Smaller calcite lattice deformation caused by occluded organic material in coccoliths than in mollusk shell.

7 pages; International audience; The growth and nucleation of biominerals are directed and affected by associated biological molecules. In this paper, we investigate the influence of occluded biomolecules on biogenic calcite from the coccolithophorid Pleurochrysis carterae and from chalk, a rock composed predominantly of fossil coccoliths. We compare the results with data on chalk from the extensively studied mussel Pinna nobilis that served as a control. Using high resolution synchrotron powder X-ray diffraction combined with in situ heating, the influence of organic compounds on the structure of the inorganic phase was probed. Two heating cycles allow us to differentiate the effects of th…