Martínez-Suz’s research focuses on mycorrhizal fungi, a large group of fungi that coexist with the root systems of plants. Mycorrhizal fungi form networks that can surround and sometimes inside plant roots, transferring nutrients and water to plants in exchange for carbon. About 90 percent of plant species are known to establish these symbiotic trade networks with different fungal species. “These plants are covered in these fungi. Is incredible. They are small but they are everywhere,” says Martínez-Suz.
This has serious implications for tree planting plans. Planting new forests is a great hope for carbon sequestration, but there is growing evidence that mycorrhizal networks could be crucial to the success of these attempts. One replanting study found that a birch-pine forest planted on a moor in northern Scotland did not increase soil carbon stocks, even after almost 40 years underground. The researchers who carried out the study think that it could be because the arrival of new trees altered the delicate mycorrhizal networks of the already present paramos.
“Replacing the entire fungal suite with other fungi has implications for long-term carbon sequestration in soil and biodiversity,” says Martínez-Suz. Her current project involves comparing samples of forests in low-polluting sites such as northern Finland with those in highly polluted regions such as Belgium and the Netherlands. Fungi in polluted regions are less diverse, she says, and this could have a knock-on effect on how well those forests store carbon.
The main culprit here is nitrogen pollution, which enters soils through the burning of fossil fuels for electricity and transportation, and through agriculture. Too much nitrogen changes the composition of soil fungi, so that fungi that are best at retaining nutrients and pumping carbon into the soil decline.
But there is some hope that forests can change the situation. A study in the Netherlands found that when nitrogen pollution was reduced, beneficial fungal species began to return to forests. The danger, Martínez-Suz says, is that if ecosystems are pushed too far, there may be no fungal spores left to boost populations.
If we want to better understand how these fungi influence critical ecosystems, then we must become familiar with all of these species. Mycologists believe almost 90 per cent of the world’s mushroom species are still undiscovered, and Kew archivists are only halfway through the long process of digitizing their collection so researchers can easily know where and when it was found. a kind.
About 5,000 additional specimens enter the fungarium each year, and shelves are packed with specimens waiting to be dehydrated and stored. Many of them, Davies says, are sent by amateur mycologists fascinated by the world of fungi. “People from academic institutions like this send them material to work with and make identifications, because they are world experts even though they do not have formal training. They are really obsessive. It’s so good.”
This article appears in the July/August 2024 issue of UK WIRED Magazine.