Beneath the earth, vast networks of fungi quietly support flora and play a crucial role in regulating the planet’s climate by helping to maneuver carbon into the soil. Now, researchers have created the primary global maps showing where these underground fungal networks are found and the way a lot of them exist worldwide.
The research, published in , focuses on arbuscular mycorrhizal fungi, a gaggle of fungi that partner with most plants on Earth. Along with the research, the scientists released an interactive visualization that enables users to explore the remarkable scale of this hidden underground infrastructure. The maps are expected to assist researchers and policymakers discover areas where these fungal networks are thriving and where they could be in danger.
Among the important findings of the study:
- Soils worldwide contain an estimated ~110 quadrillion kilometers (~68 quadrillion miles) of arbuscular mycorrhizal fungal networks, made up of thread-like structures called hyphae. This distance is about one billion times the space from Earth to the Sun.
- Grasslands comprise about 40% of the Earth’s arbuscular mycorrhizal fungal infrastructure. Particularly dense networks are predicted within the flooded grasslands of South Sudan, the Everglades in Florida, and the Tibetan Plateau.
- AM fungal networks transport an estimated ~4 billion tons of CO2e to soil annually (akin to 11% of all human-related carbon dioxide emissions).
- Network density is predicted to be ~50% lower on average in large agricultural farmlands. Researchers caution that less dense fungal networks can reduce soil’s ability to soak up carbon, cycle nutrients, and withstand environmental stressors.
Hidden partnerships support flora.
Arbuscular mycorrhizal fungi, commonly known as AM fungi, form mutually useful relationships with roughly 70% of plant species worldwide. Plants provide carbon produced through photosynthesis to fungi, while fungi provide nutrients and water to plants.
These underground networks act as living infrastructure that helps maintain ecosystems and transport carbon into the soil. In 2025, researchers published a A global analysis of belowground mycorrhizal fungal diversity I also launched a digital platform called Underground Atlas to assist discover potential biodiversity hotspots below the surface. However, until now, scientists had not attempted to estimate and map the physical density and worldwide distribution of AM fungal networks themselves.
Mapping 110 Quadrillion Kilometers of Fungal Networks.
To create the brand new maps, the researchers compiled measurements from greater than 16,000 soil cores collected world wide. They then used machine learning models that incorporated ecological data from deserts, tundra, forests and other ecosystems to estimate the density of fungal networks in regions where direct measurements weren’t available.
Working with the Physics of Behavior group on the AMOLF Research Institute, the team also used robotic imaging to research 300,000 live AM fungal hyphae grown under laboratory conditions. Combining all these data sources allowed the researchers to estimate each the entire length and mass of the worldwide network.
Their evaluation shows that the AM fungal network spans about ~110 quadrillion kilometers and incorporates about ~300 megatons of carbon (4-6x the quantity of all living humans).
“It is difficult to overstate the importance and extent of these fungi,” said lead creator Dr. Justin Stewart with the Society for the Protection of Underground Networks (SPUN). “Just one teaspoon of soil can contain up to 10 meters (32 feet) of mycorrhizal network.”
Earth’s underground circulatory system
Scientists often describe mycorrhizal networks as one in all the Earth’s circulatory systems because they transport carbon, nutrients, and water in underground ecosystems.
In healthy soils, these fungal networks can increase the effective forage area of plant roots as much as 100 times and supply greater than 80 percent of the plant’s phosphorus needs.
“With the emergence of new technologies in high-resolution imaging, machine learning and robotics, we are beginning to reveal what is hidden beneath our feet,” said co-lead creator Dr. Corinth Bisot, an AMOLF biophysicist. “We are learning how the complex bodies of network-forming fungi help transport nutrients and regulate climate.”
A brand new global fungal infrastructure map
To help visualize the outcomes, the researchers teamed up with award-winning data visualization designer Moritz Steffner. Map of mycorrhizal infrastructure.
The project provides probably the most detailed global view yet of Earth’s fungal infrastructure. Estimates were made every 1 km.2 of terrestrial land, excluding ice caps and regions where data were insufficient for reliable predictions.
The data behind the maps is publicly available, giving governments and other decision makers recent tools to observe the health of underground fungal communities.
Work is finished. Previous research I used to be published by several of the identical authors. This study examined how mycorrhizal fungi and plants form a highly efficient system for exchanging carbon and nutrients. The researchers measured the movement of carbon through these living networks at a speed of 120 um/sec (if one were contained in the network, this speed would feel like ~400km/hr). The recent study extends work on how these flows work on a planetary scale.
Threats to subterranean fungal ecosystems
The researchers also identified areas of concern.
Network density in farmland is predicted to be near half that present in wild ecosystems. At the identical time, wild grasslands contain about 40% of the world’s arbuscular mycorrhizal biomass.
Despite their importance, grasslands are among the many least protected ecosystems on Earth and are being converted to agricultural land 4 times faster than forests.
These results support previous SPUN research showing that 95% of biodiversity hotspots for arbuscular mycorrhizal fungi are outside protected areas.
For evolutionary biologist Dr. Toby Kears, executive director of SPUN, the growing body of evidence highlights the necessity to include fungi in climate and conservation planning.
“Fungi have long been neglected in climate and conservation. It is time to change that momentum.”
Kearse was recently named a MacArthur Fellow and received the Tyler Prize, sometimes called the “Nobel Prize of the environment” for his work on plant and fungal relationships.
What scientists do not know yet
“Mycorrhizal fungi have shaped life on Earth for hundreds of millions of years, but we still understand little about how the infrastructure of these living transport systems is distributed across the planet,” added co-author and biologist Dr. Merlin Sheldrake. “This study is an exciting step toward understanding how this planetary circulation system works and suggests ways we can better work with fungi to help tackle the many looming challenges of our time, from food security to climate change.”
While the brand new maps reveal the extraordinary scale of Earth’s underground fungal networks, additionally they highlight major gaps in scientific knowledge. Large regions of the world are unsampled, providing a roadmap for future research in one in all the planet’s most significant and least visible ecosystems.