Juvenile coral night and day growth: 3D tomographies of Sr distribution imaging both below and above the absorption edge

Corals incorporate Sr in the CaCO3 aragonitic skeleton, when Sr2+ ions are available in the environment. We are using in-situ pulse-labeling by strontium, to map growth of the early stages of coral larva shortly after settlement. We propose to image the ~2% Sr-enriched layers added to the skeleton by the young organisms by day or night. We propose to use tomographic imaging at energies both above and below the Sr edge of 16.105 eV as well as by high-energy phase contrast enhanced microCT. We will create Sr-edge difference tomographis to visualize and study juvenile growth patterns across diel cycles. This information will help elucidate fundamental aspects of mineral accretion in these ecologically critical animals