Hydrological Feedbacks on Peatland CH4 Emission Under Warming and Elevated CO2: A Modeling Study

Authors

Fenghui Yuan, San Diego State University
Yihui Wang, San Diego State University
Daniel M. Ricciuto, Oak Ridge National Laboratory
Xiaoying Shi, Oak Ridge National Laboratory
Fengming Yuan, Oak Ridge National Laboratory
Thomas Brehme, San Diego State University
Scott Bridgham, University of Oregon
Jason Keller, Chapman UniversityFollow
Jeffrey M. Warren, Oak Ridge National Laboratory
Natalie A. Griffiths, Oak Ridge National Laboratory
Stephen D. Sebestyen, USDA Forest Service Northern Research Station
Paul J. Hanson, Oak Ridge National Laboratory
Peter E. Thornton, Oak Ridge National Laboratory
Xiaofeng Xu, San Diego State University

Document Type

Article

Publication Date

11-3-2021

Abstract

Peatland carbon cycling is critical for the land–atmosphere exchange of greenhouse gases, particularly under changing environments. Warming and elevated atmospheric carbon dioxide (eCO₂) concentrations directly enhance peatland methane (CH₄) emission, and indirectly affect CH₄ processes by altering hydrological conditions. An ecosystem model ELM-SPRUCE, the land model of the E3SM model, was used to understand the hydrological feedback mechanisms on CH₄ emission in a temperate peatland under a warming gradient and eCO₂ treatments. We found that the water table level was a critical regulator of hydrological feedbacks that affect peatland CH₄ dynamics; the simulated water table levels dropped as warming intensified but slightly increased under eCO₂. Evaporation and vegetation transpiration determined the water table level in peatland ecosystems. Although warming significantly stimulated CH₄ emission, the hydrological feedbacks leading to a reduced water table mitigated the stimulating effects of warming on CH₄ emission. The hydrological feedback for eCO₂ effects was weak. The comparison between modeled results with data from a field experiment and a global synthesis of observations supports the model simulation of hydrological feedbacks in projecting CH₄ flux under warming and eCO₂. The ELM-SPRUCE model showed relatively small parameter-induced uncertainties on hydrological variables and their impacts on CH₄ fluxes. A sensitivity analysis confirmed a strong hydrological feedback in the first three years and the feedback diminished after four years of warming. Hydrology-moderated warming impacts on CH₄ cycling suggest that the indirect effect of warming on hydrological feedbacks is fundamental for accurately projecting peatland CH₄ flux under climate warming.

Comments

This article was originally published in Journal of Hydrology, volume 603 section D, in 2021. https://doi.org/10.1016/j.jhydrol.2021.127137

Recommended Citation

Yuan, F., Wang, Y., Ricciuto, D.M., Shi, X., Yuan, F., Brehme, T., Bridgham, S., Keller, J., Warren, J.M., Griffiths, N.A., Sebestyen, S.D., Hanson, P.J., Thornton, P.E., Xu, X., 2021. Hydrological Feedbacks on Peatland CH4 Emission Under Warming and Elevated CO2: A Modeling Study. J. Hydrol. 603(D) https://doi.org/10.1016/j.jhydrol.2021.127137

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This work is licensed under a Creative Commons Attribution 4.0 License.