Blog & News

July 30th, 2024

The Climate Solution Beneath Our Feet

Author: Drake Austro-Stasyshyn

Beneath the lush greenery of our planet's forests and the expanses of its grasslands lies a hidden powerhouse in the battle against climate change: mycorrhizal fungi. These intricate and expansive underground networks are not just another component of the soil; they are crucial allies that capture and store carbon, offering a promising avenue for environmental conservation. A recent study was the first to truly quantify the amounts of carbon sequestered by fungi within the soil, and the numbers are massive. More than a third of the world's annual fossil fuel emissions are trapped by these rather mysterious organisms.

What many people visualize when they hear the word "fungi" are colorful mushrooms or tasty dishes featuring popular mushrooms like portabellas or shitakes, but these examples represent only the small fruiting body of a much larger organism. Fungi, like the carbon-storing mycorrhizal fungi, can exist entirely underground, growing to cover great distances under our feet. The largest of them covers an area of almost 2,400 acres. But how do these organisms survive and thrive on such massive scales under our feet?

Mycorrhizal fungi are a type of symbiotic fungi that form mutually beneficial relationships with plant roots. In these symbiotic relationships, the fungi enhance plant growth by improving nutrient and water uptake. In exchange, plants provide the fungi with carbohydrates synthesized through photosynthesis. There are two main types of mycorrhizal associations: ectomycorrhizal, which forms an external network on the plant's root surface, and arbuscular mycorrhizal, which penetrates root cells.

This symbiotic relationship dates back over 400 million years and is the primary pathway for the fungi's incredibly effective carbon sequestration. Forests are known for being crucial in offsetting our carbon output. By capturing carbon that would otherwise go directly into our atmosphere, forests protect us from much faster rates of climate change than we are currently seeing. Forests absorb an estimated one-third of all human CO₂ emissions.

While the trees absorb carbon, they don’t do it alone, and the most efficient carbon absorbers are those that share the soil with ectomycorrhizal fungi. One of the two designations of symbiotic fungi, these organisms form more extensive networks within boreal and temperate forests where they draw down plant-fixed carbon and store it within the soil beneath forests. The larger the network, the more efficiently carbon is transported and stored. These networks also slow the rate of decomposition.

It is also important to note that the survival and effectiveness of these mycorrhizal fungi are under threat. Land degradation and nitrogen pollution significantly disrupt these fungal networks. High levels of nitrogen, often resulting from agricultural runoff and fossil fuel combustion, can lead to an imbalance in soil ecosystems. This imbalance favors non-mycorrhizal plants, reducing the fungi's presence and diversity, which in turn disrupts their ability to sequester carbon efficiently. Excess nitrogen can alter soil chemistry and microbial communities, leading to a decline in mycorrhizal fungi populations. Studies have shown that nitrogen deposition can decrease the colonization of roots by mycorrhizal fungi, reducing their capacity to aid in carbon sequestration.

 In addition, land-use changes such as deforestation, urbanization, and intensive agriculture physically disrupt these fungal networks, making it harder for them to recover and function optimally  To combat these threats, it is important to adopt sustainable agricultural practices that minimize nitrogen runoff and reduce reliance on fossil fuels. Strategies such as using cover crops, reducing tillage, and promoting organic farming can help maintain the health of mycorrhizal networks. Cover crops, for instance, protect soil from erosion and improve soil organic matter, which supports fungal growth.

The Hudson Highlands Fjord Trail, a project that Great Ecology is conducting natural resource surveys and providing habitat restoration recommendations for, is a great example of how we can support the survival of the fungi. The trail will be a 7.5-mile trail and linear park along the Hudson River connecting Cold Spring, NY and Beacon, NY. Extensive habitat restoration along the trail’s corridor aims to improve biodiversity, and thus, soil health, which is essential for the survival of mycorrhizal fungi. The restoration efforts include planting native vegetation, which forms symbiotic relationships with mycorrhizal fungi, enhancing their ability to sequester carbon. It also incorporates sustainable land management practices that protect and restore natural habitats, providing a model for how ecological principles can be integrated into landscape design to support mycorrhizal fungi and other vital ecosystem functions.

Safeguarding mycorrhizal fungi requires efforts to reduce pollution, protect natural habitats, and implement sustainable land-use practices. Organizations like Great Ecology are leading the way by incorporating these principles into their projects, providing a model for how we can achieve ecological balance and sustainability. The Hudson Highlands Fjord Trail Master Plan is an excellent example of how ecological restoration can support the survival of mycorrhizal fungi, ensuring their continued role in carbon sequestration and climate mitigation. Let us commit to these efforts, ensuring that these hidden allies continue to protect our planet for generations to come.