title: Effects of predation and dispersal on bacterial abundance and contaminant biodegradation.
abstract: Research into the biodegradation of soil contaminants has rarely addressed the consequences of predator-prey interactions. Here, we investigated the joint effect of predation and dispersal networks on contaminant degradation by linking spatial abundances of degrader (Pseudomonas fluorescens LP6a) and predator (Bdellovibrio bacteriovorus) bacteria to the degradation of the major soil contaminant phenanthrene (PHE). We used a laboratory microcosm with a PHE passive dosing system and a glass fiber network to facilitate bacterial dispersal. Different predator-to-prey ratios and spatial arrangements of prey and predator inoculation were used to study predation pressure effects on PHE degradation. We observed that predation resulted in (i) enhanced PHE-degradation at low predator counts (PC) compared to controls lacking predation, (ii) reduced PHE-degradation at elevated PC relative to low PC, and (iii) significant effects of the spatial arrangement of prey and predator inoculation on PHE degradation. Our data suggest that predation facilitated by dispersal networks (such as fungal mycelia) may support the build-up of an effective bacterial biomass and, hence, contaminant biodegradation in heterogeneous systems such as soil.
authors.affiliation: UFZ-Helmholtz Centre for Environmental Research, Department of Environmental Microbiology, Permoserstr. 15, 04318 Leipzig, Germany.
authors.forename: Sally
authors.initials: S
authors.lastname: Otto
authors.affiliation: UFZ-Helmholtz Centre for Environmental Research, Department of Environmental Microbiology, Permoserstr. 15, 04318 Leipzig, Germany.|German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103 Leipzig, Germany.
authors.forename: Hauke
authors.initials: H
authors.lastname: Harms
authors.affiliation: UFZ-Helmholtz Centre for Environmental Research, Department of Environmental Microbiology, Permoserstr. 15, 04318 Leipzig, Germany lukas.wick@ufz.de.
authors.forename: Lukas Y
authors.initials: LY
authors.lastname: Wick
mesh_terms: D001501:Bdellovibrio / Q000254:growth & development / Q000502:physiology; D001673:Biodegradation, Environmental; D018533:Biomass; D020387:Food Chain; D011551:Pseudomonas fluorescens / Q000378:metabolism / Q000502:physiology*; D012989:Soil Pollutants / Q000032:analysis / Q000378:metabolism*
chemical_list: D012989:Soil Pollutants
keywords: Bdellovibrio bacteriovorus 109J; Prey-predator interaction; Pseudomonas fluorescens; biodegradation; dispersal network; passive dosing; phenanthrene; predation pressure