Abstract

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.

Keywords

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

Published in

Freshwater Biology
2021, Volume: 66, number: 6, pages: 1049-1059
Publisher: WILEY

SLU Authors

• Bertilsson, Stefan

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    

Sustainable Development Goals

Protect, restore and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss


UKÄ Subject classification

Fish and Aquacultural Science


Publication identifier

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

Permanent link to this page (URI)

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