FN Archimer Export Format
PT J
TI Structure of an amorphous calcium carbonate phase involved in the formation of Pinctada margaritifera shells
BT 
AF Grünewald, Tilman A.
   Checchia, Stefano
   Dicko, Hamadou
   Le Moullac, Gilles
   Sham Koua, Manaarii
   Vidal-Dupiol, Jeremie
   Duboisset, Julien
   Nouet, Julius
   Grauby, Olivier
   Di Michiel, Marco
   Chamard, Virginie
AS 1:1;2:2;3:1;4:3;5:3;6:4;7:1;8:5;9:6;10:2;11:1;
FF 1:;2:;3:;4:PDG-RBE-RMPF;5:PDG-RBE-RMPF;6:PDG-RBE-IHPE;7:;8:;9:;10:;11:;
C1 Aix-Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, Marseille, F-13013 France
   ESRF – The European Synchrotron, Grenoble Cedex, F-38043 France
   Ifremer, IRD, Institut Louis‐Malardé, Univ Polynésie française, EIO, F-98719 Taravao Tahiti, Polynésie française, France
   IHPE, University Montpellier, CNRS, IFREMER, University Perpignan Via Domitia, Montpellier, France
   Geosciences Paris Saclay, Université Paris-Saclay, CNRS, 91405 Orsay, France
   Aix-Marseille Univ, CNRS, CINaM, Campus Luminy, Marseille, France
C2 UNIV AIX MARSEILLE, FRANCE
   ESRF – THE EUROPEAN SYNCHROTRON, FRANCE
   IFREMER, FRANCE
   IFREMER, FRANCE
   UNIV PARIS SACLAY, FRANCE
   UNIV AIX MARSEILLE, FRANCE
SI TAHITI
   MONTPELLIER
SE PDG-RBE-RMPF
   PDG-RBE-IHPE
UM IHPE
   EIO
IN WOS Ifremer UMR
   copubli-france
   copubli-univ-france
IF 11.1
TC 9
UR https://archimer.ifremer.fr/doc/00801/91305/97081.pdf
   https://archimer.ifremer.fr/doc/00801/91305/97082.pdf
LA English
DT Article
DE ;biomineralization;nonclassical crystallization;calcium carbonate;amorphous calcium carbonate
AB Some mollusc shells are formed from an amorphous calcium carbonate (ACC) compound, which further transforms into a crystalline material. The transformation mechanism is not fully understood but is however crucial to develop bioinspired synthetic biomineralization strategies or accurate marine biomineral proxies for geoscience. The difficulty arises from the simultaneous presence of crystalline and amorphous compounds in the shell, which complicates the selective experimental characterization of the amorphous fraction. Here, we use nanobeam X-ray total scattering together with an approach to separate crystalline and amorphous scattering contributions to obtain the spatially resolved atomic pair distribution function (PDF). We resolve three distinct amorphous calcium carbonate compounds, present in the shell of Pinctada margaritifera and attributed to: interprismatic periostracum, young mineralizing units, and mature mineralizing units. From this, we extract accurate bond parameters by reverse Monte Carlo (RMC) modeling of the PDF. This shows that the three amorphous compounds differ mostly in their Ca–O nearest-neighbor atom pair distance. Further characterization with conventional spectroscopic techniques unveils the presence of Mg in the shell and shows Mg–calcite in the final, crystallized shell. In line with recent literature, we propose that the amorphous-to-crystal transition is mediated by the presence of Mg. The transition occurs through the decomposition of the initial Mg-rich precursor into a second Mg-poor ACC compound before forming a crystal. 
PY 2022
PD NOV
SO Proceedings Of The National Academy Of Sciences Of The United States Of America
SN 0027-8424
PU Proceedings of the National Academy of Sciences
VL 119
IS 45
UT 000907643500059
DI 10.1073/pnas.2212616119
ID 91305
ER

EF