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Evidence for Interactions between Surface Water and Periphyton Biofilms in Artificial Streams
Citation:
Peed, L., C. Kelty, Mano Sivaganesan, T. Mooney, C. Nietch, AND O. Shanks. Evidence for Interactions between Surface Water and Periphyton Biofilms in Artificial Streams. Presented at International Society of Microbial Ecology 14, Copenhagen, DENMARK, August 19 - 24, 2012.
Impact/Purpose:
Inform the scientific community of study results.
Description:
Studies suggest that periphyton in streambeds can harbor fecal indicator bacteria (FIB) and, under certain circumstances, can be transferred from the periphyton biofilm into the surface water. An indoor mesocosm study was conducted at the U.S. Environmental Protection Agency Experimental Stream Facility in Milford, OH to explore potential interactions between periphyton, water quality, and storm hydrology. The experiment was conducted over a 26 week period and organized into three phases: 1) a colonization period, 2) a wastewater loading period, and 3) a recovery period. To simulate point-source loading in the wastewater loading phase, treated sewage effluent from an adjacent treatment plant was pumped directly and continuously into select mesocosms. Inflow and overflow surface water grabs were paired with the collection of periphyton samples on a weekly basis. Samples were analyzed with five qPCR assays detecting E. coli, enterococci, and Bacteroidales, as well as human host-associated genetic markers (HF183 and HumM2). In surface water samples, culture-based methods were used to measure E. coli and enterococci concentrations. For periphyton, genetic markers were detected in 93 to 99% of samples, while human-associated markers were detected in less than 16%. In surface water samples, genetic markers were detected in 55-92% of samples and human-associated markers were detected in 48%. Results of this study suggest that periphyton biofilms can act as both a sink and source of fecal indicators including host-associated genetic markers.