Pseudomonas fluorescens dynamics in the soil surface to subsurface transect

• Published in: Journal of environmental science and health. Part B, Pesticides, food contaminants, and agricultural wastes Pesticides, food contaminants, and agricultural wastes, 2006-01, Vol.41 (4), p.415-425
• Main Authors: Langenbach, T, Maciel, S.J, Neves, B.C.V, Hagler, A.N, Mano, D.M, Vugman, N.V
• Format: Article
• Language: English
• Subjects: adsorption; Agronomy. Soil science and plant productions; Animal, plant and microbial ecology; bacterial motility; Biodegradation, Environmental; Biological and medical sciences; Colony Count, Microbial; Dose-Response Relationship, Drug; Fundamental and applied biological sciences. Psychology; leachates; leaching; microbial activity; Microbial association to iron; Microbial ecology; microbial growth; Microbial leaching; Microbial movement; Microflora of plants; mortality; Pesticides - metabolism; Population Dynamics; Pressure; Pseudomonas fluorescens; Pseudomonas fluorescens - growth & development; Pseudomonas fluorescens - metabolism; rainfall simulation; Resistance to pressure; Soil and water pollution; soil bacteria; soil chemical properties; soil depth; soil horizons; Soil Microbiology; Soil science; viability
• ISSN: 0360-1234; 1532-4109
• DOI: 10.1080/03601230600616890

Microbial displacement in the soil is an important process for bioremediation and dispersal of wastewater pathogens. We evaluated cell movement in surface and subsurface red-yellow podzolic soil driven by advection and microbial motility and also survival of a microbial population at high pressure as is prevalent in deep soil layers. Pseudomonas fluorescens Br 12, resistant to rifampycin and kanamycin, was used as a model organism traceable in non-sterile soil. Our results showed that more than 40% of the P. fluorescens population survived under high pressure, and that microbial motility was not a major factor for its displacement in the soil. Cells were adsorbed in similar amounts to surface and subsurface soils, but more viable cells were present in the leachate of surface than in subsurface soils. The nature of this unexpected cell binding to the subsurface soil was studied by EPR, Mossbauer, NMR, and infrared techniques, suggesting iron had a weak interaction with microbes in soil. P. fluorescens movement in soil resulted mainly from convection forces rather than microbial motility. The transport of this bacterium along the transept toward groundwater encountered restricted viability, although it survived under high pressure conditions simulating those in deep soil layers.