, for human exploration of the liquid oceans hypothesized to exist under the ice that covers some of our solar system’s moons, including Jupiter’s Ganymede and Europa, and Saturn’s Enceladus.
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