Evidence for microbial enhanced electrical conductivity in hydrocarbon‐contaminated sediments

[1] Bulk electrical conductivity of sediments during microbial mineralization of diesel was investigated in a mesoscale laboratory experiment consisting of biotic contaminated and uncontaminated columns. Population numbers of oil degrading microorganisms increased with a clear pattern of depth zonation within the contaminated column not observed in the uncontaminated column. Microbial community structure determined from ribosomal DNA intergenic spacer analysis showed a highly specialized microbial community in the contaminated column. The contaminated column showed temporal increases in bulk conductivity, dissolved inorganic carbon, and calcium, suggesting that the high bulk conductivity is due to enhanced mineral weathering from microbial activity. The greatest change in bulk conductivity occurred in sediments above the water table saturated with diesel. Variations in electrical conductivity magnitude and microbial populations and their depth distribution in the contaminated column are similar to field observations. The results of this study suggest that geophysical methodologies may potentially be used to investigate microbial activity.

[1]  L. Slater,et al.  Effect of different phases of diesel biodegradation on low frequency electrical properties of unconsolidated sediments , 2004 .

[2]  A. Venosa,et al.  Selective enumeration of aromatic and aliphatic hydrocarbon degrading bacteria by a most-probable-number procedure. , 1996, Canadian journal of microbiology.

[3]  Anthony L. Endres,et al.  Investigating the geoelectrical response of hydrocarbon contamination undergoing biodegradation , 2003 .

[4]  Rosemary Knight,et al.  Ground Penetrating Radar for Environmental Applications , 2001 .

[5]  F. Rodríguez-Valera,et al.  Use of the 16S--23S ribosomal genes spacer region in studies of prokaryotic diversity. , 1999, Journal of microbiological methods.

[6]  William A. Sauck,et al.  A model for the resistivity structure of LNAPL plumes and their environs in sandy sediments , 2000 .

[7]  D. Hunkeler,et al.  Engineered and subsequent intrinsic in situ bioremediation of a diesel fuel contaminated aquifer. , 2002, Journal of contaminant hydrology.

[8]  J. Thioulouse,et al.  Heterogeneous Cell Density and Genetic Structure of Bacterial Pools Associated with Various Soil Microenvironments as Determined by Enumeration and DNA Fingerprinting Approach (RISA) , 2000, Microbial Ecology.

[9]  Barbara A. Bekins,et al.  Microbial populations in contaminant plumes , 2000 .

[10]  Estella A. Atekwana,et al.  In-situ apparent conductivity measurements and microbial population distribution at a hydrocarbon-contaminated site , 2004 .

[11]  Jillian F. Banfield,et al.  Biogeochemical weathering of silicate minerals , 1997 .

[12]  L. Slater,et al.  Effects of microbial processes on electrolytic and interfacial electrical properties of unconsolidated sediments , 2004 .

[13]  R. Krishnamurthy,et al.  Seasonal variations of dissolved inorganic carbon and δ13C of surface waters : application of a modified gas evolution technique , 1998 .

[14]  P. Bradley,et al.  Evidence for Enhanced Mineral Dissolution in Organic Acid‐Rich Shallow Ground Water , 1995 .

[15]  P. Bennett,et al.  Microbial Control of Silicate Weathering in Organic-Rich Ground Water , 1992, Science.

[16]  B. Bekins,et al.  Distribution of Microbial Physiologic Types in an Aquifer Contaminated by Crude Oil , 1999, Microbial Ecology.