03/06/2015

Decomposition by Ectomycorrhizal Fungi Alters Soil Carbon Storage in Simulation Model

Summary

Carbon cycle models often lack explicit belowground organism activity, yet belowground organisms regulate carbon storage and release in soil. Ectomycorrhizal fungi are important players in the carbon cycle because they are a conduit into soil for carbon assimilated by the plant. It is hypothesized that ectomycorrhizal fungi can also be active decomposers when plant carbon allocation to fungi is low. In this study, researchers developed a simulation model of the plant-mycorrhizae interaction where a reduction in plant productivity stimulates ectomycorrhizal fungi to decompose soil organic matter. The model output suggests that ectomycorrhizal activity accounts for a portion of carbon decomposed in soil, but this portion varied with plant productivity and the mycorrhizal carbon uptake strategy simulated. Lower organic matter inputs to soil were largely responsible for reduced soil carbon storage. Using mathematical theory, the researchers demonstrated that biotic interactions affect predictions of ecosystem functions. Specifically, they developed a simple function to model the mycorrhizal switch in function from plant symbiont to decomposer. The study shows that including mycorrhizal fungi with the flexibility of mutualistic and saprotrophic lifestyles alters predictions of ecosystem function.

References

Moore, J. A. M., J. Jiang, W. M. Post, and A. T. Classen. 2015. ā€œDecomposition by Ectomycorrhizal Fungi Alters Soil Carbon Storage in a Simulation Model,ā€ Ecosphere 6(3), 29. DOI:10.1890/ES14-00301.1