Global climate change has increased water temperatures in the world’s oceans, often causing mass coral bleaching and mortality, which harms not only corals, but also the vast ecosystems they support. Using innovative methods, researchers at Penn State University have identified a new species of stress-tolerant Symbiodinium, a genus of algae that occurs mutualistically with corals in a partnership that promotes the health and growth of coral reef ecosystems. The team’s paper, which appears in a recent issue of the journal Phycologia, also describes the geographical distribution of Symbiodinium glynnii, how it differs from other stress-tolerant symbiont species, and its capacity to spread to places around the Pacific and live with different coral hosts.