Outer slope extends over the range 15-150 m. In this environment, there is adequate sunlight for corals and algae to grow. It is also below the depth of wave action, so its reasonably well protected. Buttress zone extends from low tide to 15 m. Wave energy is absorbed and dissipated in this zone. In addition, channels in the buttress zone allow sediments on the crest and flat to be drained to the outer slope and greater depths.
Reef crest is exposed at high tide.
It is continuously pounded by waves. Reef flat and lagoon is a quiet-water, protected environment. It is the home to a large number of coral species. Coral bleaching is a clear indication of a reef under stress. The increasing occurrence of colar bleaching may be an indicator of global warming.