Water flow drives small scale biogeography of pesticides and bacterial pesticide degraders - A microcosm study using 2,4-D as a model compound

Pinheiro, Marc; Pagel, Holger; Poll, Christian; Ditterich, Franziska; Garnier, Patricia; Streck, Thilo; Kandeler, Ellen; Gonod, Laure Vieublé

doi:10.1016/j.soilbio.2018.09.024

Cited by 11 publications

(24 citation statements)

References 54 publications

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“…Among the scarce relevant datasets, we used the two sets of cm-scale soil-core experiments of Pinheiro et al (2015Pinheiro et al ( , 2018 performed on similar repacked soil columns for the degradation of 2,4-D under different initial distributions and transport conditions. Mostly reported independently, they have shown first that the proximity between bacteria and heterogeneously distributed substrate sources, referred to as "accessibility" of bacteria to substrate (Dungait et al, 2012), is a strong control of mineralization.…”

Section: Introductionmentioning

confidence: 99%

“…Substrate diffusion does not compensate for accessibility, as bacteria clusters located far from the substrate source are only exposed to highly diluted substrate (Babey et al, 2017). However, the hydrodynamic dispersion of both bacteria and substrate away from the substrate source strongly increased the bacterial degradation of the substrate that was not leached out (Pinheiro et al, 2018). We briefly introduce the experiments to show their potential to further explore bio-physical coupling within the unified quantitative framework proposed later in the article.…”

Section: Introductionmentioning

confidence: 99%

“…1B,C ). Two sets of experiments, referred to as “hydrostatic” and “percolation” conditions, were performed respectively with only substrate diffusion (Pinheiro et al, 2015), or with additional substrate and bacterial advection and dispersion caused by water percolation (Pinheiro et al, 2018) ( Fig. 1C ).…”

Section: Introductionmentioning

confidence: 99%

“…Among the scarce relevant datasets (e.g. Dechesne et al, 2010), we used the two sets of cm-scale soil-core experiments performed by Pinheiro et al (2015, 2018), in which the degradation of 2,4-D under different initial spatial distributions and transport conditions was measured in similar repacked soil columns. Mostly reported independently, they have shown first that the proximity between bacteria and the initial location of a heterogeneously distributed substrate exerts a strong control on mineralization.…”

Section: Introductionmentioning

confidence: 99%

“…Experimental setup and mineralization (adapted fromPinheiro et al (2018Pinheiro et al ( , 2015, permission for reproduction granted by Elsevier). (A) Sketch of soil columns experimental design and their decomposition into elementary soil cubes.…”

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confidence: 99%

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Competition within low-density bacterial populations as an unexpected factor regulating carbon decomposition in bulk soil

Coche

Babey

Rapaport

et al. 2020

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Bacterial decomposition of organic matter in soils is generally believed to be mainly controlled by the accessibility of bacteria to their substrate. The influence of bacterial metabolic traits on this control has however received little attention in highly heterogeneous spatial conditions under advective-dispersive transport of bacteria and substrates. Here, we develop a biochemical transport model to screen the interactive impacts of dispersion and metabolic traits on mineralization. We compare the model results with two sets of previously performed cm-scale soil-core experiments in which the mineralization of the pesticide 2,4-D was measured under well-controlled initial distributions and transport conditions. Bacterial dispersion away from the source of substrate induced a significant increase in 2,4-D mineralization, revealing the existence of a control of decomposition by the bacterial density, in addition to the accessibility to the substrate. This regulation of degradation by density becomes dominant for bacteria with an efficient uptake of substrate at low substrate concentrations (i.e. oligotrophs). The model output suggests that the distance between bacteria adapted to oligotrophic environments is a stronger regulator of degradation than the distance between substrate source and these bacteria. Such oligotrophs, commonly found in soils, compete with each other for substrate even under remarkably low population densities. The ratio-dependent Contois growth model, which includes a density regulation in the expression of the uptake efficiency, appears more versatile and accurate than the substrate-dependent Monod model. In view of their strong interactions, biochemical and transport processes cannot be handled independently but should be integrated, in particular when biochemical processes of interest are carried out by oligotrophs.Abstract FigureHighlights–Biodegradation in soils results from strong biochemical and transport couplings–Biodegradation depends on bacterial density, in addition to substrate accessibility–Bacterial density regulation counterbalances substrate accessibility regulation–Density regulation is enhanced for oligotrophic bacteria–The ratio-dependent Contois model is relevant to represent this double regulation

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%