Zonation

Most accounts of coral reefs draw attention to the coral zones that they invariably create. These zones have been likened to zones of vegetation found on mountain slopes, as well they might, but on coral reefs they are mostly created by decreasing light and turbulence with increasing depth and, even in very clear water, this occurs within a depth range of less than 50 meters. Zonation patterns of Middleton Reef. South-eastern Australia. Photograph: David Doubilet. Contrary to popular belief, species diversity is not at its highest on the scenically attractive reefs found in clear oceanic water. It reaches a peak for any given region on fringing reefs protected from strong wave action, especially where the water is slightly turbid. This is partly because Acropora, by far the most common Indo-Pacific coral, seldom dominates these habitats.

J.E.N. Veron