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During a cruise over the Atlantic from 40øS to 50øN in March-April 1987 the concentrations of dimethylsulfide (DMS) in the ocean and atmosphere were measured as well as the distribution of its precursor, dimethylsulfoniopropionate (DMSP), and of several biological parameters such as chlorophyll, phytoplankton species, and adenosine-5-triphosphate (ATP) in the surface water. The DMS concentration varied in the range 0.2-2 nmol DMS L -1 (surface water) and 0.05-3 nmol DMS m -3 (atmosphere) in the region of the remote tropical and subtropical Atlantic and increased to 2-10 nmol DMS L -1 (surface water) and 1-8 nmol DMS m -3 (atmosphere) north of 40øN and in the English Channel. Based on these results the mean flux of DMS from the Atlantic to the atmosphere is estimated to be 4-4.65 nmol DMS m -2 min -1 . A moderate diurnal variation of atmospheric DMS was found with a minimum during daytime. The DMS concentration in seawater correlated well with the concentration of DMSP and showed a similar trend to ATP, chlorophyll, and some phytoplankton species. Paper number 89JD03776. 0148-0227/90/89 JD-03776505.00 evidence for the role of DMSP as the biogenic precursor of DMS, the major volatile sulfur compound in seawater. EXPERIMENTAL METHODS Sampling of SeawaterSurface water samples were taken 3 times a day (08.30, 12.30, and 16.30 hours) with a 10-L bucket in front of or in the bow wave of the ship. They were used for the analysis of chlorophyll a, salinity, DMSP, and ATP as well as for phytoplankton counting. The seawater samples analyzed for DMS were obtained by means of the ship's pumping system from a depth of 10 m below the surface at 6-hour intervals (0100, 0700, 1300, and 1900).

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Nematodes belonging to the family Oncholaimidae are known to aggregate at sites of organic pollution. The oncholaimid Adoncholaimus thalassophygas (De Man, 1876), collected from the Weser Estuary, FRG, in 1989, has the capability to take up acetate at naturally occurring concentrations. Under almost axenic conditions, ca 2.3 to 3.0 ng sodium acetate was taken-up per worm within 24 h, when an ambient concentration of 0.33 mmol was offered. The concentration factor was ca 8.5 to 11.1. The results suggest that a highly motile oxybiotic nematode may benefit from the fermentation products of anoxic habitats.