Microscopic Life Thrives in 'Martian'
Environment
By Jay Wrolstad
NewsFactor Sci::Tech,
Part of the NewsFactor Network
January 18, 2002
If indeed there is life on Mars, some of its forms may resemble the organisms found in an
inhospitable, underground environment on Earth that scientists believe closely resembles
that of the red planet.
A research team led by Derek Lovley, head of the microbiology department at the University
of Massachusetts, and Francis H. Chappelle of the U.S. Geological Survey (USGS) recently
discovered a community of microoganisms that require no solar energy or organic sustenance
to survive. The unique life form is thriving 200 meters below the Earth's surface in the
Beverhead Mountains of Idaho.
Living on Hydrogen and CO2
"This is a microbial community that is different than any other thus far found on
Earth," Lovley told NewsFactor. "While we know there are organisms that live by
combining hydrogen with carbon dioxide to produce methane gas, in this environment, over
90 percent of the microorganisms were supported by hydrogen gas."
While there is speculation that life may exist on Mars and other planets in the solar
system, it would need both water and energy to survive, Lovley said. "But the only
source of water on Mars is beneath the surface where there is no sunlight, so it would
require an alternative energy source, such as hydrogen, which we know is there."
A Long Search
The microbial community studied in Idaho closely resembles what geochemists have suggested
might be found below the surface of Mars, based on what is known of Martian subsurface
chemistry. "We can use this community to test hypotheses about hydrogen-based
subsurface life and to search for such communities elsewhere," Lovley said.
The search for these geological conditions has been underway for a decade by geologists
and microbiologists, Lovley said. The Idaho site was chosen by Chappelle because it has
water that has not seen the light of day for thousands of years. Held deep within volcanic
rocks in geothermal springs, the water contains high levels of hydrogen.
Previous underground sites that looked promising revealed microorganisms whose DNA
signatures indicated they lived on organic matter that was present in the groundwater or
that had been deposited along with the subsurface of rocks, Lovley reported. Those
environments do not represent conditions on Mars, because such organic matter would not be
available on that planet.
The study, published in the January 17th edition of the journal Nature, was funded by the
USGS and a grant from the Life in Extreme Environments program of the National Science
Foundation.
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