Scarratt, M. G.. Department of Fisheries and Oceans Canada,
Levasseur, M. G.. Department of Fisheries and Oceans Canada,
Schultes, S. Universite de Quebec a Rimouski,
Michaud, S. Department of Fisheries and Oceans Canada,
Cantin, G. Department of Fisheries and Oceans,

Bacterial production and consumption of dimethylsulfide (DMS) were studied at several stations in the northwest Atlantic ranging from the Sargasso Sea to the Grand Banks. The kinetics of DMS production were studied in short-term experiments using additions of dissolved dimethylsulfoniopropionate (DMSP-D) (0 to 3000 nM). Measurements of DMS and DMSP-D were made hourly for 3 hours. The kinetics curves are very linear and show no saturation of DMS production at high DMSP-D concentrations. Rates and rate constants show a strong positive relationship with water temperature. In longer-term incubations following an initial 100 nM pulse of DMSP-D, DMS production continued to be linear for up to 48 hours or until the substrate was depleted. Measurements of DMS consumption were made by adding dissolved DMS to pre-filtered water samples and incubating them for 48 h. Measurable DMS consumption was observed at some but not all stations. The highest rate of DMS consumption (4.2 nmole/L/h) was observed where the DMS-producing prymnesiophyte Phaeocystis sp. was present in the surface water, along with high ambient concentrations of DMS. This rate is very high in comparison to other published rates. This suggests that bacterial DMS consumption may be elevated only where high DMS concentrations are found.
Day: Friday, Feb. 5
Time: 12:00 - 12:15pm
Location: Sweeney Center
Code: SS37FR1200S