Researchers have mapped an underground network of arbuscular mycorrhizal fungi spanning 110 quadrillion kilometres, a scale equivalent to reaching the Sun nearly a billion times. According to the Society for the Protection of Underground Networks (SPUN), this biological infrastructure supports 70% of land plants, sequesters one billion metric tons of carbon annually, and is significantly depleted by intensive agricultural practices like deep tilling.
How does the “Wood Wide Web” function?
The “wood wide web” refers to a vast, interconnected system of fungal threads known as hyphae that link plant roots. As reported by SPUN, these fungi act as a biological trade network: plants provide sugars derived from photosynthesis, while fungi supply essential nutrients like phosphorus and nitrogen harvested from the soil. This symbiotic relationship, which dates back 475 million years, allows plants to access resources beyond their root zones. Research suggests these networks may even facilitate the transfer of chemical distress signals between plants facing drought or insect threats.
The carbon stored within these fungal networks is estimated at 300 megatons—roughly four to six times the combined mass of every human on Earth.
Why are scientists comparing this network to Project Hail Mary?
The comparison to Andy Weir’s science-fiction novel Project Hail Mary stems from the book’s “Astrophage,” a microscopic organism that manages energy on a planetary scale. While researchers emphasize that these fungi are terrestrial and not alien, the metaphor highlights the immense, invisible influence both systems exert. Like the fictional Astrophage, these fungal networks operate as a hidden infrastructure that sustains life, moves resources across vast distances, and maintains ecosystem stability, even though they remain entirely unseen by the human eye.
What is the impact of modern agriculture on fungal health?
Intensive farming is actively damaging these underground systems. According to data from the SPUN-led international study, fungal concentrations in agricultural croplands are nearly 50% lower than in undisturbed natural ecosystems. Practices such as deep tilling and heavy synthetic fertiliser use disrupt the delicate hyphal networks. Scientists warn that this decline forces crops to become more reliant on artificial inputs and less resilient to environmental stressors like climate change.
How can we protect these underground ecosystems?
Future conservation efforts may shift toward soil restoration rather than just surface-level protection. Experts suggest that by minimizing soil disturbance and reducing reliance on intensive tilling, we can preserve the fungal density required for carbon sequestration. Identifying biodiversity hotspots—such as the Florida Everglades or the Sudd wetlands in South Sudan—is the first step toward creating protected zones where these fungal networks can thrive without human interference.
If you are a gardener, consider reducing the frequency of tilling your soil. Minimal disturbance allows the natural mycorrhizal networks to remain intact, which improves nutrient absorption for your plants and helps store carbon locally.
Frequently Asked Questions
Are these fungal networks a single, giant organism?
No. According to the study, there is no single giant fungus. The 110 quadrillion-kilometre figure represents the combined length of countless individual fungal networks spread across ecosystems globally.
Do these fungi help fight climate change?
Yes. By sequestering up to one billion metric tons of carbon annually and moving carbon-rich compounds deep into the soil, these networks act as a significant natural ally in regulating the Earth’s climate.
How many land plants depend on these fungi?
Approximately 70% of all land plants form mutually beneficial relationships with arbuscular mycorrhizal fungi to survive and thrive, according to research published by SPUN.
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