Abstract

We measured continuous CO2, CH4, and H2O fluxes in an artificial inland salt marsh created in 2008 on a soda ash production settling basin ("Solvay waste") in Camillus, New York, using the eddy covariance method over the 2019 and 2020 growing seasons and compared our results to data gathered shortly after the wetland was created, between 2011 and 2013. We found that wintertime flux measurements indicated a net accumulation of water, while growing season measurements indicated a net loss of water. We synthesized our temporally disjointed measurements into a single composite year, where we found 18% greater evapotranspiration than precipitation on an annual basis. We found similar results for carbon, with a net loss of carbon from the site in winter while the summer served as a moderate sink for carbon. When we synthesized the data into a single composite year, we found that the site was a slight carbon sink annually of about 50 gC m−2. We also investigated CH4 fluxes at the site but found that they were only 0.05% of the magnitude of CO2 fluxes when we had observations, indicating only marginal vertical exchange. Overall, CH4 contributed very little to the site's carbon or warming budgets. Finally, we investigated the ecosystem drivers of CO2, H2O, and CH4. We found that carbon fluxes and water fluxes were highly correlated, indicating that the water fluxes were largely driven by vegetative processes. The drivers of carbon and water flux shifted only slightly from 2011/2013 to 2019/2020, possibly indicating a maturing of the vegetation cover in the wetland site.