Basis for Skeletal Plasticity among Reef-building Corals

摘要: Reef corals are remarkably variable in growth form and skeletal configuration. This high degree of phenetic diversity has contributed greatly to the success hermatypic scleractinians as widespread reef builders tropical oceans. Although variability or “plasticity” is common, its cause remains obscure, because species genetically stable. The extent surprising view morphologic simplicity animal itself. Carbon isotope ratios have been used determine changes relative proportions carbon carbonate derived from sea-water bicarbonate metabolic dioxide sources. Increasing amounts respiratory CO 2 incorporated into aragonite attributed decreasing efficiency metabolite excretion. Isotope data indicate that zooxanthellae effectively removing waste products tissues scleractinians, that, for these corals, diffusion not an important excretion mechanism. Ahermatypic however, depend on processes eliminate products. 13 C/ 12 C among ahermatypes, small corallum geometry result greater coarctation polyps (or) a decrease size polyp surface exposed sea water large effect isotopic composition carbonate. These findings suggest do build reefs restricted relatively simple forms serious difficulties they would encounter more complex geometries. In case hermatypes, problems limit range possible configurations resolved by zooxanthellae. spectacular thus achieved through symbiotic association with