We tend to think of the ground beneath our feet as just… as a place to walk upon. Something to wipe off our feet, dig a garden into, or pour concrete over and build the cities.Most of us never give it a second thought. But soil is far from empty. Beneath every step you take lies a hidden, living world that is so vast and busy that scientists have only begun to understand it truly.Scientists say that there is an entire ‘Fungi city’ with an intense network, that is massive enough to stretch from our planet to the Sun almost 750 million times over.
Representative Image
There is an extremely intense and massive mycorrhizal network of fungi
According to a study published in the journal Science, the soils of the Earth contain enough subterranean fungi to stretch from our planet to the Sun almost 750 million times over.These are arbuscular mycorrhizal fungi, vast webs of microscopic, tubular threads called hyphae that have quietly sustained life on land for about 475 million years.They form partnerships with more than 70% of the world’s plants, trading nutrients and water for the carbon that plants pull from the air. In doing so, they also help cool the planet by locking carbon away in the soil.
The numbers are almost impossible to imagine
Researchers calculated that, laid end to end, these fungal threads would run roughly 110 quadrillion kilometres which is almost 750 million times the distance between the Earth and the Sun. As lead author Dr Justin Stewart said, there could be “up to 10 metres of mycorrhizal network in just a teaspoon of soil.”To build the first global map of this hidden infrastructure, a team from the Society for the Protection of Underground Networks (Spun), founded in 2021, studied data from more than 16,000 soil samples worldwide into machine-learning models. The map reveals where these networks thrive and, more worryingly, where they’re under threat.
So, who is the threat exactly, and how does it impact the network?
That threat is largely us. The study found that fungal networks in cropland are, on average, 47.3% less dense than in wild ecosystems. Much of the damage, according to Stewart, comes from intensive farming, especially tilling, which physically rips the soil apart, along with fertilisers and fungicides that disrupt the delicate partnership between plant and fungus.The consequences of losing these networks could ripple far and wide. Thinner fungal webs mean soils that store less carbon, distribute fewer nutrients, and do a poorer job of shielding rivers and lakes from agricultural runoff.“If they disappear, there’s going to be a lot more chemicals going into waterways,” warned Dr Toby Kiers, another author of the study.
Which is the most intense place in this fungal network
The map also pinpoints the planet’s richest underground hotspots. Grasslands, the researchers found, hold the densest networks of all, with regions such as Florida’s Everglades, the Sudd wetlands of South Sudan, and prairie and steppe ecosystems showing exceptionally high density. Yet many of these areas are poorly protected and increasingly degraded.The team hopes their findings will change how we farm and what we choose to protect. They argue that working with soil fungi, rather than against them, could help plants feed themselves naturally, cut fertiliser use, and trap more carbon underground.
