Wildfire Smoke Carries Viable Microbes

Smoke from large wildfires that can be seen from space, does more than lower air quality and limit visibility. Wildfire smoke also transports viable bacteria and fungi from plants, woody debris, and soils.

When Leda Kobziar, a University of Idaho associate professor of wildland fire science in the College of Natural Resources, along with colleagues in Florida collected smoke samples from burning forests in Florida they discovered that over 80% of the microbes in the smoke were viable. In samples of crown fire smoke collected in Utah with drones, researchers found 60% of microbes were viable. 

Kobziar and her colleagues estimated that 40 trillion to more than 100 trillion microbes are released into the atmosphere in smoke for each hectare (about 2.5 acres) burned in low-intensity and higher intensity, wildfire-like burns, respectively.

“This means that larger fires would be predicted to mobilize even larger numbers of microbes,” Kobziar said.

Results showed that the majority of the microbes were attached to particles or clumped in groups depending on the type of materials, including plants, wood, and soils that were burned.

Researchers also measured the potential for the microbes to enhance the condensation and freezing of water in the lower atmosphere by acting as ice nucleating particles.

If these particles are transported to clouds they could potentially affect precipitation or even form pyrocumulus clouds over high-intensity wildfires, Kobziar said. 

The work shows that microbes living on, and in plants and soils can disperse around the planet potentially spreading pathogens or toxins or affecting the biological functioning of the places they land. 

Kobziar’s studies were part of a collaboration between scientists from the University of Florida, the Desert Research Institute, and the Colorado School of Mines.

Article by Ralph Bartholdt, University Communications and Marketing.

Photo by David Vuono.

Published in February 2021.