Contributors: Osaka Metropolitan University; University of British Columbia Vancouver; Lawrence Berkeley National Laboratory Berkeley (LBNL); Department of Environmental Science, Policy, and Management Berkeley (ESPM); University of California Berkeley (UC Berkeley); University of California (UC)-University of California (UC); US Geological Survey Jamestown; United States Geological Survey Reston (USGS); Prairie and Northern Wildlife Research Centre; Environment and Climate Change Canada (ECCC); Climate and Ecosystem Sciences Division; Research Faculty of Agriculture; Hokkaido University Sapporo, Japan; University of Illinois Chicago (UIC); University of Illinois System; Department of Earth and Environmental Sciences Chicago (EAES); University of Illinois System-University of Illinois System; Rutgers University Newark; Rutgers University System (Rutgers); Department of Earth and Environmental Science Newark; Rutgers University System (Rutgers)-Rutgers University System (Rutgers); US Geological Survey Menlo Park; NASA Goddard Space Flight Center (GSFC); Biospheric Sciences Laboratory; Department of Earth System Science Stanford (ESS); Stanford EARTH; Stanford University-Stanford University; Stanford University; Michigan State University System; University of Wisconsin-Madison; Department of Atmospheric and Oceanic Sciences Madison; Université de Rennes (UR); Ecosystèmes, biodiversité, évolution Rennes (ECOBIO); Université de Rennes (UR)-Institut Ecologie et Environnement - CNRS Ecologie et Environnement (INEE-CNRS); Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR); Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS); Shinshu University Nagano; National Center for Agro-Meteorology; Helsingin yliopisto = Helsingfors universitet = University of Helsinki; Swedish University of Agricultural Sciences = Sveriges lantbruksuniversitet (SLU); Department of Forest Ecology and Management; Université de Montréal (UdeM); University of Eastern Finland; School of Forest Sciences; Seoul National University Seoul (SNU); Department of Landscape Architecture and Rural Systems Engineering; Institute of Arctic Biology; University of Alaska Fairbanks (UAF); Max Planck Institute for Biogeochemistry (MPI-BGC); Max-Planck-Gesellschaft; Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO); Bureau de Recherches Géologiques et Minières (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC); Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris; Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris; Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS); Sol Agro et hydrosystème Spatialisation (SAS); Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut Agro Rennes Angers; Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro); German Research Centre for Geosciences - Helmholtz-Centre Potsdam (GFZ); We acknowledge support from the John Wesley Powell Center for Analysis and Synthesis of the U.S. Geological Survey (USGS)(“Wetland FLUXNET Synthesis for Methane” working group, https://www.usgs.gov/centers/john-wesley-powell-center-for-analysis-and-synthesis/science/wetland-fluxnet-synthesis), the USGS Ecosystem Mission Area, Land Change Science programs and USGS Water Mission Area, Earth System Processes Division. We thank Dr. Eric J Ward for providing useful comments on the manuscript. ESE was supported by the grants from the Arctic Observatory Program of the National Science Foundation (grant numbers 1936752, 1503912, 1107892) and by the US Geological Survey, Research Work Order 224 to the University of Alaska Fairbanks, the Bonanza Creek Long-Term Ecological Research Program funded by the National Science Foundation (NSF DEB-1026415, DEB-1636476) and the NSF Long-Term Research in Environmental Biology Program (NSF LTREB 2011276). MU was supported by the Arctic Challenge for Sustainability II (ArCS II; JPMXD1420318865) and JSPS KAKENHI (20 K21849). AD was supported by US DOE AmeriFlux (7544821). IM was supported by ICOS-Finland (3119871), Academy of Finland project N-PERM and Horizon Europe project GreenFeedBack (101056921). MK was supported by the Rural Development Administration (PJ014892022022). TS was supported by the Helmholtz Association of German Research Centres (VH-NG-821). DE-Zrk is a Terrestrial Environmental Observatories Network (TERENO) site. SB was supported by the U.S. Geological Survey, Ecosystems Mission Area, Land Change Science Program. SG was supported by the SNO Tourbières, CNRS-INSU. OS was supported by the Canada Research Chairs, Canada Foundation for Innovation Leaders Opportunity Fund, and Natural Sciences and Engineering Research Council Discovery Grant Programs. WJR and KYC were supported by the Reducing Uncertainties in Biogeochemical Interactions through Synthesis and Computation (RUBISCO) Scientific Focus Area, Office of Biological and Environmental Research of the U.S. Department of Energy Office of Science. YR was supported by the Ministry of Environment of Korea (2022003640002). Lawrence Berkeley National Laboratory (LBNL) is managed by the University of California for the U.S. Department of Energy under contract DE-AC02-05CH11231, California Department of Water Resources, CA Fish and Wildlife, Delta Stewardship Council and US DOE Ameriflux. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
نبذة مختصرة : International audience ; 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 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 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 production appeared to be the most important process, followed by oxidation in explaining inter-site variations in CH4 emissions. Based on a sensitivity analysis, CH4 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 transport. Contributions from ebullition and diffusion were relatively high during low LAI (<20%) periods. The lag time between CH4 production and CH4 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 production, plant-mediatedtransport, 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 emissions across biomes. These processes and associated parameters for CH4 emissions among and within the wetlands provide useful insights for interpreting observed net CH4 fluxes, estimating sensitivities to biophysical variables, and modeling global CH4 fluxes.
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