Environmental concern is presently one of the major driving forces in biogeochemical research. The combination of three disciplines (biology, geology and chemistry), rather than the individual ones, is important to better understand processes in nature. When abiotic and biotic components of processes in situ can be distinguished, it might be easier to predict the results of perturbations.

My research interest is in unraveling geochemical processes, particularly those involved with the fate of simple organic compounds in marine environments. Most of my work focuses on near-shore sediments and coastal waters. Sediment characteristics throughout seasonal or diel cycles are determined with microelectrodes (oxygen, sulfide, redox, pH, gases and temperature) and depth profiles of chemical compounds and microbiota are measured. These data are then used to design laboratory experiments with intact muds, slurries or (defined) microbial cultures.

I employ this approach to study the sulfur cycle and its role in the functioning of marine ecosystems including seagrass beds in Long Island Sound, stromatolites in the Bahamas, local saltmarsh sediments, marine aquaculture systems and several coastal water bodies and hypersaline lakes. In addition, I am working on applied problems such as halocarbon degradation (alternative freons, methyl bromide) and biofilm formation on heat exchange systems.

Visscher, P.T. and B.F. Taylor. 1993. A new mechanism for the aerobic catabolism of dimethyl sulfide. Appl. Environ. Microbiol. 59: 3784-3789.

Visscher, P.T. and B.F. Taylor. 1993. Aerobic and anaerobic degradation of a range of alkyl sulfides by a denitrifying bacterium. Appl. Environ. Microbiol. 59: 4083-4089.

Visscher, P.T., R.P. Kiene and B.F. Taylor. 1994. Demethylation and cleavage of dimethylsulfoniopropionate in marine intertidal sediments. FEMS Microbiol. Ecol 14: 179-190.

Oremland, R.S., J. Switzer Blum, C.W. Culbertson, P.T. Visscher, L.G. Miller, P. Dowdle and F.E. Strohmaier. 1994. Isolation, growth and metabolism of an obligately anaerobic selenate-respiring bacterium, strain SES-3. Appl. Environ. Microbiol. 60: 3011-3019.

Visscher, P.T., C.W. Culbertson and R.S. Oremland. 1994. Degradation of trifluoracetate in oxic and anoxic sediments. Nature (London) 369: 729-731.

Taylor, B.F. and P.T. Visscher. 1996. Metabolic pathways involved in DMSP degradation. In: R.P. Kiene, P.T. Visscher, M.D. Keller and G.O. Kirst (eds.). Biological and Environmental Chemistry of DMSP and Related Sulfonium Compounds. Plenum Press, NY. pp. 265-276.

P.T. Visscher. 1996. Microbial turnover of volatile sulfur compounds. In: J.C. Murrell and D.P. Kelly (eds.). Microbiology of Atmospheric Trace Gases: Sources, Sinks and Global Change Processes. Springer-Verlag, Berlin. pp. 227-242.

---