An Integrative Model for Soil Biogeochemistry and Methane Processes: I. Model Structure and Sensitivity Analysis

Authors

Daniel M. Ricciuto, Oak Ridge National Laboratory
Xiaofeng Xu, San Diego State University
Xiaoying Shi, Oak Ridge National Laboratory
Yihui Wang, San Diego State University
Xia Song, San Diego State University
Christopher W. Schadt, Oak Ridge National Laboratory
Natalie A. Griffiths, Oak Ridge National Laboratory
Jiafu Mao, Oak Ridge National Laboratory
Jeffrey M. Warren, Oak Ridge National Laboratory
Peter E. Thornton, Oak Ridge National Laboratory
Jeff Chanton, Florida State University
Jason K. Keller, Chapman UniversityFollow
Scott D. Bridgham, University of Oregon
Jessica Gutknecht, University of Minnesota
Stephen D. Sebestyen, USDA Forest Service Northern Research Station
Adrien Finzi, Boston University
Randall Kolka, USDA Forest Service Northern Research Station
Paul J. Hanson, Oak Ridge National Laboratory

Document Type

Article

Publication Date

7-13-2021

Abstract

Environmental changes are anticipated to generate substantial impacts on carbon cycling in peatlands, affecting terrestrial-climate feedbacks. Understanding how peatland methane (CH₄) fluxes respond to these changing environments is critical for predicting the magnitude of feedbacks from peatlands to global climate change. To improve predictions of CH₄ fluxes in response to changes such as elevated atmospheric CO₂ concentrations and warming, it is essential for Earth system models to include increased realism to simulate CH₄ processes in a more mechanistic way. To address this need, we incorporated a new microbial-functional group-based CH₄ module into the Energy Exascale Earth System land model (ELM) and tested it with multiple observational data sets at an ombrotrophic peatland bog in northern Minnesota. The model is able to simulate observed land surface CH₄ fluxes and fundamental mechanisms contributing to these throughout the soil profile. The model reproduced the observed vertical distributions of dissolved organic carbon and acetate concentrations. The seasonality of acetoclastic and hydrogenotrophic methanogenesis—two key processes for CH₄ production—and CH₄ concentration along the soil profile were accurately simulated. Meanwhile, the model estimated that plant-mediated transport, diffusion, and ebullition contributed to ∼23.5%, 15.0%, and 61.5% of CH₄ transport, respectively. A parameter sensitivity analysis showed that CH₄ substrate and CH₄ production were the most critical mechanisms regulating temporal patterns of surface CH₄ fluxes both under ambient conditions and warming treatments. This knowledge will be used to improve Earth system model predictions of these high-carbon ecosystems from plot to regional scales.

Comments

This article was originally published in Journal of Geophysical Research: Biogeosciences, volume 126, in 2021. https://doi.org/10.1029/2019JG005468

Recommended Citation

Ricciuto, D. M., Xu, X., Shi, X., Wang, Y., Song, X., Schadt, C. W., et al. (2021). An integrative model for soil biogeochemistry and methane processes: I. Model structure and sensitivity analysis. Journal of Geophysical Research: Biogeosciences, 126, e2019JG005468. https://doi.org/10.1029/2019JG005468

Copyright

The authors

Creative Commons License

This work is licensed under a Creative Commons Attribution-Noncommercial 4.0 License