title: Ultrastructure, chemistry and mineralogy of the growing shell of the European abalone Haliotis tuberculata.
abstract: An integrated study of shell formation was initiated covering the entire life cycle of the marine gastropod Haliotis tuberculata. Shell microstructure, chemistry and mineralogy were investigated by polarized microscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDX) and infra-red (IR) spectroscopy. SEM images of trochophore and veliger larvae showed the different stages of shell growth from the initial shell field to the late calcified protoconch. Cross-sections revealed the microstructural arrangement of biominerals, showing the progressive mineralization of the organic protoconch prior to metamorphosis. To gain more information on mineralogical composition, EDX analyses and IR spectroscopy were performed along the development stages. The results demonstrated that early protoconch was mostly composed of amorphous calcium carbonate, while veliger stages showed a gradually crystallization under the form of aragonite. Post-metamorphic shell contained two distinct parts, the original protoconch supporting the new juvenile shell characterized by a marked sculptural pattern. The shells from post-larval and juvenile abalones were essentially made of aragonite.
authors.affiliation: UMR BOREA (Biologie des Organismes et Ecosystèmes Aquatiques), MNHN/CNRS-7208/IRD-207/UPMC, Muséum National d'Histoire Naturelle, Station de Biologie Marine, 29900 Concarneau, France. bordenav@mnhn.fr
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Auzoux-Bordenave
authors.forename: Aïcha
authors.initials: A
authors.lastname: Badou
authors.forename: Béatrice
authors.initials: B
authors.lastname: Gaume
authors.forename: Sophie
authors.initials: S
authors.lastname: Berland
authors.forename: Marie-Noëlle
authors.initials: MN
authors.lastname: Helléouet
authors.forename: Christian
authors.initials: C
authors.lastname: Milet
authors.forename: Sylvain
authors.initials: S
authors.lastname: Huchette
mesh_terms: D000818:Animals; D002119:Calcium Carbonate / Q000737:chemistry; D049851:Gastropoda / Q000737:chemistry* / Q000648:ultrastructure*; D007814:Larva / Q000737:chemistry* / Q000648:ultrastructure*; D008855:Microscopy, Electron, Scanning; D008859:Microscopy, Polarization; D013052:Spectrometry, X-Ray Emission; D013055:Spectrophotometry, Infrared
chemical_list: D002119:Calcium Carbonate