Nanoscale trace metal imprinting of biocalcification of planktic foraminifers by Toba’s super‑eruption

Laurence Lemelle (1) , Annachiara Bartolini (2, 3) , Alexandre Simionovici (4) , Rémi Tucoulou (5) , Wout de Nolf (5) , Franck Bassinot (6, 7) , Thibault de Garidel‑thoron (8)

1 LGL-TPE - Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement
2 MNHN - Muséum national d'Histoire naturelle
3 CR2P - Centre de Recherche en Paléontologie - Paris
4 ISTerre - Institut des Sciences de la Terre
5 ESRF - European Synchrotron Radiation Facility
6 LSCE - Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette]
7 PALEOCEAN - Paléocéanographie
8 CEREGE - Centre européen de recherche et d'enseignement des géosciences de l'environnement

Bioactive metal releases in ocean surface water, such as those by ash falls during volcanic super-eruptions, might have a potentially toxic impact on biocalcifier planktic microorganisms. Nano-XRF imaging with the cutting-edge synchrotron hard X-ray nano-analysis ID16B beamline (ESRF) revealed for the first time a specific Zn-and Mn-rich banding pattern in the test walls of Globorotalia menardii planktic foraminifers extracted from the Young Toba Tuff layer, and thus contemporaneous with Toba's super-eruption, 74,000 years ago. The intra-test correlation of Zn and Mn patterns at the nanoscale with the layered calcareous microarchitecture, indicates that the incorporation of these metals is syngenetic to the wall growth. The preferential Mn and Zn sequestration within the incipient stages of chamber formation suggests a selective incorporation mechanism providing a resilience strategy to metal pollution in the test building of planktic foraminifers.

Domaines: Minéralogie; Climatologie; Océanographie

Laurence Lemelle, Annachiara Bartolini, Alexandre Simionovici, Rémi Tucoulou, Wout de Nolf, et al.. Nanoscale trace metal imprinting of biocalcification of planktic foraminifers by Toba’s super‑eruption. Scientific Reports, 2020, 10, pp.10974. ⟨10.1038/s41598-020-67481-w⟩. ⟨hal-02867755⟩