Research Interests
My research focuses on the biogeochemistry of trace elements in the environment. I am interested in how trace elements behave in natural systems, where they are subject to chemical influences from minerals, organic matter, bacteria, fungi, and dissolved compounds. Bacteria in particular can profoundly influence the geochemical behavior of many trace elements, including chromium, arsenic, uranium and exotic pollutants such as plutonium and technetium. Understanding how bacteria can control metal geochemistry helps us deal with heavy metal pollution, radioactive waste, and how ore-bearing rocks form.
Specific topics that I am currently investigating include; the influence of geochemical variables on uranium reduction and biomineralization by metal-reducing bacteria, the role of bacteria in the biogeochemical cycling of uranium in natural systems, the process of microbial metal reduction and how it affects the environmental mobility of redox-inactive heavy metals such as Pb, Zn, Cd, Cu, and the rare earth elements, the geochemistry of metal-oxidizing bacteria in acid mine drainage, and biomonitoring atmospheric metal-pollutant fallout with lichens.
Publications
Recent Journal Articles:
Koretsky, C.M., Haas J.R., Noah N.T. and Miller D. (2006) Seasonal variations in vertical redox stratification and potential influence on trace metal speciation in minerotrophic peat sediments. Water, Air and Soil Pollution, in press.
Haas J. R. (2004) Effects of cultivation conditions on acid-base titration properties of Shewanella putrefaciens. Chemical Geology 209, 67-81.
Haas J. R. and Northup A. (2004) Effects of aqueous complexation on reductive precipitation of uranium by Shewanella putrefaciens. Geochemical Transactions 5(3), 41-48.
Haas J. R. and DiChristina T.J. (2002) Effects of Fe(III) chemical speciation on dissimilatory Fe(III) reduction by Shewanella putrefaciens. Environmental Science and Technology 36, 373-380.
Haas J. R., DiChristina T.J. and Wade R. Jr. (2001) Thermodynamics of U(VI) sorption to Shewanella putrefaciens. Chemical Geology 180(1-4), 33-54.
Book Chapters:
Haas J. R. and Purvis O. W. (2006) Lichen Biogeochemistry, In: Fungi in Biogeochemical Cycles, G. M. Gadd, editor. Cambridge University Press. In press. |
