title: Microbial indicators in natural biofilms developed in the riverbed.
abstract: Microbial indicators such as heterotrophic bacteria, total coliforms, and Escherichia coli in naturally developed riverbed biofilms were investigated. Pebbles covered with natural biofilm were sampled directly from the riverbed at sampling stations ranging from the upstream region within a quasi-national park to the midstream in the urban district. Heterotrophic bacteria densities in biofilm positively correlated with stream discharge. E. coli densities in biofilm positively correlated with temperature, which suggests the growth in the biofilm. It was considered that the attachment of planktonic bacteria to biofilm was negligible. The biofilm may serve as an internal source of false positive indication of fecal contamination in the water column.
authors.affiliation: Department of Natural Sciences, Osaka Kyoiku University, Kashiwara Osaka 582-8582, Japan. hirotani@cc.osaka-kyoiku.ac.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hirotani
authors.forename: Miyuki
authors.initials: M
authors.lastname: Yoshino
mesh_terms: D018441:Biofilms / Q000254:growth & development*; D004755:Enterobacteriaceae / Q000502:physiology*; D005243:Feces / Q000382:microbiology*; D019015:Geologic Sediments / Q000382:microbiology*; D052836:Heterotrophic Processes; D045483:Rivers / Q000382:microbiology*; D013997:Time Factors; D014871:Water Microbiology; D014873:Water Pollutants
chemical_list: D014873:Water Pollutants