The Tiny Fungi Fighting Climate Change

Somewhere in all this dirt, there are fungi. But we’re not going to find shiitakes or lion’s mane. Instead, we’re on the hunt for microscopic organisms that might just hold the key to reducing carbon emissions. Nicholas: About 10% of the estimated biodiversity of fungi produce mushrooms. Most of them are underground and are microscopic. Nicholas: Here in the root lab at the Morton Arboretum, we study how fungi are produced underground and when they're produced. Nicholas: And how that relates to the rest of the organs in a tree. When stems grow, when leaves grow, and how they all work together. These underground growths are called mycorrhizal fungi: “myco-” meaning “fungus” and “rhiza” meaning “root.” These organisms do look like roots, but they were actually named for their function. Mycorrhizal fungi and tree roots are in a symbiotic relationship, like oxpeckers picking parasites off a giraffe. Nicholas: It's an exchange of resources. The tree or plant does photosynthesis. And it produces lots of sugar. And it has extra to give around. Nicholas: It's released through the root. And that's when the fungi capitalize and use that as energy. Nicholas: In return, the fungi are thinner versions of roots, so they have more surface area so they can absorb water and nutrients that are dissolved in the soil water, and they give it back to the plant. The exchange of sugar, carbon, and other nutrients makes a big difference. These trees grow 10 to 20% faster than trees without any fungal friends, which shows just how beneficial this relationship is to both parties. Mycorrhizal fungi also naturally store carbon passed down from trees—about 13.12 billion tons of it per year. That’s more than 30% of global fossil fuel emissions. Nicholas: We usually think of trees for carbon storage, in producing wood that lasts for hundreds of years. A lot of the sugar that goes below ground into the mycorrhizal fungi, that is also an important store of carbon. That’s why we’re digging around in the dirt. Climate scientists have historically searched for carbon storage solutions above ground. Now, they’re looking for answers beneath our feet. How do mycorrhizal fungi capture and store so much carbon? And how can we make sure they continue to thrive? This is a big project, and research is ongoing. But all the while, our understanding of these tiny organisms continues to expand. Nicholas: Basically, without mycorrhizal fungi, trees could not do what they do to make our ecosystems better, to store carbon, and mitigate climate change. Nicholas: Because mycorrhizal fungi are really capturing a lot of the carbon that we emit. So they're helping us solve global issues. Nicholas: It kind of helps me be more humble, as a researcher and human for how to make the most of the world and Earth.