title: Microbial responses to polycyclic aromatic hydrocarbon contamination in temporary river sediments: Experimental insights.
abstract: Temporary rivers are characterized by dry-wet phases and represent an important water resource in semi-arid regions worldwide. The fate and effect of contaminants have not been firmly established in temporary rivers such as in other aquatic environments. In this study, we assessed the effects of sediment amendment with Polycyclic Aromatic Hydrocarbons (PAHs) on benthic microbial communities. Experimental microcosms containing natural (Control) and amended sediments (2 and 20 mg PAHs kg(-1) were incubated for 28 days. The PAH concentrations in sediments were monitored weekly together with microbial community structural (biomass and phylogenetic composition by TGGE and CARD-FISH) and functional parameters (ATP concentration, community respiration rate, bacterial carbon production rate, extracellular enzyme activities). The concentration of the PAH isomers did not change significantly with the exception of phenanthrene. No changes were observed in the TGGE profiles, whereas the occurrence of Alpha- and Beta-Proteobacteria was significantly affected by the treatments. In the amended sediments, the rates of carbon production were stimulated together with aminopeptidase enzyme activity. The community respiration rates showed values significantly lower than the Control after 1 day from the amendment then recovering the Control values during the incubation. A negative trend between the respiration rates and ATP concentration was observed only in the amended sediments. This result indicates a potential toxic effect on the oxidative phosphorylation processes. The impoverishment of the energetic resources that follows the PAH impact may act as a domino on the flux of energy from prokaryotes to the upper level of the trophic chain, with the potential to alter the temporary river functioning.
authors.affiliation: Istituto di Ricerca Sulle Acque, Consiglio Nazionale delle Ricerche (IRSA-CNR), Via Salaria km 29.300, CP10, 00015 Monterotondo, Roma, Italy. Electronic address: zoppini@irsa.cnr.it.
authors.forename: Annamaria
authors.initials: A
authors.lastname: Zoppini
authors.affiliation: Istituto di Ricerca Sulle Acque, Consiglio Nazionale delle Ricerche (IRSA-CNR), Via Salaria km 29.300, CP10, 00015 Monterotondo, Roma, Italy.
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Ademollo
authors.affiliation: Istituto di Ricerca Sulle Acque, Consiglio Nazionale delle Ricerche (IRSA-CNR), Via Salaria km 29.300, CP10, 00015 Monterotondo, Roma, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Amalfitano
authors.affiliation: Istituto di Ricerca Sulle Acque, Consiglio Nazionale delle Ricerche (IRSA-CNR), Via Salaria km 29.300, CP10, 00015 Monterotondo, Roma, Italy.
authors.forename: Silvio
authors.initials: S
authors.lastname: Capri
authors.affiliation: Istituto di Ricerca Sulle Acque, Consiglio Nazionale delle Ricerche (IRSA-CNR), Via Salaria km 29.300, CP10, 00015 Monterotondo, Roma, Italy.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Casella
authors.affiliation: Istituto di Ricerca Sulle Acque, Consiglio Nazionale delle Ricerche (IRSA-CNR), Via Salaria km 29.300, CP10, 00015 Monterotondo, Roma, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Fazi
authors.affiliation: Limnologische Fluss-Station des Max-Planck-Instituts für Limnologie, Schlitz, Germany and Institut für Allgemeine und Spezielle Zoologie, Tierökologie, Justus-Liebig-Universität, Gießen, Germany.
authors.forename: Juergen
authors.initials: J
authors.lastname: Marxsen
authors.affiliation: Istituto di Ricerca Sulle Acque, Consiglio Nazionale delle Ricerche (IRSA-CNR), Via Salaria km 29.300, CP10, 00015 Monterotondo, Roma, Italy.
authors.forename: Luisa
authors.initials: L
authors.lastname: Patrolecco
mesh_terms: D018533:Biomass; D004784:Environmental Monitoring; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis* / Q000633:toxicity; D045483:Rivers / Q000737:chemistry*; D014871:Water Microbiology; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000633:toxicity
chemical_list: D011084:Polycyclic Aromatic Hydrocarbons; D014874:Water Pollutants, Chemical
keywords: Microbial communities; Polycyclic aromatic hydrocarbons (PAHs); Temporary river sediments; Toxicity