Crystallinity of foraminifera shells: A proxy to reconstruct past bottom water CO 3 = changes?

• Published in: Geochemistry, Geophysics, Geosystems
• Main Authors: Bassinot, Franck, Mélières, Frédéric, Gehlen, Marion, Levi, Camille, Labeyrie, Laurent
• Other Authors: Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Paléocéanographie (PALEOCEAN), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Muséum national d'Histoire naturelle (MNHN), Modelling the Earth Response to Multiple Anthropogenic Interactions and Dynamics (MERMAID)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2004
• Subjects: bottom water CO3; calcite crystallinity; carbonate dissolution; foraminifers; [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; Planktonic foraminifera
• Online Access: https://hal.science/hal-02921898; https://hal.science/hal-02921898/document; https://hal.science/hal-02921898/file/2003GC000668.pdf; https://doi.org/10.1029/2003GC000668

International audience [1] The reconstruction of past changes in bottom water CO 3 = is central to evaluating competing oceanic scenarios that deal with long-term variations in atmospheric pCO 2. In search of a quantitative bottom water CO 3 = proxy, we analyzed the variations of calcite crystallinity of planktonic foraminifera Globigerinoides ruber shells picked from core top samples along three depth transects: Ontong Java Plateau and the northeast margin of Irian Jaya, in the western equatorial Pacific, and the Sierra Leone Rise, in the eastern tropical Atlantic. The strong empirical relationship between calcite crystallinity (inferred from the full width at half maximum (FWHM) of calcite (104) X-ray diffraction peak) and bottom water saturation relative to calcite (DCO 3) shows that foraminifera calcite crystallinity could be a promising proxy for the reconstruction of upper Pleistocene bottom water carbonate ion concentration.