Sammanfattning

Reservoir sediments are subjected to highly variable hydrostatic pressures, but little is known about the direct impacts of this environmental variable on microbial communities and biogeochemical processes mediated by microbes in the numerous deep reservoirs (>100 m) scattered across our planet.To address this gap, the organic matter degradation and community assembly of sediment bacteria were studied in bioreactors maintained under different hydrostatic pressures (0.5-3.0 MPa) and explored using 16S rRNA amplicon sequencing analysis.Our results showed that rates of CO2 and CH4 production and microbial activity decreased significantly with increasing pressure, at least when exceeding 1.0 MPa. In contrast, alpha-diversity and community structure of the active (16S rRNA) and total (16S rRNA gene) bacterial communities did not show any significant response to the different hydrostatic pressures, but a co-occurrence network demonstrated that interactions between bacterial populations were stronger at higher pressures (>= 1.5 MPa).Moreover, ecological null model analyses revealed that when the pressure exceeded 1.5 MPa, the main assembly processes of bacterial communities changed from stochastic to deterministic. These findings corroborate an important role of pressure in the assembly and emerging interactions within sediment bacterial communities.Our results imply that increased hydrostatic pressure caused by dam constructions may hamper the metabolism of the sediment microbiota, and that this may result in enhanced sediment burial of nutrients and organic matter, at least when pressures exceed 1.0 MPa.

Nyckelord

bacterial community; bacterial community composition; deep reservoirs; hydrostatic pressure; methane release; microbial interactions; reservoir sediment; respiration

Publicerad i

Freshwater Biology
2021, Volym: 66, nummer: 6, sidor: 1049-1059
Utgivare: WILEY

SLU författare

• Bertilsson, Stefan

  • Institutionen för vatten och miljö, Sveriges lantbruksuniversitet
    

Globala målen

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

Fisk- och akvakulturforskning


Publikationens identifierare

DOI: https://doi.org/10.1111/fwb.13697

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/111109