Date of Award


Degree Name

Master of Science


Biological Sciences

First Advisor

Dr. Silvia Rossbach

Second Advisor

Dr. Estella Atekwana

Third Advisor

Dr. Karim Essani

Fourth Advisor

Dr. Jay Means

Access Setting

Masters Thesis-Open Access


The Crystal Refinery is a former refinery site in Carson City Michigan that has had historic releases of refined and unrefined crude oil dating back to the late 1940's. The contamination of soil with light non-aqueous phase liquids (LNAPL) has had a dynamic impact on the subsurface environment in adjacent Carson City Park. Very little is known about the complex interactions between microbial communities, geochemistry and geophysics. In order to investigate possible connections between these parameters a multidisciplinary study was undertaken to investigate the hypothesis that the degradation of LNAPL by resident microbial communities causes a local increase in organic acid concentrations, which in turn cause an increase in native mineral weathering and a concurrent decrease in the bulk electrical resistivity of soil.Microbial community structure was analyzed using a 96-well most probable number (MPN) method and rDNA intergenic spacer region analysis (RISA). In addition to the observational study of this field site, a controlled lab experiment was preformed in an attempt to simulate field conditions and responses.

Microbial community structure was found to change in the presence of LNAPL and was consistently observed in regions of anomalously low resistivity. Thus, geophysical methods for monitoring the subsurface are a promising new technology for monitoring changes in microbial community structure and simultaneous changes in geochemistry that are associated with LNAPL degradation.

Included in

Geology Commons