title: Seasonal variations and resilience of bacterial communities in a sewage polluted urban river.
abstract: The Zenne River in Brussels (Belgium) and effluents of the two wastewater treatment plants (WWTPs) of Brussels were chosen to assess the impact of disturbance on bacterial community composition (BCC) of an urban river. Organic matters, nutrients load and oxygen concentration fluctuated highly along the river and over time because of WWTPs discharge. Tag pyrosequencing of bacterial 16S rRNA genes revealed the significant effect of seasonality on the richness, the bacterial diversity (Shannon index) and BCC. The major grouping: -winter/fall samples versus spring/summer samples- could be associated with fluctuations of in situ bacterial activities (dissolved and particulate organic carbon biodegradation associated with oxygen consumption and N transformation). BCC of the samples collected upstream from the WWTPs discharge were significantly different from BCC of downstream samples and WWTPs effluents, while no significant difference was found between BCC of WWTPs effluents and the downstream samples as revealed by ANOSIM. Analysis per season showed that allochthonous bacteria brought by WWTPs effluents triggered the changes in community composition, eventually followed by rapid post-disturbance return to the original composition as observed in April (resilience), whereas community composition remained altered after the perturbation by WWTPs effluents in the other seasons.
authors.affiliation: Ecology of Aquatic Systems, Université Libre de Bruxelles, Campus de la Plaine, Brussels, Belgium.
authors.forename: Tamara
authors.initials: T
authors.lastname: García-Armisen
authors.affiliation: Ecology of Aquatic Systems, Université Libre de Bruxelles, Campus de la Plaine, Brussels, Belgium.
authors.forename: Özgül
authors.initials: Ö
authors.lastname: İnceoğlu
authors.affiliation: Ecology of Aquatic Systems, Université Libre de Bruxelles, Campus de la Plaine, Brussels, Belgium.
authors.forename: Nouho Koffi
authors.initials: NK
authors.lastname: Ouattara
authors.affiliation: Ecology of Aquatic Systems, Université Libre de Bruxelles, Campus de la Plaine, Brussels, Belgium.
authors.forename: Adriana
authors.initials: A
authors.lastname: Anzil
authors.affiliation: Department of Water Pollution Control, Université Libre de Bruxelles, Campus Plaine, Brussels, Belgium.
authors.forename: Michel A
authors.initials: MA
authors.lastname: Verbanck
authors.affiliation: Analytical and Environmental Chemistry, Vrije Universiteit Brussels, Brussels, Belgium.
authors.forename: Natacha
authors.initials: N
authors.lastname: Brion
authors.affiliation: Ecology of Aquatic Systems, Université Libre de Bruxelles, Campus de la Plaine, Brussels, Belgium.
authors.forename: Pierre
authors.initials: P
authors.lastname: Servais
mesh_terms: D001419:Bacteria / Q000145:classification / Q000187:drug effects / Q000235:genetics / Q000254:growth & development*; D001530:Belgium; D004269:DNA, Bacterial / Q000032:analysis; D012336:RNA, Ribosomal, 16S / Q000235:genetics*; D045483:Rivers / Q000737:chemistry / Q000382:microbiology*; D012621:Seasons; D012722:Sewage / Q000382:microbiology*; D014505:Urban Population; D062065:Wastewater / Q000382:microbiology*; D014874:Water Pollutants, Chemical / Q000494:pharmacology*; D018508:Water Purification
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S; D012722:Sewage; D062065:Wastewater; D014874:Water Pollutants, Chemical