By Deborah Zabarenko, Environment Correspondent
Just as some people lose their appetites in warm weather, mushrooms and other fungi that feast on dead vegetation in the soil in dry northern areas like Alaska and Siberia eat less and produce less climate-warming carbon dioxide when the temperature climbs, researchers reported on Monday.
"The temperature is reducing their ability to eat the carbon in the soil," said Steven Allison of the University of California, Irvine. "These are fungi that live up in Alaska, which is typically a pretty cold place, so they may not be adapted to deal with these higher temperatures.
The dry mushrooms' ability to decrease carbon emissions might offset 10 percent of the entire amount of carbon dioxide released by human activities, Allison said.
Because the fungi in the dry northern areas are off their feed, they process less of the greenhouse gas carbon dioxide, leaving more of it locked in the soil and less of it in the atmosphere, Allison and his colleagues wrote in the journal Global Change Biology.
This was not what the scientists expected to find when they started investigating what happens to fungi in dry parts of the Northern Hemisphere, Allison said by telephone.
Mushrooms that grow in cooler, wetter soil produce less carbon dioxide than those in drier regions of the north, including Alaska, Canada, Scandinavia and Siberia, the researchers wrote.
Initially, the scientists theorized that fungi in dry northern areas would produce carbon dioxide faster, fueling global warming, but it did not happen that way, Allison said.
About 30 percent of the world's boreal, or northern, forests are in dry areas and that is where the fungi's impact might be felt. The other 70 percent are in wet places that are going to release more carbon dioxide as the planet warms, Allison said.
Global warming is expected to hit far northern latitudes hardest, raising temperatures between 7 and 12.6 degrees F (5 and 7 degrees C) by the year 2100 by some estimates.