Spatial variation of methane emissions and methane-cycling communities in a coastal salt marsh

Authors

• Jongsun Kim, The University of Texas Rio Grande ValleyFollow
• Bongkeun Song, Virginia Institute of Marine Science
• Myung Hwangbo, The University of Texas Rio Grande Valley
• Mark J. Brush, Virginia Institute of Marine Science
• Iris Anderson, Virginia Institute of Marine Science
• William Reay, Virginia Institute of Marine Science

Document Type

Article

Publication Date

1-1-2026

Abstract

Coastal salt marshes are highly valuable ecosystems that function as significant methane (CH4) sources. CH4 emissions in salt marsh ecosystems result from a range of production and consumption pathways affected by biotic factors, including plant types and microbial communities. Although salt marsh ecosystems are known to be important, there is still a notable lack of understanding of the specific microbial processes and mechanisms that result in spatial variability of CH4 production and emission rates. Thus, this study was to identify the spatial variability of CH4 fluxes across different vegetation zones, determine potential CH4 production rates across varying soil depths, and characterize microbial communities associated with CH4 cycling in a salt marsh ecosystem on Goodwin Island, York River, VA. We found that the edge of the salt marsh, dominated by Sporobolus alterniflorus, exhibited higher CH4 fluxes, reaching up to 59.19 μmol m⁻² h⁻¹, compared to marsh interiors dominated by Spartina patens and Distichilis spicata. The top 5 cm of soils at the marsh edge showed the highest CH4 production rate, up to 6.0 μmol g⁻¹ d⁻¹ based on laboratory incubation experiments. The microbial community analysis further suggested the coexistence of methanogenic archaea and sulfate-reducing bacteria in low-sulfate environments, which might be influenced by groundwater discharge. Accordingly, the integrated findings demonstrated salt marsh ecosystems, especially at the marsh edge, as CH4 emission hotspots by specific microbial communities and dominant vegetation types. This also highlights the importance of incorporating these spatially explicit mechanisms into global CH4 emission assessments.

Comments

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Recommended Citation

Kim, Jongsun, Bongkeun Song, Myung Hwangbo, Mark J. Brush, Iris Anderson, and William Reay. "Spatial variation of methane emissions and methane-cycling communities in a coastal salt marsh." Marine Pollution Bulletin 222 (2026): 118811. https://doi.org/10.1016/j.marpolbul.2025.118811

Publication Title

Marine Pollution Bulletin

DOI

10.1016/j.marpolbul.2025.118811