When soil in these forests is warmed, fungi that feed on dead plant material dry out and produce significantly less climate-warming carbon dioxide than fungi in cooler, wetter soil.
This came as a surprise to scientists, who expected warmer soil to emit larger amounts of carbon dioxide because extreme cold is believed to slow down the process by which fungi convert soil carbon into carbon dioxide.
Knowing how forests cycle carbon is crucial to accurately predicting global climate warming, which in turn guides public policy to curb greenhouse gas emissions. This is especially important in northern forests, which contain an estimated 30 percent of the Earth’s soil carbon, equivalent to the amount of atmospheric carbon.
“We don’t get a vicious cycle of warming in dry, boreal forests. Instead, we get the reverse, where warming actually prevents further warming from occurring,” said Steven Allison, ecology and evolutionary biology assistant professor and lead author of the study. “The Earth’s natural processes could give us some time to implement responsible policies to counteract warming globally.”
This study appears online Nov. 3 in the journal Global Change Biology.
Soils in the far north contain a lot of carbon from dead grasses, trees and shrubs. Like humans, fungi and bacteria in soil use plant carbon as a food source and convert it into carbon dioxide.
Allison and his colleague, Kathleen Treseder, sought to find out what happens to carbon dioxide levels when boreal forest soil not containing permafrost is warmed. About one-third of the world’s boreal forests do not contain permafrost, which is mostly located in Alaska, Canada, Western Siberia and Northern Europe.
Global warming is expected to hit northern latitudes hardest, raising temperatures between 5 and 7 degrees Celsius by the year 2100.
The scientists conducted their experiment in a spruce forest near Fairbanks, Alaska. They built small greenhouses and identified similar unheated plots nearby to serve as controls. Both plots received equal amounts of water.
In mid-May when growing season began, air and soil temperatures were the same in greenhouses and control plots. When greenhouses were closed, air temperature rose about 5 degrees Celsius, and soil temperature rose about 1 degree.
The scientists took measurements in the greenhouses and unheated plots and found that by growing season’s end in mid-August, soil in warmed greenhouses produced about half as much carbon dioxide as soil in cooler control plots.
A soil analysis found that about half as much active fungi were present in experimental greenhouse samples compared with samples from the controls. When fungi dry out, they either die or become inactive and stop producing carbon dioxide, the scientists said.
“It’s fortuitous for humans that the fungi are negatively affected by this warming,” said Treseder, ecology and evolutionary biology associate professor. “It’s not so great for the fungi, but might help offset a little bit of the carbon dioxide we are putting directly into the atmosphere by burning fossil fuels.”
This work was supported by the National Science Foundation, the U.S. Department of Energy, and a NOAA Climate and Global Change Postdoctoral Fellowship.
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University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
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Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
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Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
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