The Science

The results of this study suggest that carbon expenditures to support nitrogen-acquiring microbial symbionts have critical impacts on Earth’s climate, and carbon–climate models that omit these processes will over-estimate the land carbon sink and under-predict climate change.

The Impact

This work shows the importance of nutrient cycling to climate in Earth system models from a plant-microbe interaction standpoint. This important process had been missing in Earth system models until now—these models are now improved because of this work.

Summary

The carbon spent on supporting symbiotic nitrogen uptake reduced net primary production by 8.1 Pg C yr^-1, with the largest absolute effects occurring at low-latitudes and the largest relative changes occurring at high-latitudes. There are strong regional climate impacts if the carbon spent on supporting symbiotic nitrogen uptake is considered in the Community Atmosphere Model (CAM), with the largest impact occurring in high-latitude ecosystems, where such costs were estimated to increase temperature by 1.0 °C and precipitation by 9 mm yr^-1. Thus, our results suggest that carbon expenditures to support nitrogen-acquiring microbial symbionts have critical consequences for Earth’s climate.

Principal Investigator

Joshua Fisher
University of California, Los Angeles/NASA Jet Propulsion Laboratory
joshbfisher@gmail.com

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, Office of Biological and Environmental Research, Terrestrial Ecosystem Science Program, and National Science Foundation Ecosystem Science.

References