Sammanfattning

Multiple anthropogenic drivers are changing ecosystems globally, with a disproportionate and intensifying impact on freshwater habitats. A major impact of urbanization are inputs from wastewater treatment plants (WWTPs). Initially designed to reduce eutrophication and improve water quality, WWTPs increasingly release a multitude of micropollutants (MPs; i.e., synthetic chemicals) and microbes (including antibiotic-resistant bacteria) to receiving environments. This pollution may have pervasive impacts on biodiversity and ecosystem services. Viewed through multiple lenses of macroecological and ecotoxicological theory, we combined field, flume, and laboratory experiments to determine the effects of wastewater (WW) on microbial communities and organic-matter processing using a standardized decomposition assay. First, we conducted a mensurative experiment sampling 60 locations above and below WWTP discharges in 20 Swiss streams. Microbial respiration and decomposition rates were positively influenced by WW inputs via warming and nutrient enrichment, but with a notable exception: WW decreased the activation energy of decomposition, indicating a "slowing" of this fundamental ecosystem process in response to temperature. Second, next-generation sequencing indicated that microbial community structure below WWTPs was altered, with significant compositional turnover, reduced richness, and evidence of negative MP influences. Third, a series of flume experiments confirmed that although diluted WW generally has positive influences on microbial-mediated processes, the negative effects of MPs are "masked" by nutrient enrichment. Finally, transplant experiments suggested that WW-borne microbes enhance decomposition rates. Taken together, our results affirm the multiple stressor paradigm by showing that different aspects of WW (warming, nutrients, microbes, and MPs) jointly influence ecosystem functioning in complex ways. Increased respiration rates below WWTPs potentially generate ecosystem "disservices" via greater carbon evasion from streams and rivers. However, toxic MP effects may fundamentally alter ecological scaling relationships, indicating the need for a rapprochement between ecotoxicological and macroecological perspectives.

Nyckelord

biodiversity; carbon processing; cotton-strip assay; micropollutants; next-generation sequencing; nutrients; temperature; warming

Publicerad i

Global Change Biology
2020, Volym: 26, nummer: 11, sidor: 6363-6382

SLU författare

• Burdon, Francis

  • Institutionen för vatten och miljö, Sveriges lantbruksuniversitet
    
  • Eawag, Eidgenössische Anstalt für Wasserserversorgung, Abwasserrreinigung und Gewässerschutz

Associerade SLU-program

AMR: Bakterier


Globala målen

SDG3 Säkerställa hälsosamma liv och främja välbefinnande för alla i alla åldrar
SDG6 Säkerställa tillgången till och en hållbar förvaltning av vatten och sanitet för alla
SDG11 Göra städer och bosättningar inkluderande, säkra, motståndskraftiga och hållbara
SDG15 Skydda, återställa och främja ett hållbart nyttjande av landbaserade ekosystem, hållbart bruka skogar, bekämpa ökenspridning, hejda och vrida tillbaka markförstöringen samt hejda förlusten av biologisk mångfald


UKÄ forskningsämne

Ekologi
Miljövetenskap


Publikationens identifierare

DOI: https://doi.org/10.1111/gcb.15302

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/107804