Tessa Page & JONATHON stillman
the quest for coral color: understanding coral bleaching
Image by Jason Sanders.
T
he vivid pink, fluorescent green, and other stunningly colored pigments produced by corals make reef aquaria beautiful, but a coral’s drab brown color may be the most important to its health. The phenomenon of coral losing their brown color and turning white is called coral bleaching. Bleached corals are not dead, but they are
weakened because they have lost an important energy source: their photosynthetic symbionts. Weakened, bleached corals are less able to grow and compete for space, fight off disease, and respond to other stressors. Sometimes, bleached corals regain symbionts and their color, but often, their weakened state leads to death. Coral bleaching is considered a global threat to coral reefs worldwide and is a glaring sign of unhealthy conditions in a reef aquarium. Understanding the how’s and why’s of coral bleaching may help reef hobbyists and coral reef conservation biologists alike and is an active area of research. Here, we provide some basic background on coral bleaching as well as some scientific research so that we can better understand and care for the corals in our aquariums. 16