CoRo project : Biomineral Architectures

** CoRo – Biomineral Architectures : the "Red Coral" model

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**Summary

Precious red corals from the Mediterranean (Corallium rubrum) and the western Pacific (Corallium Japonicum and Corallium Elatius) are excellent model organisms for better understanding bio-assisted crystal growth and structural organization in complex systems at the organic/inorganic interface.

In this project, we plan to decipher the chemical / physical / morphological hierarchical organization of the skeletons of these different corals and their sclerites using crystallography as a guiding principle. We will use the following techniques : optical microscopy, scanning and transmission microscopy, backscattered electron diffraction (EBSD), synchrotron X-ray diffraction, chemical mapping by electron microprobe, SIMS and nano-SIMS. We will also characterize the porosity, an aspect often neglected in these biomineral structures by isothermal manometry.

Experimental syntheses of calcium carbonate by hydrothermal carbonation are also planned to explore the relationships between calcite crystal surfaces and organic compounds. Two major series of experiments will be conducted : (1) sub-micrometric calcite overgrowth on pre-existing calcium carbonate surfaces (red coral skeleton and sclerites), and (2) calcite nucleation and growth in the presence of model organic molecules, natural or synthetic.

This project involves two partners : (1) CINaM - Marseille specializes in the characterization of the physico-chemical properties of organic and inorganic materials of nano on a macro scale, (2) ISTerre - Grenoble specializes in the growth of calcite in solution. This project will also benefit from long-established collaborations with various oceanographic institutions (ICM Barcelona, COM Marseille, CSM Monaco) and other laboratories (BioGéosciences Dijon, Caltech Pasadena). This project is part of the COST action TD0903’Understanding and manipulating enzymatic and proteomic processes in biomineralization’.