Crawling with microbes under the Antarctic ice – TF1

– Video above: Antarctic glaciers melting at a point of no return –

Located 800 meters below the ice Antarctica, deep in the dark and cold, Lake Whillans remained isolated from the surface for thousands of years. Researchers have yet to identify nearly 4,000 species of microbes in its waters at 0 ° C. Analysis of water and reassembled Lake Whillans sediments reveals a “microbial community” surprisingly complex: many bacteria composing this broth culture glacial able to exploit minerals from the soil to produce energy and 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 by the journal Nature.

Scientists have been trying for decades to determine if life forms could persist or even evolve separately, the vast icy expanses of 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, to 3,769.3 meters into 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.

Hot water and clean all floors

Researchers, mostly American, have used such a system injection of hot water, filtered and UV disinfected, to drill a well of 60 cm diameter in the thickness of ice lying above the lake. And they claim to have thoroughly cleaned their equipment and instruments before each intervention. 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 of the basement was barely below 0 ° C.

A genetic analysis of microorganisms in the lake water has identified the presence of microbes or 3,931 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 biological mechanisms are quite different bacteria. 793 bodies have however not been classified. Many of the microbes working in the Lake Whillans seem able to reduce nitrogen, iron and sulfur in the water or sediment rock to produce energy, the study said.

“Buried under 800 feet of ice in Antarctica lies an unexplored part of our biosphere. WISSARD The project provided an overview of the nature of the microbial life that could hide under more thirteen million km2 of polar ‘cap, says Brent Christner, lead author of the study, in a statement from the American National Science Foundation (NSF). 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.