Laboratory-Controlled Experiments Reveal Microbial Community Shifts during Sediment Resuspension Events

Genes (Basel). 2022 Aug 9;13(8):1416. doi: 10.3390/genes13081416.


In freshwater ecosystems, dynamic hydraulic events (floods or dam maintenance) lead to sediment resuspension and mixing with waters of different composition. Microbial communities living in the sediments play a major role in these leaching events, contributing to organic matter degradation and the release of trace elements. However, the dynamics of community diversity are seldom studied in the context of ecological studies. Therefore, we carried out laboratory-induced leaching experiments, using sediments from the Villerest dam reservoir (Villerest, France). To assess whole microbial community diversity, we sequenced the archaeal and bacterial 16S rRNA genes using Illumina MiSeq. Our results suggest that the degree of dissolved oxygen found in the water during these resuspension episodes influenced community dynamics, with anoxic waters leading to drastic shifts in sedimentary communities compared to oxic waters. Furthermore, the release of microbial cells from sediments to the water column were more favorable to water colonization when events were caused by oxic waters. Most of the bacteria found in the sediments were chemoorganotrophs and most of the archaea were methanogens. Methylotrophic, as well as archaeal, and bacterial chemoorganotrophs were detected in the leachate samples. These results also show that organic matter degradation occurred, likely participating in carbonate dissolution and the release of trace elements during freshwater resuspension events.

Keywords: archaea; bacteria; dam freshwater; dam sediment; sediment leaching.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Archaea / genetics
  • Bacteria
  • Geologic Sediments / microbiology
  • Microbiota* / genetics
  • RNA, Ribosomal, 16S / genetics
  • Trace Elements* / metabolism
  • Water / metabolism


  • RNA, Ribosomal, 16S
  • Trace Elements
  • Water

Grants and funding

This research was supported by the Canada Research Chair in Aquatic Environmental Genomics, and a Natural Sciences and Engineering Research Council discovery grant RGPIN-2019-06670 both awarded to C.S.L.