A maritime accident provides evidence for alternate stable states in benthic communities on coral reefs

An a posteriori examination of the site of a ship wreck on the outer edge of the Great Barrier Reef revealed an unique, macroalgal-dominated benthic community. The persistence of community structure throughout a year of observation in an environment characterised by intensely grazed microalgae, and in the absence of a measurable wreck-derived influence, provides circumstantial evidence that it represents an alternative stable state. A mechanism for effecting state shifts in coral reef algal communities involves the size-dependent response by grazing organisms to algae in a perturbed environment.