Seasonal variations and resilience of bacterial communities in a sewage polluted urban river

PLoS One. 2014 Mar 25;9(3):e92579. doi: 10.1371/journal.pone.0092579. eCollection 2014.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacteria / classification
  • Bacteria / drug effects
  • Bacteria / genetics
  • Bacteria / growth & development*
  • Belgium
  • DNA, Bacterial / analysis
  • RNA, Ribosomal, 16S / genetics*
  • Rivers / chemistry
  • Rivers / microbiology*
  • Seasons*
  • Sewage / microbiology*
  • Urban Population
  • Wastewater / microbiology*
  • Water Pollutants, Chemical / pharmacology*
  • Water Purification

Substances

  • DNA, Bacterial
  • RNA, Ribosomal, 16S
  • Sewage
  • Waste Water
  • Water Pollutants, Chemical

Grants and funding

This study was mainly performed in the scope of the GESZ research project (Towards the Good Ecological Status of River Zenne: Reevaluating Brussels wastewater management) from the “Impulse Environment 2008” program of the Brussels Institute for Research and Innovation (Innoviris). A part of the work was also performed in the scope of the project “Tracing and Integrated Modelling of Natural and Anthropogenic effects on Hydrosystems” (TIMOTHY), an Interuniversity Attraction Pole (IAP6.13) funded by the Belgian Federal Science Policy Office (BELSPO). Ö Ýnceoðlu benefits from a FNRS (Fonds National de la Recherche Scientifique, Belgium) grant. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.