The role of dimethylsulphoxide in the marine biogeochemical cycle of dimethylsulphide

Dimethylsulphoxide ((CH₃)₂SO; DMSO) occurs naturally in marine and freshwater environments, rainwater, and the atmosphere. It is thought to be an environmentally significant compound due to the potential role it plays in the biogeochemical cycle of the climatically active trace gas, dimethylsulphide (DMS). Generally it has been assumed mat the photochemical and bacterial oxidations of DMS to DMSO represent major sources of this compound and significant sinks for DMS in the marine environment Conversely, it has also been suggested that DMSO may be a potential source for oceanic DMS. Recent research has improved understanding of the origin and fate of DMSO in sea water, although it seems likely that the full role this compound may play in the marine sulphur cycle has still to be elucidated. The methods available for determining DMSO in aqueous samples and current knowledge of the distribution of DMSO in marine waters are reviewed. Mechanisms for DMSO production and loss pathways are also considered, as well as the possible role this compound may play in the cycling of DMS and global climate.