Sarah Knox Kyle B. Delwiche Sheel Bansal William J. Riley Dennis Baldocchi Takashi Hirano Gavin McNicol Karina Schafer Lisamarie Windham-Myers Benjamin Poulter Robert B. Jackson Kuang-Yu Chang Jiquan Chen Housen Chu Ankur R. Desai Sebastien Gogo Hiroki Iwata Minseok Kang Ivan Mammarella Matthias Peichl Oliver Sonnentag Eeva-Stiina Tuittila Youngryel Ryu Eugenie S. Euskirchen Mathias Goeckede Adrien Jacotot Mats B. Nilsson Torsten Sachs Masahito Ueyama 2023 <div class="abstract-group"><div class="article-section__content en main"><p>Wetlands are the largest natural source of methane (CH₄) to the atmosphere. The eddy covariance method provides robust measurements of net ecosystem exchange of CH₄, but interpreting its spatiotemporal variations is challenging due to the co-occurrence of CH₄<span>&nbsp;</span>production, oxidation, and transport dynamics. Here, we estimate these three processes using a data-model fusion approach across 25 wetlands in temperate, boreal, and Arctic regions. Our data-constrained model—iPEACE—reasonably reproduced CH₄<span>&nbsp;</span>emissions at 19 of the 25 sites with normalized root mean square error of 0.59, correlation coefficient of 0.82, and normalized standard deviation of 0.87. Among the three processes, CH₄<span>&nbsp;</span>production appeared to be the most important process, followed by oxidation in explaining inter-site variations in CH₄<span>&nbsp;</span>emissions. Based on a sensitivity analysis, CH₄<span>&nbsp;</span>emissions were generally more sensitive to decreased water table than to increased gross primary productivity or soil temperature. For periods with leaf area index (LAI) of ≥20% of its annual peak, plant-mediated transport appeared to be the major pathway for CH₄<span>&nbsp;</span>transport. Contributions from ebullition and diffusion were relatively high during low LAI (&lt;20%) periods. The lag time between CH₄<span>&nbsp;</span>production and CH₄<span>&nbsp;</span>emissions tended to be short in fen sites (3 ± 2 days) and long in bog sites (13 ± 10 days). Based on a principal component analysis, we found that parameters for CH₄<span>&nbsp;</span>production, plant-mediated transport, and diffusion through water explained 77% of the variance in the parameters across the 19 sites, highlighting the importance of these parameters for predicting wetland CH₄<span>&nbsp;</span>emissions across biomes. These processes and associated parameters for CH₄<span>&nbsp;</span>emissions among and within the wetlands provide useful insights for interpreting observed net CH₄<span>&nbsp;</span>fluxes, estimating sensitivities to biophysical variables, and modeling global CH₄<span>&nbsp;</span>fluxes.</p></div></div> application/pdf 10.1111/gcb.16594 en Wiley Modeled production, oxidation, and transport processes of wetland methane emissions in temperate, boreal, and Arctic regions article