| Abstract
| - Dimethyl sulfide, the most important form of sulfur gas, isformed by bacterial degradation of dimethylsulfoniopropionate (DMSP) in the Lake of Galilee. DMSP isbelievedto be a methionine metabolite produced by marine algaeand higher plants as part of their osmoregulatory systems.Until now, this process was found exclusively insalinewater and therefore was regarded as insignificant for theformation of DMS in freshwaters. It is herebydemonstratedthat the process can be dominant in freshwater systems aswell, and its product can even affect the odor quality ofsome drinking and recreational water systems.Peridinium gatunense, a freshwater dinoflagellatewhichdominates the phytoplankton population in the lake duringthe winter−spring season, stores a considerable amount(up to 5.5 pg/cell) of DMSP. P. gatunense growthcurvesreveal an increased storage of DMSP toward the stationaryand declining growth phases. The DMSP undergoesbacterial and chemical degradation to release DMS.Releasedfluxes of DMS from the Lake of Galilee are estimated tobe in the range of 0.1 mmol/m2 month during thelateperiod of the Peridinium bloom season.
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