Wastewater microorganisms impact microbial diversity and important ecological functions of stream periphyton. (15th October 2022)

• Record Type: Journal Article
• Authors: Carles, Louis; Wullschleger, Simon; Joss, Adriano; Eggen, Rik I.L.; Schirmer, Kristin; Schuwirth, Nele; Stamm, Christian; Tlili, Ahmed
• Is Part Of: Water research. Volume 225(2022)
• Publication Date: 2022-10-15
• Subjects: Stream biofilm -- Prokaryotes -- Eukaryotes -- DNA metabarcoding -- Micropollutants -- Pollution-induced community tolerance; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2022.119119
• Languages: English
• ISSNs: 0043-1354

Abstract

Highlights: Wastewater induced a decrease in C:N and C:P molar ratio in periphyton. Wastewater microorganisms induced changes in the respiration profiles of periphyton. Wastewater microorganisms induced higher tolerance of periphyton to micropollutants. Colonization of periphyton by wastewater prokaryotes is higher than by eukaryotes. Wastewater microorganisms decreased diatoms abundance in periphyton. Abstract: Effluents of wastewater treatment plants can impact microbial communities in the receiving streams. However, little is known about the role of microorganisms in wastewater as opposed to other wastewater constituents, such as nutrients and micropollutants. We aimed therefore at determining the impact of wastewater microorganisms on the microbial diversity and function of periphyton, key microbial communities in streams. We used a flow-through channel system to grow periphyton upon exposure to a mixture of stream water and unfiltered or ultra-filtered wastewater. Impacts were assessed on periphyton biomass, activities and tolerance to micropollutants, as well as on microbial diversity. Our results showed that wastewater microorganisms colonized periphyton and modified its community composition, resulting for instance in an increased abundance of Chloroflexi and a decreased abundance of diatoms and green algae. This led to shifts towards heterotrophy, as suggested by the changes in nutrient stoichiometry and the increased mineralization potential of carbon substrates. An increased tolerance towards micropollutants was only found for periphyton exposed to unfiltered wastewater but not to ultra-filtered wastewater, suggesting that wastewater microorganisms were responsible for this increased tolerance. Overall, our results highlight the need to consider the role of wastewater microorganisms when studying potential impacts of wastewater on the receiving water body. Graphical abstract: Image, graphical abstract