1. Influence of a Wastewater Treatment Plant on Functional Characteristics of Microbial Communities Matthew S. Luckenbaugh Department of Biological Sciences, York College of Pennsylvania INTRODUCTION Functional dynamics within a community provide important information about how organisms carry out their ecological roles. Functional diversity, evenness, and richness of biofilm and planktonic forms of microbial communities can be used to compare community structure along a pollution gradient. This concept can be applied to wastewater treatment plants and the effect their effluent has on nearby creeks.  Biofilms are composed of numerous types of microorganisms, such as bacteria, fungi, protozoa, and algae, that attach to a substrate and have the ability of existing in a symbiotic relationship. Many microorganisms lack the capability of forming biofilms and thus must remain as planktonic, or free-floating, throughout their entire life cycle (O’Toole et al. 2000).  There are four main stages that occur within the life cycle of a biofilm: initiation, maturation, maintenance, and dissolution. Microbes will disassemble from the biofilm to find nutrients when they are in short supply (O’Toole et al. 2000).  Functional richness (S) is the number of species that can utilize a particular substrate. Functional evenness (E) shows the relative dominance of species in the community. Functional diversity (H) provides an estimate of how many organisms can use different substrates within the environment. BIOLOG microplates provide access to data on functional characteristics of communities (Garland and Mills 1991).  The concepts of this study can estimate whether or not a wastewater treatment plant is functioning adequately. This can be accomplished by studying microbial communities upstream and downstream from the wastewater treatment plant.  This is a novel study since most microbial communities are examined using molecular methods, such as rRNA differences, rather than methods that utilize physiological differences. Additionally, no studies have been completed using these methods to compare microorganisms in planktonic and biofilm communities. Acknowledgements Thanks to all who have helped me with this project. This includes, but is not limited to: Dr. Carolyn Mathur, Dr. Karl Kleiner, Sally Hoh, Dr. Jessica Nolan, and the employees of the Dover Twp. Wastewater Treatment Plant. OBJECTIVES Determine whether or not the released effluent from the plant affects the:  functional diversity  functional evenness  functional richness of the biofilm and planktonic communities in the Little Conewago Creek. METHODS Before Plant (BP)After Plant (AP) Two - 500 mL samples each Pool each to 1 L 700 mL used for growth containers in incubator/shaker 300 mL used for immediate GN2 and ECO plate inoculation and reading 2.5 weeks incubation Determine max. average well color development Calculate functional diversity, functional evenness, and functional richness using absorbance data from each plate Compare values of BP and AP for planktonic at t=0, biofilm, and planktonic samples RESULTS  There was no difference in the functional richness, functional evenness, and functional diversity between the BP and AP samples.  For each sample, there was no difference observed between the results of the GN2 and ECO plates. CONCLUSIONS  The effluent released from the Dover Twp. Wastewater Treatment Plant had no impact on the functional characteristics of the planktonic and biofilm forms of microbial communities in Little Conewago Creek.  Biolfilm and planktonic samples showed similarities in the functional characteristics. Literature Cited Choy, K-H. and Dobbs, F.C. 1999. Comparison of Two Kinds of Biolog Microplates (GN and ECO) in Their Ability to Distinguish Among Aquatic Microbial Communities. Journal of Microbiological Methods 36:203-213. Garland, J.L. and Mills, A.L. 1991. Classification and Characterization of Heterotrophic Microbial Communities on the Basis of Patterns of Community-Level Sole-Carbon-Source Utilization. Applied and Environmental Microbiology 57(8):2351-2359. Ibekwe, A.K., Grieve, C.M., and Lyon, S.R. 2003. Characterization of Microbial Communities and Composition in Constructed Dairy Wetland Wastewater Effluent. Applied and Environmental Microbiology 69(9):5060-5069. O’Toole, G., Kaplan, H.B. and Kolter, R. 2000. Biofilm formation as microbial development. Annual Reviews of Microbiology 54:49-79.