Dimethylsulphide (DMS) has been measured in the water of the Weddell Sea during the austral summer 1988–1989. In the Summer Surface Water, which generally contained a maximum at 20–50 m depth, the concentrations were extremely high, up to 12 000 ng 1 −1 DMS, but showed a significant spatial variability. Data from the central part of the Weddell Sea show a steep gradient downwards, and below about 200 m depth, in the Weddell Sea Deep Water, concentrations were below the detection limit of 1 ng 1 −1. The high-density Ice Shelf Water, when flowing down the continental slope, brings DMS down to the Weddell Sea Bottom Water in significant amounts before its eventual decay.