The effect of microbial processes on electrical properties of unconsolidated sediments was investigated in a laboratory experiment consisting of biotic and abiotic sand columns. The biotic column (nutrient, diesel and bacteria) showed (a) temporal increase in the real, imaginary, and surface conductivity, and (b) temporal decrease in the formation factor. The abiotic columns (nutrient; and nutrient and diesel) showed no significant changes. Increase in microbial population numbers, decrease in organic carbon source, nitrate, and sulfate and increase in dissolved inorganic carbon and fluid conductivity were indicative of microbial activity in the biotic column. We also measure relative increase in the interfacial electrical properties that exceed relative increase in the electrolytic conductivity. Thus changes in the real and imaginary conductivity were induced by microbial processes. These results suggest that interpretation of geoelectrical data from near surface environments should consider effects of microbial processes.


Geosciences and Geological and Petroleum Engineering

Keywords and Phrases

Biological Effects; Exploration Geophysics; Magnetic And Electrical Methods; Physical Properties Of Rocks; Electric Conductivity; Electrolysis; Electrolytes; Geophysics; Microorganisms; Nutrients; Organic Carbon; Abiotic Sand Columns; Electrolytic Conductivity; Microbial Processes; Sediments; Electrical Property; Microbial Activity; Sediment Property; Unconsolidated Medium; Dissolved Inorganic Carbon; Interfacial Electrical Properties; Laboratory Experiments; Microbial Activities; Microbial Populations; Surface Conductivity; Unconsolidated Sediment; Electromagnetism; Groundwater quality; Hydrology

International Standard Serial Number (ISSN)


Document Type

Article - Journal

Document Version

Final Version

File Type





© 2004 American Geophysical Union (AGU), All rights reserved.

Publication Date

01 Jun 2004

Included in

Geology Commons