Fungal Relationships for a Healthy Ecosystem
Fungi act as primary investigators and stewards of many biogeochemical cycles, but the viewscape of fungi is temporary and their significance is frequently obscured. This little excerpt of our Community Training Day’s Mycology Talk will dive into how fungi play essential roles in the health of our ecosystems in symbiotic relationships and as recomposers in nutrient cycling. Many interactions with our fungal friends support the resilience, growth, and communication between many different organisms within ecosystems.
When talking about our fungi friends, the mycelium is the network of vegetative filaments of hyphae (branches) that exist within the soil. The Mycorrhizosphere is the soil community that contains the roots, mycelium, associated microorganisms, and of course – soil. Soil has twice the biomass of the earth’s animals and is the central axis in nutrient cycles, but is easily wounded! So learning more about the many fungal processes that increase soil health and resilience is fundamental in holistic forest restoration.
Mycorrhizal symbiosis is when a fungus grows with the roots of a plant in a symbiotic or pathogenic relationship. This relationship is probably one of the better known interactions that fungi partake in. Fungi have a symbiosis with at least 90% of the world’s plants and are found in all habitats and latitudes. There are around 8 miles of mycelium in 1 cubic inch of soil! In mycorrhizal relationships mycelium wraps around a plant’s root tips and enters the root cellular structure to the first few cell layers. Typically, the mycorrhizae develop root hairs, where the plant absorbs most of its water and nutrients.
Ectomycorrhizal relationships, when the fungus enters roots to only a shallow depth, are often on woody plants like birch, willow, pine, or rose. Endomycorrhizal relationships, when the fungus penetrates the walls of root cells, do not form mushrooms and instead inhabit tissue inside roots, stems, leaves, grasses, etc. This symbiosis creates a host defense technology that gives plants the ability to resist disease and have a higher thermotolerance. The hyphae in mycorrhizal fungi extend to draw in water, nitrogen, phosphorous, and nutrients that the thick and slow growing root hairs would not be able to reach on their own.
During our Mycology Talk, we stood under trees harboring a few mushrooms of the species Fomes fomentarius. This fungi is a brown rot species, which primarily degrades tree cellulose. The mycelium penetrates the wood of the trees, causing rot in the host. The resultant material is resistant to further degradation and acts as a type of natural sponge that holds water and nutrients, and provides refuge for insects and microbes.
Saprophytic fungi are the soil magicians. Often deemed as decomposers, they are equivalently the recomposers of life. They grow on dead material and are responsible for 90% of all decomposition. Fungi take in nutrients and transform them into new compounds that other species use to survive. They contribute to the movement of nitrogen in the nitrogen cycle, which represents one of the most important nutrient cycles that sustains life on earth. The degradation process relies on digestive enzymes that break down components such as tree cellulose or lignin. This same process that breaks down complex plant cell structures is also responsible for the amazing mycoremediation powers that fungi possess.
Mycoremediation is a form of bioremediation and is a process of using fungi to degrade contaminants in the environment, both in soil and water. Fungi have the ability to filter many contaminants from agriculture, pesticide use, mining, oil and gas operations, fertilizers, and sewage using their digestive enzymes. The past two centuries have seen a new human sourced destruction and toxic pollution of healthy soil for short term, short sighted profits, and since the 1980’s, research has investigated ways in which industrial pollutants can restore to a state of non-toxicity.
Mycoremediation studies are finding many examples of species degrading specific toxins, and many people are working with native fungi in ways that encourage a healthy diversity of many other healing microbes in remediation practices. Digestive enzymes are a catalyst to bring biochemical reaction and are used to transform nutrients from an unavailable form into an available form that plants can readily take up and metabolize.
Plants and fungi have co-evolved over millions of years and we live immersed in a rich world of plant and microbe diversity. Our awareness of the importance of this diversity and is foundational for most environmental issues. Fungi are extremely social creatures, who not only like to disassemble, but also live in direct contact with thousands of other beings, just like ourselves.
Sources
Butin, Heinz; Lonsdale, D. (1995). Tree Diseases and Disorders. Oxford University Press. pp. 167–8. ISBN 978-0-19-854932-1.
Singh, H. (2006). Mycoremediation: Fungal bioremediation. Hoboken, NJ: Wiley-Interscience.
Schindler, J. (2012). FUNGI FOR THE PEOPLE. Retrieved March 06, from http://fungiforthepeople.org/
McCoy, P. (2016). Radical Mycology: A treaties on seeing and working with fungi. Portland, OR.
Adenipekun, C. O., & Lawal, R. (2012). Uses of mushrooms in bioremediation: A review. Biotechnology and Molecular Biology Reviews Biotechnol. Mol. Biol. Rev., 7(3).
Post written by: Gabriela D’Elia
Gabriela is a senior at Seattle University studying Environmental Studies and Philosophy. She is passionate for the life cycles of our ecosystems and most specifically all things fungal! Born and raised in the mountains of Utah, she has a deep curiosity for the interrelationships between our healing as well as the earth’s. When not outside dancing around in the mushrooms all over the PNW, she is most likely playing music, writing, or reading.