110 Quadrillion Kilometers of Fungi Mapped

An international team has produced the first complete global map of the planet’s mycorrhizal fungal network. The study estimates the network stretches about 110 quadrillion kilometers, holds roughly 300 megatons of carbon, and drives soil processes linked to c

The ground under us is alive in a way most of us never see.

For the first time. an international team of researchers has pieced together a global map of the mycorrhizal fungal network—an underground web of fungal filaments that forms partnerships with plants across the planet. The numbers are so vast they don’t feel real at first: the team estimates the network stretches for roughly 110 quadrillion kilometers in total. nearly 1 billion times the distance between the Earth and the sun.

The study, published in Science, adds a new kind of scale to a phenomenon that has long been known about but rarely quantified. Before, scientists could talk about patterns. Now they have a map that tries to show where the network lives and how much of the planet it covers.

Arbuscular mycorrhizal fungi (AM fungi) build these networks using microscopic filaments known as hyphae. The fungi form symbiotic relationships with plant roots, supplying water and nutrients in exchange for carbon produced through photosynthesis. The reach of that relationship is broad enough to matter to entire ecosystems: current estimates suggest that about 70 percent of all plant species depend on these mycorrhizal partnerships for their survival.

What’s changed now is not the basic biology. It’s the ability to measure the underground system as a worldwide, physical presence.

To create the first global map, the authors compiled data from 322 previous studies, along with 16,000 soil samples taken from a wide range of terrestrial ecosystems. They used machine learning techniques and advanced imaging technologies to estimate both the network’s total extent and its biomass.

“With the advent of new technologies in high-resolution imaging. machine learning. and robotics. we are beginning to reveal what has long remained hidden beneath our feet. ” said coauthor Corentin Bisot. “We are discovering how the complex network-forming structures of fungi transport nutrients and help regulate the climate.”.

The results put an astonishing weight on that “beneath our feet” claim. The researchers estimate the underground fungal network has a total length of approximately 110 quadrillion kilometers. They also calculate it contains about 300 megatons of carbon in biomass—equivalent to roughly four to six times the total mass of all living humans.

And the network’s footprint isn’t only measured in carbon stored underground. According to the study. these fungal networks transport the equivalent of around 4 billion metric tons of carbon dioxide into the soil each year. representing approximately 11 percent of annual human-caused carbon dioxide emissions.

Justin Stewart. the lead author of the study. put the scale into a more tactile perspective: “It is difficult to overstate the importance and sheer scale of these fungi. ” said Justin Stewart of the Society for the Protection of Underground Networks. “A single teaspoon of soil can contain up to 10 meters of mycorrhizal network.”.

For all the awe, the paper also carries a warning—one that hits hardest because it’s about land being changed right now.

The researchers found that the density of underground fungal networks in agricultural soils is only about half that found in natural ecosystems. They also highlight grasslands as a critical. fragile case: grasslands contain an estimated 40 percent of the world’s arbuscular mycorrhizal biomass. yet they are among the least protected ecosystems. Those grasslands are being converted to agricultural land at a rate four times faster than forests.

The scientists warn that less dense fungal networks could reduce the soil’s capacity to store carbon and recycle nutrients.

That’s where the map starts to feel less like a scientific milestone and more like a prompt for policy and practice. If these living transport systems are tied to carbon storage and nutrient cycling at such scale. then weakening them isn’t just an environmental detail—it could undermine part of how ecosystems keep themselves running.

Merlin Sheldrake. a coauthor of the study. framed the stakes plainly: “Mycorrhizal fungi have shaped life on Earth for hundreds of millions of years. yet we still know remarkably little about how the infrastructure of these living transport systems is distributed across the planet. ” said Merlin Sheldrake. “This study marks an exciting step toward understanding how this planetary circulatory system functions. and it points to ways we can work more effectively with fungi to address many of the defining challenges of our time. from food security to climate change.”.

The work is also a reminder of how much remains hidden even when we think we’ve mapped the surface. Researchers now have a first global picture of the network that plants quietly rely on. The next question—built into the warning signs—is whether the world can keep that hidden infrastructure dense enough to keep doing what it does.

mycorrhizal fungi underground fungal network global map Science machine learning soil samples climate change carbon storage agricultural soils grasslands