title: Yes, it turns: experimental evidence of pearl rotation during its formation.
abstract: Cultured pearls are human creations formed by inserting a nucleus and a small piece of mantle tissue into a living shelled mollusc, usually a pearl oyster. Although many pearl observations intuitively suggest a possible rotation of the nucleated pearl inside the oyster, no experimental demonstration of such a movement has ever been done. This can be explained by the difficulty of observation of such a phenomenon in the tissues of a living animal. To investigate this question of pearl rotation, a magnetometer system was specifically engineered to register magnetic field variations with magnetic sensors from movements of a magnetic nucleus inserted in the pearl oyster. We demonstrated that a continuous movement of the nucleus inside the oyster starts after a minimum of 40 days post-grafting and continues until the pearl harvest. We measured a mean angular speed of 1.27° min(-1) calculated for four different oysters. Rotation variability was observed among oysters and may be correlated to pearl shape and defects. Nature's ability to generate so amazingly complex structures like a pearl has delivered one of its secrets.
authors.affiliation: Ifremer , UMR 241 EIO, UPF-ILM-IRD, Labex Corail , BP 7004, 98719 Taravao, French Polynesia ; Ifremer , UMR 5244 IHPE, UPVD, CNRS, Université de Montpellier , CC 80, 34095 Montpellier, France.
authors.forename: Yannick
authors.initials: Y
authors.lastname: Gueguen
authors.affiliation: Ifremer , UMR 241 EIO, UPF-ILM-IRD, Labex Corail , BP 7004, 98719 Taravao, French Polynesia.
authors.forename: Yann
authors.initials: Y
authors.lastname: Czorlich
authors.affiliation: Ifremer , Centre Atlantique, Rue de l'Ile d'Yeu , BP 21105, 44311 Nantes Cedex 03, France.
authors.forename: Max
authors.initials: M
authors.lastname: Mastail
authors.affiliation: Véga Industrie , 12 avenue Maurice Thorez , 94200 Ivry sur Seine, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Le Tohic
authors.affiliation: Véga Industrie , 12 avenue Maurice Thorez , 94200 Ivry sur Seine, France.
authors.forename: Didier
authors.initials: D
authors.lastname: Defay
authors.affiliation: Ifremer , UMR 241 EIO, UPF-ILM-IRD, Labex Corail , BP 7004, 98719 Taravao, French Polynesia.
authors.forename: Pierre
authors.initials: P
authors.lastname: Lyonnard
authors.affiliation: Ifremer , UMR 241 EIO, UPF-ILM-IRD, Labex Corail , BP 7004, 98719 Taravao, French Polynesia.
authors.forename: Damien
authors.initials: D
authors.lastname: Marigliano
authors.affiliation: Laboratoires ICP-TEXINFINE , 60 rue Duguesclin, 69006 Lyon, France.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Gauthier
authors.affiliation: Pearl and Jewellery Museum , Qatar Museums , Doha, Qatar.
authors.forename: Hubert
authors.initials: H
authors.lastname: Bari
authors.affiliation: Direction des Ressources Marines et Minières , BP 20, 98713 Papeete, Tahiti, French Polynesia.
authors.forename: Cedrik
authors.initials: C
authors.lastname: Lo
authors.affiliation: Université de Polynésie Française, laboratoire GEPASUD , BP 6570, 98702 Faa'a, Tahiti, French Polynesia.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Chabrier
authors.affiliation: Ifremer , UMR 241 EIO, UPF-ILM-IRD, Labex Corail , BP 7004, 98719 Taravao, French Polynesia.
authors.forename: Gilles
authors.initials: G
authors.lastname: Le Moullac
keywords: biomineralization; pearl oyster; pearl rotation