14/06/2026
The first global map of arbuscular mycorrhizal fungi has revealed networks stretching 110 quadrillion kilometres beneath our feet, roughly 750 million times the Earth-to-sun distance.
Published in Science by the Society for the Protection of Underground Networks (Spun), the study used machine-learning models and data from over 16,000 soil cores worldwide. There could be up to 10 metres of fungal network in a single teaspoon of soil.
These fungi form critical partnerships with over 70% of plants, exchanging nutrients and water for carbon, and drawing CO₂ into soils. Grasslands contain the densest networks, including the Everglades and Sudd floodplains.
The threat picture is stark. Cropland fungal density is 47.3% lower than wild ecosystems, driven by tilling, fertilisers, and fungicides. Consequences include reduced carbon storage, weaker nutrient distribution, and greater chemical runoff into waterways.
Researchers will present findings to governments at the desertification COP in Mongolia this August, with the aim of establishing benchmarks for healthy underground communities.
DOI: 10.1126/science.adu4373
