title: Microstructure and chemical composition of giant avian eggshells.
abstract: The microstructure and composition of the layers of two giant avian eggshells were investigated using a combination of scanning electron microscopy, electron probe microanalyses, and X-ray absorption near-edge structure spectroscopy (XANES). The two species have some similarities and differences in their microstructure and composition; the composition is not homogeneous throughout the eggshell thickness. XANES studies show that sulfur is associated with amino acids in the inner organic membranes, whereas in the mineralised layers the sulfur is mainly associated with sulfated polysaccharides. These results are similar to those obtained on chicken eggshells, and confirm the active role of sulfated acidic polysaccharides in biomineralisation processes of carbonate skeletons.
authors.affiliation: UMR IDES 8148, Bât 504, Université Paris XI-Orsay, 91405, Orsay Cedex, France. dauphin@geol.u-psud.fr
authors.forename: Yannicke
authors.initials: Y
authors.lastname: Dauphin
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Cuif
authors.forename: Murielle
authors.initials: M
authors.lastname: Salomé
authors.forename: Jean
authors.initials: J
authors.lastname: Susini
authors.forename: C Terry
authors.initials: CT
authors.lastname: Williams
mesh_terms: D000818:Animals; D004528:Egg Shell / Q000737:chemistry* / Q000648:ultrastructure*; D008855:Microscopy, Electron, Scanning; D008903:Minerals / Q000737:chemistry; D046108:Palaeognathae; D013057:Spectrum Analysis; D013455:Sulfur / Q000737:chemistry
chemical_list: D008903:Minerals; D013455:Sulfur