Hines, M. E. University of Alaska Anchorage, afmeh@uaa.alaska.edu
Kiene, R. E. University of South Alabama, Rkiene@jaguar1.usouthal.edu

 
CONTROLS ON EMISSIONS OF DIMETHYLSULFIDE FROM FRESHWATER WETLANDS
 
Dimethylsulfide (DMS) is produced and emitted from a variety of aquatic and terrestrial habitats. In general, it is believed that marine environments, which are rich in S, are the primary emitters of gaseous DMS due to the degradation of dimethylsulfoniopropionate (DMSP). However, DMS formation can be important in anoxic freshwaters. Fluxes of DMS were determined using a dynamic flow-through chamber system in a variety of aquatic and terrestrial environments. Direct measurements of DMS fluxes from wetlands, such as Sphagnum bogs and fens, revealed unusually high rates, especially in the most oligotrophic areas. Fluxes were highest from hummocks, in areas without terrestrial or stream influences, and in areas with low pH. Flooding of a wetland greatly decreased DMS emission despite increased CH4 and CO2 fluxes. Studies using slurries of wetland peats were conducted to investigate controls on DMS production, consumption and emission. Methylation of methane thiol was the primary source of DMS. DMSP was not a source of DMS. Inhibition studies and comparisons of various habitats demonstrated that the high flux of DMS in certain areas is due to the lack of any use of DMS by methanogenic bacteria.
 
Day: Friday, Feb. 5
Time: 10:45 - 11:00am
Location: Sweeney Center
 
Code: SS37FR1045S