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)