Microbes 'could survive on Mars'

Not quite the red sands of Mars, but close

By Dr David Whitehouse BBC News Online science editor

Microbes may be able to survive on Mars according to new simulations of the Martian environment.

Researchers used a device called the Andromeda Chamber to simulate Martian conditions. They discovered that microorganisms called methanogens could grow at low pressures.

They say their findings imply that life could have existed on the Red Planet in the past, present, or at some point in the future.

"Our goal is first to get the organisms to grow well, then experiment with conditions found on Mars," Professor Timothy Kral of the University of Arkansas told BBC News Online.

Andromeda Chamber

The Andromeda Chamber

Kral and his team first grew test tube cultures of various methanogens in a Mars soil simulant. Derived from altered volcanic ash, it approximates the composition, grain size, density, and magnetic properties of Martian soil.

The scientists exposed the cultures to an atmosphere that consisted only of hydrogen and carbon dioxide, the raw materials methanogens need to produce energy. They incubated them at each methanogen's optimal growth temperature.

Because methanogens release methane as a waste product the researchers were able to measure their growth by detecting the methane produced.

After successfully growing three different methanogens on Mars soil simulant, they moved on to the next step - simulating various Martian conditions in the Andromeda Chamber, a large stainless steel vacuum container.

The chamber, which was originally constructed for comet simulations, consists of an insulated compartment with heating and cooling elements. A sample container can be lowered into the chamber, which contains various detection and monitoring instruments.

Living microbes

Prof Timothy Kral

The researchers grew methanogenic cultures in bottles and froze them. They then placed them below the surface of the soil simulant in the sample container.

So far, the Andromeda Chamber studies indicate that organisms are living under low pressures. Martian life would have to be able to survive at such pressures, since Mars' atmosphere is much less dense than Earth's.

Professor Kral says his work received a significant boost from the discovery earlier this year of large quantities of frozen water below the surface of Mars.

"With the recent successful missions to Mars and especially the discovery that there is probably a vast ocean of frozen water below the surface, there is a greater possibility that life may exist below the surface today."

Kral doesn't want to rush to conclusions about the implications of his research, but if methanogens can grow well under simulated Martian conditions, it might be possible to take the organisms to Mars if humans ever colonise the planet.

"Of course, there are many potential ethical and environmental problems with this," Kral told BBC News Online.

"Since methane is a greenhouse gas methanogens could be used to raise Mars' surface temperature, eventually "terraforming" the planet so that it could support life."