Soil Dwellers' DNA May Change as Planet Warms

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Even the ground beneath our feet may be changing as the climate warms. Communities of tiny, soil-dwelling lifeforms, or microbes, changed after above-ground temperatures were artificially raised for 10 years, in a recently completed experiment in Oklahoma.

“In models of climate change it is a black box (for) what happens to the carbon in soil,” said study co-author Kostas Konstantinidis of Georgia Tech in a press release.

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Some scientists speculate that increasing carbon dioxide and air temperatures could fuel faster plant growth. The increase in plants could help suck carbon dioxide out of the air and reduce a major cause of climate change.

Plants use carbon to form cellulose, a structural material needed for strength and support. The carbon becomes trapped in the plants and subsequently escapes slowly as the plants die and decay.

However, the results of this new study suggest that soil microbes may pick up their pace as well and break down plant residues more quickly. This could result in the carbon being released from the decaying plants more quickly than it does now.

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In the warmed soil, microbes’ genetic makeup changed to increase the ability to break down cellulose by 13 percent. Genes related to the microbes’ production of carbon dioxide increased by 10 percent, while metabolic pathways used in dealing with nitrogen increased by 12 percent.

These adaptations may have resulted from an increase in plant growth. During the decade of warmth, plants grew faster and taller in the warmed soil compared to plants in nearby unaltered plots. The tiny soil organisms may have rapidly evolved to take advantage of the abundance of cellulose from the vigorous plants’ roots and other residues.

For 10 years in the experiment, radiators heated the air above the soil by 2 degrees Celsius. Konstantinidis and his team used genetic analysis of soil samples to determine the makeup of the microbe community, which contained thousands of different species. The research was published in Applied and Environmental Microbiology.

Photos: ThomasVogel/Getty Images (top), Mengting Yuan, University of Oklahoma, (above)

 

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