Scientists Map Earth's Hidden Fungal Superhighway for the First Time | SpeakBase Times
Level 1 - Absolute Beginner
Under the ground, there are tiny threads made by fungi. Fungi are living things, like mushrooms. These threads connect the roots of plants together. Scientists call this a 'fungal network.'
Scientists have now made a map of these networks all around the world. They found that most plants use these networks. The networks help plants get food and water from the soil.
The networks are also very important for our planet. They store a lot of carbon dioxide gas inside the ground. Carbon dioxide is the gas that warms our planet, so storing it is very good.
fungi
a group of living things including mushrooms and mold that grow in soil or on plants
network
a system of connected things that work together
roots
the underground parts of a plant that absorb water and nutrients
soil
the top layer of the ground where plants grow
carbon dioxide
a gas in the air that plants absorb; too much of it warms the planet
map
a picture that shows where things are in the world
store
to keep something in a place for later use
thread
a long, thin strand of material, like a tiny fiber
Level 2 - Elementary
Scientists published a landmark study in the journal Science on June 15, 2026, revealing the first complete map of arbuscular mycorrhizal (AM) fungal networks across Earth's topsoils. These underground threads, which can be thinner than a human hair, connect the roots of about 70 percent of all plant species worldwide.
To create the map, researchers analyzed more than 16,000 soil samples collected from over 4,000 locations around the globe. They used machine-learning models to fill in the gaps between sampling sites. The total length of the fungal threads discovered is approximately 110 quadrillion kilometers, an almost unimaginable distance.
The study found that these fungal networks store around four billion tonnes of carbon dioxide each year by absorbing it from plant roots and locking it in the soil. However, scientists warned that the networks are most at risk in tropical regions, where farming and deforestation are destroying them fastest.
arbuscular mycorrhizal
a type of fungus that lives inside plant root cells and exchanges nutrients with the plant
topsoil
the upper layer of soil, roughly the first 30 centimeters, where most plant roots and organisms live
landmark study
an important piece of research that changes understanding of a subject
machine learning
a type of computer program that learns from large amounts of data to make predictions
quadrillion
the number 1,000,000,000,000,000, or one thousand trillion
tonne
a metric unit of mass equal to 1,000 kilograms
deforestation
the large-scale cutting down of forests, usually to use the land for farming
sampling
collecting small amounts from many locations to study the whole area
Level 3 - Intermediate
A global mapping effort led by Justin D. Stewart and colleagues from the Society for the Protection of Underground Networks (SPUN) has produced the first quantitative atlas of arbuscular mycorrhizal (AM) fungal hyphae in Earth's topsoils, published in Science on June 15, 2026 (DOI: 10.1126/science.adu4373). Analysing over 16,000 soil cores from more than 4,000 sites worldwide and using machine-learning extrapolation to cover unsampled regions, the team estimated a total hyphal length of approximately 110 quadrillion kilometers in the top 30 centimeters of soil.
AM fungi form obligate symbioses with roughly 70 percent of terrestrial plant species, threading filaments called hyphae through root cells to exchange mineral nutrients for photosynthetically derived carbon. The new map reveals that these networks collectively sequester approximately four billion tonnes of atmospheric CO2 per year, an ecosystem service equivalent to about 13 percent of global fossil-fuel emissions, by incorporating organic carbon into stable soil aggregates.
The map also identifies a troubling geographical pattern: hyphal density is highest in humid tropical forests, precisely the ecosystems experiencing the greatest rates of agricultural conversion and deforestation. The researchers developed an interactive tool called the Mycorrhizal Infrastructure Map to allow policymakers and conservationists to identify priority zones for soil protection and direct subsidies toward practices that preserve underground biodiversity alongside the more visible canopy.
hyphae
the microscopic thread-like filaments that make up the body of a fungus
obligate symbiosis
a relationship where two organisms are completely dependent on each other for survival
extrapolation
using known data from sampled areas to estimate values in unsampled areas
sequester
to capture and store a substance, especially carbon dioxide, preventing its release into the atmosphere
soil aggregate
a cluster of soil particles bound together by organic material, fungi, or minerals
photosynthetically derived
produced by plants using the energy from sunlight to convert CO2 into sugars
agricultural conversion
the process of changing natural land into farmland
canopy
the uppermost layer of a forest, formed by the crowns of the tallest trees
Level 4 - Advanced
The publication by Stewart et al. in Science (DOI: 10.1126/science.adu4373, June 15, 2026) of a global, high-resolution quantitative map of arbuscular mycorrhizal (AM) hyphal biomass represents a transformative advance in soil biogeography. By assimilating 16,000 soil cores from 4,000-plus globally distributed sites into a gradient-boosted ensemble model, the SPUN consortium produced gridded estimates of AM hyphal length at 1-kilometer resolution across all ice-free land surfaces, yielding a total infrastructure figure of 110 quadrillion kilometers, a value that dwarfs every human-built network by roughly twelve orders of magnitude.
The ecological significance of this infrastructure operates at two scales. At the plant level, AM hyphae penetrate host root cortical cells, forming arbuscules that mediate a bidirectional exchange of mineral phosphorus and micronutrients from fungal scavenging against hexose sugars translocated from photosynthate, an obligate mutualism that enabled the colonization of terrestrial environments by vascular plants some 450 million years ago. At the planetary level, the map's carbon accounting reveals that AM networks immobilize approximately four billion tonnes of atmospheric CO2 annually by incorporating glomalin-related soil protein and hyphal walls into macro-aggregate structures resistant to microbial mineralization, an ecosystem service that existing Earth-system models have systematically underestimated.
The map's most alarming finding is the inverse relationship between AM hyphal density and land conversion pressure: peak hyphal biomass is concentrated in humid tropical forests, the same landscapes subjected to the highest rates of agricultural frontier expansion. Stewart et al. calculate that maintaining current deforestation trajectories would eliminate roughly 30 percent of the AM hyphal infrastructure in carbon-critical biomes within thirty years, releasing a pulse of soil-stored carbon that would materially offset decarbonization gains from renewable energy deployment. The authors recommend integration of mycorrhizal health indices into national greenhouse-gas inventories and the designation of high-hyphal-density soils as protected carbon assets under IPCC reporting frameworks.
biogeography
the study of the distribution of species and ecosystems across geographic space and through time
gradient-boosted ensemble model
a machine-learning approach that combines many decision-tree models, each correcting the errors of the previous, to improve prediction accuracy
arbuscule
a tree-like structure formed by AM fungi inside plant root cells that facilitates nutrient exchange
glomalin
a glycoprotein produced by AM fungi that binds soil particles into stable aggregates and stores carbon
macro-aggregate
a large cluster of soil particles and organic material held together by fungal threads and organic glues
microbial mineralization
the breakdown of organic carbon compounds by soil microbes into CO2, releasing carbon to the atmosphere
agricultural frontier expansion
the process by which farming extends into previously wild or forested areas
decarbonization
the process of reducing or eliminating carbon dioxide emissions from energy and economic systems
Scientists Map Earth's Hidden Fungal Superhighway for the First Time
Researchers publishing in Science on June 15, 2026 revealed the first global map of arbuscular mycorrhizal fungal networks in Earth's topsoils, showing that 110 quadrillion kilometers of these underground threads connect the roots of about 70 percent of all plant species, sequester four billion tonnes of carbon dioxide each year, and are most threatened in the world's most biodiverse tropical regions.
By SpeakBase Times Editorial Team
Level 1 - Absolute Beginner
Ready
Reading PassageTap highlighted words for definitions
Under the ground, there are tiny threads made by fungi. Fungi are living things, like mushrooms. These threads connect the roots of plants together. Scientists call this a 'fungal network.'
Scientists have now made a map of these networks all around the world. They found that most plants use these networks. The networks help plants get food and water from the soil.
The networks are also very important for our planet. They store a lot of carbon dioxide gas inside the ground. Carbon dioxide is the gas that warms our planet, so storing it is very good.
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Key Vocabulary
fungi —a group of living things including mushrooms and mold that grow in soil or on plants
network —a system of connected things that work together
roots —the underground parts of a plant that absorb water and nutrients
soil —the top layer of the ground where plants grow
carbon dioxide —a gas in the air that plants absorb; too much of it warms the planet
map —a picture that shows where things are in the world
store —to keep something in a place for later use
thread —a long, thin strand of material, like a tiny fiber
Exercises
Multiple Choice
1What do fungal networks connect underground?
2What important gas do the fungal networks store in the ground?
3What did scientists make for the first time?
4What are fungi similar to?
5What do the fungal networks help plants get?
True or False
6Fungal networks connect plant roots underground.
7Fungi are the same as animals.
8The networks store carbon dioxide in the ground.
9Only a few plants use fungal networks.
10Scientists made a world map of fungal networks for the first time.
Fill in the Blank
11Fungal networks are made of tiny ___ that grow underground.
12The networks connect the ___ of many different plants together.
13The networks store ___ dioxide inside the ground.
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