Published

Cryo-FIB-SEM Foraminifera Version 140

Daniel Francois (Royal Netherlands Institute for Sea Research) Royal Netherlands Institute for Sea Research https://doi.org/10.25850/nioz/7b.b.xk

Geochemical signatures of the calcium carbonate shells of foraminifera form the basis of many proxies used in climate reconstructions. Yet, key physiological controls governing mineral precipitation remain unknown, limiting a mechanistic understanding of proxy sensitivity and interspecific variability. Here, we combine cryo–focused ion beam milling with scanning electron microscopy to reconstruct the in vivo three-dimensional ultrastructure of the foraminiferal calcification site. The images reveal a semi-open system, in which the calcifying fluid is largely isolated from ambient seawater by a thin cellular barrier, while discrete ~30 nm openings allow limited fluid exchange. This configuration provides a link between seawater and the site of calcification, offering a mechanistic explanation for the correlation between shell trace-element ratios and ambient seawater composition, complementing the ion uptake through transmembrane transport. This, in turn, improves understanding of element incorporation and enhances the reliability of foraminiferal calcite as a paleoproxy.

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Field Value
Subject Earth and Environmental Sciences
DAS Code 7b.b.xk
Source https://doi.org/10.25850/nioz/7b.b.xk
Version 140
Creator(s)
Francois, Daniel (Royal Netherlands Institute for Sea Research)
ORCID
Contact the corresponding author
Depositor Daniel do Nascimento Silva (daniel.do.nascimento.silva@nioz.nl)
Publication Date 2026-06-16T10:53:20.0085662
Deposit Date 2026-06-16
Dataset Persistent Identifier DOI:10.25850/nioz/7b.b.xk
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Contributor Royal Netherlands Institute for Sea Research (NIOZ)
Distributor Research Data Management(NIOZ Royal Netherlands Institute for Sea Research)
Distribution Date 2026-06-16
Production Date 2026-06-16
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