(ORDO NEWS) — We know that there are truly hardy microorganisms that can survive, for example, in outer space or deep underground, but the group of microbes identified in the new study may be the most impressively hardy.
The study describes fungi and bacteria that not only survived the 2016 Soberanes megafire in California’s red tanuk forests, but thrived as a result of the fire. Understanding how and why this happens can help recovery efforts in regions affected by the devastating effects of wildfires.
Further analysis showed that the microbes that actually clung to life and subsequently thrived are genetically related, which should provide more clues as to why these lifeforms were able to survive the fire.
“They share adaptive traits that allow them to respond to fire, and this improves our ability to predict which microbes will respond, positively or negatively, to such events,” says mycologist Sidney Glassman of the University of California, Riverside.
Soil samples were taken from sites that researchers established in the mid-2000s to study an outbreak of sudden oak death; they first collected samples in 2013 and compared their contents with samples taken just after the fire in 2016.
Not all of the sites created were affected by the fire, so the team even had access to an unburnt control site for comparison.
Overall, fungal species richness was reduced by 70 percent and bacteria decreased by 52 percent in each sample. However, some groups of bacteria, including Actinobacteria (which help decompose plant material) and Firmicutes (which help plants grow and control plant pathogens), ended up thriving.
As far as fungi are concerned, the heat tolerant yeast Basidioascus has seen tremendous growth. These yeasts decompose various components of wood, including lignin (the tough part of plant cell walls that keeps them structured and protected).
Penicillium is another genus that has weathered the fire quite well, and a team of researchers is now looking to figure out how these various microbes increased. It is likely that different types of microbes used different methods.
“Penicillium likely takes advantage of food excreted from necromass, or ‘dead bodies’, and some species may also feed on charcoal,” says Glassman.
Megafires – a term used to describe the historically significant, large-scale fires of recent years that have become increasingly intense and cover a large area – are occurring with increasing frequency as climate change leads to higher temperatures and more snowmelt.
Although wildfires are a natural part of many ecosystems, they used to be of minor intensity and quickly passed over an area, helping to revitalize the soil, remove some dead plants and help others reproduce.
However, megafires lead to catastrophic destruction of ecosystems. For example, the 2016 Soberanes Megafire burned about 132,127 acres or 53,470 hectares of land.
At the moment, little is known about how soils and their microbiomes respond to megafires, partly because it is very difficult to predict where the flames will start and where they will then move.
The experts’ next step will be to study the survival strategies offered by these fungi and bacteria and develop ways to use them in restoration work – returning forests to their former biodiverse state.
“It’s unlikely plants will be able to recover from megafires without beneficial fungi that provide nutrients to the roots, or bacteria that convert the extra carbon and nitrogen in the soil after a fire,” says Glassman. “Understanding microbes is key to any recovery effort.”
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