Microbial Growth and Biofilm Formation in Geological Media Is Detected with Complex Conductivity Measurements
Complex conductivity measurements (0.1-1000 Hz) were obtained from biostimulated sand-packed columns to investigate the effect of microbial growth and biofilm formation on the electrical properties of porous media. Microbial growth was verified by direct microbial counts, pH measurements, and environmental scanning electron microscope imaging. Peaks in imaginary (interfacial) conductivity in the biostimulated columns were coincident with peaks in the microbial cell concentrations extracted from sands. However, the real conductivity component showed no discernible relationship to microbial cell concentration. We suggest that the observed dynamic changes in the imaginary conductivity (σ″) arise from the growth and attachment of microbial cells and biofilms to sand surfaces. We conclude that complex conductivity techniques, specifically imaginary conductivity measurements are a proxy indicator for microbial growth and biofilm formation in porous media. Our results have implications for microbial enhanced oil recovery, CO2 sequestration, bioremediation, and astrobiology studies.
C. A. Davis et al., "Microbial Growth and Biofilm Formation in Geological Media Is Detected with Complex Conductivity Measurements," Geophysical Research Letters, American Geophysical Union (AGU), Jan 2006.
The definitive version is available at http://dx.doi.org/10.1029/2006GL027312
Geosciences and Geological and Petroleum Engineering
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© 2006 American Geophysical Union (AGU), All rights reserved.