Bacteriofiles

This episode: Many organisms produce the smell of earth, geosmin, and many others can sense it–but why? Download Episode (6.0 MB, 8.7 minutes) Show notes: Microbe of the episode: Acidianus spindle-shaped virus 1   News item   Takeaways The smell of soil or earth is one of the most recognizable smells, and comes largely from a chemical called geosmin, produced by many different kinds of bacteria. Many animal species are sensitive to geosmin, some attracted by it and others repelled. But it is still not entirely understood what is the evolutionary benefit to the microbes that produce it, or the reason why different animals are sensitive to it in different ways. In this study, different geosmin-producing bacteria were paired with tiny bacteria-eating roundworms, nematodes, to see how the chemical affected their interactions. Production of geosmin affected the worms' movement, apparently inducing them to avoid colonies of the producing microbes in some cases, though the worms still sometimes fed on the bacteria