There's an Astounding Amount of Fungi Beneath Our Feet

Beneath your feet lies a hidden "infrastructure" that makes highways look tiny, and scientists just drew its first global map. NPR's Adrian Florido talks with ecologist Justin Stewart about the vast web of mycorrhizal fungi—microscopic filaments that attach themselves to plant roots and quietly shuttle resources through the soil. "There's no mushroom, but it's a vast network," Stewart explains. These fungi, which have been partnering with plants for roughly 450 million years, trade nutrients like nitrogen and phosphorus for carbon produced by photosynthesis, then push that carbon deep underground.

A single teaspoon of soil can hold up to 100 meters of fungal threads, Stewart says; globally, his team estimated there are about 68 quadrillion miles of these networks on Earth—roughly 730 million times the distance to the sun. Using soil samples, satellite data, and AI, researchers with the Society for the Protection of Underground Networks mapped where these filaments are densest (think wetlands like the Everglades) and where they're scarcest (deserts like the Sahara). Stewart says the goal is simple: "You can't protect what you don't know." Indeed, the New York Times reports they found "particularly dense" fungal networks under grasslands, which are typically less of a conservation focus than forests. Read the full interview at NPR.