HR: 0830h
AN: NS51B-08    [Abstracts]
TI: Investigating the structure and dynamics of microbial communities in zones of anomalous geophysical signatures and the effect of these communities on electrical properties
AU: * Allen, J P
EM: jonathan.allen@wmich.edu
AF: Western Michigan University, Department of Biological Sciences, Kalamazoo, MI 49008-5410 United States
AU: Atekwana, E A
EM: atekwana@umr.edu
AF: University of Missouri-Rolla, Department of Geological Sciences and Engineering, Rolla, MO 65409-1060 United States
AU: Atekwana, E A
EM: eliota@umr.edu
AF: University of Missouri-Rolla, Department of Geological Sciences and Engineering, Rolla, MO 65409-1060 United States
AU: Davis, C
EM: cadk9d@umr.edu
AF: University of Missouri-Rolla, Department of Geological Sciences and Engineering, Rolla, MO 65409-1060 United States
AU: Slater, L
EM: lslater@andromeda.rutgers.edu
AF: Rutgers University, Department of Earth & Environmental Sciences, Newark, NJ 07102 United States
AU: Eversole, R R
EM: eversole@wmich.edu
AF: Western Michigan University, Department of Biological Sciences, Kalamazoo, MI 49008-5410 United States
AU: Rossbach, S
EM: silvia.rossbach@wmich.edu
AF: Western Michigan University, Department of Biological Sciences, Kalamazoo, MI 49008-5410 United States
AB: It has been recently recognized that microorganisms can impact both the electrolytic and interfacial electrical properties of subsurface geologic media and thereby influencing geoelectrical measurements. We hypothesize that geoelectrical methods in turn, can be used to delineate subsurface zones containing maximal microbial activity allowing for a better understanding of geomicrobiological processes and characterization of the microbial community. To investigate the structure and dynamics of microbial communities in zones of anomalous geophysical signatures, we used traditional culture-based microbiological and non-culture-based molecular methods. The employment of culture-based enrichment techniques at a hydrocarbon-polluted study site resulted in the isolation of multiple strains of the bacterial Rhodococcus species. Since it is known that only a fraction of the microbial soil community is amenable to enrichment cultures, we chose a non-culture-based approach as well. We constructed two clone libraries based on the 16S rRNA gene of bacteria, one from the hydrocarbon-contaminated study site and one from a non-contaminated background site. The comparison of the two clone libraries will reveal whether there is any significant difference in microbial community composition associated with areas of anomalous geoelectrical measurements. Moreover, to study the effects of microbial biofilm formation on the physical properties of sediments, we inoculated sterile sand with known bacterial cultures and monitored the biofilm formation over time using colorimetric dyes and microscopic methods. Increased biofilm formation was observed between 3 and 6 days after inoculation. Resulting changes in the porosity and surface area of the sands will be measured by induced polarization methods. This interdisciplinary project between geophysicists and microbiologists will enhance our understanding of the effects of microorganisms on geologic media and their influence on geoelectrical signatures of subsurface sediments.
DE: 0400 Biogeosciences
DE: 5109 Magnetic and electrical properties
SC: Near-Surface Geophysics [NS]
MN: 2005 Joint Assembly