Porewater nutrient concentrations from control plots and fertilized plots at Spartina alterniflora, S.patens and Typha sp. marshes, Plum Island Ecosystem LTER, MA (1999-2025).

Porewater samples from five marsh locations in the Plum Island Ecosystems (PIE) LTER site were collected and analyzed for salinity as well as ammonium, phosphate, sulfide and chloride concentrations throughout the growing season. Three sites (a Typha-dominated brackish marsh, a Spartina alterniflora-dominated salt marsh, and a S. patens-dominated salt marsh) are part of a long term study, and include fertilized and non-fertilized sample plots. Two additional, non-fertilized marsh sites, are located on Nelson Island, near Stackyard Road within the Parker River National Wildlife Refuge.