Root fungi key to soil carbon

Ecosystems differ in the type of plant-associated mycorrhizal fungi (root symbionts associated with nearly all land plants) that dominate. Ectomycorrhiza and ericoid mycorrhizal (EEM) fungi produce nitrogen-degrading enzymes, whereas arbuscular mycorrhiza do not, leading to the prediction that plants in the EEM ecosystems will compete with decomposers for soil nitrogen and therefore increase soil carbon storage. These authors assemble a global data set to show that this is indeed the case, with 70% more carbon storage in EEM ecosystems than in ecosystems dominated by arbuscular mycorrhiza, and that mycorrhizal type is more important than other determinants of soil carbon storage levels.