110 Quadrillion Kilometers of Fungal Threads Under Your Feet

There is more fungal network in a teaspoon of healthy soil than you have blood vessels in your entire body. Probably more than you're comfortable knowing. A new study just mapped it for the first time, and the numbers are genuinely hard to hold in your head.

Arbuscular mycorrhizal fungi are networks of tubular cells called hyphae that have been quietly running the planet's logistics for about 475 million years. They link up with more than 70 percent of plant species, trading water and nutrients for the carbon those plants produce. They pull carbon into the soil. They keep nitrogen and phosphorus out of waterways. They are, functionally, the infrastructure that most of plant life on Earth is plugged into. And until now, nobody had actually mapped where they were or how dense they got.

The Society for the Protection of Underground Networks (SPUN) used machine-learning models and data from more than 16,000 soil cores to produce the first global map of these networks. What they found: if you stretched all the hyphae end to end, you'd cover 110 quadrillion kilometers (about 68 quadrillion miles). That's roughly 750 million times the distance from Earth to the sun. It takes a moment.

The study also found that network densities in cropland run about 47 percent lower than in wild ecosystems. Tilling, fungicides and heavy fertilizer use disrupt the symbiosis. Grasslands, including the Everglades and vast prairie systems, showed the highest densities and are among the least protected landscapes on Earth.

The researchers plan to bring this data to governments at the upcoming desertification COP in Mongolia in August.

The underground fungal infrastructure was always under our feet. We just didn't know its extent.

Read the full story at The Guardian, June 11, 2026

Hot Take: The 47 percent density drop in cropland isn't a footnote; it's a warning sign that the longest-running ultramarathon on Earth is starting to cramp.