Compounded effects on wetland greenhouse gas fluxes from climate change and water management along a saline to freshwater gradient
Abstract
Saline and freshwater wetlands store large amounts of carbon, which has driven interest in their role as nature-based climate solutions. Because these ecosystems can be both sinks and sources of carbon to the atmosphere as environmental conditions and human influence change, the net climate mitigation potential of wetlands at regional to global scales remains uncertain. We used a data-driven approach to measure ground-based and airborne fluxes to upscale carbon dioxide (CO 2 ) and methane (CH 4 ) fluxes using satellite-based surface reflectances at 500-m resolution across a gradient of saline to freshwater wetlands in Southern Florida, USA. Daily time series of CO 2 and CH 4 fluxes from 2000 to 2024 integrated surface properties related to vegetation productivity, flooding, and disturbance, and captured 80% and 91% of the variability in annual fluxes of CO 2 and CH 4 , respectively. Long-term (23-y) patterns in the fluxes of CH 4 , CO 2 , and their CO 2 -equivalent (CO 2 eq) are represented as Global Warming Potential 100 (GWP100) and were shown to vary spatially with wetland management, revealing higher carbon uptake in mangroves susceptible to hurricane damage and coastal hydrology, and greater carbon emissions in freshwater sawgrass marshes where freshwater hydrology is managed for restoration. Regional net annual CO 2 eq uptake in coastal and freshwater wetlands increased by 18% from −7.0 ± 3.3 MMT CO 2 eq y −1 in ~2003 to −8.4 ± 3.8 MMT CO 2 eq y −1 in ~2020 at an uptake rate of −0.06 ± 0.01 MMT CO 2 eq y −2 . Annually, roughly 43% of CO 2 uptake was offset by CH 4 emissions from all wetlands in the region (from 16% in mangroves to 82% in freshwater marshes).
Article Details
Journal Info
Proceedings of the National Academy of Sciences
National Academy of Sciences
Authors (31)
Cheryl L. Doughty
Earth System Science Interdisciplinary Center, University of Maryland
Qing Ying
Earth System Science Interdisciplinary Center, University of Maryland
Eric Ward
Earth System Science Interdisciplinary Center, University of Maryland
Erin Delaria
Earth System Science Interdisciplinary Center, University of Maryland
Glenn M. Wolfe
Atmospheric Chemistry and Dynamics Laboratory, National Aeronautics and Space Administration Goddard Space Flight Center
Sparkle L. Malone
Yale School of the Environment, Yale University
David E. Reed
Yale School of the Environment, Yale University
Tiffany Troxler
Institute of Environment, Florida International University
John S. Kominoski
Institute of Environment, Florida International University
Edward Castañeda-Moya
Institute of Environment, Florida International University
W. Barclay Shoemaker
United States Geological Survey Caribbean-Florida Water Science Center
David Yannick
Department of Biological Sciences, University of Alabama
Gregory Starr
Department of Biological Sciences, University of Alabama
Steven F. Oberbauer
Institute of Environment, Florida International University
Abigail Barenblitt
Earth System Science Interdisciplinary Center, University of Maryland
Anthony Campbell
Biospheric Sciences Laboratory, National Aeronautics and Space Administration Goddard Space Flight Center
Sean Charles
Integrated Coastal Program, East Carolina University
Lola Fatoyinbo
Biospheric Sciences Laboratory, National Aeronautics and Space Administration Goddard Space Flight Center
Jonathan Gewirtzman
Thomas Hanisco
Atmospheric Chemistry and Dynamics Laboratory, National Aeronautics and Space Administration Goddard Space Flight Center
Reem Hannun
Atmospheric Science Branch, National Aeronautics and Space Administration Ames Research Center
Stephan Kawa
Atmospheric Chemistry and Dynamics Laboratory, National Aeronautics and Space Administration Goddard Space Flight Center
David Lagomasino
Integrated Coastal Program, East Carolina University
Leslie Lait
Atmospheric Chemistry and Dynamics Laboratory, National Aeronautics and Space Administration Goddard Space Flight Center
Ayia Lindquist
Biospheric Sciences Laboratory, National Aeronautics and Space Administration Goddard Space Flight Center
Paul Newman
Earth Sciences Division, National Aeronautics and Space Administration Goddard Space Flight Center
Peter Raymond
Yale School of the Environment, Yale University
Judith Rosentreter
Faculty of Science and Engineering, Southern Cross University
Kenneth Thornhill
National Aeronautics and Space Administration Langley Research Center
Derrick Vaughn
Yale School of the Environment, Yale University
Benjamin Poulter