Articles | Volume 23, issue 5
https://doi.org/10.5194/bg-23-2023-2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/bg-23-2023-2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
18 Mar 2026
Research article |
| 18 Mar 2026
| 18 Mar 2026
The 3D submicron-scale skeletal reconstruction of Nannoconus (Cretaceous calcareous nannofossil) – Insights into biomineralization
Rajkumar Chowdhury
CORRESPONDING AUTHOR
Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, IRD, Univ. Gustave Eiffel, ISTerre, 38000 Grenoble, France
LGL-TPE, UCB Lyon1, UJM, UMR CNRS 5276, ENS de Lyon, 46 Allée d'Italie – 69364, Lyon CEDEX 07, France
Pôle d'Etudes et de Recherche de Lacq, TotalEnergies, BP 47 – RD 817, 64170, Lacq, France
Redhouane Boudjehem
Univ. Grenoble Alpes, CNRS, Institut Néel, 38042 Grenoble, France
Baptiste Suchéras-Marx
Aix Marseille Univ, CNRS, IRD, INRAE, CEREGE, Aix-en-Provence, France
Maxime Dupraz
Univ. Grenoble Alpes, CNRS, Institut Néel, 38042 Grenoble, France
Anico Kulow
Univ. Grenoble Alpes, CNRS, Institut Néel, 38042 Grenoble, France
Julio Cesar da Silva
Univ. Grenoble Alpes, CNRS, Institut Néel, 38042 Grenoble, France
Jean Louis Hazemann
Univ. Grenoble Alpes, CNRS, Institut Néel, 38042 Grenoble, France
Marie-Pierre Aubry
Department of Earth and Planetary Sciences, Rutgers University, New Brunswick, New Jersey 08854, USA
Javier Pérez
SWING Beamline, Synchrotron SOLEIL, L'Orme des Merisiers, Départementale 128, 91190 Saint-Aubin, France
Alejandro Fernandez-Martinez
Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, IRD, Univ. Gustave Eiffel, ISTerre, 38000 Grenoble, France
Fabienne Giraud
Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, IRD, Univ. Gustave Eiffel, ISTerre, 38000 Grenoble, France
Cited articles
Aubry, M. P.: Remarques sur la systématique des Nannoconus de la craie, Cahiers de Micropaleontology, 4, ISBN 978-2-22201-737-0, 1974.
Aubry, M. P.: Cenozoic Coccolithophores: Braarudosphaerales, Atlas of Micropaleontology series Micropaleontology Press, New York, 336 pp., ISBN 978-0-9766734-4-4, 2013.
Aubry, M. P.: Biomineralization in the Calcareous Nannoplankton Phenotypic Expressions Across Life Cycles, Geometric Control on Diversification, and Origin, Minerals, 15, 322, https://doi.org/10.3390/min15030322 2025.
Beuvier, T., Probert, I., Beaufort, L., Suchéras-Marx, B., Chushkin, Y., Zontone, F., and Gibaud, A.: X-ray nanotomography of coccolithophores reveals that coccolith mass and segment number correlate with grid size, Nat. Commun., 10, 751, https://doi.org/10.1038/s41467-019-08635-x, 2019.
Bouché, P.: Eléments pour une définition d'un stratotype du Barrémien. Etat des connaissances sur les Nannofossiles calcaires du Crétacé inférieur, Mémoires du Bureau de Recherches Géologiques et Minières, 34, 451–459, 1965.
Bown, P. R.: Cenozoic calcareous nannofossil biostratigraphy, ODP Leg 198 Site 1208 (Shatsky Rise, northwest Pacific Ocean), in: Proceedings of the Ocean Drilling Program, scientific results, 1–44, http://www-odp.tamu.edu/publications/198_SR/104/104.htm (last access: 4 March 2026), 2005.
Bown, P. R.: Calcareous nannofossils from the Paleocene/Eocene Thermal Maximum interval of southern Tanzania (TDP Site 14), Journal of Nannoplankton Research, 31, 11–38, 2010.
Bown, P. and Cooper, M.: Jurassic, Calcareous nannofossil biostratigraphy, British Micropalaeontological Society Publication Series, 34–85, https://shorturl.at/teID7 (last access: 4 March 2025), 1998.
Bralower, T. J., Monechi, S., and Thierstein, H. R.: Calcareous nannofossil zonation of the Jurassic-Cretaceous boundary interval and correlation with the geomagnetic polarity timescale, Mar. Micropaleontol., 14, 153–235, 1989.
Brönnimann, P.: Microfossils incertae sedis from the Upper Jurassic and Lower Cretaceous of Cuba, Micropaleontology, 28–51, https://doi.org/10.2307/1484409, 1955.
Chowdhury, R.: Chemical and physical characterization of Nannoconus, the main planktonic bio-producer of carbonates in the cretaceous seas: insights into biomineralization processes, PhD Thesis, Université Grenoble Alpes, https://theses.hal.science/tel-05080049 (last access: 3 March, 2026), 2025.
Chowdhury, R., Fernandez-Martinez, A., and Giraud, F.: Code for the 3D submicron-scale skeletal reconstruction of Nannoconus, Zenodo [code], https://doi.org/10.5281/zenodo.14925063, 2025.
Covington, J. M. and Wise, S. W.: Calcareous nannofossil biostratigraphy of a lower Cretaceous Deep-sea fan complex: Deep-Sea Drilling Project Leg-93 Site-603, Lower Continental Rise, Initial Reports of the Deep Sea Drilling Project, 93, 617–660, 1987.
Derès, F. and Achéritéguy, J.: Contribution à l'étude des Nannoconidés dans le Crétacé inférieur du Bassin d'Aquitaine, Mémoires du Bureau de Recherches Géologiques et Minières, 77, 153–159, 1972.
Derès, F. and Achéritéguy, J.: Biostratigraphie des Nannoconides, B. Cent. Rech. Expl., 4, 1–53, 1980.
Dierolf, M., Menzel, A., Thibault, P., Schneider, P., Kewish, C. M., Wepf, R., Bunk, O., and Pfeiffer, F.: Ptychographic X-ray computed tomography at the nanoscale, Nature, 467, 436–439, https://doi.org/10.1038/nature09419, 2010.
Erba, E.: Nannofossils and superplumes: The Early Aptian “nannoconid crisis”, Paleoceanography, 9, 483–501, https://doi.org/10.1029/94PA00258, 1994.
Erba, E.: The first 150 million years history of calcareous nannoplankton: Biosphere–geosphere interactions, Palaeogeogr. Palaeocl., 232, 237–250, https://doi.org/10.1016/j.palaeo.2005.09.013, 2006.
Hagino, K., Tomioka, N., Young, J. R., Takano, Y., Onuma, R., and Horiguchi, T.: Extracellular calcification of Braarudosphaera bigelowii deduced from electron microscopic observations of cell surface structure and elemental composition of pentaliths, Mar. Micropaleontol., 125, 85–94, https://doi.org/10.1016/j.marmicro.2016.04.002, 2016.
Hart, M., Hylton, M., Oxford, M., Price, G., Hudson, W., and Smart, C.: The search for the origin of the planktic Foraminifera, J. Geol. Soc., 160, 341–343, 2003.
Hattner, J. G. and Wise, S. W.: Upper Cretaceous calcareous nannofossil biostratigraphy of South Carolina, South Carolina Geology, 24, 41–117 1980.
Henriksen, K., Young, J. R., Brown, P. R., and Stipp, S. L. S.: Coccolith biomineralisation studied with atomic force microscopy, Palaeontology, 47, 725–743, https://doi.org/10.1111/j.0031-0239.2004.00385.x, 2004.
Hoffmann, R., Kirchlechner, C., Langer, G., Wochnik, A. S., Griesshaber, E., Schmahl, W. W., and Scheu, C.: Insight into Emiliania huxleyi coccospheres by focused ion beam sectioning, Biogeosciences, 12, 825–834, https://doi.org/10.5194/bg-12-825-2015, 2015.
Jiang, W., Pacella, M. S., Athanasiadou, D., Nelea, V., Vali, H., Hazen, R. M., Gray, J. J., and McKee, M. D.: Chiral acidic amino acids induce chiral hierarchical structure in calcium carbonate, Nat. Commun., 8, 15066, https://doi.org/10.1038/ncomms15066, 2017.
Jiang, W., Pacella, M. S., Vali, H., Gray, J. J., and McKee, M. D.: Chiral switching in biomineral suprastructures induced by homochiral L-amino acid, Science advances, 4, eaas9819, https://doi.org/10.1126/sciadv.aas9819, 2018.
Jiang, W., Yi, X., and McKee, M. D.: Chiral biomineralized structures and their biomimetic synthesis, Mater. Horiz., 6, 1974–1990, 2019.
Kamptner, E.: Nannoconus steinmanni nov. gen., nov. spec., ein merkwürdiges gesteinsbildendes Mikrofossil aus dem jüngeren Mesozoikum der Alpen, Paläont. Z., 13, 288–298, 1931.
Kooistra, W. H., Gersonde, R., Medlin, L. K., and Mann, D. G.: The origin and evolution of the diatoms: their adaptation to a planktonic existence, Evolution of primary producers in the sea, 207–249, https://doi.org/10.1016/B978-012370518-1/50012-6, 2007.
Ky, F.: Convex sets and their applications, Argonne National Laboratory, https://books.google.fr/books?id=QKkrAAAAYAAJ (last access: 4 March 2026), 1959.
Lees, J. A. and Bown, P. R.: New and intriguing calcareous nannofossils from the Turonian (Upper Cretaceous) of Tanzania, Journal of Nannoplankton Research, 36, 83–95, 2016.
OSUG: OSUG-COLLECTIONS is a database of rocks, minerals and fossils, OSUG, UGA, https://doi.org/10.17178/OSUG-COLLECTIONS.all, 2021.
Perch-Nielsen, K.: Mesozoic calcareous nannofossils, in: Plankton Stratigraphy, edited by: Bolli H. M., Saunders J. B., and Perch-Nielsen K., Cambridge University Press, Cambridge, 329–426, ISBN 9780521367196, 1985.
Reinhardt, P.: Zur Taxionomie und Biostratigraphie des fossilen Nannoplanktons aus dem Malm, der Kreide und dem Alttertiär Mitteleuropas: mit 1 Tabelle, PhD Thesis, Dt. Verlag für Grundstoffindustrie, https://d-nb.info/457917237 (last access: 4 March, 2026), 1966.
Reza, A. M.: Realization of the contrast limited adaptive histogram equalization (CLAHE) for real-time image enhancement, J. VLSI Sig. Proc. Syst., 38, 35–44, 2004.
Reznikov, N., Buss, D. J., Provencher, B., McKee, M. D., and Piché, N.: Deep learning for 3D imaging and image analysis in biomineralization research, J. Struct. Biol., 212, 107598, https://doi.org/10.1016/j.jsb.2020.107598, 2020.
Schiebel, R. and Hemleben, C.: Planktic foraminifera in the modern ocean, Springer, https://doi.org/10.1007/978-3-662-50297-6, 2017.
Siesser, W. G. and Winter, A.: Coccolithophores, Cambridge University Press, ISBN 0-521-38050-2, 1994.
Stradner, H. and Grün, W.: On Nannoconus abundans nov. spec. and on laminated calcite growth in Lower Cretaceous nannofossils, Verhandlungen der Geologischen Bundesanstalt, 2, 267–283, 1973.
Suchéras-Marx, B., Giraud, F., Simionovici, A., Daniel, I., and Tucoulou, R.: Perspectives on heterococcolith geochemical proxies based on high-resolution X-ray fluorescence mapping, Geobiology, 14, 390–403, https://doi.org/10.1111/gbi.12177, 2016a.
Suchéras-Marx, B., Giraud, F., Lena, A., and Simionovici, A.: Picking nannofossils: How and why, J. Micropalaeontol., 36, 219–221, https://doi.org/10.1144/10.1144jmpaleo2016-013, 2016b.
Suchéras-Marx, B., Mattioli, E., Allemand, P., Giraud, F., Pittet, B., Plancq, J., and Escarguel, G.: The colonization of the oceans by calcifying pelagic algae, Biogeosciences, 16, 2501–2510, https://doi.org/10.5194/bg-16-2501-2019, 2019.
Toplak, M., Birarda, G., Read, S., Sandt, C., Rosendahl, S., Vaccari, L., Demšar, J., and Borondics, F.: Infrared orange: connecting hyperspectral data with machine learning, Synchrotron Radiation News, 30, 40–45, 2017.
Trejo, H.: La familia Nannoconidae y su alcance estratigrafico en America: Boletin de la Asociacion Mexicana de Geologos Petroleros, 12, https://shorturl.at/CljTB (last access: 4 March 2026), 1960.
Ueshima, R. and Asami, T.: Single-gene speciation by left–right reversal, Nature, 425, 679–679, 2003.
Van Niel, B.: A review of the terminology used to describe the genus Nannoconus (calcareous nannofossil, incertae sedis), Cahiers de Micropaléontologie, 9, 29–55, 1994.
Van Niel, B. E.: Early Cretaceous Nannoconus(calcareous nannofossil, incertae sedis) in NW Europe, University of London, University College London (United Kingdom), https://discovery.ucl.ac.uk/id/eprint/1317948 (last access: 4 March 2026), 1993.
Van Rossum, G. and Drake, F. L.: Python 3 Reference Manual, CreateSpace, Scotts Valley, CA, ISBN 1441412697, 2009.
Wakonig, K., Stadler, H.-C., Odstrčil, M., Tsai, E. H., Diaz, A., Holler, M., Usov, I., Raabe, J., Menzel, A., and Guizar-Sicairos, M.: PtychoShelves, a versatile high-level framework for high-performance analysis of ptychographic data, J. Appl. Crystallogr., 53, 574–586, 2020.
Walker, J., Marzec, B., Ozaki, N., Clare, D., and Nudelman, F.: Morphological development of Pleurochrysis carterae coccoliths examined by cryo-electron tomography, J. Struct. Biol., 210, 107476, https://doi.org/10.1016/j.jsb.2020.107476, 2020.
Walker, J. M., Greene, H. J. M., Moazzam, Y., Quinn, P. D., Parker, J. E., and Langer, G.: An uneven distribution of strontium in the coccolithophore Scyphosphaera apsteinii revealed by nanoscale X-ray fluorescence tomography, Environ. Sci.-Proc. Imp., 26, 966–974, https://doi.org/10.1039/d3em00509g, 2024.
Young, J. R. and Henriksen, K.: Biomineralization within vesicles: the calcite of coccoliths, Rev. Mineral. Geochem., 54, 189–215, 2003.
Young, J. R., Davis, S. A., Bown, P. R., and Mann, S.: Coccolith Ultrastructure and Biomineralisation, J. Struct. Biol., 126, 195–215, https://doi.org/10.1006/jsbi.1999.4132, 1999.
Young, J .R., Bown P. R., and Lees J. A.: Nannotax3 website, International Nannoplankton Association, https://www.mikrotax.org/Nannotax3 (last access: 29 September 2025), 2022.
Yu, S.-H., Cölfen, H., Tauer, K., and Antonietti, M.: Tectonic arrangement of BaCO3 nanocrystals into helices induced by a racemic block copolymer, Nat. Mater., 4, 51–55, 2005.
Short summary
Nannoconus, a major marine planktonic biocarbonate producer of the Early Cretaceous (150–120 Ma), biomineralized heavy (200–1400 picogram) skeletons (5–20 μm) of interlocking lamellae spanned around a central canal, by an unknown process. With the first-ever application of synchrotron-based ptychographic X-ray computed tomography (PXCT) of nanometric resolution, we reconstructed the 3D skeleton by combining segments of lamellae and inferred its possible biomolecule(s)-“templated” calcification.
Nannoconus, a major marine planktonic biocarbonate producer of the Early Cretaceous (150–120...
Altmetrics
Final-revised paper
Preprint