Fly agaric fungi
As the world develops policies and implements procedures to address the rapidly warming climate, researchers at the University of Sheffield (UK) have discovered that one of our greatest assets may be beneath us.
Mycorrhizal fungi make up a vast underground network beneath grasslands and forests, as well as roads, gardens, and even houses on every continent on Earth. The fungi have been doing this for over 400 years, enjoying symbiotic relationships with plants that have become crucial to global ecosystems.
Researchers have long known that as the fungi form beneficial relationships with plants, they transport carbon—converted into sugars and fats by the plant—into the soil. But, until now, the true extent of just how much carbon the fungi were storing wasn’t known—and the number shocked researchers.
The new study, published in Current Biology, shows an estimated 13.12 gigatons of carbon is transferred from plants to mycorrhizal fungi annually. That’s the equivalent of 36 percent of yearly global fossil fuel emissions, and more than China emits each year. In other words, the soil beneath our feet is a massive carbon pool, and the most effective carbon capture storage unit in the world.
The researchers analyzed 194 datasets to derive this data, the first global quantitative estimates of carbon allocation from plants to the mycelium of mycorrhizal fungi.
“We always suspected that we may have been overlooking a major carbon pool,” said Heidi Hawkins, lead author of the study and professor at the University of Cape Town. “Understandably, much focus has been placed on protecting and restoring forests as a natural way to mitigate climate change, but little attention has been paid to the fate of the vast amounts of carbon dioxide that are moved from the atmosphere during photosynthesis by those plants and sent below ground to mycorrhizal fungi.”
Hawkins and her co-authors are now calling for fungi to be considered in biodiversity and conservation policies, given its proven crucial role in cutting carbon emissions. At the current rate, the UN warns that 90 percent of soils could be degraded by 2050, which would be catastrophic not only for curbing climate change but for the global food supply as well.
“Soil ecosystems are being destroyed at an alarming rate through agriculture, development and other industry, but the wider impacts of disruption of soil communities are poorly understood,” said co-author Katie Field, professor of plant-soil processes at the University of Sheffield. “More needs to be done to protect these underground networks. We already knew that they were essential for biodiversity, and now we have even more evidence that they are crucial to the health of our planet.”
Using simulated future climates in specialized outdoor field experiments, the research team is now investigating how long carbon is stored by the fungi in the soil, and are seeking to further explore the role that fungi play in Earth’s ecosystems. They hope the next part of their study will improve understanding of soil fungi, as well as other microbes, and how their role will be impacted by future climate change.
“Mycorrhizal fungi lie at the base of the food webs that support much of life on Earth, but we are just starting to understand how they actually work. There’s still so much to learn,” said Toby Kiers, senior author from Vrije University in Amsterdam.