Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar (CSIC), Pg Marítim de la Barceloneta 37-49, 08003 Barcelona, Catalonia, Spain. mariavila@icm.csic.es
Dimethylsulfoniopropionate (DMSP) accounts for most of the organic sulfur fluxes from primary to secondary producers in marine microbial food webs. Incubations of natural communities and axenic cultures with radio-labeled DMSP showed that dominant phytoplankton groups of the ocean, the unicellular cyanobacteria Prochlorococcus and Synechococcus and diatoms, as well as heterotrophic bacteria take up and assimilate DMSP sulfur, thus diverting a proportion of plankton-produced organic sulfur from emission into the atmosphere.