Symbiotic algae living inside corals provide those animals with their vibrant color, as well as many of the nutrients they need to survive. That algae, and other microbes within the bodies of corals, have been extensively studied—yet until now, researchers have largely ignored the microbial communities just outside of the coral colonies. A new study from scientists at the Woods Hole Oceanographic Institution (WHOI) has begun to describe and catalogue microbes that live just a few centimeters from the surface of corals, laying the groundwork for future studies. The researchers' work will be published May 21 in the journal Limnology and Oceanography.