Diverse Soil Communites May Offset the Impacts of Global Warming

It turns out that soil may help offset the impacts of global warming. Scientists have discovered that healthy and diverse soil communities may limit the effects of climate change.

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 or methane into the atmosphere. This amounts to about ten times the greenhouse gas production of humans worldwide. Warming has the potential to accelerate this process, which is why researchers decided to take a closer look at soil.

In this latest study, scientists manipulated soil communities to establish four levels of community complexity. This allowed them to see which types of community would be most affected by global change factors, such as warming temperatures.

"In disturbed environments, where soil animals are not present, the feedback between climate change and microbial carbon production was strong," said Thomas Crowther, one of the researchers, in a news release. "Meanwhile when the soil community is healthy and diverse, we saw that animals feed on the microorganisms, limiting the feedback effects."

The researchers actually found that small animals, such as insects and worms, can play a similar regulatory role in soil ecosystems by feeding on microbes that can trigger increased carbon emissions. This top-down control, though, only matters when there are no limitations to the production of nutrients at the bottom of the food web, such as those conditions that would occur as a result of climate change.

"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," said Crowther. "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."

The findings are published in the journal Proceedings of the National Academy of Sciences.

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