Their results were surprising. Turetsky and her colleagues studied areas affected by permafrost degradation across a large region of Canada. They initially expected to find that the melting ice would
( trigger a release of greenhouse gases to the atmosphere, as previously frozen plant and animal remains became susceptible to decay.
This could serve as a positive feedback to climate change, where typically warming causes changes that release more greenhouse gases, which in turn causes more warming, and more emissions, and so on, she said.
But what the researchers actually found is not such a clear-cut climate story.
Permafrost collapse in peatlands tends to result in the slumping of the soil surface and flooding, followed by a complete change in vegetation, soil structure, and many other important aspects of these ecosystems, Turetsky said. The study showed that vegetation responds to the flooding with a boost in productivity. More vegetation sequesters more carbon away from the atmosphere in plant biomass.
This is actually good news from a greenhouse gas perspective, Turetsky said.
However, the report also cautions that this flooding associated with collapsing permafrost also increases methane emissions. Methane is an important greenhouse gas, which is more powerful than carbon dioxide in its ability to trap heat in the earths atmosphere.
Turetsky said it seems the permafrost degradation initially causes increased soil carbon sequestration, rather than the large releases of carbon to the atmosphere originally pred
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Contact: Sue Nichols
nichols@msu.edu
517-353-8942
Michigan State University
9-Aug-2007