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Conservation Science for a Healthy Planet

Diverse soil communities can help offset impacts of global warming

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Earthworm in soil (stock image). “In disturbed environments, where soil animals are not present, the feedback between climate change and microbial carbon production was strong,” said the lead author of the study. “Meanwhile, when the soil community is healthy and diverse, we saw that animals feed on the microorganisms, limiting the feedback effects.”
Credit: © Henrik Larsson / Fotolia

Diverse soil communities can help offset impacts of global warming

Posted: 19 May 2015 10:28 AM PDT

Small soil animals can limit the effects of climate change, a team of researchers has shown through a long-term study. In the same way that Yellowstone’s wolves regulate plant diversity by controlling the number of grazing elk, the researchers found that insects, worms and other small creatures can play a similar regulatory role in soil ecosystems by feeding on the microbes that can trigger increased carbon emissions. In a long-term study, researchers showed that small soil animals can limit the effects of climate change, which would otherwise stimulate the loss of carbon from the soil into the atmosphere. The study provides key new insights into how the interactions between organisms in the soil are likely to be critical for controlling the changes in carbon cycling under current and future climate scenarios.
The results were published in the Proceedings of the National Academy of Sciences. Decomposition of dead plant and animal material by soil microorganisms generates an annual global release of 50 to 75 petagrams of carbon — in the form of carbon dioxide and methane — into the atmosphere (1 petagram equals 1 billion metric tons). This amounts to almost ten times the greenhouse gas production of humans worldwide. Scientists have known for a long time that warming has the potential to accelerate this process, leading to increased carbon emissions that will accelerate climate change through a dangerous feedback cycle. However, until now, little has been known about which ecosystems will be most affected and why. The study — an international collaboration between researchers at the Yale School of Forestry & Environmental Studies (F&ES), the University of Helsinki, the Institute of Microbiology of the ASCR in the Czech Republic, and the University of New Hampshire — was designed to shed light on this issue. “In disturbed environments, where soil animals are not present, the feedback between climate change and microbial carbon production was strong,” said Thomas Crowther, a postdoctoral fellow at Yale F&ES and lead author of the study. “Meanwhile, when the soil community is healthy and diverse, we saw that animals feed on the microorganisms, limiting the feedback effects.”…. Crowther said. “As a result of climate change, there’s going to be more nitrogen deposition, it’s going to be warmer — many of the things that limit fungal growth are going to be alleviated,” he said. “And by stimulating microbial activity it will trigger higher carbon emissions. So when those ‘bottom up’ limitations are gone, the grazing animals become even more important.”… “Our current understanding of carbon cycle feedbacks to climate change stem mostly from the physical sciences; this study shows that precise global predictions can be achieved only if we understand the interactions between organisms,” he said.

 

Thomas W. Crowther, Stephen M. Thomas, Daniel S. Maynard, Petr Baldrian, Kristofer Covey, Serita D. Frey, Linda T. A. van Diepen, Mark A. Bradford. Biotic interactions mediate soil microbial feedbacks to climate change. Proceedings of the National Academy of Sciences, 2015; 201502956 DOI: 10.1073/pnas.1502956112

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