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- An exotic Earth bacteria that thrives
in laboratory conditions mimicking the environment of Mars is raising fresh
hope that the Red Planet once harbored life, a researcher says.
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- Timothy A. Kral of the University of
Arkansas says that a methane-making, oxygen-hating microbe "grows
just fine and dandy" in a simulated Martian environment that could
not support most forms of life on Earth.
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- Kral, who will present his research Wednesday
at the national meeting of the American Society for Microbiology, says
he and a colleague, Curtis Bekkum, created an environment that contained
no oxygen, but was bathed in carbon dioxide and hydrogen gases.
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- The soil in the experiment resembles
what is known about Martian dirt, with no organic nutrients and only a
small trace of water.
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- "We made the assumption that there
is liquid water beneath the surface," says Kral. Many planet experts
believe Mars once had great amounts of water and that traces of it still
remain beneath the surface.
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- Into this mix the researchers placed
a group of microbes called methanogens, a type of bacteria that on Earth
lives in places where there is no oxygen, such as deep under the ground
or around sea floor vents.
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- All of these types of microbes, he says,
use nitrogen and hydrogen to make methane, a natural gas that can be used
as fuel.
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- To determine whether the bacteria lived
in the simulated Martian environment, Kral measured the amount of methane
produced inside the sealed culture dishes.
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- "It made methane just like it does
on Earth," he says. "It grows just fine in the Martian conditions."
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- Although the experiment is far from the
final answer, Kral says the fact that the microbes thrived "cautiously
increases our belief that life on Mars is possible, or at least it was
possible."
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- The experiment also raises the possibility
the microbes could be used to alter Mars' cool climate, Kral says. Microbes
sent to the planet could help methane collect in the atmosphere, eventually
creating a greenhouse effect, he says.
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- Methane also could provide the energy
for a human colony on Mars, says Kral. The gas can be used as fuel and
could even be processed into a rocket propellant.
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