Sep. 15, 2007 Last month, UAF researcher Katey Walter brought a National Public Radio crew to Alaska’s North Slope, hoping to show them examples of what happens when methane is released when permafrost thaws beneath lakes.
When they reached their destination, Walter and the crew found even more than they bargained for: a lake violently boiling with escaping methane.
“It was cold, wet and windy. We were dropped off in the middle of nowhere by a helicopter and paddled out to a huge methane plume in the middle of the lake with no idea what to expect, how strong the bubbling plume would be, whether or not our raft would stay afloat, how dangerous it would be to breath the gas,” said Walter, an assistant professor in UAF’s Institute of Northern Engineering and International Arctic Research Center. “The violent streams of bubbles made the lake appear as if it were boiling, but the water was pretty cold."
Walter studies methane emissions from arctic lakes, especially the connection between thawing permafrost and climate change. As permafrost around a lake’s edges thaws, the organic material in it--dead plants and animals--can enter the lake bottom, where bacteria convert it to methane, which bubbles into the atmosphere, sometimes in a spectacular fashion. Methane is much more potent greenhouse gas than carbon dioxide.
Walter said this summer’s fieldwork indicates that methane hotspots, such as the one she and the crew experienced, can come from various sources, not just thawing permafrost. Her next goal is to identify and quantify the sources of the methane hotspots around Alaska.
“It is unlikely that this methane plume was related to permafrost thaw,” said Walter, adding that the methane boiling out of the lake was more likely related to natural gas seepage. “Should large quantities of methane be released from methane hydrates, for instance, in association with permafrost thaw, then we could have large sudden increases in atmospheric methane with potentially large affects on global temperatures.”
Walter’s project is one of many at UAF happening as part of the International Polar Year, an international event that will focus research efforts and public attention on the Earth’s polar regions.
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