Effects of Ammonia and Density on Filtering of Commensal and Pathogenic Escherichia coli by the Cladoceran Daphnia magna.
Grazing by cladocerans can reduce the survival of enteric bacteria associated with fecal pollution. This study examined the potential of Daphnia magna to filter commensal and pathogenic Escherichia coli of human origin. Grazing on commensal and pathogenic bacteria was comparable, but slightly greater at 20 compared to 15 and 25°C. Filtering activity was strongly dependent on D. magna and E. coli densities at environmentally relevant bacterial concentrations. Maximum feeding rates were >107cells h-1daphnid-1, clearance rates were 1-6 mL h-1daphnid-1, and filtering was independent of bacterial cell sizes between 0.7 and 1.8 µm. Filtering and ingestion of E. coli by D. magna was susceptible to acute inhibition by unionized ammonia with a 24 h EC50 of 0.18 mg L-1NH3-N, and a LOEC of 0.09 mg L-1NH3-N. The study indicated that biological and chemical constraints should be considered when applying Daphnia for attenuation of fecal pollution.
Section of Biology and Environmental Science, Department of Chemistry and Bioscience, Aalborg University, Frederik Bajers Vej 7H, Aalborg, DK, 9220, Denmark.|School of Biological Sciences, Monash University, Melbourne, VIC, 3800, Australia.
Louise Solveig
LS
Nørgaard
Section of Biology and Environmental Science, Department of Chemistry and Bioscience, Aalborg University, Frederik Bajers Vej 7H, Aalborg, DK, 9220, Denmark. pr@bio.aau.dk.
Peter
P
Roslev
D000641:Ammonia / Q000494:pharmacology*; D000818:Animals; D001673:Biodegradation, Environmental / Q000187:drug effects*; D003621:Daphnia / Q000187:drug effects* / Q000254:growth & development; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000187:drug effects* / Q000254:growth & development / Q000472:pathogenicity*; D005243:Feces / Q000382:microbiology*; D005247:Feeding Behavior / Q000187:drug effects*; D006801:Humans; D013559:Symbiosis; D013696:Temperature
D000641:Ammonia
Ammonia; Daphnia magna; Density; Escherichia coli; Fecal pollution; Pathogens; Temperature; Zooremediation