The establishment of O2 gradients in liquid columns by bacterial metabolic activity produces a spatially-structured environment. This produces a high-O2 region at the top that represents an un-occupied niche which could be colonised by biofilm-competent strains. We have used this to develop an experimental model system using soil-wash inocula and a serial-transfer approach to investigate changes in community-based biofilm-formation and productivity. This involved 10 transfers of mixed-community or biofilm-only samples over a total of 10–60 days incubation. In all final-transfer communities the ability to form biofilms was retained, though in longer incubations the build-up of toxic metabolites limited productivity. Measurements of microcosm productivity, biofilm-strength and attachment levels were used to assess community-aggregated traits which showed changes at both the community and individual-strain levels. Final-transfer communities were stratified with strains demonstrating a plastic phenotype when migrating between the high and low-O2 regions. The majority of community productivity came from the O2-depleted region rather than the top of the liquid column. This model system illustrates the complexity we expect to see in natural biofilm-forming communities. The connection between biofilms and the liquid column seen here has important implications for how these structures form and respond to selective pressure.
- Air-liquid (A-L) interface biofilm
- Bacterial communities
- Community-aggregated traits
- Community change
- Experimental microcosm
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Understanding the eco-evolutionary dynamics underpinning changes in air-liquid interface biofilms in radiating populations and multi-species communitiesAuthor: Jerdan, R., 16 Apr 2021
Student thesis: Doctoral ThesisFile