Professor, Bishop Professor of Freshwater Biology
Phone: (205) 348-4167
Robert Findlay received a Ph.D. in Microbial Ecology from Florida State University in 1986 and completed his postdoctoral research at the University of Miami. Prior to joining the department as the Bishop Professor of Freshwater Ecology in 2003, he was a faculty member at Miami University.
Three major themes or interests tie my research activities together. These are the community and ecosystem ecology of microorganisms, the applied ecology of microbial communities and the development of methods for the determination of microbial biomass, activity, community structure and trophic interactions. I also have a strong interest in independent and collaborative research.
My major focus is on aquatic microbial communities and their role within ecosystems, first in marine sediments and more recently in freshwater and groundwater sediments. I have often investigated factors that control the distribution and abundance of microorganisms and structure their communities. Factors include predation, light, flow, food resource, temperature, and sediment disruption. Several of the factors (light, temperature and predation) combine to produce a seasonal pattern of change in benthic microbial community structure. A current Ph.D. student is supported by a grant from the National Science Foundation to investigate energy flow in streams. Complex dissolved organic matter (DOM) in stream water supports, in part, microbial communities in sediments and on rock surfaces. As part of a multidisciplinary team, we are interested in understanding if scaling rules describing the relationship between stream size and nutrient utilization hold for DOM. We have produced 13C-labeled DOM and using Stable Isotope Probing (SIP) will determine which microorganisms are important to DOM processing in streams and if they process DOM in the same manner as they process nutrients. A second NSF-funded grant has provided for the purchase of a gas-source stable isotope mass spectrometer that is fitted with both an elemental analyzer and a gas chromatograph and allows compound specific stable isotope analysis. This capacity is driving a renewed effort within the laboratory to determine the role of microorganisms as a food resource for animals.
I include studies of the impacts of human society on the environment among my research activities. Studies have included organic pollution and bacterial contamination in groundwater, effects of fishing activity on marine sediments, introduction of drilling fluids in the marine environment, the environmental impacts of salmonid net-pen culture in both marine and freshwater systems and various aspects of lipophilic pollutants in marine and freshwater systems. A current M.S. student is focusing on the impacts of nutrients in shallow estuarine systems. A recently funded DOE-funded grant will investigate microbial redox metabolism in biostimulated uranium (VI)- contaminated subsurface sediments and we are currently seeking funding for research into production of a novel biofuel from plant biomass.
Throughout all the described projects, effort is directed toward the development, evaluation and application of state-of-the-art biogeochemical and microbiological methods. Past efforts include detection of bacterial cell wall components as a measure of bacterial biomass, detection of phospholipid as a measure of microbial biomass, quantification of the bacterial storage lipid polymeric beta-hydroxyalkanoates as a measure of nutritional status, measuring the rate of incorporation of 14C-labeled substrates into structural and storage lipids as a determination of activity and nutritional status and the use of phospholipid fatty acid analysis to quantify microbial community structure. All these efforts were directed toward complex sedimentary communities. In addition, I have investigated using the response of microbial communities to detect nutrient enrichment, anthropogenic stress and have adapted the phospholipid method to simultaneously determine lipophilic pollutant concentration. Current method development efforts include application of compound-specific stable isotope ratios of fatty acids to both foodweb analysis and organic matter utilization using the recently acquired stable isotope mass spectrometer. A current student is expanding this research to include 15N studies of amino acids to further elucidate the trophic structure of ecosystems.
Opportunities for undergraduate and graduate research in my laboratory are open to any of the above questions or to new questions supported by the array of techniques available within the laboratory.
Levy, J., K. Sun, R.H. Findlay, F.T. Farruggia, J.A. Porter, K.L. Mumy, J.M. Brannock, and A.T. Tomaras. 2007. Transport of Escherichia coli bacteria through laboratory columns of glacial outwash sediments: estimating model parameter values with sediment characteristics. Journal of Contaminant Hydrology 89: 71–106.
Rypel, A.L., R.H. Findlay, J.B. Mitchell, D.R. Bayne. 2007. Variations in PCB concentrations between Genders of Six Warmwater Fish Species in Lake Logan Martin, Alabama, U.S.A. Chemosphere 68: 1707–1715.
Shelobolina, E.S. H.A. Vrionis, R.H. Findlay, and D.R. Lovley. 2008. Geobacter uraniireducens sp. nov., isolated from subsurface sediment undergoing uranium bioremediation. International Journal of Systematic and Evolutionary Microbiology 58: 1075-1078.
Findlay, R.H., C. Yeates, M.A.J. Hullar, D.A. Stahl and L.A. Kaplan. 2008. Biome level biogeography of streambed microbiota. Applied and Environmental Microbiology 74: 3014-3021.
Rypel, A.L. W.R. Haag, and R.H. Findlay. 2008. Validation of annual growth rings in freshwater mussel shells using crossdating. Canadian Journal of Fisheries and Aquatic Sciences 65: 2224-2232.
Rypel, A.L., D.A. Arrington and R.H. Findlay. 2008. Mercury in southeastern US riverine fish populations linked to water body type. Environmental Science and Technology 42: 5118–5124.
Rypel, A.L., W.R. Hagg and R.H. Findlay. 2009. Pervasive hysdrologic effects on freshwater mussels and riparian tress in southeastern floodplain ecosytems. Wetlands 29: 497–504.
Caldwell, K.A., Tucci, M.L., Armagost, J., Hodges, T.W., Chen, J., Memon, S.B., Blalock, J.E., DeLeon, S.M., Findlay, R.H., Ruan, Q., Webber, P.J., Standaert, D.G., Olson, J.B., and Caldwell, G.A. 2009. Investigating bacterial sources of toxicity as an environmental contributor to dopaminergic neurodegeneration. PLoS ONE 4: e7227.
Smoot, J.C., and Findlay, R.H. 2010. Microbes as food for sediment-ingesting detritivores: low-density particles confer a nutritional advantage. Aquatic Microbial Ecology 59: 103-109.
Smoot, J.C., and Findlay, R.H. 2010. Caloric needs of detritivorous gizzard shad Dorosoma cepedianum are met with sediment bacterial and algal biomass Aquatic Biology 8: 105-114.
J.J. Mosher, G.C. Klein, A.G. Marshall and R.H. Findlay. 2010. Geological influences of natural organic matter structure in stream waters by FT-ICR- MS. Organic Geochemistry 41:1177-1188.