Abstract
Epilithic bacterial community viability was assessed on natural biofilm assemblages from environmentally contrasting locations over a 17-months period to determine if it reflects environmental conditions or conditions within the biofilm assemblage. Vital state was assessed by membrane integrity using LIVE/DEAD® BacLight™ staining kit. Samples were regularly collected in a large river, up and downstream of a large urban centre. Epilithic biomasses were similar between sites irrespective of the distinct water quality but varied temporarily, peaking up to 48 g AFDM m−2. Bacterial community composition assessed by 16S rDNA based PCR-DGGE significantly differed between sites. Bacterial densities (median of 2.5 × 1011 cell g AFDM−1) were stable whatever the sample origin or biomass. Viable bacterial fractions ranged between 13 and 83% of the total bacterial densities and were correlated with hydrological stability indicators (average of 41.9% during stable water periods, 62.4% during intermediate flow regimes and 50.0% during flow instability) and seasonal parameters. At the river section and epilithic community scales, consistent bacterial densities per unit of biomass could reflect a biofilm assemblage carrying capacity while variable membrane integrity likely integrates changes in the vital state of the community under changing environmental conditions.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.