The micro-ecology of stream biofilm dynamics: environmental drivers, successional processes, and forensic applications

Date of Award


Degree Name

Ph.D. in Biology


Department of Biology


Advisor: Ryan W. McEwan


Microbial activity has an essential role in ecosystem processes, and in stream ecosystems, biofilms are the base of the food web that is fueled by photosynthesis and they are integral to nutrient processing. Stream biofilms are microbial communities of algae, bacteria, fungi, and protozoa encased in an extracellular polymeric substance (EPS) (molecules secreted by the microbes) that are attached to a substrate (e.g. rocks, leaves) in an aqueous environment. The substrate categorizes the biofilm, and organic matter like leaves and carrion such as salmon carcasses are important substrates for nutrient dynamics. In special instances, human remains may be deposited into streams and colonized by biofilms; therefore, assessing these biofilms can have direct application to the forensic sciences. Stream ecologists have extensively investigated how environmental factors influence algal community composition, while environmental microbiologists have focused on the role of bacterial communities in nutrient dynamics. My dissertation marries these two approaches by considering biofilm communities as a functioning ecosystem and uses ecological theory as a framework to understand the dynamics of this micro-ecosystem. This framework uses aspects from landscape ecology within a larger context of community ecology to explain how the development of biofilm communities is altered by environmental factors. In addition, this framework was used to investigate biofilm development on carrion (dead animal) in a forensic science context.


Biofilms Ecology, Forensic biology, Microbial ecology, Stream ecology, Microbiology, Biology, Ecology, epilithic, epinecrotic, succession, grazing, autumn, biofilm

Rights Statement

Copyright © 2015, author