Fungi could hold untapped potential for carbon storage, study says

Fungal networks can store an estimated 36% of annual carbon-dioxide emissions from fossil fuels

More than 13 gigatonnes of carbon dioxide equivalent passes through an underground network of mycelium every year, a study suggests. University of Sheffield

Fungi could be an “untapped potential” of carbon storage, with more than 13 gigatonnes of carbon dioxide equivalent passing through an underground network of mycelium every year, a study suggests.

Equal to 36 per cent of annual carbon dioxide emissions from fossil fuels, the carbon is stored at least temporarily in the fungi, although the researchers said more work is needed to understand how much is retained long term.

Scientists already knew of the mycorrhizal fungi’s storage ability because they form symbiotic relationships with almost all land plants and transport carbon, converted into sugars and fats by the plant, into soil.

Now an international team, publishing in the journal Current Biology, has revealed the possible scale of fungi’s carbon-capture powers by conducting a meta-analysis of hundreds of other studies of plant-soil processes.

They estimate that 13.12 gigatonnes of carbon dioxide equivalent passes through fungal networks every year, in addition to that sequestered by trees through photosynthesis.

“We don’t have any off-the-shelf solutions just yet but I think what our numbers show is that there is untapped potential there," said Prof Katie Field, of the University of Sheffield, who is also co-author of the study.

“They’re unlike any other organisms on Earth and they’ve been overlooked for almost the entirety of biological study.

“We’ve only just scratched the surface in how important they might be in terms of environmental function.

“There’s an estimated between and six and seven million species of fungi but we’ve only ever described between 12,000 to 15,000. So there’s so much we don’t know.”

Equivalent to 36% of annual CO2 emissions from fossil fuels, the carbon is stored at least temporarily in the fungi, though the researchers said more work is needed. University of Sheffield

Mycorrhizal fungi have existed for about 500 million years and make up vast underground networks in every landscape on every continent on Earth, even under roads in urban environments.

Prof Field hopes the work will lead to changes in environmental policy and towards managing land in a “fungi-friendly fashion”.

This would include encouraging farming practices that use fewer pesticides while preventing soil degradation.

It would allow fungal networks to grow in their own natural way and improve the fertility of the soil through boosting organic matter, Prof Field said.

The UN estimates that 90 per cent of the world’s topsoil could be degraded by 2050, which would be hugely damaging for our ability to grow food and slow climate change.

“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," Prof Field said.

“When we disrupt the ancient life support systems in the soil, we sabotage our efforts to limit global heating and undermine the ecosystems on which we depend.

“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.”