Benthic Diatom Communities in an Alpine River Impacted by Waste Water Treatment Effluents as Revealed Using DNA Metabarcoding

Freshwater ecosystems are continuously affected by anthropogenic pressure. Wastewater treatment plant (WWTP) effluents represent one of the main contamination sources. Compared to urban effluents, hospital ones usually contain more pharmaceutical substances that may affect recipient aquatic ecosystems. Benthic algae diatoms are ubiquitous and used for water quality monitoring worldwide. In this study advanced metabarcoding was applied to characterize diatom community composition in response to urban vs hospital treated waste effluents.

Diatom communities within treated effluents were dominated by a few rather resistant groups and were found either associated with beta-blockers and non-steroidal anti-inflammatory drugs in urban effluents or antibiotics and nutrients (phosphate) in hospital effluents. Furthermore, 27% of the diatom groups detected in the river downstream from the WWTP output were found to indicate treated effluents and could be used as bioindicators in the future. The biological diatom index (BDI) calculated to evaluate the ecological status of the sampling site suggested a local water quality decrease linked to the release of WWTP effluents.

Thus, in-depth assessment of diatom community composition using DNA metabarcoding is proposed as a promising technique to highlight the disturbing effect of pollutants in Alpine rivers.


Science Flash Chonova

Figure 1 - (A) Sampling site map; (B) Relative abundances of diatom genera; (C) Phylogenetic tree of benthic diatoms. Colors delineate indicator OTUs for each location. U - urban treated effluent (in blue); H - hospital treated effluent (in black); RU - river upstream (in green); RD - river downstream (in red).


For her paper in the journal Frontiers in Microbiology DP-member Teofana Chonova received the LFUI Best Student Paper Award 2019.


Chonova T, Kurmayer R, Rimet F, Labanowski J, Vasselon V, Keck F, Illmer P, Bouchez A. (2019) Benthic diatom communities in an Alpine river impacted by waste water treatment effluents as revealed using DNA metabarcoding. Frontiers in Microbiology 10:653,


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