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

Daniel M. Ricciuto, Xiaofeng Xu, Xiaoying Shi, Yihui Wang, Xia Song, Christopher W. Schadt, Natalie A. Griffiths, Jiafu Mao, Jeffrey M. Warren, Peter E. Thornton, Jeff Chanton, Jason K. Keller, Scott D. Bridgham, Jessica Gutknecht, Stephen D. Sebestyen, Adrien Finzi, Randall Kolka, Paul J. Hanson

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

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.

Original languageEnglish (US)
Article numbere2019JG005468
JournalJournal of Geophysical Research: Biogeosciences
Volume126
Issue number8
DOIs
StatePublished - Aug 1 2021

Bibliographical note

Funding Information:
This material is based upon work supported by the US Department of Energy, Office of Science, Office of Biological and Environmental Research. Oak Ridge National Laboratory is managed by UT-Battelle, LLC, for the US Department of Energy under contract DE-AC05-00OR22725. The views expressed in this article do not necessarily represent the views of the US Department of Energy or the United States Government. The authors would like to thank Randall K. Kolka, USDA Forest Service, Northern Research Station for working in collaboration with the Oak Ridge National Laboratory to enable access to and use of the S1-Bog of the Marcell Experimental Forest for the SPRUCE experiment and affiliated studies. This research used resources of the Compute and Data Environment for Science (CADES) at the Oak Ridge National Laboratory, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC05-00OR22725.

Funding Information:
This material is based upon work supported by the US Department of Energy, Office of Science, Office of Biological and Environmental Research. Oak Ridge National Laboratory is managed by UT‐Battelle, LLC, for the US Department of Energy under contract DE‐AC05‐00OR22725. The views expressed in this article do not necessarily represent the views of the US Department of Energy or the United States Government. The authors would like to thank Randall K. Kolka, USDA Forest Service, Northern Research Station for working in collaboration with the Oak Ridge National Laboratory to enable access to and use of the S1‐Bog of the Marcell Experimental Forest for the SPRUCE experiment and affiliated studies. This research used resources of the Compute and Data Environment for Science (CADES) at the Oak Ridge National Laboratory, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE‐AC05‐00OR22725.

Publisher Copyright:
© 2021. The Authors.

Keywords

  • CH
  • elevated CO
  • model
  • peatland
  • warming

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