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Tundra soil carbon is vulnerable to rapid microbial decomposition under climate warming

Washington Post writes: Scientists just found yet another reason to worry about Arctic permafrost - Worries about thawing permafrost, and the carbon emissions it produces as it warms, have become a standard in conversations about climate change — but scientists are quick to point out that there’s a lot they still don’t understand. And one of the biggest questions has to do with some of the tiniest inhabitants of the Arctic.

Microorganisms in the Arctic soil are a critical component of permafrost’s role in the carbon cycle. These little guys munch on organic matter in the ground — the process we know as “decomposition” — and produce carbon byproducts, such as carbon dioxide and methane, that can then escape into the atmosphere.

In general, scientists know that warming causes permafrost to thaw, which results in more active microbes and greater carbon emissions. But how exactly these microbial communities are changing in response to the warming soil has been poorly understood. “We use models to predict how ecosystems will respond to temperature increase or [carbon dioxide] increase,” said Jizhong Zhou, director of the Institute for Environmental Genomics at the University of Oklahoma. “But we have little knowledge about how microbial communities will respond to this.”

Now Zhou and a group of colleagues from universities in both the U.S. and China have published a new study, out today in the journal Nature Climate Change, which attempts to shed some light on the specific ways microbe communities respond to hikes in their soil temperature, and what that might mean for the amount of carbon they produce. It’s an important question given that many experts fear permafrost could become a significant source of carbon feedback in the future. The warmer it gets, the more carbon emissions the thawing permafrost produces, which accelerates atmospheric warming and causes even more thawing in a kind of a vicious cycle.

“We definitively need more knowledge about responses in the microbial community, and especially in the real situation, the field, that is addressed in this study,” said Mette Marianne Svenning, a professor of Arctic and marine biology at the Arctic University of Norway, who was not involved with the new paper.

WP article available here:

Scientific publication (paywall):