Beneath our feet lies a network of cosmic proportions. An international team of scientists has published the first global map of the arbuscular mycorrhizal fungal network, an intricate underground structure connecting plant roots and playing a crucial role in the carbon cycle and ecosystem health. Based on data from 322 previous studies and 16,000 soil samples, the research reveals an estimated total length of about 110 quadrillion kilometers, far surpassing any human-made infrastructure.
Arbuscular mycorrhizal fungi and their symbiosis with plants
Arbuscular mycorrhizal (AM) fungi form underground networks through microscopic filaments called hyphae. These hyphae establish symbiotic relationships with plant roots, supplying water and nutrients in exchange for carbon produced through photosynthesis. It is estimated that about 70% of all plant species depend on these mycorrhizal partnerships for survival. The scale is enormous: a single teaspoon of soil can contain up to 10 meters of mycorrhizal network.
Sponsored Protocol
How the global fungal map was created
To create the first global map, the authors compiled data from 322 previous studies and 16,000 soil samples collected from a wide range of terrestrial ecosystems. Using machine learning techniques and advanced imaging, the team estimated both the network's total extent and its biomass. "With the advent of new technologies in high-resolution imaging, machine learning, and robotics, we are beginning to reveal what has long remained hidden beneath our feet," said coauthor Corentin Bisot. "We are discovering how the complex network-forming structures of fungi transport nutrients and help regulate the climate."
A planetary circulatory system with massive carbon storage capacity
The researchers calculated that the underground fungal network contains about 300 megatons of carbon in biomass, equivalent to four to six times the total mass of all living humans. Each year, these networks transport the equivalent of around 4 billion metric tons of carbon dioxide into the soil, representing approximately 11% of annual human-caused CO2 emissions. The fungal network thus acts as a gigantic natural carbon sink. However, the researchers warn that the density of fungal networks in agricultural soils is only about half that found in natural ecosystems. Grasslands, which contain an estimated 40% of the world's arbuscular mycorrhizal biomass, are among the least protected ecosystems and are being converted to agricultural land at a rate four times faster than forests.
Sponsored Protocol
Implications for climate and food security
The global map offers important insights for addressing challenges such as climate change and food security. "Mycorrhizal fungi have shaped life on Earth for hundreds of millions of years, yet we still know remarkably little about how the infrastructure of these living transport systems is distributed across the planet," said coauthor Merlin Sheldrake. "This study marks an exciting step toward understanding how this planetary circulatory system functions, and it points to ways we can work more effectively with fungi to address many of the defining challenges of our time, from food security to climate change." The research underscores the importance of protecting natural ecosystems to maintain these vital networks. In a broader context, evidence-based environmental policies, such as the UK generational tobacco ban discussed in a related article, demonstrate how understanding natural systems can guide effective decisions. For more on mycorrhizal fungi, see the Wikipedia entry.
Sponsored Protocol
