Researchers led by the Society for the Protection of Underground Networks (SPUN) have created the first global map of arbuscular mycorrhizal fungi networks, revealing a total length of 110 quintillion kilometers, nearly one billion times the distance between Earth and the Sun. This groundbreaking map highlights the immense scale of fungal networks that store about 1 billion tons of carbon annually, and shows that agricultural practices have halved fungal density, making protection critical for climate and ecosystem health. The fungal mycelium total mass is equivalent to about five times the weight of all humans on Earth. Grasslands, which hold 40% of the global arbuscular mycorrhizal fungi biomass, are being converted to farmland four times faster than forests.
Arbuscular mycorrhizal fungi (AMF) form symbiotic relationships with about 80% of land plants, helping them absorb nutrients like phosphorus and nitrogen. These fungi expand plant root systems through thread-like hyphae, creating vast underground networks that also improve soil structure and carbon storage. SPUN, founded in 2021, aims to map and protect these networks.