Stressed Corals Dim Then Glow Brightly Before They Die

Anyone who has gone scuba diving or snorkeling in a coral reef will likely never forget the dazzling colors and other-worldly shapes of these underwater communities. Home to some of the world’s most diverse wildlife hotspots, reefs are worth an annual $400 billion in tourist dollars and in the ecosystem services they provide, such as buffering shores from storms and providing habitat for fish that people eat.

Yet it’s a well known fact that coral reefs around the world are in decline thanks to pollution and rapidly warming oceans. However, determining just how reefs are faring—and designing steps to protect them—requires a way to accurately measure their health. Researchers tend to rely upon invasive, damaging techniques to figure out how corals are coping, or else they perform crude spot checks to determine reef health based on coral color alone. But now, scientists have announced a new method of determining coral health that relies upon measuring the intensity of corals’ fluorescent glow.