Understanding Cold Season Hydrology and Carbon Export in Salt Marshes

Cold season freeze–thaw processes, groundwater flow, and carbon dynamics remain major uncertainties in coastal wetland science, yet they are increasingly important as climate change drives shifting temperatures and influences carbon outwelling at regional and global scales. This study uses an integrated suite of geophysical, hydrological, and geochemical sensors and samples to investigate how marshes function during winter and to quantify how porewater, groundwater, and carbon are exported from the marsh platform to tidal channels during the cold season. In 2025, the project team conducted monthly fieldwork at the Wells Reserve at Laudholm in Maine throughout fall, winter, and spring, collecting the data needed to improve our understanding of cold season carbon fluxes and strengthen predictive models of coastal‑carbon cycling.