The world of fungi is very mysterious, with about 475 million years of evolution. Many people think that fungi are just mushrooms what they sometimes find across in the woods. Fungi actually form giant underground networks, and most people have no idea how big they are and what they are for. The fungal network can be as large as the whole city.

It serves, for example, as a communication channel for trees. Through a fungal network, the trees exchange information, for example, about insect infestations and fires. These networks enrich the soil and make many plants thrive. They are essential for carbon capture and unfortunately are rapidly disappearing from this planet.

Credit: Yoshihiro Kobae – Caption root and fungal mycelium

Exploring a worldwide fungal network

So far, no one has mapped the size of the global mushroom network. The nonprofit Society for the Protection of Underground Networks (SPUN) is taking on a massive, first-time project to map the global fungal network. Fungal networks underpin life on earth, but we are destroying them at an alarming rate. SPUN’s aim is to save trillions of kilometers of underground networks threatened by human impact and climate extremes and utilize fungal networks to help sequester carbon, move nutrients, and protect ecosystem biodiversity.

Credit: Victor Caldas – Caption High- resolution mycelium network

Together with researchers, explorers, and local communities, they are working across continents to protect underground ecosystems currently absent from conservation and climate agendas.

Protecting uderground networks

SPUN will lead the first ever global exploration of fungal networks. This move marks a major turning point in conservation and climate agendas, as leaders realize the need to focus on underground ecosystems, and the fungal networks that draw carbon into soils.

SPUN has mapped its first 10,000 network samples, and will collect an additional 10,000 across ecosystems of all continents in the next 18 months to map carbonsequestration hotspots.

Credit: Vasilis Kokkoris – Caption Confocal 3D-image of a fungal network with reproductive spores containing nuceli (smaller dots)

Together with new visualizations of nutrients flows inside networks, these maps will be used to identify high-priority sites with the potential to store more carbon and survive extreme climate events.

The team at the Society for the-Protection of Underground Networks, Credit: Seth Carnill

Fungi networks absorb more carbon than rainforests

Soils are home to 25% of all species on earth. Current plans to conserve above ground biodiversity hotspots still fail to protect over 50% of the most biodiverse below ground ecosystems.

Globally, the total length of fungal mycelium in the top ten centimeters of soil is more than 450 quadrillion kilometers: around half the width of our galaxy. Globally, approximately 75% of the terrestrial carbon is in the soil. This is three times more than the amount stored in living plants and animals. Fungal networks make up to 50% of the living biomass of soils.

Previous estimates suggest 5 billion tons of carbon dioxide flow into fungal networks each year, equal to more than half of all energy-related CO2 emissions in 2021. Scientists are now revising this estimate, which could be three times this amount (~ 17 billion tons ), when all types of fungal networks are included.

It is generally assumed that rainforests hold the majority of the earth’s terrestrial carbon, but high-latitude belowground ecosystems hold 13-times more carbon.

Credit: Loreto Oyarte Galvez – Caption High-resolution mycelium network

Current trends suggest that more than 90% of the Earth’s soil will be degraded by 2050. Protecting the underground from cropland expansion could save the release of 41 billion tons of CO2 from soil stocks over the next 30 years, equal to 8 times the annual CO2 emissions of the USA.

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