Abstract

Despite its relatively low crustal abundance, arsenic can reach significant levels in some environments. The sources may be natural or anthropologic. The contamination of well water in Bangladesh is linked to arsenic in the aquifer sediments. Closer to home, organoarsenicals are routinely applied to golf courses (e.g., monosodium methane arsonate) and fed to chickens (e.g., roxarsone). Both inorganic and organic forms of arsenic are readily transformed by microorganisms. These transformations include the oxidation of arsenite and reduction of arsenate as well as biotransformation of the organic forms. The organisms responsible are phylogenetically diverse and different biochemical pathways are involved. The activities of these organisms impact the speciation and mobilization of arsenic in the environment and affect water quality. Two genome projects (Genome Atlantic, DOE-JGI) are currently underway. Four arsenate respiring bacteria and two arsenite oxidizing bacteria are being sequenced in order to better understand the pathways and mechansisms involved in microbial arsenic transformation.

Biographical Sketch

John F. Stolz is a Professor in the Department of Biological Sciences at Duquesne University. He has studied community structure in stratified microbial mats (including stromatolites) and the physiology, phylogeny, and biochemistry of metal and metalloid reducing bacteria. His current research focuses on the role arsenic metabolizing microbes have in the speciation and mobilization of arsenic in the environment.

Some recent papers my group has published:

Oremland, R.S., and Stolz, J.F. 2005. Arsenic, microbes, and contaminated aquifers. Trends in Microbiology.13:45-49

Oremland, R.S., Stolz, J.F., and Hollibaugh, J.T. 2004. The microbial arsenic cycle in Mono Lake, California. FEMS Microbiol. Ecol. 48:15-27

Oremland, R.S., and Stolz, J.F. 2003. The ecology of arsenic. Science 300:939-944

Stolz, J.F., Feinstein, T.N.,.Salsi, J., Visccher, P.T., and Reid, R.P 2001 TEManalysis of microbial mediated sedimentation and lithification in a modern marine stromatolite Am. Min. 86:826-833.

Light refreshments are served in the Interaction Area (4th floor of the Oceanography/Physics Building) at 4:00 p.m.

All seminars begin at 3:00 p.m. and are held in room 200 of the Oceanography/Physics building.