Scholarlink

<p>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.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

The link between seawater and foraminiferal calcite chemistry

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2026年7月25日

查看全文
  • Daniel François,
  • Gert-Jan Reichart,
  • Rona Roverts,
  • Ben Joosten,
  • Lennart de Nooijer

摘要

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.