AMHERST, Mass., Jan. 29 (UPI) -- U.S. scientists said deposits of natural gas created by bacteria during the last ice age might lead to technology making natural gas a renewal resource.

Steven Petsch and colleagues at the University of Massachusetts studied natural gas reservoirs in Michigan's Antrim Shale and determined carbon-hungry bacteria trapped in the rock beneath ice sheets produced the gas during the ice age, as glaciers advanced and retreated over Michigan.

"Bacteria digested the carbon in the rocks and made large amounts of natural gas in a relatively short time -- tens of thousands of years instead of millions," said Petsch. "This suggests that it may be possible to seed carbon-rich environments with bacteria to create natural gas reservoirs."

He said his findings help explain high levels of methane in the atmosphere that occurred between ice ages, a trend recorded in ice cores from Greenland and Antarctica. "When the ice sheets retreated, it was like uncapping a soda bottle," said Petsch, a geoscientist.

He said that information can be used in current climate change models to account for the effects of melting glaciers.

The research is reported in the February issue of the journal Geology.