Data associated with the publication: Sedimentary pyrite formation in a seasonally oxygen-stressed estuary: potential imprints of microbial ecology and position-specific isotope fractionation

This study focuses on geochemical analyses of shallow sediments from two sites in Chesapeake Bay. We used these analyses to study the effects of seasonal oxygen decline and biological turnover on pyrite burial rates and pyrite sulfur isotope compositions. Pyrite burial in marine and estuarine sediments is a key process that impacts oxygen levels in the ocean-atmosphere system over geological timescales. Pyrite’s sulfur isotope composition can also be used to study ancient environmental conditions. We found that at both studied sites, pyrite primarily forms in the summer and dissolves in the winter. The more frequently ventilated site had higher pyrite concentrations because of higher rates of formation in the summer, which may be influenced by sulfur oxidizing microbial communities. Despite differences in rates of pyrite formation between sites, sulfur isotope ratios (34S/32S) of pyrite are similar between the sites and are lower than the 34S/32S ratios of coexisting pyrite precursors. This offset between pyrite sulfur isotopes and pyrite precursors may be due to position-specific isotope effects. Here, we include the following data that support these results: 1) Solid phase sulfur and carbon isotope geochemistry for sediment samples from Chesapeake Bay Sites CB4.3C and CB4.3W, 2) Radiogenic isotope data (Pb-210, Ra-226, Cs-137, Be-7) for sediment samples from Chesapeake Bay Sites CB4.3C and CB4.3W, 3) Matlab code for the position-specific isotope effect model. (2023-01)