Skeletal density and growth form of corals

This paper explores inter-specific variation in the density of coral skeletons. I present new data on the porosity of 7 species of reef-building scleractinians, and briefly review 20 previous studies on approximately 23 addihonal corals. Although the total number of species examined so far is still small, the review reveals a consistent pattern of skeletal density among different morphological groups of corals. The most porous corals are massive or bushy. Delicate foliaceous corals are the most dense. Tall branching corals exhibit a marked axial gradient in density, i.e. growing tips are very porous while basal regions are extremely dense. These results are consistent with differences in the mechanical requirements of various colony shapes.