Background
Dimethylsulfide or DMS, to quote the authors, "is produced by marine phytoplankton activity, and its content in the surface mixed layer is supersaturated with respect to the atmosphere," so that "the net flux of DMS is driven from sea to air." This fact is very important because, as they continue, "in the atmosphere, DMS is rapidly oxidized to form sulfur aerosols, and the cloud condensation nuclei derived from DMS act to counter global greenhouse warming."

What was done
Working with sea surface DMS data and other hydrographic parameters measured in the part of the North Pacific Ocean located between latitudes 25 and 55°N, Watanabe et al. developed and validated an empirical equation for sea surface DMS concentration that uses sea surface temperature, sea surface nitrate concentration and latitude as input data.

What was learned
By applying the algorithm they developed to hydrographic time series datasets pertaining to the western North Pacific that span the period 1971 to 2000, the seven researchers found that the annual flux of DMS from sea to air in that region increased by 1.9-4.8 µmol m^-2 year^-1, which increase, in their words, "was equal to the annual [our italics] rate of increase of about 1% of the climatological annual averaged flux of DMS in the western North Pacific in the last three decades."

What it means
These observations suggest that the negative climate feedback phenomenon derived from increasing oceanic DMS concentrations is "alive and well," as it were, and as is further indicated by the many other pertinent reports we have filed under the general heading of Dimethylsulfide in our Subject Index.