There is a nice story in today’s News and Observer, the local paper for the Research Triangle, in North Carolina. Wade
“Marine scientist John Bruno became interested in coral reefs as a boy snorkeling in the turquoise waters off the Florida Keys above reefs of golden corals the size of football fields.
“It just went on for acres and acres,” recalls Bruno, 43, an associate professor at UNC-Chapel Hill. “They were just full of fish. We’d see hammerhead sharks on the reef and big critters. That is all gone. The corals are gone and the big fish are gone,” he says. “That’s happened in my lifetime.”
“It’s a wonderful murder mystery for ecologists,” says Bruno, who has been the studying the effects of disease and warming sea water on coral reefs. “It’s not obvious what the cause is. There are lots of potential culprits.”
Among the suspects are pollution, destructive fishing practices, predators that feed on corals, disease and warmer ocean waters.
In the ocean, reef-building corals, which are marine polyps, a class of animals, typically exist in colonies of many identical individuals. They fill the role of trees in a forest, Bruno says. The skeletons of corals create the hardened framework of a reef and, over time, build up and provide habitat for thousands of other animals and plants. Corals require warm, clear water and are sensitive to temperatures.
A warming of the ocean by just a degree or two for a few weeks in summer can disrupt the life cycle of corals, Bruno says. Reef-building corals contain tiny plant-like algae that live within their tissue in a mutually beneficial relationship. The algae provide the coral with food and oxygen, as well as the vibrant colors for which corals are known. In return, the organisms receive shelter and nutrients.