Pyroaerobiology: Elucidating the composition, diversity, and ecological role of microorganisms in wildfire smoke

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The talk will be held over Zoom. Please connect at the following url: https://oist.zoom.us/j/96428330188?pwd=ZXBBaEZib0prV1k0aWRDM0wzdFZ1UT09

Meeting ID: 964 2833 0188

Passcode: 641777

Abstract

The atmosphere contains a diverse reservoir of microbes but the sources and factors contributing to microbial aerosol variability are not well described. To advance understanding of microbial emissions in wildfire smoke, we used unmanned aircraft systems to analyze the aerosols above high-intensity forest fires in the western United States. Samples of wildfire smoke contained four-fold higher concentrations of cells (1.02 ± 0.26 × 10⁵ m⁻³) compared to background air, with 78% of microbes in smoke inferred to be viable. Fivefold higher taxon richness and ~threefold enrichment of ice nucleating particle concentrations in smoke implies that wildfires are an important source of diverse bacteria and fungi as well as meteorologically relevant aerosols. We estimate that such fires emit 3.71 × 10¹⁴ microbial cells per hectare under typical wildfire conditions in western US forests and demonstrate that wildland biomass combustion has a large-scale influence on the local atmospheric microbial assemblages. Given the long-range transport of wildfire smoke emissions, these results expand the concept of a wildfire’s perimeter of biological impact and have implications to biogeography, gene flow, the dispersal of plant, animal, and human pathogens, and meteorology.

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