WASHINGTON, Jan. 15 (UPI) -- Huge methane gas bursts on Mars appear to be caused by bacteria rather than volcanic activity, U.S. government scientists said Thursday.
The researchers at NASA's Goddard Space Flight Center in Greenbelt, Md., did not say what bacteria created the methane, the principal component of natural gas.
But their findings, published in the journal Science, suggest the possibility of present-day microbes living on the fourth planet from the sun, The New York Times reported.
On Earth, bacteria known as methanogens produce methane as a metabolic byproduct, the newspaper said.
These bacteria are common in wetlands, where they are responsible for marsh gas, as well as in hot springs and at hydrothermal vents at the bottoms of oceans.
In most environments, the release of methane is the final step in the decomposition of biomass, scientists say.
The National Aeronautics and Space Administration researchers said it was unlikely the methane came from hot springs or hydrothermal vents because Mars shows no signs of recent volcanism or hot spots.
So they said they're focusing on bacteria as the methane source.
The scientists said mineralogy of Mars's surface indicated the bedrock might be covering gas-rich materials, suggesting biological life may exist underground.
