title: Microbial community responses to bioremediation treatments for the mitigation of low-dose anthracene in marine coastal sediments of Bizerte lagoon (Tunisia).
abstract: OBJECTIVE
  The main goals of this study were to investigate (1) the behavior of microbial communities in response to low-dose bioavailable anthracene addition in lightly contaminated sediment from Bizerte Lagoon and (2) the effects of bioremediation treatments on microbial biomass, activity, and community structure.
  
  
  METHODS
  Sediment microcosms amended with 1 ppm anthracene were incubated in triplicate during 30 days. Biostimulation (addition of nitrogen and phosphorus fertilizer) and bioaugmentation (inoculation of a hydrocarbonoclastic bacterium) were used as bioremediation treatments. Bacterial biomass was estimated using flow cytometry. Sediment oxygen consumption was measured with oxygen microelectrodes. Bacterial community structure was assessed by molecular fingerprints (terminal restriction fragment length polymorphism; T-RFLP) analysis.
  
  
  RESULTS
  Anthracene contamination resulted in a significant reduction of bacterial abundance with an impact on cell integrity. Concomitantly, sediment oxygen consumption was strongly inhibited. Correspondence analysis on T-RFLP data indicated that bacterial community structures from anthracene-contaminated microcosms were different from that of the control. Interestingly, the changes observed in microbial biomass, structure, and activities as a result of anthracene contamination were not alleviated even with the use of biostimulation and combination of biostimulation and bioaugmentation strategy for anthracene bioremediation. Nevertheless, both treatment methods resulted in different community structures relative to the contaminated and control microcosms with the appearance of distinct populations.
  
  
  CONCLUSIONS
  Anthracene spiking severely affected microbial communities, suggesting dominance of nontolerant populations in this lightly-contaminated sediment. Although biostimulation and/or bioaugmentation treatments did not alleviate the anthracene toxic effects, the changes observed in microbial population and structure suggest that the proposed treatments might be promising to promote bacterial growth. Further works are still required to propose a more efficient strategy to stimulate biodegradation that takes into account the complex interactions between species for resource access.
authors.affiliation: Laboratoire de Biosurveillance de l'Environnement, Faculté des Sciences de Bizerte, 7021 Zarzouna, Bizerte, Tunisia.
authors.forename: Hela
authors.initials: H
authors.lastname: Louati
authors.forename: Olfa
authors.initials: O
authors.lastname: Ben Said
authors.forename: Patrice
authors.initials: P
authors.lastname: Got
authors.forename: Amel
authors.initials: A
authors.lastname: Soltani
authors.forename: Ezzeddine
authors.initials: E
authors.lastname: Mahmoudi
authors.forename: Cristiana
authors.initials: C
authors.lastname: Cravo-Laureau
authors.forename: Robert
authors.initials: R
authors.lastname: Duran
authors.forename: Patricia
authors.initials: P
authors.lastname: Aissa
authors.forename: Olivier
authors.initials: O
authors.lastname: Pringault
mesh_terms: D000873:Anthracenes / Q000032:analysis*; D001419:Bacteria / Q000254:growth & development*; D001673:Biodegradation, Environmental; D018533:Biomass; D005308:Fertilizers; D019015:Geologic Sediments / Q000737:chemistry* / Q000382:microbiology; D012150:Polymorphism, Restriction Fragment Length; D014416:Tunisia; D014871:Water Microbiology; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D000873:Anthracenes; D005308:Fertilizers; D014874:Water Pollutants, Chemical; C034020:anthracene