Scientists have barely scratched the surface of the world of fungi, with only about 200,000 known species and an estimated two million species waiting to be discovered.
It is only since 1997 that scientists have understood that mycorrhizal fungi are vital to the support and growth of plants on the planet. They form a symbiotic relationship with plants and create vast networks between root systems.
- Fungi guide: all you need to know about nature's hidden kingdom, including how fungi differs to plants
- Fungi vs plants - what's the difference?
Now in a new study, published in the journal Science, a group of scientists and researchers have created an interactive visualisation that shows just how vast the network of arbuscular mycorrhizal (AM) fungi is.
To collect the data shown in the models, around 16,000 soil cores were sampled from around the world. Researchers then used machine learning models, as well as data from various ecosystems, to predict fungal network density where direct measurements weren't available.
300,000 living AM fungi hyphae – the tiny tendrils that spread throughout soil – were also analysed.
The team, which was led in co-operation with the scientific research organisation Society for the Protection of Underground Networks (SPUN), uncovered astonishing results.
The data suggests that AM fungal networks spread around 110 quadrillion kilometres – which is almost a billion times the distance from the Earth to the sun.
These networks also contain around 300 megatons of carbon (which is about six times the mass of all living humans).
"It is hard to overstate the importance and enormity of these fungi," explains Justin Stewart, the lead author of the study with SPUN.
"There could be up to 10 meters (32 feet) of mycorrhizal network in just a teaspoon of soil."
The importance of fungi
In healthy soils, fungal networks can help to increase the span of plant roots and help them with around 80 per cent of its phosphorous needs. It is thought that denser fungal networks could help the soil's ability to withstand environmental stress and store carbon.
AM fungal networks are estimated to help move around four billion tons of carbon dioxide out of the air and into soils every year.
Researchers worked together with data visualisation designer Moritz Stefaner to create the Mycorrhizal Infrastructure Map, an interactive map available for anyone to explore.
- 7 weirdest fungi in the world you haven't heard of
- Photosynthesis: what it is, how it works and why it fuels life on Earth
It is hoped that by seeing the network and identifying areas that are thriving and those that are not, conservation efforts can be focused.
The study found that grasslands contain around 40 per cent of the Earth's AM fungi, but are one of the least protected areas of the world. It is thought that large agricultural croplands have about 50 per cent lower network densities on average.
"Mycorrhizal fungi have shaped life on Earth for hundreds of millions of years, but we still understand too little about how the infrastructure of these living transport systems is distributed across the planet," says co-author Merlin Sheldrake.
"This study is an exciting step towards understanding how this planetary circulatory system operates and suggests ways that we can better work with fungi to help address many of the unfolding challenges of our times, from food security to climate change."
