Microstructure of common reef-building coral genera Acropora, Pocillopora, Goniastrea and Porites: constraints on spatial resolution in geochemical sampling

Scleractinian corals are increasingly used as recorders of modern and paleoclimates. The microstructure of four common reef-building coral genera is documented here: Acropora, Pocillopora, Goniastrea, and Porites. This study highlights the complexity and spatial variability of skeletal growth in different coral genera and suggests that a single growth model is too generalized to allow the accurate depiction of the variability observed in the four genera studied. New models must be introduced in order for coral skeletogenesis to be understood adequately to allow coral skeletons to serve as repositories of temporally constrained geochemical data. Owing to differences in microstructural patterns in different genera, direct observation of microstructural elements and growth lines may be necessary to allow microsamples to be placed into series that represent temporal sequences with known degrees of time averaging. Such data are critical for constraining microsampling strategies aimed at developing true time series geochemical data at very fine spatial and temporal scales.