Dimethylsulfide and Phaeocystis poucheti in the southeastern Bering Sea

Dimethylsulfide (DMS), a volatile excretion product of marine phytoplankton, was determined in the water column during the spring phytoplankton bloom on the southeastern Bering Sea shelf. In the same samples, a broad range of variables which characterize the biological processes in this region were measured. DMS was correlated with phytoplankton chlorophyll in the outer shelf and oceanic domains, but not in the middle shelf domain. A very strong correlation between the cell density of the haptophyte Phaeocystis poucheti and the DMS concentration in seawater was found, which suggests that this species accounts for most of the DMS present in the study region. We propose that in P. poucheti and certain other phytoplankton species the excretion of DMS is incidental to the release of acrylic acid which serves to inhibit bacterial attack upon the algae.