Just over twenty years ago, researchers discovered a photosynthetic marine microorganism now known as Prochlorococcus. Though each individual organism is very small, only 0.6 µm, it turns out that Prochlorococcus is one of the most abundant organisms on the planet -- a single milliliter of water can contain 100,000 cells or more. It also has a big effect on the rest of the world, as this one organism is thought to account for as much as half of the photosynthesis in the oceans. In this segment, guest host Joe Palca talks with Penny Chisholm, a biologist at MIT who first reported the discovery of the tiny organism.
Produced by Charles Bergquist, Director and Contributing Producer