Nature's Air Conditioners: How Mushrooms Regulate Their Temperature and Keep Cool

Recently, researchers have found that mushrooms and other forms of fungi, like yeasts and molds, are able to maintain a cooler temperature than the surrounding air around them. This fascinating ability allows them to adapt to their environment and thrive in various conditions and climates. Though mushrooms may not be as cool as ice, they’re definitely “chilled to the gills.”

An unexpected finding

This discovery came as an accident when a group of molecular biologists from the Johns Hopkins Bloomberg School of Public Health went out into the woods with a thermal camera to examine how the coloring of mushrooms could impact their surface temperature. They recorded around twenty different wild mushrooms and found that they all had cooler temperatures than their surrounding environment. Fascinated by their findings, the scientists studied some mushrooms more closely in their lab and found that not only mushrooms but also nineteen types of molds, yeasts, and even human pathogens all had the same effect. The temperature difference ranged from around 34.5°F for the American star-footed amanita (Amanita brunnescens) to almost 43°F for the oyster mushroom (Pleurotus ostreatus). These fungi not only kept their cool in warm temperatures but also remained cooler than room temperature and low air temperatures that were close to freezing. 

How fungi lower their temperature

Though scientists may not know precisely why fungi cool themselves off, they’ve at least figured out how. Just like humans, when mushrooms are exposed to conditions that make them need to cool down, they begin to “sweat.” Of course, this sweating process isn’t the same as humans or animals since fungi do not have sweat glands. Instead is the release of moisture from the fungi’s cells. Mushrooms have a high water content, ranging from 80-90% moisture. This water is stored in their cells as they gradually release moisture which can bring down their temperature to significantly lower levels. Scientists speculate that mushrooms may have this cooling system simply because they prefer cooler temperatures, or this advantage could help with the development of the fruiting body and the timing to release their spores (1).

One study found that when mushrooms evaporate water from their system, it creates slow air movements that can carry away the mushroom’s spores and lift them into the air (2). As a result, mushrooms can release their spores into the air without the help of wind. Furthermore, the study found that this ability of mushrooms allowed them to impact the temperature of the air around them by up to 36°F. The evaporation of their water vapor creates small wind patterns around the mushroom, which affects the climate around them.

Mushrooms continue to release moisture and stay cool after they are removed from their original substrate and mycelium system. The scientists discovered that different parts of mushrooms are able to dissipate heat at different levels. The hymenium, or underside of the mushroom, has the coldest temperate compared to the rest of the fruiting body. 

What surprised the researchers even more was that single-cell fungi like Brewer’s yeast still had the same cooling mechanisms as larger fungal organisms like mushrooms. Despite their lower surface area per volume, they still demonstrated a noticeable decrease in temperature. The temperatures were lowest towards the center of the fungal colonies and gradually increased at the surrounding edges. Scientists speculate that this evaporative cooling technique could be an evolutionary mechanism for fungi thermoregulation. Microbiologist Radamés Cordero tells Science.org, “This phenomenon is a widespread feature of the fungal kingdom.” This cooling behavior is not a niche trait possessed by a few select species but rather a necessary, shared characteristic that can be found across all fungal species, from single-celled yeasts to more complex mushrooms.

Using fungal cooling mechanisms for practical applications

This new discovery will open up new ways to understand how fungi interact and adapt to their surrounding environment. Despite their seemingly simple structure, fungi have evolved sophisticated methods to regulate their temperature so that they can survive and flourish in varying conditions.

More research into these evaporative cooling techniques could inspire the development of new technologies that use or mimic the natural cooling system of fungi.

The cooling capabilities of mushrooms could be practically utilized in systems such as air conditioners or coolers. To investigate this, the researchers conducted an experiment using one pound of button mushrooms, known scientifically as Agaricus bisporus. The mushrooms were placed in a small Styrofoam box with two holes for air circulation. An exhaust fan was inserted into one hole to ensure air movement. Then, the smaller box was placed within a larger Styrofoam container.

Impressively, the temperature inside the larger container had dropped to 50°F within just forty minutes. Furthermore, the temperature was maintained for a further thirty minutes before gradually increasing again. The researchers named this mushroom-based cooling system the MycoCooler™. They plan to further study and apply this knowledge to other applications. 

Beyond their potential for small-scale cooling systems, fungi may also play a significant role in influencing local environmental temperature, especially considering that they make up around 2% of Earth’s biomass. Researchers estimate that the Earth would be approximately 0.25 to 0.5% warmer without fungi. These findings suggest a potential solution for mitigating the effects of global warming. If large-scale mushroom farms or “myco-cultures” were established in select locations, they could potentially help to offset local trends of rising temperatures (3).

The solutions to some of our most troubling problems can often come from the most unexpected places. Fungi, such as the humble mushroom, could be a surprising ally in our fight against climate change. Extensive cultivation of these fungi could help bring down our planet’s temperatures. If we create farms with edible mushrooms, we sustainably solve problems with food scarcity. Plus, their cooling mechanism could revolutionize the way we deal with temperature regulation, from food storage to air conditioning. 

References

1. Cordero, Radames J.B., Ellie Rose Mattoon, Ramos Zulymar, and Arturo Casadevall. 2023. “The Hypothermic Nature of Fungi.” Proceedings of the National Academy of Sciences 120 (19). https://doi.org/10.1073/pnas.2221996120.
2. Dressaire, Emilie, Lisa Yamada, Boya Song, and Marcus Roper. 2016. “Mushrooms Use Convectively Created Airflows to Disperse Their Spores.” Proceedings of the National Academy of Sciences 113 (11): 2833–38. https://doi.org/10.1073/pnas.1509612113.
3. Cordero, Radames JB, Ellie Rose Mattoon, and Arturo Casadevall. 2020. “Fungi Are Colder than Their Surroundings.” BioRxiv , May. https://doi.org/10.1101/2020.05.09.085969.