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How do fungi return carbon, nitrogen, and phosphorus to ecosystems?

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Two Amanita pantherina mushrooms with brown caps covered in white spots grow among moss and fallen leaves. — fungus A pair of panther cap mushrooms (*Amanita pantherina*). Closely related to the death cap mushroom (*Amanita phalloides*), the panther cap is highly poisonous.

Fungi play a vital role in ecosystems by acting as saprotrophs, organisms that decompose nonliving organic matter and recycle essential nutrients back into the environment.12

Carbon Cycling

Fungi are highly efficient at breaking down complex organic molecules, particularly cellulose found in plant cell walls, which most other organisms cannot digest. By excreting specialized enzymes, they convert this complex detritus into simpler carbohydrates. This process releases carbon dioxide back into the environment, where it can be utilized by plants and photosynthetic organisms to create new biomass, thereby continuing the carbon cycle.23

Nitrogen and Phosphorus

Fungi contribute to nutrient cycling by decomposing organic matter that contains nitrogen and phosphorus. While fungi generally cannot fix atmospheric nitrogen, they break down nitrogen-rich proteins in dead biomass into simpler compounds, such as amino acids and ammonium, which become available for uptake by other organisms. Additionally, fungi require phosphorus for their own growth and, through the decomposition of organic matter, help release these minerals back into the soil, supporting the broader ecosystem health.124