Imagine a dark cavity, damp and chilly, buried 800 meters under the ice of Antarctica. Not really the place to put your luggage … Researchers have yet to identify about 4,000 species of microbes in water at 0 ° C Lake Whillans, isolated from the surface for thousands of years. Researchers, mostly American, have used such a hot water injection system, filtered and disinfected with ultraviolet rays, to dig a well 60 cm in diameter in the thickness of ice located above the lake. And they claim to have thoroughly cleaned their equipment and instruments before each intervention.
793 organizations unknown
The analysis of water and sediment of Lake Whillans reassembled reveals a “microbial community” surprisingly complex: many bacteria composing this broth culture glacial able to exploit minerals from the soil to produce energy and to tap the carbon they need to survive in CO2. “Since it is estimated that there are more than 400 subglacial lakes and numerous rivers under the ice cap of Antarctica, these ecosystems could be commonplace,” said the study published Wednesday in the journal Nature .
According to their statements, the depth of the lake to the point of drilling was about 2.20 m and the temperature of the water, mostly from melting ice surrounding due to the heat from the soilless was just below 0 ° C. A genetic analysis of microorganisms in the lake water has identified the presence of 3,931 microbes or families of microbes.
Of these, 87% could be linked to the family of bacteria and 3.6% are classified as that of Archaea , also called “Archaea” although their mechanisms biological bacteria are different. 793 bodies have however not been classified. How do all these microbes to survive? The study said that they would be able to reduce nitrogen, iron and sulfur in the water or sediment rock to produce energy.
Previous unsuccessful
Scientists have been trying for decades to determine if life forms could persist or even evolve separately, the vast expanses of ice Antarctica. A Russian team had succeeded in February 2012, after two decades of drilling to reach Lake Vostok, as large as Lake Ontario and located in one of the most inaccessible places on Earth, 3 769.3 m depth in East Antarctica. Analysis of the samples come up from the lake, cut off from the outside world for more than ten million years, initially left thinking to the presence of microorganisms, some of which may still be unknown.
But it appeared that drilling techniques used by the Russians could result in contamination of samples – even the lake itself – by microbes from the surface, which has cast doubt on the validity of these analyzes. Team Wissard project dedicated to the study of Lake Whillans, therefore wanted to repeat the experience by surrounding himself with every precaution to avoid “polluting” the lake.
Hope for life in a hostile environment
“Buried under 800 feet of ice in Antarctica, lies an unexplored part of our biosphere. Wissard The project gave an overview of the nature of the microbial life that could hide under more than thirteen million km2 of polar cap “summarizes Brent Christner, lead author of the study, in a statement from the National Science Foundation (NSF ) American. The discovery of a rich and complex ecosystem in an apparently barren as Antarctica “can even question the existence of microbes eating rock under the ice surface of an extraterrestrial body like Mars for example” environment, says In a commentary published separately by Nature , the British glaciologist Martyn Tranter. NASA has also also supported the project.
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