Cladophora promotes escherichia coli growth and contamination of recreational waters in Lake Michigan

Escherichia coli;E.coli.;Feces--Microbiology;Cladophora glomerata;Freshwater algae--Research;Algae--Wisconsin

Vanden Heuvel, Amy L.Kleinheinz, Gregory ;

University of Wisconsin

关键词: Escherichia coli;    E.coli.;    Feces--Microbiology;    Cladophora glomerata;    Freshwater algae--Research;    Algae--Wisconsin;   

Others  :  https://minds.wisconsin.edu/bitstream/handle/1793/46219/A%20Vandenheuvel%20Thesis.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: University of Wisconsin

【 摘 要 】

In recent years, thick mats of the green alga, Cladophora, have washed ontobeaches along Lake Michigan. These mats become stranded on the shoreline, begin torot, and are malodorous. The rotting mats are a nuisance to recreational beach users andshoreline property owners. Cladophora mats have the potential to harbor Escherichiacoli, which is used as an indicator of recent fecal contamination to determine beachclosures. Cladophora mats may allow bacteria to survive and replicate by providingnutrients, elevated temperatures, and protection from UV light. Bacteria-laden matspotentially increase bacterial concentrations in surrounding recreational waters. To testthis hypothesis, stranded sampled stranded Cladophora mats were sampled for E. coli attwo beaches along Lake Michigan in Door County, Wisconsin. Random and gradientwater samples were collected to determine E. coli concentrations in water underlying themat and in surrounding water. Algal samples were collected and washed to determine E.coli concentrations attached to Cladophora. Since E. coli in recreational water shouldcorrelate with increased concentrations of pathogenic bacteria (also found in fecalmaterial), pathogen concentrations in and attached to Cladophora mats were examined.Standard microbial culture methods were used to identify and enumerate pathogens suchas Salmonella, Shigella, and Campylobacter.Escherichia coli concentrations in water underlying mats were significantlygreater than surrounding water (p < 0.001). Below mat E. coli increased as the strandedmats persisted at the beach swash zone. Water adjacent to Cladophora mats had lower E.coli concentrations but surpassed EPA swimming criteria the majority of sampling days.A significant positive association was found between E. coli concentrations attached toCladophora and in underlying water (p < 0.001). The attached E. coli likely acted as areservoir for populating water underlying the mat. Removal of Cladophora mats frombeach areas may improve aesthetic and microbial water quality at affected beaches. Fecalbacterial pathogens, however, could not be detected by microbiological culture methodseither attached to mat biomass or in underlying water. These associations call intoquestion the efficacy of using E. coli as a recreational water quality indicator of fecalcontaminations.