The unique fibrilar to platy nano- and microstructure of twinned rotaliid foraminiferal shell calcite.

Autor: Lastam J; Forschungszentrum Jülich, Institut für Energie und Klimaforschung, IEK-2, 52425, Jülich, Germany., Griesshaber E; Department für Geo- und Umweltwissenschaften, Ludwig-Maximilians-Universität München, 80333, Munich, Germany. E.Griesshaber@lrz.uni-muenchen.de., Yin X; Department für Geo- und Umweltwissenschaften, Ludwig-Maximilians-Universität München, 80333, Munich, Germany., Rupp U; Zentrale Einrichtung Elektronenmikroskopie, Universität Ulm, 89081, Ulm, Germany., Sánchez-Almazo I; Centro de Instrumentación Científica, Universidad de Granada, 18071, Granada, Spain., Heß M; Biozentrum LMU München, 82152, Planegg-Martinsried, Germany., Walther P; Zentrale Einrichtung Elektronenmikroskopie, Universität Ulm, 89081, Ulm, Germany., Checa A; Departamento de Estratigrafía y Paleontología, Universidad de Granada, 18071, Granada, Spain.; Instituto Andaluz de Ciencias de la Tierra, CSIC-Universidad de Granada, 18100, Armilla, Spain., Schmahl WW; Department für Geo- und Umweltwissenschaften, Ludwig-Maximilians-Universität München, 80333, Munich, Germany.
Jazyk: angličtina
Zdroj: Scientific reports [Sci Rep] 2023 Feb 07; Vol. 13 (1), pp. 2189. Date of Electronic Publication: 2023 Feb 07.
DOI: 10.1038/s41598-022-25082-9
Abstrakt: Diversification of biocrystal arrangements, incorporation of biopolymers at many scale levels and hierarchical architectures are keys for biomaterial optimization. The planktonic rotaliid foraminifer Pulleniatina obliquiloculata displays in its shell a new kind of mesocrystal architecture. Shell formation starts with crystallization of a rhizopodial network, the primary organic sheet (POS). On one side of the POS, crystals consist of blocky domains of 1 μm. On the other side of the POS crystals have dendritic-fractal morphologies, interdigitate and reach sizes of tens of micrometers. The dendritic-fractal crystals are twinned. At the site of nucleation, twinned crystals consist of minute fibrils. With distance away from the nucleation-site, fibrils evolve to bundles of crystallographically well co-oriented nanofibrils and to, twinned, platy-blade-shaped crystals that seam outer shell surfaces. The morphological nanofibril axis is the crystallographic c-axis, both are perpendicular to shell vault. The nanofibrillar calcite is polysynthetically twinned according to the 60°/[100] (= m/{001}) twin law. We demonstrate for the twinned, fractal-dendritic, crystals formation at high supersaturation and growth through crystal competition. We show also that c-axis-alignment is already induced by biopolymers of the POS and is not simply a consequence of growth competition. We discuss determinants that lead to rotaliid calcite formation.
(© 2023. The Author(s).)
Databáze: MEDLINE
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