Earthworms Trap Carbon, But Do They Influence Climate Change?

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http://www.livescience.com/40891-earthworms-trap-carbon-but-do-they-influence-climate-change.html

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(ISNS) -- Earthworms have long been the organic gardener's friend. They aerate soil as they burrow into the earth and release nutrients as soil passes through their digestive systems. In their tubular, segmented bodies, nutrients are transformed into a form that plants can consume. Their influence on the environment has interested scientists since Charles Darwin.

So it came as a shock earlier this year when researchers reported in Nature Climate Change that earthworms contribute to greenhouse gas emissions. They claim that, as the earthworms go about their soil-transforming business, they release carbon dioxide that was trapped in the soil. Overall, the researchers determined that earthworms' burrowing causes a 33 percent increase in carbon dioxide emissions, and a 42 percent increase in the emissions of another greenhouse gas, nitrous oxide.

Jan Willem van Groenigen of Wageningen University, in the Netherlands, and lead author on the Nature Climate Change article, doesn't advocate exterminating earthworms. “You cannot say earthworms are good or bad. They’re almost indispensible for farming systems, but they also have the side effect of increasing the emissions of greenhouse gases.”

But researchers in an international collaboration from the Chinese Academy of Sciences, the University of Georgia, Nanchang Institute of Technology, the University of Vermont, and the Guangdong Academy of Sciences have reached another conclusion. Their results, published in Nature Communications, suggest that earthworms actually trap carbon dioxide in soil for an overall decrease in emissions.