Scientists race to map earth’s hidden underground fungal networks that store billions of tons of carbon

While most researchers focus on plants and animals above ground, evolutionary biologist Toby Kiers has dedicated her career to exploring the mysterious world beneath our feet. As co-founder of the Society for the Protection of Underground Networks (SPUN), Kiers is leading an ambitious global effort to map the vast mycorrhizal fungal networks that exist in nearly every soil system on Earth.

These underground fungi form one of nature’s most sophisticated partnerships with plants. The fungi attach to plant roots and extract essential nutrients like nitrogen, phosphorus, and water from the soil. In exchange, plants feed the fungi carbon dioxide captured during photosynthesis. This intricate relationship moves more than 13 billion metric tons of CO2 from the atmosphere into underground fungal networks annually, making them a critical but underappreciated tool in the fight against climate change.

What fascinates Kiers most is how these networks operate like skilled negotiators, carefully calculating how much nutrients to provide plants based on what they receive in return. “It’s almost like watching the best poker players in the world play a game of poker,” she explains. Despite their crucial role in carbon sequestration and ecosystem health, scientists still don’t fully understand how these fungal networks make their complex decisions.

Kiers describes these underground networks as “so alive, but humble and quiet” – a hidden world that could hold keys to better understanding carbon storage and ecosystem resilience. SPUN’s mapping project aims to change that by documenting these vital but overlooked networks before they’re lost to human activity and climate change.