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Microbes as the unknown variable in thawing permafrost

Permafrost covers a quarter of the Earth’s land surface and stores significant amounts of carbon. As global temperatures rise and cause the frozen soils to thaw, so have concerns on the fate of the stored carbon and on the global climate. One of the recent studies that looked at this question was conducted by researchers at the DOE JGI, Berkeley Lab and the U.S. Geological Survey under the aegis of the DOE’s Next-Generation Ecosystem Experiments (NGEE) project to develop better climate model simulations. The work focused on the response of the microbial communities that reside in the permafrost.

Potential field test site for the Next-Generation Ecosystem Experiments (NGEE) project located some 80 miles from Nome, Alaska. (Image by Roy Kaltschmidt, Berkeley Lab)

Potential field test site for the Next-Generation Ecosystem Experiments (NGEE) project
located some 80 miles from Nome, Alaska. (Image by Roy Kaltschmidt, Berkeley Lab)


A commentary in the April 2012 issue of The ISME Journal reinforces the importance of understanding what microbes might do if the stored carbon in the permafrost becomes accessible. If the carbon is difficult to degrade, they say, then it might slowly be released as greenhouse gases (GHG) and serve as a sparse nutrient source for microbes. On the other hand, if the plant material stored in the permafrost is easy to break down, it might be easily metabolized by the microbes.
 
“Eventually, microbial activities will dictate whether permafrost environments will be a net source or sink of GHG in the coming decades and whether large-scale feedbacks to regional and global climate will develop because of increased CO2, N2O and CH4emissions and vegetation changes in the Arctic,” the researchers wrote. “The new ‘omics’ techniques of metagenomics, metatranscriptomics, metaproteomics and metabolomics are developing at an opportune time to provide process-level insights to microbial communities’ responses to rapidly changing environments..”