Ubiquity of algal dimethylsulfoxide in the surface ocean: Geographic and temporal distribution patterns

We carried out analyses of dimethylsulfoxide (DMSO) in surface–sea particulate samples collected between 1995 and 2003 in the Arctic, Antarctica, Sub-polar North Atlantic, Sargasso Sea, Sub-tropical NE Atlantic, W and E Mediterranean Seas, Black Sea, the coastal North Sea and the coastal Mediterranean Sea. Particulate DMSO (DMSOp) was found to co-occur with particulate dimethylsulfoniopropionate (DMSPp), with concentrations in the range 1–40 nM for the former and 6–340 nM for the latter. The two compounds were significantly correlated, which suggests that they both have a common origin in phytoplankton. Conversely, no significant correlation was found between DMSOp and chlorophyll-a concentrations (which spanned more than 2 orders of magnitude: 0.04–13 mg m− 3), suggesting that DMSO production, like that of DMSP, is taxon-dependent. DMSOp concentrations were generally lower than concurrent DMSPp concentrations and accounted for 8–50% (on average ca. 20%) of the intracellular dimethylated sulfur pool (DMSP + DMSO). There was a trend towards higher relative proportions of DMSO in warmer waters, and lower proportions in colder waters. This pattern with temperature was particularly apparent along an annual series in the coastal NW Mediterranean, and along a transect from cold productive waters through warm oligotrophic waters in the NW Atlantic. This is the most comprehensive dataset on DMSOp reported so far, which shows that this compound is as ubiquitous as DMSPp in the surface ocean.