Lake Munson is a shallow, 255-acre, cypress ringed lake that was once valued as a fishery. The quality of water retained in Lake Munson has been extensively reduced due to input of untreated storm water from its urbanized watershed depositing pollutants into the lake and the discharge of sewage effluent into the lake from 1934 to 1984. Although sewage is no longer discharged into Lake Munson, it is still classified as a highly impacted lake due to historical pollution, frequent algal blooms and low fish productivity. There have been studies that surveyed and compared freshwater microbial communities globally; however, little is known about the phylogenetic and functional composition of freshwater bacterial communities from high to low impacted lakes in North Florida. The objective of this study was to investigate the functional and phylogenetic diversity of the bacterial community within Lake Munson using molecular and cultivation dependent tools. Six samples were collected from transects within the lake and filtered through 0.2 μm filters. DNA was extracted from filters and 16S rRNA genes were PCR amplified utilizing universal primers and analyzed by denaturing gradient gel electrophoresis (DGGE) and cloning. Unfiltered samples (150 μl) were inoculated into a 96 well Biolog® EcoPlate.

Results/Conclusions

Results from DGGE fingerprint patterns indicate spatial differences in community structure within the lake. Biolog results revealed that substrate utilization patterns varied between different sites. These results provide insight into how bacterial communities within the same lake can spatially differ both functionally and phylogenetically, likely due to isolated pockets within the lake differing in hydrology. Additionally, results from this study show that microbial community structure revealed by DGGE complements the different substrate utilization patterns observed through Biolog, between sites within the lake. These results will be further compared to bacterial communities studied in moderate and low impacted lakes in Tallahassee, Fl.