What Is Natural?: Coral Reef Crisis

Students of marine biology have long been fascinated by the superorganisms called coral reefs, formed over thousands of years from skeletal remains and other matter. Many of those students have warned for several decades that these uncommon reefs are endangered by human development. Now, historian of science Jan Sapp writes, they are faced with another, paradoxical threat: the accelerating destruction of reefs by a creature called Acanthaster planci, the crown-of-thorns starfish. These starfish were a rarity when they were first observed off the coast of Australia in the late 1950s. Since that time their population has blossomed, with some scientists debating the cause but linking it at one time or another to familiar troublemakers, including global warming, overfishing, pesticide use, and atomic testing. Still other reputable scientists, Sapp writes, have dismissed the crown-of-thorns controversy as a hoax, claiming that most coral reefs are in no danger. "Facts, theories, values, and politics were so entangled in the controversy that it was often as difficult for us to separate them as it was for scientists to separate anthropogenic from natural change," he notes. Among the points in the debate that he finds most interesting is this: What happens when a natural predator threatens an already endangered species or habitat? The answers that he suggests are far from definitive, but they open up a discussion that will become increasingly important as more and more ecosystems require protection. --Gregory McNamee