Microbes with fire-resistant properties: The growth of something remarkable from small beginnings...
Increasing megafires worldwide have taken a devastating toll, with Australia registering over 24 million hectares burned during the 2019-2020 bushfire season. A massive fire event in California's Big Sur region in 2016 saw 53,400 hectares of redwood tanoak forest go up in flames, including sites undergoing fire-ecology studies. Biologists saw this as an opportunity to investigate the response of soil microbe communities to megafires.
Soil microbes, including bacteria, fungi, protozoa, and nematodes, play a crucial role in nutrient cycling, essential for maintaining plant and animal life. Fungi, in particular, have a symbiotic relationship with plants, helping them acquire nitrogen, a vital nutrient. However, the impact of megafires on these microbes is still largely unknown.
Sydney Glassman, a mycologist from the University of California and the study's lead author, stated, "Plants are unlikely to recover from megafires without beneficial fungi that supply roots with nutrients, or bacteria that transform extra carbon and nitrogen in post-fire soil. Understanding the microbes is key to any restoration effort."
The researchers collected soil samples from the two burnt sites and an ecologically similar but unburnt site. Their goal was to quantify and qualify the diversity of microbes before and after the mega-fire event, with a focus on bacteria and fungi.
Following the megafire, the number of microbial species had decreased significantly, with fungi operational taxonomy units (OTU) decreasing by 70% and bacteria OTU by as much as 52% in the burnt areas compared to the unburnt. The composition of the community also changed dramatically, with Ascomyocota becoming dominant after the mega-fire, while Basidiomycota fell by 35%, and Mucoromycota was wiped out.
For bacteria, the communities were previously dominated by Proteobacteria and Acidobacteria. After the fire, Proteobacteria numbers plummeted, while Firmicutes became the front-runner, and Acidobacteria benefited slightly. Penicillium and some species able to eat charcoal were among the microbes that prospered.
The team's results have been published in Molecular Ecology. Glassman emphasized, "One of the reasons there is so little understanding of fungi is that there are so few mycologists who study them. But they really do have important impacts, especially in the aftermath of major fires which are only increasing in frequency and severity both here and across the globe."
Originally published by Cosmos.
Megafires trigger complex, dynamic shifts in soil microbial communities, with implications for ecosystem resilience and recovery. However, direct empirical studies linking megafires specifically to bacterial and fungal diversity remain limited, as most research focuses on broad microbial biomass and activity rather than comprehensive species-level analyses.
The study on soil microbes reveals that megafires lead to significant decreases in microbial species, particularly fungi and bacteria, with consequences for plant and animal life recoveries. Furthermore, the researchers have highlighted the need for more direct empirical studies to link megafires to bacterial and fungal diversity, given the limited research in this area and the increasing frequency of severe fires globally, impacting health-and-wellness, environmental-science, climate-change, and fitness-and-exercise by altering ecosystems.
