Journal article
Compounded effects on wetland greenhouse gas fluxes from climate change and water management along a saline to freshwater gradient
Proceedings of the National Academy of Sciences - PNAS, Vol.123(8), pp.1-10
17/02/2026
PMID: 41701819
Metrics
1 Record Views
Abstract
To manage a large wetland landscape like the Everglades as a net carbon sink, carbon uptake and emissions must be balanced along a gradient of coastal saline mangroves and marshes to nontidal freshwater marshes and forests. Pairing ground and airborne measurements with long-term satellite imagery helps monitor how greenhouse gas exchange changes with wetland vegetation, salt and freshwater levels, disturbances, and management of these compounding factors. Our dataset revealed the importance of restoring hydrologic flows to potentially increase aerobic conditions that minimize freshwater marshes as methane sources and to maximize carbon dioxide uptake in healthy and recovering mangroves. Data upscaling enabled a landscape perspective of carbon exchange needed to improve carbon inventories and manage diverse wetlands as nature-based climate solutions. 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 (CO2) and methane (CH4) 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 CO2 and CH4 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 CO2 and CH4, respectively. Long-term (23-y) patterns in the fluxes of CH4, CO2, and their CO2-equivalent (CO2eq) 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 CO2eq uptake in coastal and freshwater wetlands increased by 18% from −7.0 ± 3.3 MMT CO2eq y−1 in 2003 to −8.4 ± 3.8 MMT CO2eq y−1 in 2020 at an uptake rate of −0.06 ± 0.01 MMT CO2eq y−2. Annually, roughly 43% of CO2 uptake was offset by CH4 emissions from all wetlands in the region (from 16% in mangroves to 82% in freshwater marshes).
Details
- Title
- Compounded effects on wetland greenhouse gas fluxes from climate change and water management along a saline to freshwater gradient
- Creators
- Cheryl L. Doughty - University of Maryland, College ParkQing Ying - University of Maryland, College ParkEric Ward - University of Maryland, College ParkErin Delaria - University of Maryland, College ParkGlenn M. Wolfe - University of Maryland, College ParkSparkle L. Malone - Yale UniversityDavid E. Reed - Yale UniversityTiffany Troxler - Florida International UniversityJohn S. Kominoski - Florida International UniversityEdward Castañeda-Moya - Florida International UniversityW. Barclay Shoemaker - United States Geological SurveyDavid Yannick - University of AlabamaGregory Starr - University of AlabamaSteven F. Oberbauer - Florida International UniversityAbigail Barenblitt - University of Maryland, College ParkAnthony Campbell - University of Maryland, College ParkSean Charles - Coastal Carolina UniversityLola Fatoyinbo - University of Maryland, College ParkJonathan Gewirtzman - Yale UniversityThomas Hanisco - University of Maryland, College ParkReem Hannun - National Aeronautics and Space AdministrationStephan Kawa - Goddard Space Flight CenterDavid Lagomasino - Coastal Carolina UniversityLeslie Lait - University of Maryland, College ParkAyia Lindquist - University of Maryland, College ParkPaul Newman - University of Maryland, College ParkPeter Raymond - Yale UniversityJudith Rosentreter - Southern Cross UniversityKenneth Thornhill - Langley Research CenterDerrick Vaughn - Yale UniversityBenjamin Poulter - University of Maryland, College Park
- Publication Details
- Proceedings of the National Academy of Sciences - PNAS, Vol.123(8), pp.1-10
- Publisher
- National Academy of Sciences
- Grant note
- We would like to acknowledge the support of the NASA Carbon Monitoring System and Terrestrial Ecology Programs toward the BlueFlux field campaign (CMS grant #80NSSC21K1564).
- Identifiers
- 991013357073102368
- Copyright
- © 2026 the Author(s).
- Academic Unit
- Faculty of Science and Engineering
- Language
- English
- Resource Type
- Journal article