Mushrooms, members of the kingdom Fungi, are living organisms that release carbon dioxide through respiration. Unlike plants, which absorb CO2 for photosynthesis, mushrooms obtain nutrients from other sources and release CO2 as a metabolic byproduct.
How Mushrooms Produce Carbon Dioxide
Mushrooms produce carbon dioxide through a metabolic process called cellular respiration. Similar to animals, fungi are heterotrophs, meaning they acquire nutrients by breaking down organic matter rather than producing their own food. They absorb organic compounds from their environment, such as decaying leaves, wood, or other dead organic material.
During cellular respiration, mushrooms take in oxygen from the air. This oxygen breaks down absorbed organic matter, converting stored chemical energy into a usable form for growth and functions. This biochemical conversion yields energy, releasing carbon dioxide and water as waste products. This continuous process sustains their life. The hyphae, thread-like filaments forming the main fungal body, are filled with mitochondria, responsible for this aerobic respiration.
Mushrooms’ Contribution to the Carbon Cycle
Mushrooms, as members of the fungal kingdom, play a significant role in the global carbon cycle, particularly as decomposers. They break down complex organic materials like dead plants, wood, and other decaying biomass that would otherwise accumulate. This decomposition process involves the release of enzymes that break down substances such as lignin and cellulose, which are major components of plant matter.
As fungi decompose these materials, a portion of the carbon stored within them is released back into the atmosphere as carbon dioxide through their respiration. This action ensures carbon is recycled, making nutrients available for new plant growth. While plants absorb CO2 during photosynthesis, fungi act as agents of carbon release, balancing the cycle by returning carbon to the atmosphere. Fungi are also involved in forming stable soil organic matter, which can store carbon for extended periods.
Why This Matters for Mushroom Cultivation
The CO2 produced by mushrooms during respiration has practical implications for cultivation, especially in enclosed growing environments. If left unmanaged, this continuously released CO2 can accumulate to high concentrations, negatively impacting mushroom development.
Excessive CO2 levels, typically above 1,000 to 1,500 ppm during the fruiting stage, can lead to undesirable growth characteristics, such as elongated stems and smaller, misshapen caps. To prevent these deformities and promote optimal growth, growers must implement effective ventilation and air exchange systems. Introducing fresh air removes accumulated CO2 and supplies mushrooms with the oxygen they need for respiration. Specific CO2 levels are needed for different growth stages and mushroom types; higher concentrations (10,000-20,000 ppm) can benefit initial mycelial growth, while much lower levels (400-800 ppm) are generally required for proper fruiting.