It is recognized that in porous environments (e.g. soils, aquifers), biofilms control key functions Still, present reports of biofilms (porosity, permeability) give us a general picture of these situations. By consequence, the spatial heterogeneity of the environment with which the biofilms interact stays out of the question, remaining unexplored.

Swiss researchers have used several tools as microfluidics, sequencing and modeling in porous environments in order to explore biofilms in a 3D manner. Their recent report discloses that there is an architectural plasticity supporting biofilms to differentiate into base biofilms and streamers to complementarily use the space offered by the grain–pore complexes. This will intensify the carrying capacity of biofilms, being a groundwork of the ecological success of the microbial communities.

References: Lei G, Dong PC, Wu ZS, Gai SH, Mo SY, Li Z. Multi-scale structures of porous media and the flow prediction. J Nat Gas Sci Eng. 2014;21:986–92; Gelhar L, Welty C, Rehfeldt K. A critical review of data on field‐ scale dispersion in aquifers. Water Resour Res. 2010;28:1955–74.

Abstract

Biofilms regulate critical processes in porous ecosystems. However, the biophysical underpinnings of the ecological success of these biofilms are poorly understood. Combining experiments with fluidic devices, sequencing and modeling, we reveal that architectural plasticity enhances space exploitation by multispecies biofilms in porous environments. Biofilms consistently differentiated into an annular base biofilm coating the grains and into streamers protruding from the grains into the pore space. Although different flow-related processes governed the differentiation of these architectures, both BB and streamers were composed of similar bacterial assemblages. This is evidence for architectural plasticity. Architectural plasticity allowed for complementary use of the space provided by the grain–pore complexes, which increased biofilm carrying capacity at the larger scale of the porous system. This increase comes potentially at the cost of a tradeoff. Contrasting time scales of oxygen replenishment and consumption, we show that streamers locally inhibit the growth of the BB downstream from the grains. Our study provides first insights into the biophysical underpinnings to the success of multispecies biofilms in porous environments.

Reference: David Scheidweiler, Hannes Peter, Paraskevi Pramateftaki, Pietro de Anna, Tom J. Battin. Unraveling the biophysical underpinnings to the success of multispecies biofilms in porous environments. The ISME Journal (2019).

https://www.nature.com/articles/s41396-019-0381-4