Ecosystems Research Division

Biographical Information

Title: Senior Research Scientist

Telephone: (706)-355-8117; Email: zepp.richard@epa.gov

Education:

B.S., Furman University; Ph.D., Florida State University, Postdoctoral research, Michigan State University, Research Associate of Professor Peter J. Wagner (Organic Photochemistry)

Expertise/Research Interests:

1. Assessing impacts of solar UV radiation on biogeochemical cycles
2. Mathematical models for interactions of UV radiation with aquatic environments and soil and plant surfaces
3. Effects of fire, land use and climatic change on nutrient and carbon cycles and trace gas exchange between biosphere and atmosphere.
4. Photochemistry in aquatic and terrestrial environments, including direct and sensitized photoreactions (of pesticides, polycyclic aromatics, halogenated pollutants, metals) light-initiated free radical reactions, photoreactions on soil and plant surfaces. Emphasis on kinetic, mechanistic and photoproduct studies relevant to risk assessment.

Professional Activities:

Editorial Advisory Board, Environmental Science & Technology, 1986-1994; Co-Editor of EnvirofACS, newsletter of Environmental Chemistry Division, American Chemical Society, 1988-1991; Editorial Board, Environmental Toxicology and Chemistry, 1984-87; Editorial Board, Environmental Technology Letters, 1987-1993; Canvassing Committee, ACS Award for Creative Advances in Environmental Science and Technology, Member 1986-1988, Chairman 1989; Member-at-large, Executive Committee, Environmental Chemistry Division, 1987-1993; Society of Environmental Toxicology and Chemistry (SETAC) Strategic Planning Committee, 1988-present; Chemists in SETAC ad hoc Committee, 1994-2000; Board of Directors, 1996-1999; Nominations, 1997; Intl. Programs, 1997
SIGMA XI: U. Georgia Chapter, Membership Committee, 1988-1992; Vice-Chairman, Gordon Research Conferences: Environmental Science 1982; Organizing Committee, NATO Advanced Research Institute, Photochemistry of Natural Waters 1982-83; Ad hoc Task Force to Monitor ES&T (J. Calvert, Chmn), 1986; National Science Foundation panel on Chemistry and the Environment, 1988; Co-Chairman, Workshop on Effects of Solar Radiation on Biogeochemical Dynamics in the Hydrosphere, Marine Biological Laboratory, Woods Hole, MA 1989; Organizing Committee, Workshop on Microbial Sources and Sinks of Radiatively Important Trace Gases, U. Georgia, Athens, GA 1989; Member, EPA Stratospheric Ozone Subcommittee/Air & Radiation Research Committee; EPA Global Change Research Team 1990-present; SCOPE/ICSU Committee on Effects of Solar Ultraviolet Radiation on Ecosystems, 1990-1993; Chairman, International Symposium on Climate-Biosphere Interactions: Biogenic Emissions and Environmental Effects of Climate Change, Beijing, P.R. China 1991; Co-Chairman, Symposium on Environmental Aspects of Surface and Aquatic Photochemistry, National Am. Chem. Soc. Meeting, San Francisco 1992; Co-Chair, Session on Climate Change Effects on Trace Gas Fluxes Between the Atmosphere and Biosphere, Fall Am. Geophs. Union Meeting, 1993; Co-Chairman, Dahlem Conference on Role of Non-Living Organic Matter in the Earth's Carbon Cycle 1993; UNEP Panel on Environmental Effects of Ozone Depletion 1993-present; Program Committee, Am. Geophys. Union Chapman Conference on Biomass Burning and Global Change, 1995; Chair, Session on Impacts of Solar UV Radiation on Aquatic Biogeochemical Cycles, SETAC Annual Meeting, 1998; member of American Chemical Society; American Geophysical Union; Society of Environmental Toxicology and Chemistry; AAAS; Inter-American Photochemical Society; American Society of Limnology and Oceanography; American Society of Photobiology; Adjunct Professor: University of Miami, Rosenstiel School of Marine and Atmospheric Sciences; Adjunct Professor: SUNY, College of Environmental Sciences and Forestry, Syracuse NY.

Select Publications:

Bushaw, K. L., R. G. Zepp, M. A. Tarr, D. Schulz-Jander, R. A. Bourbonniere, R. E. Hodson, W. L. Miller, D. A. Bronk, and M. A. Moran. Photochemical release of biologically labile nitrogen from dissolved organic matter. Nature, 381, 404-407, 1996.

Zepp, R.G.,W.L. Miller, M.A.Tarr, R.A. Burke, D. Parsons, and M. Scholes. Dynamics of carbon monoxide emissions from soil and vegetation in a southern African Savanna, in Biomass Burning and Global Change, J. Levine, Ed., pp. 381-388, 1996.

Plane, J.M.C., N.V. Blough, M.G. Ehrhardt, K. Waters, R.G. Zepp, R.G. Zika, Photochemistry in the sea-surface microlayer, in The Sea Surface and Global Change, P. Liss and R. Duce, Eds., Cambridge University Press, 1996, pp.71-92.

Zepp, R.G., W. L. Miller, M. A. Tarr, R.A. Burke and B.J. Stocks. Soil-atmosphere fluxes of carbon monoxide during early stages of post-fire succession in upland Canadian boreal forests, J. Geophys Res., 102(D24), 29, 25,665-25,674, 1997.

Burke, R.A., R.G. Zepp, M.A. Tarr, W.L. Miller, and B.J. Stocks. Effect of fire on soil-atmosphere exchange of carbon dioxide and methane in a Canadian boreal forest, J. Geophys Res., 102(D24), 29, 29,289-29,300, 1997.

Bourbonniere, R.A., W.L. Miller, and R.G. Zepp. Distribution, flux, and photochemical formation of carbon monoxide in a boreal beaver impoundment, J. Geophys Res., 102 (D24), 29,321-29,329, 1997.

Moran, M.A. and R.G. Zepp. Role of photoreactions in the formation of biologically labile compounds from dissolved organic matter, Limnol. Oceanog., 42(6), 1317-1324,1997.

Gao, H. and R. G. Zepp. Factors influencing photoreactions of dissolved organic matter in a coastal river of the southeastern United States. Environ. Sci. Technol. 32:2940-2946, 1998.

Zepp, R.G., T.V. Callaghan, and D.J. Erickson. Effects of enhanced ultraviolet radiation on biogeochemical cycles. J. Photochem. Photobiol. B 46: 69-82, 1998.

Kerstetter, R.E., R. G. Zepp, and L. H. Carreira. Peroxidases in grass dew derived from guttation: role in polymerization of soil organic matter, Biogeochemistry, 42: 311-323, 1998.

Kuhlbusch, T.A.J., R. G. Zepp, W. L. Miller, and R. A. Burke, Jr. CO soil-atmosphere deposition velocities of different soil layers in upland Canadian boreal forests. Tellus, 50B: 353-365, 1998.

Zepp, R.G., M. Gumz, W.L. Miller, and H. Gao. Photoreaction of valerophenone in aqueous solution, J. Phys. Chem. 102:5716-5723, 1998.

Kuhlbusch, T.A.J. and R. G. Zepp. Carbon trace gases in lake and beaver pond ice near Thompson, Manitoba, Canada. J. Geophys. Res. 104: 27693-27698, 1999.

Moran, M.A. and R.G. Zepp. Carbon loss and optical property changes during long-term photochemical and biological degradation of estuarine dissolved organic matter. Limnol. Oceanog., 45:1254-1264, 2000.

Erickson, D., R. G. Zepp and E. Atlas. Ozone depletion and the air-sea exchange of greenhouse and chemically reactive trace gases. Chemosphere- Global Change Science 2: 137-149, 2000.

Moran, M. A. and R. G. Zepp. UV radiation effects on microbes and microbial processes. In: D. L. Kirchman and R. Mitchell, eds. Microbial ecology of the oceans, Wiley, 2000.

Opsahl, S. and R. G. Zepp. Photochemically-induced alteration of stable carbon isotopes ratios (?13C) in terrigenous dissolved organic carbon, Geophys. Res. Lett., 28(12): 2417-2420, 2001

Erickson, D., R. G. Zepp and E. Atlas. Ozone depletion and the air-sea exchange of greenhouse and chemically reactive trace gases. Chemosphere: Global Change Science 2: 137-149, 2000.

Anderson, S., R. Zepp, J. Machula, D. Santavy, L. Hansen, G. Cherr, and E. Mueller, Indicators of UV exposure in corals and their relevance to global climate change and coral bleaching, Human and Ecological Risk Assessment, 7(5):1271-1282, 2001.

Miller, W.L., M.A. Moran, W.M. Sheldon, R.G. Zepp and S.P. Opsahl. Determination of Apparent Quantum Yield Spectra for the Formation of Biologically Labile Photoproducts. Limnology and Oceanography. 47(2):343-352, 2002.

Pinto, A.S., Bustamante, M.M.C., Kisselle, K., Burke, R., Zepp, R., Viana, L.T., Varella, R.F., Molina, M. Soil emissions of N2O, NO and CO2 in Brazilian Savannas: effects of vegetation type, seasonality and prescribed fires. Journal of Geophysical Research 107 (D20), 8089, doi:10.1029/2001JD000342, 2002.

Kisselle, K.W., Zepp, R.G., Burke, R.A., Pinto, A.S., Bustamante, M.M.C., Opsahl, S., Varella, R.F., Viana, L.T. Seasonal soil fluxes of carbon monoxide in burned and unburned Brazilian savannas. Journal of Geophysical Research 107 (D20), 8051, doi:10.1029/2001JD000638, 2002.

Varella, R. F., Bustamante, M.M.C, Pinto, A.S., Kisselle, K. W., Santos, R.V., Burke, R., Zepp. R., Viana, L.T. Soil fluxes of CO2, CO, NO and N2O from an active old-pasture and from native savanna in Central Brazil. Ecological Applications, in press.

Zepp, R.G., T.V. Callaghan, and D.J. Erickson. 2003. Interactive Effects of Ozone Depletion and Climate Change on Biogeochemical Cycles. Photochem. Photobiol. Sci., 2, 51-61 2003.

Zepp, R.G. 2002. Solar Ultraviolet Radiation And Aquatic Carbon, Nitrogen, Sulfur And Metals Cycles. In UV Effects In Aquatic Organisms And Ecosystems, E.W.Helbling & H. Zagarese (Eds), Royal Society of Chemistry, Cambridge UK, pp. 137-183.

Current Projects:

Impacts of Deforestation on Carbon and Nutrient Cycles and Trace Gas Exchange in Amazônian Soils. R. G. Zepp (P.I.); Co-Investigators: R. A. Burke, M. Molina.1998-2003; Effects of Land Use Changes on the Functioning of Soils and Watersheds of Central Brazil Savannas: Impacts On Nutrient And Carbon Cycles And Trace Gas Exchange. R. G. Zepp(P.I.); Co-Investigators: M. Bustamante, R. A. Burke, M. Molina, A. Rosado. 2003-2006; Effects of Biological and Photochemical Degradation on the Optical Properties of CDOM Exported to Coastal Marine Environments. M. A. Moran and R. G. Zepp (P.I.s); 1998-2003; Interactions of Nitrogen and Nonliving Organic Matter in the Formation and Decomposition of CDOM in Coastal Marine Environments, R.G. Zepp (P.I.), 2003-2006; Global Change Effects on Aquatic Ecosystems: UV Exposure, Principal Investigator: R. G. Zepp, 2000-present