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The climate-driven migration of beavers into the Arctic tundra is releasing more methane, a greenhouse gas, into the atmosphere.
Methane is also emitted when organics-rich permafrost thaws as a result of heat transported by the spreading water. Environmental Research Letters published research associating Arctic beavers to an increase in methane release. Beavers, as we all know, enjoy building dams. These dams create floods, inundating vegetation and turning Arctic streams and creeks into a series of ponds. Beaver ponds and surrounding waterlogged vegetation can be devoid of oxygen and rich in organic debris, which emits methane as it decays. Jason Clark, a former postdoctoral scholar at the University of Alaska Fairbanks Geophysical Institute, is the lead author. Clark's adviser and co-author is Geophysical Institute Research Professor Ken Tape. Benjamin Jones, a research assistant professor at the University of Alaska Institute of Northern Engineering, and researchers from the National Park Service and NASA's Jet Propulsion Laboratory are also co-authors. Tape has conducted substantial research on beaver migration northward and its impact on the Arctic environment. What we found is that there are lots of methane hotspots right next to ponds and they start to diminish as you go away from the pond, he said. The new study is the first to link large numbers of new beaver ponds to methane emissions at the landscape scale. It suggests that beaver engineering in the Arctic will at least initially increase methane release. We say initially because thats the data we have, Tape said. What the longer-term implications are, we dont know. As a greenhouse gas, methane is 25 times more potent than carbon dioxide at trapping heat in Earths atmosphere. It accounts for about 20 per cent of global greenhouse gas emissions, according to the U.S. Environmental Protection Agency. The agency says human activities have more than doubled atmospheric methane concentrations in the past two centuries. The new research focused on 166 square miles of the lower Noatak River basin in Northwest Alaska. Data was obtained by airborne hyperspectral imaging through NASAs Arctic-Boreal Vulnerability Experiment program. That program and the National Science Foundation funded the research. Hyperspectral cameras image an area in hundreds of wavelengths across the electromagnetic spectrum, including many not visible to the human eye. That differs from other cameras, which typically only image in the primary colours of red, green and blue. The researchers compared the location of methane hot spots to the locations of 118 beaver ponds and to a number of nearby unaffected stream reaches and lakes. They analyzed the area up to approximately 200 feet from the perimeter of each water body and found a significantly greater number of methane hot spots around beaver ponds. We have these datasets that largely overlap, in space and mostly in time, Tape said. Its kind of a simple design relying on a new tool. (ANI)
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