title: Microbial Transport, Retention, and Inactivation in Streams: A Combined Experimental and Stochastic Modeling Approach.
abstract: Long-term survival of pathogenic microorganisms in streams enables long-distance disease transmission. In order to manage water-borne diseases more effectively we need to better predict how microbes behave in freshwater systems, particularly how they are transported downstream in rivers. Microbes continuously immobilize and resuspend during downstream transport owing to a variety of processes including gravitational settling, attachment to in-stream structures such as submerged macrophytes, and hyporheic exchange and filtration within underlying sediments. We developed a stochastic model to describe these microbial transport and retention processes in rivers that also accounts for microbial inactivation. We used the model to assess the transport, retention, and inactivation of Escherichia coli in a small stream and the underlying streambed sediments as measured from multitracer injection experiments. The results demonstrate that the combination of laboratory experiments on sediment cores, stream reach-scale tracer experiments, and multiscale stochastic modeling improves assessment of microbial transport in streams. This study (1) demonstrates new observations of microbial dynamics in streams with improved data quality than prior studies, (2) advances a stochastic modeling framework to include microbial inactivation processes that we observed to be important in these streams, and (3) synthesizes new and existing data to evaluate seasonal dynamics.
authors.affiliation: †Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois 60208, United States.
authors.forename: Jennifer D
authors.initials: JD
authors.lastname: Drummond
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Davies-Colley
authors.forename: Rebecca
authors.initials: R
authors.lastname: Stott
authors.forename: James P
authors.initials: JP
authors.lastname: Sukias
authors.forename: John W
authors.initials: JW
authors.lastname: Nagels
authors.affiliation: §University of Waikato, Hamilton, New Zealand.
authors.forename: Alice
authors.initials: A
authors.lastname: Sharp
authors.affiliation: †Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois 60208, United States.
authors.forename: Aaron I
authors.initials: AI
authors.lastname: Packman
mesh_terms: D003198:Computer Simulation; D004926:Escherichia coli / Q000502:physiology*; D050296:Microbial Viability; D008962:Models, Theoretical; D045483:Rivers / Q000382:microbiology*; D012621:Seasons; D013269:Stochastic Processes