title: Top-Down Control of Diesel-Degrading Prokaryotic Communities.
abstract: Biostimulation through the addition of inorganic nutrients has been the most widely practiced bioremediation strategy in oil-polluted marine waters. However, little attention has so far been paid to the microbial food web and the impact of top-down control that directly or indirectly influences the success of the bioremediation. We designed a mesocosm experiment using pre-filtered (<50 μm) surface seawater from the Bay of Banyuls-sur-Mer (North-Western Mediterranean Sea) and examined the top-down effect exerted by heterotrophic nanoflagellates (HNF) and virus-like particles (VLP) on prokaryotic abundance, activity and diversity in the presence or absence of diesel fuel. Prokaryotes, HNF and VLP abundances showed a predator-prey succession, with a co-development of HNF and VLP. In the polluted system, we observed a stronger impact of viral lysis on prokaryotic abundances than in the control. Analysis of the diversity revealed that a bloom of Vibrio sp. occurred in the polluted mesocosm. That bloom was rapidly followed by a less abundant and more even community of predation-resistant bacteria, including known hydrocarbon degraders such as Oleispira spp. and Methylophaga spp. and opportunistic bacteria such as Percisivirga spp., Roseobacter spp. and Phaeobacter spp. The shift in prokaryotic dominance in response to viral lysis provided clear evidence of the 'killing the winner' model. Nevertheless, despite clear effects on prokaryotic abundance, activity and diversity, the diesel degradation was not impacted by top-down control. The present study investigates for the first time the functioning of a complex microbial network (including VLP) using a nutrient-based biostimulation strategy and highlights some key processes useful for tailoring bioremediation.
authors: UPMC Univ Paris 06, UMR 7621, Laboratoire d'Océanographie Microbienne, Observatoire Océanologique, Sorbonne Universités, 66650, Banyuls-sur-mer, France.
authors: Caroline
authors: C
authors: Sauret
authors: Daniela
authors: D
authors: Böttjer
authors: Agathe
authors: A
authors: Talarmin
authors: Catherine
authors: C
authors: Guigue
authors: Pascal
authors: P
authors: Conan
authors: Mireille
authors: M
authors: Pujo-Pay
authors: Jean-François
authors: JF
authors: Ghiglione
mesh_terms: D001419:Bacteria / Q000145:classification / Q000378:metabolism*; D001673:Biodegradation, Environmental; D017753:Ecosystem; D059013:Microbial Consortia; D010578:Petroleum / Q000382:microbiology; D012623:Seawater / Q000382:microbiology*; D014871:Water Microbiology
chemical_list: D010578:Petroleum