Putting corallites on a pedestal: identifying corallite morphologies that optimize mass transfer across platelike corals

Abstract

Mass transfer in corals is dependent on sufficient flow over individual polyps, and thus is influenced by both gross coral morphology and local surface texture. This study uses plaster dissolution models and flow analysis to examine the effects of verrucose, pocked, and furrowed surface morphologies on potential mass transfer across plate corals. It also examines how flow interacts with these surfaces across platelike and cylindrical objects. Generally, dissolution per unit profile area increased with added ornamentation and surface area. However, there were diminishing returns with regards to material investment; the more surface area there was for dissolution, the less efficient dissolution was per unit surface area. Secondly, surface texture dictated flow of water, either directing flow to or away from the colony, or quelling movement completely. Surface texture also directs flow differently depending on gross morphology. Understanding flow at small scales, particularly around locations of polyps, is important for understanding mass transfer. This study is a first order attempt to address this issue, but further work is needed to quantify flow at the locations of polyps and the role of particular surface textures in engineering local flow regimes.