title: Contrasted effects of natural complex mixtures of PAHs and metals on oxygen cycle in a microbial mat.
abstract: The contamination of polluted environments is often due to a complex mixture of pollutants sometimes at trace levels which nevertheless may have significant effects on the diversity and functioning of organisms. The aim of this study was to assess the functional responses of a microbial mat exposed to a natural complex mixture of PAHs and metals as a function of the maturation stage of the biofilm. Microbial mats sampled in a slightly polluted environment were exposed to contaminated water of a retention basin of an oil refinery. The responses of the microbial mats differed according to season. In spring 2012, strong inhibition of both oxygen production and respiration was observed relative to the control, with rates representing less than 5% of the control after 72 h of incubation. A decrease of microbial activities was followed by a decrease of the coupling between autotrophs and heterotrophs. In contrast, in autumn 2012, no significant changes for oxygen production and respiration were observed and the coupling between autotrophs and heterotrophs was not altered. The differences observed between the spring and autumn mats might be explained by the maturity of the microbial mat with dominance of heterotrophic bacteria in spring, and diatoms and cyanobacteria in autumn, as well as by the differences in the chemical composition of the complex mixture of PAHs and metals.
authors.affiliation: UMR 9190 MARBEC IRD-Ifremer-CNRS-Université de Montpellier, Place Eugène Bataillon, case 093, 34095 Montpellier cedex 5, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Pringault
authors.affiliation: Equipe Environnement et Microbiologie, UMR IPREM 5254, IBEAS BP 1155, Université de Pau et des Pays de l'Adour, 64013 Pau cedex, France.
authors.forename: Johanne
authors.initials: J
authors.lastname: Aube
authors.affiliation: Plateforme Génomique Campus INRA, 24 chemin de borde rouge, 31326 Castanet-Tolosan Cedex, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Bouchez
authors.affiliation: Plateforme Génomique Campus INRA, 24 chemin de borde rouge, 31326 Castanet-Tolosan Cedex, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Klopp
authors.affiliation: Plateforme Génomique Campus INRA, 24 chemin de borde rouge, 31326 Castanet-Tolosan Cedex, France.
authors.forename: Jérome
authors.initials: J
authors.lastname: Mariette
authors.affiliation: Plateforme Génomique Campus INRA, 24 chemin de borde rouge, 31326 Castanet-Tolosan Cedex, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Escudie
authors.affiliation: Plateforme Génomique Campus INRA, 24 chemin de borde rouge, 31326 Castanet-Tolosan Cedex, France.
authors.forename: Pavel
authors.initials: P
authors.lastname: Senin
authors.affiliation: Equipe Environnement et Microbiologie, UMR IPREM 5254, IBEAS BP 1155, Université de Pau et des Pays de l'Adour, 64013 Pau cedex, France.
authors.forename: Marisol
authors.initials: M
authors.lastname: Goni-Urriza
mesh_terms: D018441:Biofilms; D045424:Complex Mixtures; D000458:Cyanobacteria; D008670:Metals / Q000633:toxicity*; D010100:Oxygen; D011084:Polycyclic Aromatic Hydrocarbons / Q000633:toxicity*; D014871:Water Microbiology; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D045424:Complex Mixtures; D008670:Metals; D011084:Polycyclic Aromatic Hydrocarbons; D014874:Water Pollutants, Chemical; D010100:Oxygen
keywords: Biofilm; Carbon cycle; Maturation; Microelectrodes; Production; Respiration