A study maps global arbuscular mycorrhizal fungal networks, finding their threads can stretch far beyond Earth and that they are threatened by agricultural conversion, with grassland ecosystems holding 40% of the world's biomass but being poorly protected.
<p>Hidden underground around the world lie 110 quadrillion kilometers of arbuscular mycorrhizal fungal networks—webs of ultra-thin threads that, if connected in a single line, would stretch almost a billion times the distance between the Earth and the sun, according to new research published in Science on Thursday.</p>
<p>These fungal communities form intimate relationships with the roots of plants, which they provide with nutrients like phosphorus and nitrogen in exchange for carbon, 1 billion tons of which the networks sequester underground annually, previous research has found. If the fungal network wasn’t storing it, that carbon would be warming the atmosphere.</p>
<p>But those networks have never been mapped globally until now. The <a href="https://www.science.org/doi/10.1126/science.adu4373">new study</a> led by <a href="https://www.spun.earth/?r=0">Society for the Protection of Underground Networks</a>, or SPUN, an organization founded to map mycorrhizal fungi networks, used a combination of literature review, soil samples from around the globe, machine learning and laboratory testing to estimate the distribution and mass of these systems and <a href="https://spun-625.pages.dev/story/a-hidden-infrastructure">map</a> where they are densest.</p><p><a href="https://arstechnica.com/science/2026/06/threads-of-underground-fungal-networks-are-long-enough-to-reach-beyond-the-solar-system/">Read full article</a></p>
<p><a href="https://arstechnica.com/science/2026/06/threads-of-underground-fungal-networks-are-long-enough-to-reach-beyond-the-solar-system/#comments">Comments</a></p>
# Threads of underground fungal networks are long enough to reach beyond the Solar System
Source: [https://arstechnica.com/science/2026/06/threads-of-underground-fungal-networks-are-long-enough-to-reach-beyond-the-solar-system/](https://arstechnica.com/science/2026/06/threads-of-underground-fungal-networks-are-long-enough-to-reach-beyond-the-solar-system/)
The study only covers living arbuscular mycorrhizal fungal networks, Stewart said, and doesn’t include dead fungal networks, which also help to store carbon and add to the total biomass and influence of the networks on ecosystems\. Research into dead fungal networks is still being explored\.
The study also found where these networks are most threatened\. Fungal network densities across croplands are about half of what they are in wild ecosystems\. Meanwhile, wild grassland ecosystems hold about 40 percent of the world’s arbuscular mycorrhizal biomass\. Yet those grasslands are among Earth’s least protected ecosystems, and they are converted into farmland at four times the rate of forests, posing a potential threat to these networks and the benefits they bring to plant life and carbon storage\.
Previous research from SPUN has[found 90 percent of fungal communities](https://insideclimatenews.org/news/23072025/mycorrhizal-fungal-hotspots-lack-protections/)across the globe[are unprotected](https://insideclimatenews.org/news/23072025/mycorrhizal-fungal-hotspots-lack-protections/), and many ecosystems, like the deserts of the American Southwest,[are understudied](https://insideclimatenews.org/news/22062025/sonoran-desert-saguaro-cactus-fungi/)\.
What exactly is driving mycorrhizal fungi losses, and the consequences of that decline, need to be explored next, the researchers said, which is why the SPUN team will be at this year’s United Nations Climate Change Conference—COP31—to present to policymakers about the importance of the networks and the role they could play in protecting ecosystems and sequestering carbon\.
Understanding mycorrhizal fungi more deeply at the ground level is key, said Corentin Bisot, an AMOLF biophysicist and co\-author of the study\.
“We’re still far from completely understanding how, if you have a grassland next door, and you want to \[increase\] microbes and fungi there,” Bisot said\. “We don’t have the toolbox for you to do it\.”
This study, Stewart said, is just the first map\. And like the first maps the Spaniards drew of California—which presented the state as an island, he said, there will be new discoveries about the density of fungi networks around the globe to grow the public’s understanding of them\.
*This article originally appeared on[Inside Climate News](https://insideclimatenews.org/news/11062026/earths-massive-underground-fungal-networks/), a nonprofit, non\-partisan news organization that covers climate, energy, and the environment\. Sign up for their newsletter[here](https://insideclimatenews.org/newsletter/)\.*
A new study in Astronomy & Astrophysics suggests Earth may survive the sun's red giant phase due to less effective tidal dissipation and greater mass loss, contrary to previous predictions.
After a year of research, a universal 2x performance improvement for all modern JavaScript parsers is being implemented, starting with oxc_parser, which will speed up tools like OXLint, Vite, and Deno, and potentially major browser engines.
Harvard professor Matthew Schwartz published an article on the Anthropic blog demonstrating using large language models like Claude, GPT, and Gemini to complete a quantum chromodynamics paper in two weeks (normally taking a year), and highlighted the strengths and weaknesses of LLMs in research. The author further proposed engineering fixes, including external computation modules, verification agents, and human oversight, emphasizing using LLMs as the core engine of scientific research.