Date of Award

Spring 2008

Project Type


Program or Major

Civil Engineering

Degree Name

Master of Science

First Advisor

Nancy E Kinner


Despite extensive research on the resources required to initiate dechlorination of trichloroethene (TCE), slow rates and stalling continue to be observed in situ. The majority of research on biodegradation of TCE has focused resource availability, while predation is poorly understood. Predation has the potential to significantly alter bacterial abundance, and can play an important role in selecting what species are present, and determine if the community is capable of mineralizing TCE. The impact of protistan predation on TCE biodegradation rates, and occurrence and length of stalls was measured in this experiment. When protists were inhibited, TCE was mineralized. Protistan predation appeared to impact the success of reductive dechlorination by selecting for bacterial morphology and community composition. There was a dual threshold effect: no predation limited the ability of the dechlorinators to become dominant, while too much predation resulted in a system where the dechlorinators were grazed to extremely low levels, inhibiting reductive dechlorination.