Peichl, Matthias
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
Abstract
Northern peatlands are key carbon reservoirs and natural sources of methane (CH4). However, the environmental controls of CH4-related processes remain unclear, making modeling the emissions a challenge. In this study, we first evaluated the process-based CoupModel with unique long-term (2001-2023) in situ measurements from a pristine sedge-dominated peatland in northern Sweden. Results show that the calibrated model can reproduce the hourly CH4 fluxes (r2 = 0.63) and CO2 flux, and the abiotic variations well. The CH4 flux showed significant sensitivity (66% relative importance) to parameters related to CH4 transport, followed by production and oxidation. We further showed that CH4 fluxes respond to temperature and water table depth (WTD) with a seasonal hysteresis, suggesting a 35% higher temperature sensitivity during below-average WTD compared to above-average WTD, and a two times higher sensitivity of CH4 to lowering WTD than to elevating WTD. The hourly growing-season CH4 fluxes response to temperature also displayed a hysteresis in the diurnal cycle, with nighttime CH4 fluxes being 14%-23% higher than the daytime fluxes. We presented a CH4 budget for the site and estimated the annual mean methane emissions from 2014 to 2023 to be 12.2 +/- 1.2 gC/m2/yr, identifying the emissions predominantly contributed by diffusion. We conclude that CoupModel can effectively simulate the CH4 emission and its controls for the northern pristine peatland. Our study reveals the importance of hysteresis in the response of methane fluxes to environmental changes and highlights the need for considering the temporal and hydrologic variability in CH4-temperature dependencies in peatland management.
Keywords
northern peatland; coupmodel; methane fluxes; water table; hysteresis
Published in
Global Biogeochemical Cycles
2025, volume: 39, number: 8, article number: e2025GB008518
Publisher: AMER GEOPHYSICAL UNION
SLU Authors
Noumonvi, Koffi Dodji
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
Ratcliffe, Joshua
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
Nilsson, Mats
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
UKÄ Subject classification
Physical Geography
Environmental Sciences
Publication identifier
- DOI: https://doi.org/10.1029/2025GB008518
Permanent link to this page (URI)
https://res.slu.se/id/publ/143389