Skip to main content

Competition between growth and shear stress drives intermittency in preferential flow paths in porous medium biofilms

Author(s): Kurz, Dorothee L; Secchi, Eleonora; Carrillo, Francisco J; Bourg, Ian C; Stocker, Roman; et al

To refer to this page use:
Abstract: Bacteria in porous media, such as soils, aquifers, and filters, often form surface-attached communities known as biofilms. Biofilms are affected by fluid flow through the porous medium, for example, for nutrient supply, and they, in turn, affect the flow. A striking example of this interplay is the strong intermittency in flow that can occur when biofilms nearly clog the porous medium. Intermittency manifests itself as the rapid opening and slow closing of individual preferential flow paths (PFPs) through the biofilm–porous medium structure, leading to continual spatiotemporal rearrangement. The drastic changes to the flow and mass transport induced by intermittency can affect the functioning and efficiency of natural and industrial systems. Yet, the mechanistic origin of intermittency remains unexplained. Here, we show that the mechanism driving PFP intermittency is the competition between microbial growth and shear stress. We combined microfluidic experiments quantifying Bacillus subtilis biofilm formation and behavior in synthetic porous media for different pore sizes and flow rates with a mathematical model accounting for flow through the biofilm and biofilm poroelasticity to reveal the underlying mechanisms. We show that the closing of PFPs is driven by microbial growth, controlled by nutrient mass flow. Opposing this, we find that the opening of PFPs is driven by flow-induced shear stress, which increases as a PFP becomes narrower due to microbial growth, causing biofilm compression and rupture. Our results demonstrate that microbial growth and its competition with shear stresses can lead to strong temporal variability in flow and transport conditions in bioclogged porous media.
Publication Date: 26-Jul-2022
Electronic Publication Date: 18-Jul-2022
Citation: Kurz, Dorothee L, Secchi, Eleonora, Carrillo, Francisco J, Bourg, Ian C, Stocker, Roman, Jimenez-Martinez, Joaquin. (2022). Competition between growth and shear stress drives intermittency in preferential flow paths in porous medium biofilms. Proceedings of the National Academy of Sciences, 119 (30), 10.1073/pnas.2122202119
DOI: doi:10.1073/pnas.2122202119
ISSN: 0027-8424
EISSN: 1091-6490
Language: en
Type of Material: Journal Article
Journal/Proceeding Title: Proceedings of the National Academy of Sciences
Version: Final published version. This is an open access article.

Items in OAR@Princeton are protected by copyright, with all rights reserved, unless otherwise indicated.