Production of dimethylsulfonium propionate and dimethylsulfide by phytoplankton in estuarine and coastal waters

Abstract

We determined the concentrations of dimethylsulfide (DMS) and its metabolic precursor, dimethylsulfonium propionate (DMSP), in water and particulate samples obtained along transects through Delaware Bay, Chesapeake Bay (including the Potomac River), and Ochlockonee Bay (Florida). The Delaware and Chesapeake Bay transects extended into the open ocean. In most cases, we observed positive correlations between the concentrations of the biogenic sulfur species and salinity, particularly when the concentrations of the sulfur compounds were normalized to chlorophyll a as a measure of phytoplankton biomass. The normalized concentrations of DMS, dissolved DMSP, and particulate (intracellular) DMSP increased nonlinearly with salinity from estuarine through shelf to oceanic environments. Within each environment, dissolved DMS and dissolved and particulate DMSP correlated more strongly with salinity than with phytoplankton species composition. On the other hand, the sharp increases in Chl a #x2010;normalized biogenic sulfur concentrations from the estuarine to the coastal and shelf environments were most strongly correlated with differences in the species composition of the phytoplankton community between environments and appear to reflect differences in DMSP production between oceanic, coccolithophore#x2010;dominated communities and estuarine, diatom#x2010;dominated communities.