I love eating mushrooms. I love the aroma of cooked mushrooms. I know mushrooms are a fungus, and I generally feel positive when fungi are mentioned. My limited knowledge of fungi as the great recyclers comes from Merlin (the scientist, not the magician). My positive feelings have reduced now that I’ve read a second book featuring fungi: Blight by Emily Monosson is subtitled “Fungi and the coming pandemic”. It’s mostly about invasion.
“Rusts, molds, mildews, and mushrooms – we live in a cloud of fungal spores, microscopic spherules of nascent fungi. Fungi are everywhere.” Monosson goes on to list a wide range of examples including uncommon ones such as “in the radioactive ruins of Chernobyl, and behind damp towels hung to dry on the International Space Station”. The spores move easily. They’ve evolved to do so, staying protected as they are carried to favorable conditions where they proceed to have a growth spurt. We humans are carriers too!
Fungi are useful, and not just as edible delectable mushrooms. They’re a key bridge for recycling biomolecules, and many are symbiotic organisms. We have them in our gut microbiome. Life-saving penicillin comes from a fungus. But when you’re a recycler, you’re just as likely to be a bringer of death, not just a bringer of life. Monosson writes: “Most fungi live if not in collaboration, then in peace with other living things. But some do not. Some feed on the living rather than the dead and dying.” These are the fungal pathogens, and they wreak havoc as invaders.
In one chapter after another, Blight goes through a horror story of fungal invasion. Frogs, bananas, bats, chestnut trees, and more. Humans play a large part in unwittingly facilitating this invasion, be it through prioritizing monoculture cash crops, trading in exotic animals, indiscriminate antibiotic use, and carrying dirt, seed, spores via globalized trade and travel. Human fungal infections on the surface of our bodies are typically annoying but manageable. But once they invade the blood, fungal infections have a high mortality rate. There aren’t many of those yet, but there might be more. Why? Fungi prefer lower temperatures than found in most warm-blooded mammals. But with global warming and more significant hotter microclimates, fungi begin to adapt. It’s the law of evolution. As more warm-temperature fungi proliferate, the increased chances of a pathogenic invader arising becomes significant.
When an invasive species arrives on the scene, the question is whether the defenders have evolved appropriate mechanisms to survive and fight off the invaders. Humans have the additional advantage of building tools to aid the defense, even though we’ve not always been wise about taking precautions and anticipating side-effects. By breeding plants and animals to be juicier or fatter, we’ve inevitably bred out potentially protective wild-type genes. And when the invaders arrive, they cause devastation that we try to stem off with chemical warfare. We don’t fully understand the complexity of life and death. Maybe we never will.
I also enjoy the aroma of fresh bread. Yeast, a fungus, helps this process along. I’ve been reading The Expanse sci-fi series, and there’s an interesting conversation in Book 6 (Babylon’s Ashes) involving a scientist working to engineer a ‘harvester’ yeast to “generate its own sugars from the radioplasts, and … convert that into higher-complexity nutrients.” In the story, radioplasts are reverse-engineered chloroplasts in yeast that photosynthesize very efficiently and a way to increase food production. Actually, the scientist is being interrogated by a militarized junta who suspect him of being a traitor or part of a rebellion. Thinking he’s about to die, the scientist launches into a soliloquy about biology. I’ve strung together excerpts of his speech.
“Biological equilibria? They’re not straightforward. Never. Everyone thinks that it’s simple. New, invasive species comes in and it has an advantage and outcompetes, right? That’s the story, but there’s another part to that. Always, always, the local environment resists. Yes, yes, maybe badly. Maybe without a clear idea of coping with novelty… Even when an invasive species takes over, even when it wins, there is a counterbalancing process… And that process is so deep in the fabric of living systems, it can never be absent. However well the new species is designed, however overwhelming its advantages seem to be, the pushback will always be there. If one native impulse is overcome, there will be another… Conspecifics are outcompeted? Fine, the bacteria and viral microecologies will push back. Adapt to those, and it’ll be micronutrient levels and salinity and light. And the thing is, even when the novel species does win? Even when it takes over every niche… that struggle alone changes what it is. Even when you wipe out or co-opt the local environment, you’re changed by the pushback. Even when the previous organisms are driven to extinction, they leave markers behind. What they are can never, never be completely erased.”
I think we are the invasive species par excellence of Planet Earth. We aren’t content to increase the energy content within our bodies, we are the biggest guzzlers of energy for our lifestyle. A decade ago, I would not have anticipated that we’d be burning through planetary energy resources to build server farms to mine bitcoin, a virtual rather than physical resource. And as anthropogenic actions accelerate rising temperatures, the fungi will rise to meet the challenge. We might soon become the invaded. Perhaps the biological recyclers will have the last say.
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