A genomic approach to microbial source tracking of fecal indicator bacteria in recreational surface waters (589.2)

Abstract

We present results of a multi‐year study to identify sources of chronic high fecal indicator bacterial levels in the Lake Macatawa (Ottawa County, Michigan) watershed. In this work, we have analyzed community bacterial DNA from environmental samples to characterize total microbial community populations using traditional qPCR and next generation DNA sequencing and analysis techniques. Standard microbiological and 16S rRNA qPCR source tracking techniques have revealed widespread and possibly endogenous nonpoint sources, as well as occasional point source hotspots. These results are compared to microbial community source tracking is based on DNA information in the same marker molecule, 16S rRNA, with the community source tracking approach allowing for the monitoring all microbial groups in the same samples. The baseline information obtained on microbial communities in the watershed has facilitated development of unique microbial profiles for possible point sources and perform qPCR based microbial source tracking that is robust to false positives and false negatives. Results of suites of newly described indicator bacteria that reflect various environmental events and their associate health and environmental risks will be discussed.