Meeting Abstract
Marine invertebrates that belong to the phylum Echinodermata are uniquely susceptible to ocean acidification (OA). This is because echinoderm skeletons are classified as high-magnesium calcite (> 4% MgCO3) rather than skeletons of other marine invertebrates that are comprised primarily of aragonite or calcite. Moreover, within echinoderm skeletal elements, the higher the ratio of magnesium to calcite the greater the potential vulnerability to OA. This vulnerability is manifest in both increased susceptibility to dissolution and potentially greater investment in production and maintenance. Among echinoids, there has yet to be a detailed comparative analysis of mg-calcite composition across all the skeletal elements of an individual. Accordingly, the present study compares mg-calcite levels measured for the ambulacral plates, interambulacral plates, genital plates, and auricles of the test, primary and secondary spines, and the teeth, epiphyses, compasses, and pyramids of the Aristotle lantern of twenty adults of the common Mediterranean sea urchin Paracentrotus lividus. The findings are discussed in the context of the comparative vulnerability of skeletal elements to OA and their functional implications. Supported by the Observatoire Océanologique de Banyuls sur Mer and a Endowment to JBM from the University of Alabama at Birmingham. Indirect support was provided by NSF grant ANT-1041022 to JBM.
