Influence of surface ocean density on planktonic foraminifera calcification

• Published in: Scientific Reports
• Main Authors: Zarkogiannis, Stergios D., Antonarakou, Assimina, Tripati, Aradhna, Kontakiotis, George, Mortyn, P. Graham, Drinia, Hara, Greaves, Mervyn
• Other Authors: Laboratoire Géosciences Océan (LGO), Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2019
• Subjects: [SDU]Sciences of the Universe [physics]; Planktonic foraminifera
• Online Access: https://hal-insu.archives-ouvertes.fr/insu-03684845; https://hal-insu.archives-ouvertes.fr/insu-03684845/document; https://hal-insu.archives-ouvertes.fr/insu-03684845/file/s41598-018-36935-7.pdf; https://doi.org/10.1038/s41598-018-36935-7

International audience This study provides evidence that ambient seawater density influences calcification and may account for the observed planktonic foraminifera shell mass increase during glacial times. Volumes of weighed fossil Globigerina bulloides shells were accurately determined using X-ray Computer Tomography and were combined with water density reconstructions from Mg/Ca and δ 18 O measurements to estimate the buoyancy force exerted on each shell. After assessment of dissolution effects, the resulting relationship between shell mass and buoyancy suggests that heavier shells would need to be precipitated in glacial climates in order for these organisms to remain at their optimum living depth, and counterbalance the increased buoyant force of a denser, glacial ocean. Furthermore, the reanalysis of bibliographic data allowed the determination of a relationship between G. bulloides shell mass and ocean density, which introduces implications of a negative feedback mechanism for the uptake of atmospheric CO 2 by the oceans.