Coral reefs around the world are threatened by rising ocean temperatures, but hope is growing off the coast of Hawaii. There, researchers at the Coral Resilience Lab selectively breed corals to withstand ever-increasing amounts of heat stress.

Corals are tiny animals that have a mutually beneficial relationship with an algae that lives within their cells. When stressed by heat, many expel their algae and turn white — known as “bleaching” — losing their main source of food and often dying within days. Half of all coral has been lost since the 1950s. But some corals do survive these bleaching events, and they’ve become the focus of Kira Hughes and her team’s work. By selectively breeding the coral that doesn’t bleach, Kira hopes they can increase their resilience from one generation to the next.