A study of experimentally warmed Alaskan soil suggests rising tundra temperatures in northern latitudes could cause microbial communities to produce more of the greenhouse gases methane and carbon dioxide.
Researchers with the Georgia Institute of Technology said they saw that microbial communities respond quite rapidly, within four or five years, to even modest levels of warming, with the microbial species and their genes involved in carbon dioxide and methane release increased their abundance in response to warming treatment.
About half of Earth’s total underground carbon is stored in soils of these northern latitudes. That’s more than twice the amount of carbon currently found in the atmosphere as carbon dioxide, but until now most of that carbon has been locked up in very cold soil.
The university study, which relied on metagenomics to analyze these changes, could heighten concerns about how the release of this carbon may exacerbate climate change. Metagenomics is the study of genetic material recovered directly from environmental samples.
The study, supported by the U.S. Department of Energy and the National Foundation, was reported on July 8 in the early edition of the journal Proceedings of the National Academy of Sciences. Researchers from the University of Oklahoma, Michigan State University and Northern Arizona University collaborated with Georgia Tech on the study.
Their work underscores the importance of accurately representing the role of soil microbes in climate models.
Research began in September 2008 at a moist, acidic tundra area in the interior of Alaska near Denali National Park. Six experimental blocks were created, and in each block, two snow fences were constructed about five meters apart in the winter to control snow cover. Thicker snow cover in winter served as an insulator, creating slightly elevated temperatures of about 1.1 degrees Celsius (2 degrees Fahrenheit) in the experimental plots.
The study highlights the importance of microbial communities in contributing atmospheric methane and carbon dioxide to climate change, said Kostas Konstantinidis, a Georgia Tech professor and one of the study’s senior authors.
