Master of Science (MS), Bowling Green State University, 2007, Biological Sciences

he effects of physical disturbance on lentic periphyton, in comparison to lotic periphyton, have been overlooked by algal ecologists. Furthermore, few studies have used in situ experiments in lakes in order to understand how physical disturbance shapes periphyton communities. This thesis investigated physical disturbance in a lentic system, both through observation and in situ experimentation, and examined the effects it had on the structure and species diversity of a periphyton community. Algal species physiognomy appeared to be an important factor in the observational study: adnate taxa were more abundant in areas of high disturbance, while stalked taxa were nearly absent. In areas of lower disturbance, stalked taxa were more abundant and adnate taxa were nearly absent. Prostrate taxa accounted for 40-50% of the community in lower and higher disturbance areas, and along with filamentous and tychoplanktonic species, did not change as hypothesized. Benthic sediments were transplanted into mesocosms and manipulated with high, medium, and no physical disturbance for three weeks. At the end of the experimentation, transplanted communities did not show significant changes in community structure. Shannon diversity index values in both the observational and experimental studies resulted in a clear understanding of how species diversity in periphyton is related to physical disturbance. This study attempted to better understand lentic periphyton and succeeded in the observation study. The difficulty of in situ lentic experimentation was highlighted by this thesis.

Committee: Rex Lowe (Advisor) Subjects: Biology, Limnology