title: Community structure and nutrient level control the tolerance of autotrophic biofilm to silver contamination.
abstract: Autotrophic biofilms are complex and fundamental biological compartments of many aquatic ecosystems. Since microbial species differ in their sensitivity to stressors, biofilms have long been proposed for assessing the quality of aquatic ecosystems. Among the many stressors impacting aquatic ecosystems, eutrophication and metal pollution are certainly the most common. Despite that these stressors often occur together, their effects on biofilms have been far much studied separately than interactively. In this study, we evaluated the interactive effects of silver (Ag), a reemerging contaminant, and phosphorus (P), a nutrient often associated with freshwater eutrophication, on the structure and functioning of two types of autotrophic biofilms, one dominated by diatoms and another one dominated by cyanobacteria. We hypothesized that P would alleviate the toxic effects of Ag, either directly, through the contribution of P in metal detoxification processes, or indirectly, through P-mediated shifts in biofilm community compositions and associated divergences in metal tolerance. Results showed that Ag impacted biofilm community structure and functioning but only at unrealistic concentrations (50 μg/L). P availability led to significant shifts in biofilm community composition, these changes being more pronounced in diatom- than those in cyanobacteria-dominated biofilm. In addition, P tended to reduce the impact of Ag but only for the cyanobacteria-dominated biofilm. More generally, our results highlight the preponderant role of the initial community structure and nutrient level on biofilm response to metallic pollutants.
authors.affiliation: Laboratoire Ecologie Fonctionnelle et Environnement, UMR 5245 CNRS-INP-UPS, Université de Toulouse, 118 route de Narbonne, 31062, Toulouse, France.
authors.forename: J
authors.initials: J
authors.lastname: Leflaive
authors.forename: V
authors.initials: V
authors.lastname: Felten
authors.forename: J
authors.initials: J
authors.lastname: Ferriol
authors.forename: A
authors.initials: A
authors.lastname: Lamy
authors.forename: L
authors.initials: L
authors.lastname: Ten-Hage
authors.forename: A
authors.initials: A
authors.lastname: Bec
authors.forename: M
authors.initials: M
authors.lastname: Danger
mesh_terms: D052818:Autotrophic Processes / Q000187:drug effects; D018441:Biofilms / Q000187:drug effects*; D000458:Cyanobacteria / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D017377:Diatoms / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D017753:Ecosystem; D010758:Phosphorus / Q000494:pharmacology*; D012834:Silver / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D014874:Water Pollutants, Chemical; D010758:Phosphorus; D012834:Silver