Biogenic Trace Gases
Dacey's laboratory investigates the cycling of biogenic trace gases, particularly the radiatively important traces gases: dimethylsulfide (DMS) and methane. Dimethylsulfide studies focus on the concentration of the precursor of DMS in marine biota, and on the mechanisms for conversion of this precursor compound to DMS, such as zooplankton grazing, bacterial activity, and phytoplankton physiology. Research includes development of portable analytical equipment for rapid measurement of these labile compounds, since DMS concentration in seawater is highly variable in space and time. Methane studies focus on emissions from wetlands to the atmosphere. Particular emphases are the role of vascular plants as conduits for the emission of methane from sediments and the effect of rooted vegetation on rhizosphere processes and on marsh biogeochemistry in general. Recent work has addressed the influence of elevated atmospheric carbon dioxide on methane emission.