The next time you visit a lake or the seashore, take a deep breath. As you exhale, take a moment to be thankful for the little things: Specifically, for the microscopic, single-celled algae in the soil and waters all around you that are extracting the carbon dioxide you just exhaled and incorporating it into sugars that will eventually be used by every other organism in the biosphere. About 30% of this activity, globally, is carried out by a specialized structure in algae called the pyrenoid.