SHORT-TERM VARIABILITY IN BIOGENIC SULPHUR EMISSIONS FROM A FLORIDA SP~~~~~~ ~~~~~~~F~O~~ MARSH

Emissions of biogenic sulphur gases from a Florida Sparrina ulfernifloru zone were measured over several tidal and diel cycles using a dynamic flow chamber technique, corroborating recently published i~or~tion in the literature. The flux of hydrogen sulfide from individuaf measurements is shown to vary by over four orders of magnitude, and correhtes primarily with the stage of the tidal cycle. In contrast, the fluxes ofdimethyt sulphide, carbon disulphideand dimethyl disulphide vary by less than an order of magnitudeand correlate primarily with !he diurnal temperature changes in the sediment surface. These diflerences are discussed in terms of the various biological and physical parameters which may regulale the release of reduced sulphur compounds to the atmosphere.