Root fungi affect rate of climate change

Plants currently take up 25–30% of the CO₂ we emit, but the question is whether they will be able to continue to do so as CO₂ levels rise. Intriguingly, the answer to this might lie not in the plants themselves but in the type of fungi which grow among their roots.

César Terrer, a par ticipant of the IIASA Young Scientists Summer Program (YSSP), and colleagues found that they can predict how much CO₂ plants will use for growth through two variables— nitrogen availability and the kind of root fungi associated with the plant, known as mycorrhizae. The impact of the type of mycorrhizae has never before been tested on a large scale. “I think it’s fascinating that such tiny organisms play such a big role at a global scale on something as important as the terrestrial capacity of CO₂ uptake,” says Terrer.

Previously it was not clear whether climate change predictions overestimated how much rising levels of CO₂ would increase plant growth, because the models used did not consider nitrogen limitation. In his study, recently published in Science, Terrer discovered that certain plants are able to grow faster under both elevated CO₂ and nitrogen limitation, if they have the right fungi living among their roots. “Particular soils might have a lot of nitrogen, but the amount available for plants to absorb might be low. Some types of fungi are much more efficient in accessing nitrogen, and as they are associated with roots they allow plants to overcome these limitations,” he says.

At IIASA, Terrer collaborated with researchers from the Ecosystems Services and Management and Evolution and Ecology programs to upscale and quantify how much CO₂ plants will take up in the future. “We need to quantify mycorrhizal distribution and nitrogen availability on a global scale to predict the capacity of plants to absorb CO₂.”

Text by Anneke Brand

Last edited: 24 August 2017