Dimethylsulfide and major sulfur compounds in a stratified coastal salt pond

We conducted a diurnal study of gradients of dimethylsulfide (DMS), dimethylsulfoniopropionate (DMSP), dimethylsulfoxide (DMSO), and bacterial numbers in a stratified coastal salt pond (Salt Pond, Falmouth, Massachusetts). Microlayer samples were collected with a surface skimmer, a partially submerged rotating glass cylinder that allows the collection of a thin layer of water by adherence to the drum. All sulfur compounds and bacteria increased toward the water surface, with a diurnal signal in DMSP and DMSO. Fractionation of DMSP and DMSO in dissolved (d) and particulate (p) pools revealed that any trend in DMSP was due to the p fraction, and trends in DMSO originated from the d fraction. Photoeffects are important for the distribution of DMSPp and DMSOd. In Salt Pond, the production of DMSP is probably linked to photosynthesis, and photooxidation is of greater importance to the production of DMSO than is biological oxidation.