September 26, 2017

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A Parsimonious Modular Approach to Building a Mechanistic Belowground Carbon and Nitrogen Model

New microbial model explains observed relationship between heterotrophic respiration and temperature.

The Science

This study developed a new model of microbial soil decomposition that successfully captured the changing relationship between temperature and microbial respiration during the growing season. The scientists showed that the soil microbial response to plant inputs depends on the nitrogen content of the added plant material.

The Impact

The team developed a new model for predicting soil response to changes in soil temperature, moisture, plant inputs, and stoichiometry. This model is simple and based on well-defined physical and biological properties and could be developed to model microbial activity at larger scales.

Summary

Microorganisms that grow in the soil, like bacteria and fungi, affect how much carbon resides in the soil and how much is released to the atmosphere as carbon dioxide (CO2). Mathematical models used to make climate change predictions often struggle to capture the activity of soil microbes in realistic ways. This study uses well-established descriptions of water and temperature effects on soil microbes to predict rate of carbon and nitrogen cycling in the soil. The new model (called the Dual Arrhenius Michaelis-Menten–Microbial Carbon and Nitrogen Physiology, or DAMM-MCNiP), reproduces the changing relationship between temperature and microbial respiration during the growing season. The study also shows using a theoretical addition of root secretions that the microbial response depends on the nitrogen content of the added plant material. This model is simple and based on well defined physical and biological properties and could be developed to model microbial activity at larger scales.

Principal Investigator

Adrien Finzi
Boston University
afinzi@bu.edu

Program Manager

Daniel Stover
U.S. Department of Energy, Biological and Environmental Research (SC-33)
Environmental System Science
daniel.stover@science.doe.gov

Funding

U.S. Department of Energy, grants DE-SC0006916, DE-SC0012288, and DE-AC02-05CH11231; National Science Foundation (DEB 1237491); U.S. Department of Agriculture grant 2014-67003-22073; and  American Association of University Women Doctoral Dissertation Fellowship.

References

Abramoff, R. Z., E. A. Davidson, and A. C. Finzi. "A parsimonious modular approach to building a mechanistic belowground carbon and nitrogen model". JGR Biogeosciences 122 (9), 2418–2434  (2017). https://doi.org/10.1002/2017JG003796.