Sediment samples, Sesarma reticulatum gut and tissue samples, Spartina alterniflora leaves, and benthic diatoms were analyzed for a suite of biogeochemical parameters, including total carbon, total nitrogen, stable isotopes of carbon and nitrogen, and a subset of samples were analyzed for total hydrolyzable amino acids. Samples were collected between 2017 and 2019 on Sapelo Island, Georgia, USA. Samples were collected from Sesarma-grazed and un-grazed creeks. Analyses were conducted at the University of Florida and are associated with the manuscript by Morrison et al. entitled Influence of the keystone grazer, Sesarma reticulatum, on the hydrology and organic matter cycling of salt marshes in the southeastern United States.