Geophysical Methods for Assessing Microbial Processes in Soil: A Critical Review

Geophysical techniques have witnessed significant changes over the years and the applications are gradually shifting from its application in characterization of structure to characterization of processes. A comprehensive bibliometric analysis of the Geophysical tools in studying the microbial processes at subsurface level is presented here. Late 90s witnessed potential use of geophysical tools in characterization of contaminated lands for monitoring the changes taking place therein. Geophysical tools have achieved success in sensing the microbial processes that has stimulated the researchers' interest to study its possible application in monitoring bioremediation processes. Geophysical tools offer distinct advantages over the invasive point based methods deployed in monitoring the efficacy of remediation in view of their low cost, higher spatio-temporal resolution. A proper understanding of geophysical signatures vis-a-vis different controlling parameters is imperative to realize full potential of geophysical tool. Bibliometric analysis suggests different tools viz. DC resistivity, Self-Potential, Spectral Induced Polarization, Electro Magnetic, Ground Penetrating Radar have the potential to identify the changes in contaminated zones impacted by microbial processes. It is necessary that geophysical measurements should involve with the geochemical and microbiological measurements to avoid ambiguous results.