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Linkages Between Microbial Community Structure and Functions

Much of the work in the field of molecular microbial ecology has focused on the question “who is there?”, and only recently have molecular studies begun to focus on the question the Dunfield laboratory asks, which is instead, “what are they doing?” We attempt to link the structure of microbial communities, and in particular shifts in the composition of microbial communities, with shifts in ecosystem function. Some microbially-driven ecosystem functions which have come under scrutiny include alkaline phosphatase activity, and the balance of nitrogen cycling processes which give rise to nitrous oxide (N2O) greenhouse gas fluxes. 

Some research highlights include:

  • In collaboration with researchers at Dalhousie University and the University of Manitoba, examining changes in microbially mediated phosphorus cycling in soil managed as no-input, organic, conventional, or restored prairie for 21 years, and finding that under conditions of low phosphorus input, soil bacteria may increase alkaline phosphatase enzyme production to meet their phosphorus needs
  • Documenting shifts in bacterially-produced alkalkine phosphatase gene expression in response to different soil management treatments
  • Relating transcription of alkaline phosphatase genes to alkaline phosphatase enzyme functioning (ongoing)
  • Tying field-scale measurements of N2O flux to changes in soil microbial community composition, in terms of the diversity of genes involved in nitrification and denitrification,
  • Quantifying the changes in nitrifying and denitrifying bacterial communities and linking this to a spring thaw N2O emission event, and finding that nitrous oxide reductase transcription was inversely correlated to N2O flux in two fields