Spartina alterniflora has the highest methane emissions in a St. Lawrence estuary salt marsh

Publication associated with dataset 'Methane fluxes from four elevation zones in a St. Lawrence Estuary salt marsh' (https://doi.org/10.5281/zenodo.6500188) funded under the European Union's Marie Skłodowska–Curie Action project number 838296 MarshFlux: The effect of future global climate and land-use change on greenhouse gas fluxes and microbial processes in salt marshes. Salt marshes have the ability to store large amounts of 'blue carbon', potentially mitigating some of the effects of climate change. Salt marsh carbon storage may be partially offset by emissions of CH4, a highly potent greenhouse gas. Sea level rise and invasive vegetation may cause shifts between different elevation and vegetation zones in salt marsh ecosystems. Elevation zones have distinct soil properties, plant traits and rhizosphere characteristics, which affect CH4 fluxes. We investigated differences in CH4 emissions between four elevation zones (mudflat, Spartina alterniflora, Spartina patens and invasive Phragmites australis) typical of salt marshes in the northern Northwest Atlantic. CH4 emissions were significantly higher from the S. alterniflora zone (17.7 ± 9.7 mg C m−2h−1) compared to the other three zones, where emissions were negligible (