Scientists have created the first global map of mycorrhizal fungal networks, revealing the staggering scale of an underground biological highway that sustains most life on land. An international team led by Dr. Justin Stewart of the Society for the Protection of Underground Networks (SPUN) published their findings in the journal Science, using data from over 16,000 soil cores combined with machine learning and robotic imaging of more than 300,000 living hyphae.
The study found approximately 110 quadrillion kilometers of fungal hyphae — thread-like filaments — wind through the world's topsoils, a distance equivalent to reaching the sun one billion times over. A single teaspoon of healthy soil can contain up to 10 meters of these networks, which form symbiotic partnerships with roughly 70% of Earth's plant species and supply over 80% of a plant's phosphorus. The networks also store around 300 megatons of carbon — four to six times the mass of all living humans.
The research also sounded a conservation alarm: cropland soils hold roughly half the fungal density of wild ecosystems, and around 95% of fungal biodiversity hotspots lie entirely outside protected areas. The Mycorrhizal Infrastructure Map is the first time Earth's vast fungal infrastructure has been visualized at this resolution — one estimate per square kilometer of terrestrial land.