Geosmin, the Typical Earthy Smell Released by Mold Fungi and Other Microbes (image) Max Planck Institute for Chemical Ecology Share Print E-Mail Caption Geosmin, the typical earthy smell released by mold fungi and other microbes. In the picture is its chemical structure − a bicyclic alcohol − as well as a rotting orange infested with a Penicillium fungus. Although geosmin is very widely spread in nature, it is produced and released only by certain microbes. Credit Photo/Collage: Cell Press / Elsevier / Max Planck Institute for Chemical Ecology / Stensmyr Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.