Elemental and isoptopic composition of sediment and biomass from the Carpinteria Salt March sampled in 2020 and 2021

Here we provide data that help to evaluate organic matter sulfurization and pyrite formation in a salt marsh in California. We collected six sediment cores from three habitat types at Carpinteria Salt Marsh Reserve (34.41336°N, 119.84365°W) in July 2020. One core was used to establish dry bulk density, while the other was reserved for geochemical measurements. Both cores were kept at -20°C until analysis could be carried out. We provide elemental concentrations (organic C/N/S, Fe, pyrite) and isotopic compositions (δ13C, δ34S) of important carbon, iron and sulfur sediment pools. Additional biomass samples were collected between 2020 and 2023 and were also analyzed for elemental (C/N/S) and isotopic compositions (δ13C, δ34S). Data will be useful for those interested in assessing organic matter sulfurization and pyrite formation in blue carbon ecosystems such as mangroves, seagrass meadows and salt marshes. Data will also be informative for researchers investigating organic and inorganic sulfur cycling. Samples were collected by Lena Capece and Morgan Raven, data were interpreted by Lena Capece and Morgan Raven.