Abstract
Fungi play essential roles in global ecology and economy, but their thermal biology is widely unknown. Mushrooms were previously noticed to be colder than surrounding air via evaporative cooling or evapotranspiration. Here we applied infrared imaging to reveal that not just mushrooms, but also molds and yeasts maintain colder temperatures than their surroundings via evapotranspiration. On average, fungal specimens are ~2.5 °C colder than the surrounding temperature. The relatively cold temperature of mushrooms can be observed throughout the whole fruiting process and at the level of mycelium. The mushroom’s hymenium appeared the coldest and different areas of the Pleurotus ostreatus mushroom appear to dissipate heat differently. Evapotranspiration in yeast and mold biofilms can be measured from the accumulation of condensed water droplets above biofilms; which is significantly higher than the surrounding agar. We also present a mushroom-based air-cooling system (MycoCooler™) capable of passively reducing the temperature of a closed compartment by approximately 10 °C in 25 minutes. These findings suggest that the fungal kingdom is characteristically cold. Since fungi make up ~2% of Earth biomass, their evapotranspiration may contribute to planetary temperatures in local environments. This study present new research avenues in fungal biology, biomedicine, microclimate, and sustainable energy.
Competing Interest Statement
RJBC and AC are co-founders of MelaTech, LLC.
Footnotes
Minor revisions were made. Supplemental files were updated. Figure S2 shows an example of a pigmented mushroom in open-habitat natural conditions that appears warmer than its surroundings following exposure to sunlight. This new data is important because it confirms that fungi are relatively cold, yet can warm-up via pigment-mediate heat capture when exposed to electromagnetic radiation energy. Calculations of global temperatures lacking fungal biomass were revised. Figure 5 shows potential research avenues resulting from this study. The Discussion section was updated. The authors and author affiliations were updated.
