Dr. Tim Kral, a University of Arkansas biology professor, and graduate student Curtis Bekkum presented their findings at the annual meeting of the American Society for Microbiology in Chicago.

The researchers created a biological model of what life on Mars might be like based on what is known about the Martian landscape.

"There's nothing from Mars for us to work with," Kral said. "So you have to play the game from the standpoint of Earth."

Mars appears unfriendly towards most life forms. The planet currently contains no detectable organic matter and has extremely cold surface temperatures. So for his experiment, Kral sought microorganisms that survive in extreme conditions and thrive on inorganic matter.

He found the ideal microbes in methanogens, anaerobic microorganisms considered to be some of the most primitive life forms on earth. Methanogens can be found deep in the ocean, in the earth's crust or even in a cow's stomach, all of which are environments that might be considered harsh like Mars' surface.

To grow methanogens under some of the conditions found on Mars, Kral and Bekkum used ash from Hawaiian volcanoes -- known to share chemical characteristics with Mars soil. They also used carbon dioxide, hydrogen and water while growing the microbes. The methanogens grew successfully in the Mars soil simulant, obtaining all the macro and trace minerals they needed to survive.

The researchers probed deeper into the simulated life on Mars environment with respect to water. Mars has no liquid water on its surface, but scientists suspect the planet may harbor small amounts of liquid below its surface.

To see how methanogens fare with a limited water supply, the researchers varied the water content in the Mars soil simulant. They found that the methanogens grew even with a limited water supply.

Kral said researchers can extrapolate research like this to search for life on Mars.

"When you're looking for life there -- what do you look for?" he said. "If you have an idea of what life might look like, you may form better ideas about where to look."

Earth Invades Mars Special Report

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Nov 02, 2006