A hidden living system quietly helping life on Earth thrive
Beneath the ground we walk upon, a living architecture older than forests has been quietly sustaining the world's plant life for nearly half a billion years. Scientists have now mapped this hidden system — a web of arbuscular mycorrhizal fungi stretching 110 quadrillion kilometres through Earth's soils — revealing not merely a biological curiosity, but a foundational infrastructure of life itself. Drawing on over 16,000 soil samples, researchers have shown that these invisible threads support 70 percent of land plants, store vast quantities of carbon, and are being quietly dismantled by the very agricultural practices that feed us. To understand this network is to reckon with how much of what sustains us has always been hidden from view.
- A fungal web stretching 110 quadrillion kilometres — enough to reach the sun nearly a billion times — has been mapped for the first time, exposing a biological system most humans have never considered.
- These microscopic threads are not passive; they broker ancient trade agreements between plants and soil, moving water, phosphorus, and nitrogen in exchange for sugars, a partnership that helped plants colonise land 475 million years ago.
- The stakes extend to the climate: these networks lock away roughly 300 megatons of carbon and may sequester up to one billion metric tons annually, making their health inseparable from humanity's climate ambitions.
- Intensive farming is quietly severing this underground infrastructure — fungal concentrations in croplands run nearly 50 percent lower than in undisturbed ecosystems, leaving crops more fragile and more dependent on synthetic fertilisers.
- The new global map is now being used to identify where fungal networks are most endangered and where restoration could simultaneously improve food security, reduce chemical inputs, and strengthen carbon storage.
Beneath forests, grasslands, and gardens lies a biological system so vast that most people will never witness it directly. Scientists have now mapped this underground fungal network with unprecedented precision, revealing that microscopic threads collectively stretch across 110 quadrillion kilometres of Earth's topsoil — a distance that could reach the sun nearly a billion times over. Based on analysis of more than 16,000 soil samples, the research represents the most comprehensive global portrait yet of arbuscular mycorrhizal fungi, organisms that have been quietly sustaining life on this planet for hundreds of millions of years.
These fungi do not form a single organism circling the globe. Rather, the staggering figure represents the combined length of countless fungal networks woven through ecosystems worldwide, each thread invisible to the naked eye. The partnership between these fungi and plants operates as a natural trade agreement refined over evolutionary time — approximately 70 percent of all land plants depend on it. Plants share sugars produced through photosynthesis; in return, fungi extend far beyond plant roots, helping absorb water and essential nutrients like phosphorus and nitrogen. Scientists believe this relationship was decisive roughly 475 million years ago when plants first colonised land.
Often called the "wood wide web," these networks connect plants through the soil, allowing nutrients, water, and chemical signals to move between them. Some studies suggest plants may use these pathways to share resources or send distress signals during drought or disease, though the full extent of this communication remains debated. What is not in doubt is their role in carbon storage: Earth's topsoils hold approximately 300 megatons of carbon locked inside fungal networks, and some estimates suggest these systems help sequester up to one billion metric tons annually — making them a critical natural ally against climate change.
The study found the densest networks in natural ecosystems such as grasslands, wetlands, and floodplains, with large wetland systems like Florida's Everglades emerging as particularly important hotspots. Yet the research also revealed troubling decline. Intensively farmed croplands contain nearly 50 percent fewer fungal networks than undisturbed environments, the result of deep tilling, excessive fertiliser use, and soil disturbance. The loss makes crops more dependent on synthetic inputs and less resilient to environmental stress.
Scientists argue that conservation has long focused on visible ecosystems while overlooking the vast biological infrastructure hidden underground. The new map aims to change that — identifying where fungal networks need protection and where restoration could improve food security, reduce fertiliser dependence, and enhance carbon storage. Beneath nearly every field and forest, a sprawling living system has been quietly helping life on Earth thrive, almost entirely unseen.
Beneath the soil of forests, grasslands, and gardens lies a biological system so vast that most people will never witness it directly. Scientists have now mapped this underground fungal network with unprecedented precision, revealing that microscopic threads collectively stretch across 110 quadrillion kilometres of Earth's topsoil—a distance so immense it could reach the sun nearly a billion times over. The discovery, led by researchers affiliated with the Society for the Protection of Underground Networks and based on analysis of more than 16,000 soil samples, represents the most comprehensive global portrait yet of arbuscular mycorrhizal fungi, organisms that have been quietly sustaining life on this planet for hundreds of millions of years.
These fungi do not form a single organism circling the globe. Rather, the staggering figure represents the combined length of countless fungal networks woven through ecosystems worldwide, each thread so thin it remains invisible to the naked eye. Yet collectively, they constitute one of Earth's largest biological systems. The comparison some researchers have drawn to Astrophage, the fictional organism from Andy Weir's novel Project Hail Mary, captures something true about scale and hidden influence, even if the analogy breaks down in the details. Like that imagined lifeform, these fungi move resources across vast networks, support larger ecosystems, and exert influence far beyond what their microscopic size might suggest.
The partnership between these fungi and plants operates as a natural trade agreement refined over evolutionary time. Approximately 70 percent of all land plants depend on this relationship. Plants manufacture sugars through photosynthesis and share some of that energy with the fungi. In exchange, the fungi extend far beyond plant roots, acting as an underground extension of the plant's own root system, helping it absorb water and essential nutrients like phosphorus and nitrogen that would otherwise remain out of reach. Scientists believe these fungi played a decisive role roughly 475 million years ago when plants first colonized land, making them among the oldest and most consequential partnerships in Earth's biological history.
Researchers often call these fungal systems the "wood wide web" because they connect plants through vast underground networks. The fungal threads can link multiple plants together, allowing nutrients, water, and chemical signals to move through the soil. Some studies suggest plants may use these networks to share resources or send distress signals when threatened by disease, drought, or insect attacks, though scientists continue to debate exactly how much information travels through these systems. What remains clear is that these networks are fundamental to ecosystem health. Without them, many plants would struggle to survive.
One of the study's most significant findings concerns carbon storage. Earth's topsoils contain approximately 300 megatons of carbon locked inside these fungal networks—roughly four to six times the total mass of all humans on the planet. The fungi also help move carbon underground by transporting carbon-rich compounds from plants into the soil. Some estimates suggest these networks help sequester up to one billion metric tons of carbon each year, making them a critical natural ally in the fight against climate change. Because carbon stored underground is less likely to enter the atmosphere as carbon dioxide, healthy fungal networks can play a significant role in regulating Earth's climate.
The study found the densest fungal networks in natural ecosystems such as grasslands, wetlands, and floodplains. Large wetland systems, including Florida's Everglades and South Sudan's Sudd wetlands, emerged as particularly important hotspots. These regions support rich fungal communities that contribute to biodiversity, soil health, and carbon storage. Yet the research also revealed troubling signs of decline. Intensively farmed croplands contain significantly fewer fungal networks than nearby natural ecosystems. Practices such as deep tilling, excessive fertilizer use, and soil disturbance can damage fungal communities and reduce their abundance. According to the study, fungal concentrations in agricultural land can be nearly 50 percent lower than in undisturbed environments. The loss of these fungi may make crops more dependent on synthetic fertilizers and less resilient to drought and other environmental stresses.
Scientists believe the new map will help identify areas where fungal networks need greater protection and restoration. Protecting these hidden ecosystems could improve food security, strengthen plant resilience, reduce fertilizer use, and enhance carbon storage. Researchers argue that conservation efforts have historically focused on animals, forests, and visible ecosystems while largely overlooking the vast biological infrastructure hidden underground. For centuries, people have viewed soil as little more than dirt beneath their feet. The new research paints a very different picture. Beneath nearly every forest, grassland, and field lies a sprawling fungal network that helps sustain plants, regulate climate, and support entire ecosystems. Scientists have revealed a hidden living system stretching 110 quadrillion kilometres across the planet, quietly helping life on Earth thrive while remaining almost entirely unseen.
Citações Notáveis
These fungi move resources across vast networks, support larger ecosystems, and possess an influence far greater than their microscopic size suggests— Researchers studying the fungal networks
A Conversa do Hearth Outra perspectiva sobre a história
When you say 110 quadrillion kilometres, what does that actually mean for someone standing in a garden?
It means that in the soil beneath your feet right now, there are fungal threads so fine you'd need a microscope to see them, and if you could somehow unwind and measure all of them in your garden and every other garden and forest on Earth, they'd stretch that far. It's not one giant fungus—it's countless networks, all working at once.
Why did it take until now to map this? Haven't we known about these fungi for a long time?
We've known they exist, yes. But creating a global map required 16,000 soil samples and computer modelling sophisticated enough to piece together patterns across entire ecosystems. It's the difference between knowing something exists and actually seeing its full scale and distribution.
The comparison to Project Hail Mary—does that actually hold up, or is it just marketing?
It's more poetry than science. The novel's organism stores and transfers energy on a vast scale; these fungi do move resources through networks. But these fungi aren't alien, they're not new, and they work through partnership with plants, not alone. The comparison works because both reveal hidden systems operating at scales that dwarf human perception.
You mentioned 300 megatons of carbon. Is that enough to matter for climate change?
It's enormous. That's four to six times the mass of every human alive. And these networks sequester up to a billion metric tons of carbon annually. When carbon stays underground instead of entering the atmosphere as CO2, it matters for climate regulation. It's one of the reasons protecting these ecosystems isn't just about plants—it's about the planet's ability to regulate itself.
So why are farms destroying these networks if they're so important?
Because modern agriculture prioritizes short-term yield. Deep tilling, synthetic fertilizers, and constant soil disturbance kill the fungi. Farms with 50 percent fewer fungal networks become dependent on those synthetic fertilizers to compensate. It's a trap—you damage the system that naturally supports plants, then you have to chemically replace what you destroyed.
What happens if we start protecting these networks instead?
Better soil health, crops that need less fertilizer and are more resilient to drought, improved food security, and more carbon stored where it belongs. The research suggests we've been ignoring one of Earth's most important ecosystems simply because we couldn't see it.