Imagine an underground web of mind-boggling complexity, a bustling cosmopolis beneath your feet. Quadrillions of miles of tiny threads in the soil pulsate with real-time messages, trade vital nutrients, and form life-giving symbiotic partnerships. This is the mysterious realm of fungi. In this program, acclaimed visionary biologists Toby Kiers and Merlin Sheldrake will guide us through the intricate wonders of the mycorrhizal fungal networks that make life on Earth possible.

This is an episode of Nature’s Genius, a Bioneers podcast series exploring how the sentient symphony of life holds the solutions we need to balance human civilization with living systems. Visit the series page to learn more.

This limited series was produced as part of the Bioneers: Revolution from the Heart of Nature radio and podcast series. Visit the homepage to find out how to hear the program on your local station.

Subscribe to the Bioneers: Revolution from The Heart of Nature podcast

---

Transcript

Neil Harvey (Host): Imagine an underground web of mind-boggling complexity, a bustling cosmopolis beneath your feet. Quadrillions of miles of tiny threads in the soil – pulsing with real-time messages, trading vital nutrients, forming life-giving symbiotic partnerships. This is the mysterious realm of fungi.

We visit the intricate wonder of the mycorrhizal fungal networks that make Life on Earth possible, with biologists Toby Kiers and Merlin Sheldrake.

Fungi are one of the biological Kingdoms of Life. It’s a taxonomic category as broad as plants or animals. They evolved hundreds of millions of years ago – maybe as much as a billion – and they’re essential to the sustenance and evolution of life in all its diversity. Without them, we would certainly not exist.

Humans have long used and revered fungi for food, medicine, tools – not to mention for their consciousness-altering psychedelic effects. Yet despite fungi’s central role in evolution, in ecosystems and in human culture, they were recognized as a unique kingdom of life only in the 1960s. We’ve barely begun to scratch the surface.

But the word “kingdom” is a misnomer. After all, there are no kings in nature. Instead, let’s call it a “kin-dom” – because in nature, it’s all relatives – an intricate tapestry of evolutionary kinship.

Fungi are distinct from plants and animals, though intimately connected to both. We’re most familiar with mushrooms, the above-ground, fleshy, fruiting bodies of fungi. Yet far more extensive are the vast subterranean fungal networks spreading out across the earth, linking them to other forms of life.

At the forefront of seeking to understand these networks and their seemingly highly intelligent behavior are two visionary biologists: Merlin Sheldrake and Toby Kiers.

Their focus is on mycorrhizal fungi, a particular type that has an intimate, symbiotic relationship with plants…

Merlin Sheldrake (MS): Almost all plants depend on mycorrhizal fungi, and these fungi are chemical wizards. They’re brilliant navigators in the wild, wet world of the soil. They’re able to grow and remodel their bodies, and forage using their chemical ingenuity for nutrients. And plant partners, in exchange for these nutrients, they provide the fungi with things that the fungi need to grow.

Host: That’s Merlin Sheldrake speaking at a Bioneers conference. He’s a biologist, researcher and the author of the best-selling book “Entangled Life: How fungi make our worlds, change our minds and shape our futures.” This leading-edge scientific quest is humbling, showing how much we have to learn. 

Mycorrhizal fungi mingle with plant roots, supplying them with nutrients such as nitrogen and phosphorus. In exchange, plants trade sugars and fats they generate through photosynthesis.

These vast mycelial networks of fine tubes branch and tangle their way through the teeming life of the soil.

MS: This is really an intermingling of bodies, it’s one of the living world’s great intimacies. I suppose I would say that, but I really do believe it. And it is an astonishing way that organisms can come together to extend their reach, and to make things possible that wouldn’t otherwise be possible. This is really actually the roots of life on land. Plants would only make it out of water onto the land with the help of their fungal associates, who behaved as their root systems for tens of millions of years until plants could evolve their own roots.

At any one moment, a mycorrhizal fungus will be remodeling itself to explore the soil. It will be doing crazy things with its metabolism to forage and acquire nutrients. It will be forming relationships with crowds of microbes across its network. It will be diverting nutrients around its networks, circulating them in just the right way to enable it to trade with its plant partners. It must be integrating information across an immense number of nodes, which at any one moment can be strung between multiple plants and sprawled over meters

Globally, the total length of mycorrhizal fungal mycelium in the top ten centimeters of soil is more than 450 quadrillion kilometers, which is over half of the width of the galaxy. [AUDIENCE RESPONDS] These organisms are stationed at a vital point in global carbon and nutrient cycles, and they make up one of the circulatory systems of the planet, an ancient life support system that easily qualifies as one of the wonders of the living world.

Host: Yet the ground truth is how very little we know about the wondrous invisible world that’s living right under our feet.

MS: Mycorrhizal fungi are bathed in rich fields of sensory information. They must determine when, where and how to move resources across their networks. They must integrate myriad data streams across billions of nodes in their networks. These are complex information processing systems, solving non-trivial problems on a moment-to-moment basis, and we have no idea how they can do what they do…to achieve the astonishing feats that they achieve. Right? These ecosystem engineers.

So in Amsterdam, we, and amazing, amazing teams in these labs, working to decode the language of fungal information processing, to at last ask how fungi are able to coordinate these flows, to make decisions, to process information, and how to do what they do.

So to do this, we have a custom-built imaging robot. And this robot allows us to quantify both the architecture of the fungal network, so the branching patterns. You can think of that as the map of the roads in a city. But also the flows within the network. So you can think of this as the traffic movement on the roads within the city.

And we need to know both, because it’s in the flows that they’re encoding information but they’re only able to do that by creating a network and remodeling the network within which that information is flowing.

Host: Time-lapse footage from the lab’s imaging robot shows mycelial tubes delicately spreading and branching out – these are the fungal network’s relentlessly growing pathways.

Zooming in even further, a different video shows myriad blobs of light, rapidly flowing through tubes in real time – these are carbon and nutrients being transported around the network.

The researchers’ current technology can track over half a million fungal nodes across space and time – and they’ve discovered evidence of the networks’ extraordinary capabilities.

MS: If you could fit inside the network and ride on these flows, it would feel like you were traveling at about 40 kilometers an hour. These are rapid flows of carbon and nutrients; they’re changing direction; they’re going in opposite directions at once within the same section of pipe. Crazy things are happening at these branch points. And it’s really quite wild.

You know, we get together in the lab and sit in darkened rooms and look at these videos like children, [LAUGHTER] and just pulling our hair out. It’s like: How are they doing this? Look at this. [LAUGHTER] Do you see the blob? A blob of that junction in this video is going up the right hand branch now. Watch it. It’s going up the right hand branch, and oh, oh, no, no…

Host: The video shows a glowing blob stop in its tracks as if changing its mind, then reverse… 

MS: [LAUGHTER] It’s going to come right back down, and what’s going to—oh. [APPLAUSE]

Host: The reversing blob reaches a junction in the network and now splits into two blobs. Each heads off down separate branches – apparently with purpose. 

MS: What’s going on? [LAUGHTER] That’s one node in one small network, growing in one small dish in one laboratory in Amsterdam. [LAUGHTER]

Host: What is going on? The blobs look like they’re making deliberate decisions in real time. But is that an anthropomorphic spin on things? How can we interpret such behavior?

Well, the Amsterdam researchers are doing their best to analyze it – and their research is in review at the premier scientific journal Nature.

This sense of awe is all happening under the watchful eyes of evolutionary biologist Toby Kiers, who works closely with Merlin. In a conversation they had, she described the bewildering experience of watching these networks in action.

Toby Kiers (TK): There’s this sense of unknown. And when people come to, especially when they come to work in the lab in Amsterdam, they leave different people, because they’ve seen things that they haven’t seen before.

And one of the things is that when you’re watching these mycorrhizal networks, you’re seeing things in real time. Like I just want—I really want to drive that home. Like those flows, that’s not sped up. We’re not like, oh, let’s put it on—This is in real time. And you’re studying behaviors of organisms that don’t have brains, and you’re still watching how they solve complex problems, like in front of your eyes.

We do these—It sounds really cruel, but we do these experiments because we have to understand how the networks work, where we cut them, and we see how long it takes for them to heal. And if you make a really clean cut, like a surgeon’s cut across the network, we came back after lunch and it had reconfigured. [AUDIENCE RESPONDS] And those flows had just reinstated. Even just biochemically how that is possible is just mind-blowing.

When you watch another creature, you know, remodeling its body in that way right in front of your eyes, how could you not want to know more? How could we not all be studying this? And I think that, for me, is sort of the philosophy is just like, you get hooked. These organisms, they change your worldview.

Host: Witnessing such marvels, it’s hard to avoid the impression of a complex intelligence at work.

The Latin root of the word “intelligence” means to choose between – and it certainly appears as though deliberate, purposeful decisions are being made. After all, fungi do have hundreds of millions of years of evolutionary R&D under their belt.

Traditionally, Western science is reluctant to attribute intelligence to other-than-human creatures and organisms. This professional canon holds that we’d be anthropomorphizing, or losing “objectivity”, though objectivity itself is a questionable proposition.

However, might mainstream science accept these fungal networks as evidence of intelligence in nature? It wouldn’t be surprising. It’s well documented now that single-cell, brainless blobs of mucus called slime molds unerringly solve mazes, a traditional test for intelligence among many other traditional scientific tests that are now validating other-than-human intelligence throughout nature. In fact, we may well be living through a major paradigm shift.

Again, Merlin Sheldrake.

MS: A lot has changed in the last few years. So the cognitive sciences evolved, placing the human mind at the center of its studies, and that makes sense, because we’re humans and we’re proud of our brains and what we can do. But then, over time, that becomes very, very limiting, because you start to use the human mind and human intelligence as a yardstick by which to judge everybody else. And, of course, if you do that, then you’re going to find that, no, no, they can’t solve this problem that we can solve, and it can become very, very bigoted and very, very limiting. 

So what started to change is that, and partly because people have become much more comfortable attributing intelligence to machines, the whole language and conversation has shifted. And so now the way it’s discussed in a growing number of circles in the biological sciences is that there are intelligent behaviors. These are things like the ability to solve problems, or make decisions, or adapt to changes in one’s environment. And that all organisms to some degree are intelligent problem solvers, it’s just they’ve evolved to solve different kinds of problems. So a fungus has evolved to solve very different kinds of problems to us. 

And so I think this is not very controversial anymore, which is great. And I think that’s really helpful, because it invites us into a question that Toby and I love, this question of like: What’s it like to be you? You know? When you’re studying an organism, it’s—this really feels like the central question as a biologist: What’s it like to be you?

TK: One of the things that we do in the lab is that we set up these experiments to try to figure out that question, what it’s like to be you. And, you know, one of the things that these fungi do is they’re really good traders. Right? Their whole way that they live is dependent on getting carbon from plant roots. So they’re what we call obligate biotrophs, which means they can’t get carbon from anywhere except a root system. And so they have evolved very sophisticated trade strategies to be able to get that carbon. And because we are able to do these really, really high precision experiments, we can set up and actually track the way that they move resources to understand how they make decisions.

And the strategies they evolve are just mind-blowing. I mean, we can show that they discriminate among different plant roots and send more of the phosphorus to the root system that’s giving more carbon in return; that they can discriminate between where they’re getting the carbon.

They do these things where if you give them a lot of phosphorous, they’ll take it up into the network and actually hold back before giving it to the plant until the plant needs even more, and they get more carbon, right, if they hoard it for just a bit longer, they’ll get more carbon in return.

We were doing this experiment where we tracked the phosphorus. We attached a quantum dots, these nanoparticles, to phosphorus, and they fluoresce in really bright colors when you hit it with a UV source, and we could see that the fungi would take up the phosphorous from a very concentrated area and move it all the way across to another part of the network where the plant demand was higher, to be able to get more carbon. And so these are all laboratory experiments. Right? So be very careful about taking them to the level of the ecosystem or the forest. But when you bring these systems into the lab and actually study those very precise trading strategies, you see the kinds of problem-solving abilities that they’ve evolved. 

And we’re just—It feels like very blunt, the questions we ask: Are you going to trade here? Or are you going to trade there? Just imagine what they can actually do if we could understand just that level of complexity. 

Host: By asking detailed questions, Toby’s lab is starting to unravel just a tiny glimmer of what fungi can do.

These vast networks permeating intricate ecosystems around the globe are revealing nature’s operating instructions. To understand them in their ineffable complexity may well be beyond our comprehension.

After the break, we’ll hear more from Toby Kiers and Merlin Sheldrake about just how crucial these fungal systems are to life on Earth, the threats they’re facing – and what we can do to protect them even as we learn more from them.

Host: Fungi have been experiencing a major cultural moment these days, from the globally popular film “Fantastic Fungi” to the cover story in National Geographic for the first time in the iconic magazine’s 130-year history.

Just watching the mind-bending behavior of mycorrhizal fungi has left scientists in awe. Just their activities trading carbon and nutrients with plants make them a vital life support system for planet Earth. As such, it implies a deep responsibility not only to observe and learn, but also to protect and conserve. Then again, seeing them is the crucial first step in what has been a blind spot, says Merlin Sheldrake…

MS: Mycorrhizal fungi funnel around 13 billion tons of CO2 into the soil every year. That’s as much as a third of the total CO2 emissions produced by the burning of fossil fuels every year. It’s a significant amount of carbon. They stabilize this carbon in the soil, and power soil food webs, which contain over half above all species on the planet. 

But despite their roles in supporting planetary biodiversity and regulating the Earth’s nutrient cycles and climates, mycorrhizal fungi are a global blindspot, largely absent from climate change agendas, conservation strategies, restoration strategies, agriculture, and forestry. This is a problem. [LAUGHTER] 

It’s a problem first because mycorrhizal fungi lie at the base of the food web that sustain much of life on Earth and make a key lever in planetary ecology, and yet hardly anyone is touching this lever. It would be like trying to perform life-saving surgery without taking into account the circulatory systems of our bodies. 

It’s a problem for another reason. What we are blind to, we tend to destroy. The destruction of underground ecosystems accelerates climate change, biodiversity loss. And what’s more, when we disrupt these communities, we destroy an ancient library of solutions that fungi have evolved to rise to the challenge of living. We have no idea how many of these solutions might prove vital to life on Earth moving forward. When mycorrhizal fungi suffer, so do the organisms and the ecosystems that depend on them. 

Host: To counter the mindless destruction of such a foundational realm of life, the organization SPUN, the Society for the Protection of Underground Networks, was co-founded in 2021 by Toby Kiers and Colin Averill.

SPUN aims to catalyze the protection of mycorrhizal fungi by mapping their biodiversity. They collect fungal data from multiple places around the world and feed the data into predictive maps.

TK: Underground ecosystems are incredibly important across the Earth, and they have been ignored in biodiversity, in climate agendas. And so we wanted to activate a network of caregivers and scientists and researchers, and local communities, to start paying attention to underground ecosystems.

And so, for example, just last month, I was in Ghana. The southern coast is, from our predictive maps, it looks like one of the most biodiverse mycorrhizal spots on Earth. And sea levels are rising really fast in Ghana, and so what worries us is that a lot of these fungal communities might actually be washed away into the ocean. And so it feels really urgent.

And when we go, we always work with local scientists, and go to places that are predicted biodiversity hotspots, and then actually sample the soil and extract the fungal DNA, and then feed that back into the pipeline.

And so we work with these local scientists to create high resolution maps in those countries, and then they use that for their own research. And then, based on that, they then share the data with us, and then that gets fed into an algorithm which then we share with everybody. So really, I think, the primary focus in these areas is to answer the local questions, but as we answer those local questions, we’re building a larger map.

Host: Both the local data and the larger maps are imperative first steps to help protect key ecosystems and related human communities.

Word about the work is spreading. One community it reached was the Indigenous Sarayaku tribe of Amazonian Ecuador. They’re urgently organizing to save their lands from the threats of mining – which decimates underground ecosystems.

MS: The Sarayaku have a vision of the living forest, Kawsak Sacha, an interconnected whole, an animistic interconnected whole of the living forest. And they’ve reached out to us and said, look, we see these fungal networks that you’re describing, living in intimate reciprocal dependence with the plants; we see these as really illustrating this point, and would you help us, and by coming to map these areas with us and provide the datasets for us to be able to go to the government and say, look, these mining companies that left tons and tons of dynamite buried in our territories, this dynamite needs to go; you have a legal obligation, because we won this case, to—they won this case—you need to get this dynamite out. And we can now show you quite exactly what is at stake because we can say who is living on the ground whereas before we couldn’t

TK: Yeah and local context, again, matters so much. So one of the projects that we were doing, one of the first ones in Chile, was sampling fungi under arguably the oldest tree on Earth, the Alerce in Chile. And, you know, we got to go there and sample under this magnificent tree that may be 5,000 years old—4 to 5,000 years old. Right? But people hadn’t looked at the fungal communities that are associated with these trees. Right? And they grow so slowly. They called them a slow growth rainforest. And they accumulate carbon on a scale of millennia.

People understand how important this tree is, but as soon as we went there and said there’s a whole other dimension underground, it started getting even more attention.  And so by going there and sampling the fungi, you add this different layer that helps protect that whole forest.

Host: By helping illuminate a lifeform that’s largely invisible to humans, SPUN hopes to make it harder to ignore.

Although science recognized the true value of fungi only relatively recently, humans have long known of their precious importance. Much fungal knowledge is ancient traditional and Indigenous knowledge.

Take Otzi the Iceman – a European mummy dating back over 5,000 years, he was found with a pouch carrying multiple species of mushrooms, thought to be used for medicinal purposes and for sustaining and carrying fire for survival.

MS: So much of the body of what we call modern scientific knowledge rests on Indigenous knowledge that has been imported into the sciences and rebranded it as scientific knowledge at some earlier stage. So when male botanists were writing books about medicinal plants in the 17^th century, a lot of the time they learned about those medicinal plants by going to markets and talking to wise women, herbwives, about what they used for what. And then that was kind of laundered of that ancestral property and became part of the body of modern scientific knowledge.

So, an interesting case, incidentally, is Albert Hoffman, when he isolated LSD, stumbling on this molecule, but the reason why he was working on it, he was working on these ergot fungi, which are fungi that live inside grains and they have a history of medicinal use by midwives and herbwives to stop obstetric bleeding, to induce contractions, uterine contractions, a very, very important set of functions. And he was working for Sandoz Labs, and Sandoz Labs had employed him to work on these fungi because of this history of obstetric drugs within folk and Indigenous knowledge systems, because they wanted to find new obstetric drugs to bring into the modern pharmaceutical industry, which was why he was doing it. So just that LSD story, when you follow it back, you know, you come back to a body of ancestral knowledge right there. 

When it comes to fungi, today and in our work, our dear colleague, Giuliana Furci, who runs the Fungi Foundation, one of the projects of the Fungi Foundation is ancestral knowledge of fungi. And they are working with various traditional knowledge-holders around the world to learn about traditional uses of fungi, and to have these conversations, before a lot of this knowledge is lost. And that’s really, I think, very powerful and important work.

Host: Given today’s dire state of environmental destruction and the related precarity of the human experiment, it’s imperative to mobilize both traditional Indigenous knowledge and cutting-edge science in service of protecting the fungal kin-dom and learning from its ancient life-giving ways.

And we need to want to protect them. Part of that is inspiring people to share the “sense of wonder” that Merlin and Toby experience as they ask, “What’s it like to be you??”

As human beings, we’re hard-wired for story and metaphor, and they know that when stories change, the world changes. 

MS: It is very mythological. And I think we see the story of how life of the oceans has been more and more discussed. And I think there are analogies there. And a lot of ocean conservation, and very effective ocean conservation has worked by helping to reveal the life that lives in these places, to invite us to feel a sense of vertigo as we float on the surface of these oceans.

And I think we can apply that to soils too. I feel a sense of vertigo when I walk on the ground. Like I feel this sense of the depths below me opening up, and it makes me dizzy sometimes. But I really think that that’s a deeply important thing for us to be working with these mythological dimensions, because a lot of what we’re doing is telling stories.

TK: But the life in the soil, I think, is also something that we don’t think about. We really think of it as sort of a chemical and physical structure. There’s just so much life, that’s what’s unimaginable for me, is like there’s all these creatures that have evolved such innovative strategies that power everything that we see aboveground, but we’re not paying attention to that. I mean, it’s like science fiction down there! [LAUGHTER] It is crazy down there.

And, you know, you see it and you want everybody to see it. You can’t make this stuff up when you really start looking at the creatures there. And I just don’t want them to disappear.

Host: Sometimes science feels more like science fiction, and it just blows your mind – and opens your heart. Toby Kiers and Merlin Sheldrake…The Universe Beneath Our Feet: Mapping the Mycelial Web of Life. 

If you’d like to learn more about the extraordinary intelligence of life inherent in fungi, plants and animals, check out our Earthlings newsletter. In each issue, we delve into captivating stories and research that promise to reshape your perception of our fellow Earthlings – and point toward a profound shift in how we all inhabit this planet together.