This graph shows relative cover of reef-building stony corals and their dominant competitors, i.e., the percent of the reef bottom that is covered by stony corals, turf and macro-algae, and crustose coralline algae. The stony corals and some of the calcifying algae are the dominant taxa that build the coral reef structure, while the turf and macroalgae can compete with reef-builders and thereby limit growth of the reef structure. Also shown are the percentage cover by other living (biotic) organisms (sponges, gorgonians, zoanthids, etc) and non-living (abiotic) substrate (sand, rubble, hardbottom)