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A distinct smell of dimethylsulfide (DMS) was noted at the edge of the intertidal mudflat of Marennes-Oleron Bay, at the French Atlantic coast, where dense populations of the marine flatworm Convoluta roscoffensis Graff (Platyhelminthes: Turbellaria) were present. DMS is the cleavage product of dimethylsulfoniopropionate (DMSP). DMSP was shown to be present in high amounts in sediment containing the flatworm as well as ill axenic cultures of the Symbiotic alga Tetraselmis sp. that was isolated from the flatworm. In untreated sediment samples containing C. roscoffensis the concentration of DMS was as high as similar to 55 mu mol l(-1) sediment, and in samples that were fixed with glutaraldehyde the concentration of DMS was even three orders of magnitude higher (similar to 66 mmol l(-1) sediment. This rapid cleavage of DMSP to DMS in fixed samples was unexpected. Pure DMSP was stable in glutaraldehyde, and it was therefore concluded that a DMSP-lyase was responsible for cleavage in the field samples. The isolated symbiotic alga, Tetraselmis sp., did not show DMSP-lyase activity, indicating that DMSP-lyase may have been present in the flatworm, although the role of bacteria could not be excluded. The Chi a-specific DMSP content of C. roscoffensis (similar to 200 mmol g(-1)) was much higher than that of Tetraselmis sp. (similar to 30 mmol g(-1)). Possibly, DMSP was not only present in the symbiotic alga, but was also incorporated in the body tissue of the flatworm. It remains unclear what the function of DMSP is in C. roscoffensis, increased with increasing salinity. It was concluded that salinity probably does not play an important role in the dynamics of DMSP and DMS in sediment containing C. roscoffenis. [KEYWORDS: Desulfovibrio-acrylicus; atmospheric sulfur; dmsp-lyase; sulfide; sediments; subcordiformis; consumption; metabolism;cultures; sea]
Original languageEnglish
Pages (from-to)209-216
JournalMarine Biology
Issue number1
StatePublished - 2001

ID: 90191