The distribution of dimethylsulfide, DMS, and dimethylsulfoniopropionate, DSMP, in waters off the Western Coast of Ireland

During June and early July of 1996, we measured concentrations of dimethylsulfide, DMS, and dimethylsulfoniopropionate, DMSP, in surface waters on the continental shelf and slope off the western coast of Ireland. We examined the distribution of DMS, DMSP, and the calculated flux of DMS to the atmosphere during four time series. A band of water with high DMS concentrations (>5 nM) was found around the 200 m isobath; DMS levels decreased across horizontal concentration gradients on either side of this band. The Irish Shelf Front seems to act as the inshore boundary of the enhanced DMS water, and the movement of the front may be related to the varying position and width of this area of high DMS. The distribution of DMSP and the atmospheric emission of DMS followed a similar pattern of that found in the DMS, low values near the coast and offshore, and the highest values found in between, around the 200 m isobath.