Kasia Przybyla-Kelly Ashley Spoljaric Dawn A. Shively Richard L. Whitman Muruleedhara Byappanahalli Meredith Nevers 2016 <p>We investigated the occurrence, persistence, and growth potential of <i>Escherichia coli</i> associated with freshwater organic debris (i.e., wrack) frequently deposited along shorelines (shoreline wrack), inputs from rivers (river CPOM), and parking lot runoffs (urban litter). Samples were collected from 9 Great Lakes beaches, 3 creeks, and 4 beach parking lots. Shoreline wrack samples were mainly composed of wood chips, straw, sticks, leaf litter, seeds, feathers, and mussel shells; creek and parking lot samples included dry grass, straw, seeds, wood chips, leaf/pine needle litter; soil particles were present in parking lot samples only. <i>E. coli</i> concentrations (most probable number, MPN) were highly variable in all sample types: shoreline wrack frequently reached 10⁵/g dry weight (dw), river CPOM ranged from 81 to 7,916/g dw, and urban litter ranged from 0.5 to 24,952/g dw. Sequential rinsing studies showed that 61–87% of <i>E. coli</i> concentrations were detected in the first wash of shoreline wrack, with declining concentrations associated with 4–8 subsequent washings; viable counts were still detected even after 8 washes. <i>E. coli</i> grew readily in shoreline wrack and river CPOM incubated at 35&nbsp;°C. At 30°C, growth was only detected in river CPOM and not in shoreline wrack or urban litter, but the bacteria persisted for at least 16&nbsp;days. In summary, freshwater wrack is an understudied component of the beach ecosystem that harbors <i>E. coli</i> and thus likely influences estimations of water quality and the microbial community in the nearshore as a result of transfer between environments.</p> application/pdf 10.1016/j.jglr.2016.04.011 en International Association for Great Lakes Research Freshwater wrack along Great Lakes coasts harbors Escherichia coli: Potential for bacterial transfer between watershed environments article