Charles R. Lovell Chair and Professor of Biological Sciences Ph.D., 1984, Purdue University 803-777-5084 (Chair Office) 803-777-7036 (Research Office) 803-777-4254 (Lab) lovell@biol.sc.edu Lovell Lab North Inlet Microbial Observatory

The North Inlet Microbial Observatory:

The North Inlet Microbial Observatory (NIMO) was established in 2003 with funding from the National Science Foundation. The mission of NIMO is to understand the functions, identities, and community relationships of diazotrophic (nitrogen fixing) bacteria in a southeastern US salt marsh environment. Part of that mission is to identify and characterize novel microorganisms with unusual ecological and physiological characteristics.

NIMO is based at North Inlet, a tidally dominated estuary, at the University of South Carolina's Baruch Institute Marine Field Laboratory, which is also part of the NOAA North Inlet-Winyah Bay National Estuarine Research Reserve. The site is a near-pristine salt marsh with a distinct zonation of a small number of plant species growing along a well defined elevation gradient, which provides a unique opportunity for examining relationships among diazotrophs in sediments, their associated plant species, and abiotic environmental variables. Salt marsh systems are typically nitrogen limited and the North Inlet system receives only small inputs of nitrogen from anthropogenic sources. Diazotrophy is the main source of combined nitrogen for this system and supports the very high rates of primary production found there.

Much of our work on this project has been directed to defining diazotroph diversity, distributions, and activity. We have employed molecular biological approaches (PCR, RT-PCR, DGGE) to determine the species composition of the diazotroph assemblages found in each vegetation zone. We have also isolated into pure culture a great variety of diazotrophic organisms, some of which are entirely new to science and many of which belong to taxonomic groupings previously thought to lack diazotrophic species. We have also performed synoptic sampling at permanent stations to document environmental parameters that are likely to affect diazotroph distributions and activity. A major effort to establish correlations among diazotroph distributions, activity, and environmental variables is underway.

Interactions between infaunal marine invertebrates and associated bacteria:

Infaunal marine polychaetes and hemichordates construct tube or burrow structures in intertidal sediments. These structures provide an interface between the anoxic sediment environment and oxygenated seawater introduced by the burrow ventilation activities of the host infaunal animal. This burrow microenvironment supports extensive microbial growth and high rates of activity and represents a tractable, easily manipulated model system for examining the impact of environmental forcing factors on microbial community and functional group composition and activities.

Our current activities include 1) examination the effects of the burrow lining biofilm community on sediment geochemical processes, 2) experimental manipulation of burrow microbial community composition and activities through altering irrigation rates, burrow wall permeability, and input soluble organic compounds, and 3) determination of the roles of aerotolerant anaerobic bacteria in this interface microenvironment. My research in this area has been supported by the National Science Foundation, the Environmental Protection Agency, and the Office of Naval Research.

Selected Publications:

Criminger, J.D., T.H. Hazen, P.A. Sobecky, and C.R. Lovell. 2007. Nitrogen fixation by Vibrio parahaemolyticus and its implications for a new ecological niche. Applied and Environmental Microbiology 73:5959-5961.

Bodelier, P.L.E., B. Sorrell, H. Drake, T. Hurek, C. Lovell, P. Megonigal and P. Frenzel. 2006. Ecological aspects of microbes inhabiting the rhizosphere of wetland plants. In: J.T.A. Verhoven (ed.) Ecological Studies, Vol. 190, pp. 205-238. Springer Verlag.

Gößner, A.S., K. Küsel, D. Schulz, S. Trenz, G. Acker, C.R. Lovell,, and H.L. Drake. 2006. Trophic interaction of the aerotolerant anaerobe /Clostridium intestinale/ and the acetogen Sporomusa rhizae sp. nov. isolated from roots of the black needlerush Juncus roemerianus. Microbiology 152:1209-1219.

Lovell, C.R. 2005. Belowground interactions among salt marsh plants and microorganisms. In: E. Kristensen, J.E. Kostka, and R.H. Hease (eds.) Interactions Between Macro- and Microorganisms in Marine Sediments. pp. 61-83. Coastal and Estuarine Studies Volume 60. American Geophysical Union, Washington, D.C.

Lovell, C.R. and A.B. Leaphart. 2005. Community-level analysis: key genes of CO2?reductive acetogenesis. In J.R. Leadbetter (ed.) Methods in Enzymology. Vol. 397, pp. 454-469. Elsevier, San Diego, CA. In press.

Bagwell, C.E., and C.R. Lovell. 2004. A DNA-DNA hybridization method for the detection and quantification of specific bacterial taxa in natural environments. In: J.F.T Spencer and A.L. Ragout de Spencer (eds.) Environmental Microbiology, pp. 169-174. Methods in Biotechnology Series, Humana Press, Totowa, NJ.

LaRocque, J., P.W. Bergholz, C.E. Bagwell, and C.R. Lovell. 2004. Influence of host plant-derived and abiotic environmental parameters on the composition of the diazotroph assemblage associated with roots of Juncus roemerianus. Antonie van Leeuwenhoek 68:249-261.

Lovell, C.R. 2004. Diversity, microbial. In: M. Schaechter and J. Lederberg (eds.), The Desk Encyclopedia of Microbiology, pp. 326-339. Academic Press, San Diego, CA.

Matsui, G.Y., D.B. Ringelberg, and C.R. Lovell. 2004. Sulfate reducing bacteria in tubes constructed by the marine infaunal polychaete Diopatra cuprea. Applied and Environmental Microbiology 70:7053-7065.

Brown, M.M., M.J. Friez, and C.R. Lovell. 2003. Expression of nifH genes by diazotrophic bacteria in the rhizosphere of short form Spartina alterniflora. FEMS Microbiology Ecology 43:411-417.

Leaphart, A.B., M.J. Friez, and C.R. Lovell. 2003. Formyltetrahydrofolate synthetase sequences from salt marsh plant roots reveal a diversity of acetogenic bacteria and other bacterial functional groups. Applied and Environmental Microbiology 69:693-696.

Bagwell, C.E., J.R. La Rocque, G.W. Smith, S.W. Polson, M.J. Friez, J.W. Longshore, and C.R. Lovell. 2002. Molecular diversity of diazotrophs in oligotrophic seagrass bed communities. FEMS Microbiology Ecology 39:113-119.

Beeson, K., D.L. Erdner, C.E. Bagwell, C.R. Lovell, and P.A. Sobecky. 2002. Differentiation of plasmids in marine diazotroph assemblages determined by randomly amplified polymorphic DNA analysis. Microbiology 148:179-189.

Dang, H., and C.R. Lovell. 2002. Numerical dominance and phylotype diversity of marine Rhodobacter during early colonization of submerged surfaces in coastal marine waters as determined by 16S rDNA sequence analysis and fluorescence in situ hybridization. Applied and Environmental Microbiology 68:496-504.

Dang, H., and C.R. Lovell 2002. Seasonal dynamics of particle-associated and free-living marine Proteobacteria in a salt marsh tidal creek as determined using fluorescence in situ hybridization. Environmental Microbiology 4:287-295.

Leaphart, A.B., H.T. Spencer, and C.R. Lovell. 2002. Site directed mutagenesis of a putative catalytic and formyl phosphate binding site and substrate inhibition of N¹⁰-formyltetrahydrofolate synthetase. Archives of Biochemistry and Biophysics 408:137-143.

Lovell, C.R. 2002. Plant-microbe interactions in the marine environment. In: G. Bitton (ed.) Encyclopedia of Environmental Microbiology, Vol. 5, pp. 2539-2554. Wiley, New York, NY.

Lovell, C.R. , N. Eriksen, A.J. Lewitus, and Y.P. Chen. 2002. Resistance of the marine diatom Thalassiosira sp. to toxicity of phenolic compounds. Marine Ecology Progress Series 229:11-18.

Marinelli, R.L., C.R. Lovell, S.G. Wakeham, D. Ringelberg, D.C. White. 2002. An experimental investigation of the control of bacterial community composition in macrofaunal burrows. Marine Ecology Progress Series 235:1-13.