Billions of Tons of Methane Lurk Beneath Antarctic Ice

LiveScience.com on Yahoo ^ | 8/29/12 | Tia Ghose, LiveScience

[NormsRevenge]

Microbes possibly feeding on the remains of an ancient forest may be generating billions of tons of methane deep beneath Antarctic ice, a new study suggests.

The amount of this greenhouse gas — which would exist in the form of a frozen latticelike substance called methane hydrate — lurking beneath the ice sheet rivals that stored in the world's oceans, the researchers said.

If the ice sheet collapses, the greenhouse gas could be released into the atmosphere and dramatically worsen global warming, researchers warn in a study published in the Aug. 30 issue of the journal Nature.

"There could be tons of methane hydrate beneath the Antarctic ice sheet," said study researcher Jemma Wadham of the University of Bristol’s School of Geographical Sciences. "If you start to thin that ice cover, that hydrate starts to become unstable and turns into gas, and that gas can go into the atmosphere."[Earth in the Balance: 7 Crucial Tipping Points]

Microbes produce methane

Microbes that thrive in extreme environments often create methane as a byproduct of their metabolism; the breakdown of organic carbon under no-oxygen conditions creates methane.

"It's a way of microbes getting energy under really, really oxygen-deprived conditions," Wadham told LiveScience.

The team suspected that icy, silt-laden sediments trapped beneath the continental glacier could house such extremophiles. That’s because the sediments, possible relics of an ancient Antarctic forest and ocean, could provide a carbon-rich food source for methane producers. But drilling up to 2 miles (3.2 kilometers) through the ice to find out was extremely expensive and difficult.

Instead, Wadham and her colleagues sawed chunks of sediment from the fringes of an Antarctic glacier, where the ice was much thinner. They melted the ice and identified the methane-producing microbes living in the sediment.

[garjog]

Yes, much more scary things are buried in the ice.