Links to read:
Huffington Post:
www.huffingtonpost.com/2012/11/27/lake-vida-antarctic-lake-alien-extraterrestrial_n_2200712.html#slide=more266160
New Scientist:
http://www.newscientist.com/article/dn22535-lake-life-survives-in-total-isolation-for-3000-years.html
It is seven times as salty as the sea, pitch dark and 13 degrees below freezing. Lake Vida in East Antarctica has been buried for 2800 years under 20 metres of ice, but teems with life.
The discovery of strange, abundant
bacteria in a completely sealed, icebound lake strengthens the
possibility that extraterrestrial life might exist on planets such as
Mars and moons such as Jupiter's Europa.
"Lake Vida is a model of what happens
when you try to freeze a lake solid, and this is the same fate that any
lakes on Mars would have gone through as the planet turned colder from a
watery past," says Peter Doran
of the University of Illinois, Chicago. He is co-leader of a team
working in the Dry Valleys of Antarctica where Vida is situated. "Any
Martian water bodies that did form would have gone through this Vida
stage before freezing solid, entombing the evidence of the past
ecosystem."
The Vida bacteria, brought to the
surface in cores drilled 27 metres down, belong to previously unknown
species. They probably survive by metabolising the abundant quantities
of hydrogen and oxides of nitrogen that Vida's salty, oxygen-free water
has been found to contain.
Co-research leader Alison Murray of the Desert Research Institute
in Reno, Nevada, is now investigating this further by growing some of
the extracted cells in the lab. "We can use these cultivated organisms
to better understand the physical or chemical extremes they can tolerate
that might be relevant to other icy worlds such as Europa," she says.
Surprise composition
Murray and her colleagues were
surprised to find so much hydrogen, nitrous oxide and carbon in the
water. They speculate that these substances might originate from
reactions between salt and nitrogen-containing minerals in the
surrounding rock. Over the centuries, bacteria denied sunlight may have
evolved to be completely reliant on these substances for energy. "I
think the unusual conditions found in the lake have likely played a
significant role in shaping the diversity and capabilities of life we
found," she says.
But the existence of life in Lake Vida
does not necessarily increase the likelihood that life exists in much
older, deeper lakes under investigation in Antarctica, most notably
Vostok and Ellsworth, which are 3 kilometres down and have been isolated
for millions rather than thousands of years.
"It doesn't give us clues about
whether there's life in Vostok or Ellsworth, but it says that under
these super-salty conditions, life does OK," says Martin Siegert of the
University of Bristol, UK, and leader of an expedition to Ellsworth which set off on 25 November. "We'll be drilling down 3 kilometres into the lake," he says.
Huffington Post:
www.huffingtonpost.com/2012/11/27/lake-vida-antarctic-lake-alien-extraterrestrial_n_2200712.html#slide=more266160
New Scientist:
http://www.newscientist.com/article/dn22535-lake-life-survives-in-total-isolation-for-3000-years.html
