Antarctic bacteria a clue to different kinds of life - study

Nov 28 (Reuters) - A study by polar researchers has revealed

an ancient community of bacteria able to thrive in the

lightless, oxygen-depleted, salty environment beneath nearly 70

feet (20 metres) of ice in an Antarctic lake, giving insight

into the unique ecosystem.

The research, funded by the National Science Foundation and

NASA, provides clues about biochemical processes not linked to

sunlight, carbon dioxide and oxygen - or photosynthesis.

The authors of the study say it may explain the potential

for life in salty, cryogenic environments beyond Earth, where

energy in ecosystems is typically fueled by the sun.

The study, published this week in Proceedings of the

National Academy of Science, came out of a collaborative effort

of polar researchers from a number of institutions, including

the University of Illinois at Chicago, Montana State University

and the University of Colorado.

The energy driving bacterial life in Lake Vida, a mostly

frozen, brine lake below the Antarctic ice shield, may be

derived from chemical reactions between the salt water and the

underlying, iron-rich rock, researchers said.

Conditions at Lake Vida are similar to habitats on Mars and

are believed to be present elsewhere in the solar system,

creating a potentially new framework for evaluating the

likelihood of extraterrestrial life and how it might be

sustained.

"It can tell us about the origins of life on Earth and it

also educates us about looking for life elsewhere," said Peter

Doran, principal investigator with the Lake Vida project and

environmental sciences professor at the University of Illinois

at Chicago.

Researchers analyzed cores lifted from Lake Vida during

expeditions in 2005 and 2010. Earlier explorations indicated

that ice layers had cut the lake off from sunlight and Earth's

atmosphere for roughly 3,000 years.

Microbiologist Christian Fritsen, a co-author of the paper

and professor at the Desert Research Institute in Nevada, said

an examination of the cores showed a lake six times saltier than

sea water with an average temperature of 8 degrees Fahrenheit

(-13 Celsius) and the highest nitrous oxide levels of any

natural water body on Earth.

Researchers had expected little or no life under such

extreme conditions, Fritsen said.

"When I first looked down the microscope for bacteria, there

was so much more than I ever imagined. It was a world we hadn't

quite expected," he said.

The microbes in the isolated lake contain representatives

from eight major bacterial groups, suggesting a complex

ecosystem instead of a remnant population of a single life form,

the research shows.

"It's a dual-edged sword: We don't want to sensationalize

the findings but, at the same time, it's very exciting," Fritsen

said.

(Editing by Alex Dobuzinskis, Cynthia Johnston and Mohammad

Zargham)

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