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Author Topic: Permafrost Melt, Perhaps Not As Bad As We Feared...  (Read 2137 times)

Bob Wallace

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Permafrost Melt, Perhaps Not As Bad As We Feared...
« on: May 23, 2013, 05:26:40 AM »
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Researchers have uncovered a mechanism in the Alaskan tundra that doesn't seem to follow the climate change script for soil carbon.

For years, scientists have shown that rising temperatures stimulate microbes that decay plant matter, releasing carbon more quickly into the atmosphere. But when Seeta Sistla, a doctoral student at the University of California, Santa Barbara, came to collect data for a 20-year-old experiment at the U.S. Arctic Long-Term Ecological Research site in northern Alaska, the soil carbon levels at the site were curiously stable.

While climate change is warming the soil and spurring microorganisms to decompose leaves -- which releases carbon into the air -- the growth of more shrubbery in the tundra is soaking up that carbon and redistributing it back into the ground.

....

The researchers collected samples dating back to 1989 from greenhouses at the Arctic Long-Term Ecological Research site, the longest-running whole system tundra warming experiment.

Overall, there was no change in total soil carbon over 20 years. While the surface layer lost some of its carbon, there was a significant increase in the mineral soils more than 2 feet below the surface. These soils typically don't hold a lot of carbon, but the researchers believe warming has encouraged soil nematodes and mites, which help decompose leaves and other plant matter, to make their way to the deeper soils.

"Deeper soil food webs are looking like surface soil food webs," Schimel said.

This redistribution of soil carbon storage raises questions of whether the balance provided by larger plants will stand in the long term or whether the more active microbes detected in the deeper soils will eventually offset the increased carbon in those deeper soils.

http://www.scientificamerican.com/article.cfm?id=thawing-tundra-may-produce-less-co2

Agres

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Re: Permafrost Melt, Perhaps Not As Bad As We Feared...
« Reply #1 on: June 01, 2013, 12:00:46 AM »
Seems not to address themokarst as in:  http://www.lternet.edu/research/keyfindings/critical-permafrost

Recently there have  been several posts of photos with "mud flows" .  Those mud flows likely include permafrost materials.