Rosa Rubicondior: Refuting Creationism - A Vast Global Fungal Plant-Support System - Unintelligently 'Designed' Over 480 Million Years

Mycorrhizal fungi under the microscope at AMOLF biophysics institute in Amsterdam. The circular structures are spores. Color is altered for legibility.

Credit: Tomás Munita

New global research maps underground fungal infrastructure for the first time - Vrije Universiteit Amsterdam

An international team of researchers, led by ecologist Justin Stewart of Vrije Universiteit Amsterdam, has announced the creation of the first global map of the vast underground infrastructure formed by arbuscular mycorrhizal fungi. The team has published its findings in Science.

These are not fungi in the familiar sense of mushrooms, but microscopic, thread-like filaments, or hyphae, which form intimate partnerships with plant roots. The figures involved are astonishing. The researchers estimate that the upper layer of the world’s soils contains about 110 quadrillion kilometres of these fungal filaments — enough to stretch from Earth to the sun nearly three-quarters of a billion times, or there and back about 368 million times. The networks also transport roughly 4 billion tonnes of CO₂-equivalent into soils each year, about 11% of annual human-caused CO₂ emissions.

This is not a new evolutionary phenomenon. Arbuscular mycorrhizal fungi are part of an ancient plant-fungal symbiosis that appears to date back roughly 475–480 million years, close to the origin of the first land plants. That does not mean, of course, that the individual fungal filaments mapped today are hundreds of millions of years old, but that this type of mutualistic relationship has been evolving since the early colonisation of land by plants.

One sure way to tell that biological systems are not intelligently designed is not simply that they are complex, but that they are historically contingent. They carry the marks of accumulated compromises, improvised workarounds and layered dependencies. Evolution can only modify what already exists; it cannot scrap an imperfect arrangement and begin again with a clean sheet. Its only test is whether a change works well enough, in a particular environment, to leave more descendants than the alternatives.

None of these constraints would apply to an intelligent designer, still less to the omnipotent, omniscient, perfect designer imagined — though rarely named explicitly — by creationists trying to disguise fundamentalist creationism as science. A designed global life-support system would not be expected to emerge through countless local bargains between plants and fungi, mediated by nutrient stress, carbon demand, soil chemistry, competition, disturbance and natural selection.

So we can be as sure as it is possible to be that this vast, intricate and globally important biological infrastructure was not intelligently designed. It evolved because both partners gained from the exchange: plants provided carbon fixed by photosynthesis; fungi extended the reach of plant roots, supplying water and mineral nutrients, especially phosphorus and nitrogen. Over deep time, those local mutual advantages became part of the living fabric of terrestrial ecosystems.

The paper in Science is accompanied by a news release from Vrije Universiteit Amsterdam, which includes a link to an interactive map of this global fungal infrastructure.

Mutual Benefits in Arbuscular Mycorrhizal Symbiosis. Arbuscular mycorrhizal fungi form one of the most important mutualistic associations on Earth. Their microscopic hyphae grow through the soil and into plant roots, where they form finely branched structures called arbuscules inside root cells. These arbuscules act as exchange surfaces between plant and fungus.

What the plant gains: the fungal hyphae greatly extend the effective reach of the root system. They can penetrate small soil spaces that roots cannot enter and absorb mineral nutrients, especially phosphorus, but also nitrogen and trace elements. They can also improve water uptake and may help plants cope with drought, salinity, poor soils and some root pathogens. In effect, the fungus acts as an extended, living root system.
What the fungus gains: arbuscular mycorrhizal fungi cannot complete their life cycle without a plant host. They depend on plants for carbon compounds made by photosynthesis, including sugars and lipids. The plant therefore supplies the energy and raw materials the fungus needs for growth, maintenance and reproduction.

This is not cooperation in the sentimental sense, still less evidence of design. It is a product of natural selection. Plants that obtained extra nutrients through fungal partners left more descendants, while fungi that gained access to plant carbon also left more descendants. Over hundreds of millions of years, that reciprocal advantage produced one of the most widespread and ecologically important symbioses in the terrestrial biosphere.

The relationship is also conditional. Where nutrients are plentiful, or where a fungus gives little in return, the association can become less beneficial to the plant. That is exactly what evolution predicts: not a perfectly engineered system, but a shifting bargain shaped by local costs, benefits and competition.

New global research maps underground fungal infrastructure for the first time
Underground fungal networks prove crucial for climate, biodiversity, and food security
An international team of researchers has created the first global map of arbuscular mycorrhizal fungi: microscopic fungal networks that collaborate with plant roots underground. The study, published in Science, shows that this hidden infrastructure plays a much larger role in the functioning of ecosystems and carbon sequestration than previously assumed.

The researchers estimate that the topsoil worldwide contains approximately 110 quadrillion kilometres of fungal filaments.
That is nearly a billion times the distance between the Earth and the Sun. These underground networks form an essential transport system for water, nutrients, and carbon, and support an estimated seventy percent of all plant species on Earth.

Justin D. Stewart, first author.
Amsterdam Institute for Life and Environment (A-LIFE)
Section Ecology and Evolution
Vrije Universiteit Amsterdam
Amsterdam, Netherlands.

Four billion tons of CO₂ equivalent

The study shows that these fungal networks transport approximately four billion tons of CO₂ equivalent to the soil annually. That corresponds to approximately eleven percent of global human-caused CO₂ emissions. Consequently, fungi play an important role in climate regulation and carbon storage. For the study, scientists analyzed data from more than 16,000 soil samples from around the world. Using machine learning and advanced imaging techniques, they developed the first global maps of the density and distribution of these fungal networks. An interactive visualization was also developed to enable researchers, policymakers, and nature managers to better monitor the condition of subsurface ecosystems.

Fungal infrastructure in grasslands

The results show that grasslands worldwide harbor approximately forty percent of the total fungal infrastructure. The swamp grasslands of South Sudan, the Everglades in Florida, and the Tibetan Plateau, in particular, appear to contain exceptionally high densities of fungal networks. At the same time, grasslands are among the least protected ecosystems in the world and are converted to agricultural land four times faster than forests.

Network architecture of fungal mycelium. Mycelial architecture varies across strains and species. Networks imaged at the AMOLF biophysics institute in Amsterdam.

Credit: Corentin Bisot - VU Amsterdam, AMOLF Justin Stewart - SPUN

Close up of soil core extraction in the Gobi Desert

Credit: Tomás Munita

The researchers also identify a potential threat to soil health. In large-scale agricultural areas, fungal networks are expected to be, on average, fifty percent less dense than in natural ecosystems. Although follow-up research is needed to determine the precise influence of agricultural practices, scientists fear that a decline in these networks could reduce soils' ability to store carbon, recycle nutrients, and withstand drought and other stressors.

Including fungi in climate and nature policy

According to the researchers, the results underscore the importance of including fungi in climate and nature policy. Subsurface ecosystems often remain overlooked in nature management and protection, even though they play a fundamental role in biodiversity, food production, and climate regulation.

The new maps reveal where these crucial fungal networks are located, where they are under pressure, and which areas deserve priority for protection. At the same time, the research shows how much remains unknown: large parts of the world have barely been explored. Consequently, this study represents an important step towards a better understanding of the hidden ecosystem beneath our feet and its contribution to a resilient planet.

Publication:
Justin D. Stewart et al.
Global density and biomass of arbuscular mycorrhizal fungal networks. Science 392, 1171-1176 (2026). DOI:10.1126/science.adu4373

Abstract Arbuscular mycorrhizal fungi form symbioses with ~70% of plant species, building hyphal networks that exchange nutrients for host-derived carbon. These tubular networks move ~1 billion metric tons of carbon per year into Earth’s soils. However, we have no quantitative understanding of the hyphal infrastructure required to carry out this resource transfer. We assembled data from 322 studies representing more than 16,000 soil cores across nine biomes and developed machine-learning models to predict hyphal densities globally. With robotic imaging of more than 300,000 hyphae, we calibrated a biomass model from our spatial predictions. We estimate that global topsoils contain 1.10 × 10¹⁷ ± 0.13 × 10¹⁷ SD kilometers of living hyphae, weighing ~300 ± 60 SD megatons, ~4- to 6-fold the biomass of humans. Our uncertainty analyses identified undersampled ecosystems that require additional empirical attention.

So once again, we have a piece of science which makes no attempt to refute creationism, yet does so incidentally simply by describing reality. Beneath our feet is a vast, ancient, living infrastructure produced not by planning, foresight or magic, but by countless generations of reciprocal advantage between plants and fungi. It is exactly the sort of thing evolutionary theory predicts: a historically contingent system of compromises, dependencies and exchanges, shaped by selection over deep time.

Creationism, by contrast, has no explanatory framework for any of this. It cannot explain why plants should depend on fungi for nutrients, why fungi should depend on plants for carbon, or why such a relationship should bear the hallmarks of an ancient evolutionary bargain rather than those of competent design. It can only point at complexity and declare it inexplicable, mistaking its own lack of explanation for evidence of a designer.

But complexity is not the same as design, and dependence is not the same as purpose. The arbuscular mycorrhizal association is not a perfectly engineered system; it is a negotiated biological trade, beneficial under some conditions, less so under others, and vulnerable to disruption by changes in climate, land use and soil chemistry. That conditional, variable and historically constrained character is precisely what we should expect from evolution, and precisely what we should not expect from the work of an omniscient engineer.

The real wonder is not that some invisible designer put this hidden infrastructure in place for our benefit, but that blind, undirected natural processes, acting through ordinary selection on ordinary organisms, could produce something so vast, ancient and ecologically important. The world beneath our feet is not evidence of supernatural design. It is evidence of deep time, mutual dependence, and the creative power of evolution.

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