Climate action

Mycorrhizal fungal networks are a major global carbon sink. When we destroy this resource, we sabotage our efforts to limit global heating.

HIDDEN BUT NOT HIDING

Sequester

Mycorrhizal fungi create complex networks that move carbon from plant roots into the soil. Healthy fungal networks can help us control rising CO2 levels because carbon that enters the soil from fungal networks has a longer residence time compared to other carbon sources, like leaves.

Read more

Mycorrhizal networks are a major global carbon sink: ecosystems with plants that feed carbon to underground networks store an estimated 8 times more carbon compared to ecosystems with non-mycorrhizal vegetation. Underground fungal networks sequester carbon in three ways. First, fungi use carbon to build rapidly expanding networks in the soil. These networks are connected to plant roots, and act as nutrient highways. Second, sequestered carbon is used to create fungal exudates. Exudates are tough organic compounds that help form stronger soil aggregates, which act as a stable carbon reservoir, reducing erosion rates and maintaining soil structure. Third, sequestered carbon is stored in fungal necromass. Necromass describes underground networks that are no longer active, but whose complex architecture is structurally woven into the soil matrix. Microbial necromass is responsible for up to one-half of total soil organic matter and helps stabilize soils.

Sources
  1. Frey, S.D. “Mycorrhizal Fungi as Mediators of Soil Organic Matter Dynamics.” Ann. Rev. Ecol. Evol. Syst. 50, 237–259 (2019)
  2. Schmidt, M. et al. “Persistence of soil organic matter as an ecosystem property.” Nature 478, 49–56 (2011)
  3. Soudzilovskaia, N.A. et al. “Global mycorrhizal plant distribution linked to terrestrial carbon stocks.” Nat. Comm. 10, 1–10 (2019)

Mycorrhizal networks make up

25-50%

of the living biomass of soils.

Plants acquire as much as

80%

of their phosphorus from mycorrhizal fungi

Forage

We are on the brink of exhausting Earth’s phosphorus reserves. Mycorrhizal fungal networks can exceed the length of a plant’s roots by as much as 100 times, and have evolved sophisticated ways to find, extract, and transport nutrients – like phosphorus – around ecosystems. When we destroy fungal networks, we lose access to their powerful abilities to forage for nutrients in the soil.

Read more

Fungi are expert foragers. They are able to acquire nutrients like phosphorus and nitrogen from the soil, and trade these nutrients to their plant partners for energy-containing carbon compounds, like sugars and fats. Modern industrial agriculture adds vast quantities of chemical fertilizer which interrupts the dynamics of exchange between plants and fungi. Phosphorus fertilizer is mined as rock phosphate: a non-renewable resource that takes millions of years to form. By 2040-2050, demand for phosphorus is projected to outpace supply, with dire consequences for food production. As rock phosphate becomes scarce, the importance of high-functioning fungal networks for agricultural systems will increase. Healthy networks decrease the quantity of nutrients leached out of the soil by rainfall by as much as 50%, and can increase the nutrient density of crops. Maximizing the health and functioning of fungal networks can help reduce the growing footprint of global food production.

Sources
  1. Alaux, P.L. et al. “Can common mycorrhizal fungal networks be managed to enhance ecosystem functionality?” Plants, People, Planet 3(5), 433-444 (2021)
  2. Bielčik, M. et al. “The role of active movement in fungal ecology and community assembly.” Mov. Ecol. 7, 36 (2019)
  3. Guignard, M.A. et al. “Impacts of nitrogen and phosphorus: From genomes to natural ecosystems and agriculture.” Front. Ecol. Evol. 5, 7 (2017)
  4. Li, B. et al. “Peak phosphorus, demand trends and implications for the sustainable management of phosphorus in China.” Resour. Conserv. Recycl. 146, 316–328 (2019)
  5. Martínez-García, L.B. et al. “Symbiotic soil fungi enhance ecosystem resilience to climate change.” Glob. Change Biol. 23, 5228–5236 (2017)
  6. Pandey, D. et al. “Mycorrhizal Fungi: Biodiversity, Ecological Significance, and Industrial Applications.” In: Yadav, A. et al. “Recent Advancement in White Biotechnology Through Fungi.” Fungal Biol. Springer, Cham. 181-199 (2019)

Protect

Fungal networks support ecosystem biodiversity. From rainforests to the arctic tundra, fungal networks lie at the base of the food webs that support nearly all terrestrial organisms. Fungal networks feed plants, and protect them from metal toxicity, salinity, drought, pathogens, & herbivores.

Read more

Fungal networks are ecosystem engineers that help protect plants from a wide range of stresses. By protecting plants, fungal networks help increase plant biodiversity and ecosystem resilience. Fungal networks help prevent disease in plants, and boost the ability of plants to fight off attacks from insect pests by stimulating the production of defensive chemicals. Networks are also able to bind to heavy metals within their mycelium, protecting plants from toxicity, and can make plants less susceptible to drought and salt stress. Fungal networks also support entire ecosystems by excreting cement-like biopolymers that help reduce erosion. This helps increase biodiversity, maintain biogeochemical cycles and ecosystem productivity.

Sources
  1. Alaux, P.L. et al. “Can common mycorrhizal fungal networks be managed to enhance ecosystem functionality?” Plants, People, Planet 3(5), 433-444 (2021)
  2. Frąc, M. et al. “Fungal Biodiversity and Their Role in Soil Health.” Front. Microbiol 9, 707 (2018); Guerra, C.A. et al. “Global vulnerability of soil ecosystems to erosion.” Landsc. Ecol. 35, 823 (2020)
  3. Lehmann, A. et al. “Soil biota contributions to soil aggregation.” Nat. Ecol. Evol. 1, 1828–1835 (2017);
  4. Lehmann, A. et al. “Fungal Traits Important for Soil Aggregation.” Front. Microbiol. 10, 2904 (2020)
  5. Pandey, D. et al. “Mycorrhizal Fungi: Biodiversity, Ecological Significance, and Industrial Applications.” In: Yadav, A. et al. “Recent Advancement in White Biotechnology Through Fungi.” Fungal Biol. Springer, Cham. 181-199 (2019)
  6. Wang, Y. et al. “Non-host plants: Are they mycorrhizal networks players?” Plant Divers. In Press (2021)
  7. Yang, G. et al. “How Soil Biota Drive Ecosystem Stability.” Trends Plant Sci. 23, 1057-1067 (2018)

~90%

of plant species form symbiotic relationships with mycorrhizal fungi