Coral morphology, diversity and reef growth

The shape of reef corals is affected by light level^1,2 and by wave stress^3,4, leading to the well-known zonation of coral form associations with exposure and depth^3-6. Growth form also seems to be constrained by geometric factors^2,7,8. Similarly, coral calcification rate, of importance both for coral form and for net reef growth, is light dependant^9,10, and may be affected by other factors such as wave stress and sediment flux. Here the growth structure of raised Pleistocene reefs in New Guinea, of both fringing and barrier types, is explained in terms of variations of coral framework growth rate across the reef profile. A model for growth rate in terms of wave stress, light level and other variables is outlined, first by examining the effects of these factors on coral form and diversity.