domingo, 16 de octubre de 2011

International Antarctic Team to Explore Buried 500,000 Year-Old Lake for New Knowledge about Evolution of Life on Earth and Other Planets


"Finding life in a lake that could have been isolated from the rest of the biosphere for up to half a million years will tell us so much about the potential origin of and constraints for life on Earth, and may provide clues to the evolution of life on other extraterrestrial environments," said David Pearce, science coordinator at the British Antarctic Survey and part of the team leading the search for life in the lake water. "If we find nothing, this will be even more significant because it will define limits at which life can no longer exist on the planet."

An international team of scientists led by the UK has been given the go-ahead to explore one of the planet’s last great frontiers — an ancient lake hidden deep beneath Antarctica’s ice sheet. Buried under 3 km of ice, subglacial Lake Ellsworth— may have been isolated for hundreds of thousands of years and could contain unique forms of life. The team hopes the exploration will yield vital clues about life on Earth, climate change and future sea-level rise.

Scientists have speculated for decades that new and unique forms of microbial life could have evolved in the cold, pitch-black and isolated environment of these subglacial lakes. Sediments on the lakebed are likely to reveal vital clues about the history of life in the lake and the ancient history of the West Antarctic Ice Sheet, including past collapse.

A 16-foot-long water-sampling probe will collect 24 water samples at different lake depths. It will also capture the top layer of sediments where the lake-floor meets the water. The sediment corer can extract a core up to 10 feet long. The corer is strong enough to penetrate even the most compacted glacial sediments to extract a core sample.

Following the success in early 2008 of an International Polar Year project to map the extent and depth of subglacial Lake Ellsworth, the Natural Environment Research Council (NERC) is funding a consortium of multidisciplinary researchers from nine UK universities, the British Antarctic Survey and the National Oceanography Centre, Southampton.

During the next five years the researchers will acquire and develop the technologies needed for this ambitious project. During the 2012–2013 Antarctic winter season the research team will go ‘deep field’ into West Antarctica to sample water from the lake in the search for tiny life forms never before seen; and to extract sediment from the lake bed to find clues as to how the climate has changed over many millennia.

“This is a benchmark in polar exploration — our team will be the first to explore this ancient lake. It is a dark, cold place that has been sealed from the outside world and it’s likely to contain unique forms of life," said Martin Siegert from the University of Edinburgh. " We hope to discover more about how life can exist in extreme environments and how Antarctica has changed in the past — which might help us understand more about other places on earth.”

In such an extreme environment, the mere presence of life in itself would be a major scientific discovery, but there are very strong reasons to expect that such microorganisms would possess special or unique adaptations to this unusual and potentially hostile habitat.

David Blake, who is Head of Technology and Engineering at the British Antarctic Survey and is involved in the project, said:

“This project is a great scientific challenge and the technology required to drill 3km through the ice without contaminating the lake is equally ambitious. Over the next few years we will build a hot water drill and probe, and make preparations to transport a sophisticated operation deep into the interior of West Antarctica. We really are at the frontiers of scientific exploration.”

The exploration of subglacial lakes is part of an international effort to understand key global issues such as life in extreme environments and climate change.

In the image above, a geologist hikes above Lake Vida, a typical subglacial lake covered by some 19 meters [62 feet] of ice. Despite Antarctica's extreme temperatures, the lake is perpetually liquid, its freezing point lowered because of its high salinity—seven times that of sea water. Scientists found 2,800-year-old microbes in the ice above the lake. They came to life when thawed. Studying this lake's ecosystem could yield clues about life on Mars, where frozen surface water is speculated to hold life-forms.

Source: The Daily Galaxy

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