You can’t see them with the naked eye, but our forest ground is littered with microorganisms. They decompose falling leaves, thereby improving soil quality and counteracting climate change. But how do these single-celled organisms coordinate their tasks? An international research team has been looking into this little-understood process. The researchers were able to show that, when decomposing plant litter, bacteria produce chemical compounds that control their competitors. This competition optimizes the distribution of tasks in the community: only the microorganisms that are well adapted to the food source and can fend off competitors will prevail.