July 2014

From Microbes to Global Carbon Models

Understanding microbial community processes improves predictions of soil carbon dynamics.

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Image courtesy of reprinted by permission from Macmillan Publishers Ltd. from Wieder, Bonan, and Allison. “Global soil carbon projections are improved by modelling microbial processes,” Nature Clim. Change 3, 909–912. © 2013External link.

The Community Land Model explicitly simulates microbial-driven soil carbon cycling in aboveground, surface, and subsurface soil horizons. Ovals represent pools for litter (Lit), microbial biomass (Mic), and soil organic carbon (SOC). Fluxes between pools are shown with arrows.

The Science

Society relies on Earth system models (ESMs) to project future climate and carbon cycle feedbacks. However, the soil carbon response to climate change is highly uncertain in these models, which omit key biogeochemical mechanisms. Specifically, the traditional approach in ESMs lacks direct microbial control over soil carbon dynamics.

The Impact

Developing improved models of microbial processes will generate more accurate projections of soil carbon feedbacks on climate change and reduce a source of uncertainty in current ESMs.


ESMs draw on soil carbon cycle models that use relatively simple representations of the biogeochemical processes performed by microbial communities. Now, investigators at the University of California–Irvine have developed a new module for the Community Land Model that attempts to more accurately represent the distribution of soil microbial communities and their functional processes related to carbon degradation. Projections of climate change impacts on soil carbon stocks using this module showed improved agreement with results observed during experimental studies.


William R. Wieder
National Center for Atmospheric Research, Boulder, Colorado 80307


The National Center for Atmospheric Research is sponsored by the National Science Foundation (NSF). This work was supported by NSF grant AGS-1020767, the NSF Advancing Theory in Biology Program, and the Office of Biological and Environmental Research within the U.S. Department of Energy’s Office of Science.


Wieder, W. R., G. B. Bonan, and S. D. Allison. “Global soil carbon projections are improved by modelling microbial processes,” Nature Clim. Change 3, 909–912 (2013). [DOI: 10.1038/NCLIMATE1951].

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Last modified: 8/1/2014 1:20:01 PM