This study was promoted by the recent efforts using larger benthic foraminiferal (LBF) shells geochemistry for the monitoring of heavy metals (HMs) pollution in the marine environment. The shell itself acts as a recorder of the ambient water chemistry in low to extreme HMs-polluted environments, allowing the monitoring of recent-past pollution events. This concept, known as sclerochronology, requires the addition of new parts (i.e., new shell) even in extreme pollution events. We evaluated the physiological resilience of three LBF species with different shell types and symbionts to enriched concentrations of Cd, Cu, and Pb at levels several folds higher than the ecological criteria maximum concentration (CMC) (165–166, 33–43, 1001–1206 µg L⁻¹, respectively), which is derived from aquatic organisms’ toxicity tests. The physiological response of the holobiont was expressed by growth rates quantified by the addition of new chambers (new shell parts), and by the chlorophyll a of the algal symbionts. The growth rate decrease varied between 0% and 30% compared to the unamended control for all HMs tested, whereas the algal symbionts exhibited a general non-fatal but significant response to Pb and Cu. Our results highlight that shell growth inhibition of LBF is predicted in extreme concentrations of 57 × CMC of Cu and 523 × CMC of Cd, providing a proof of concept for shell geochemistry monitoring, which is currently not used in the regulatory sectors.

中文翻译：

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重金属污染下大型底栖有孔虫的壳生长：对沿海环境地球化学监测的意义。

最近的一项研究是使用较大的底栖有孔虫（LBF）壳地球化学来监测海洋环境中的重金属（HMs）污染，从而促进了这项研究。外壳本身可作为HMs污染低至极端环境中环境水化学物质的记录器，从而可以监控最近发生的污染事件。这个概念被称为年代记论，即使在极端污染事件中，也需要添加新零件（即新外壳）。我们评估了三种壳类型和共生体不同的LBF物种对富集的Cd，Cu和Pb的生理适应力，其水平比生态标准最大浓度（CMC）高出几倍（165–166、33–43、1001– 1206微克L ^-1分别来自水生生物的毒性测试。通过添加新的腔室（新的壳部分）和藻类共生体的叶绿素a量化的生长速率来表示全生命周期的生理反应。对于所有测试的HM，与未经修正的对照相比，生长速率的降低在0％至30％之间，而藻类共生体对Pb和Cu表现出一般的非致命性但显着的响应。我们的研究结果表明，预计在浓度为57×CMC的铜和523×CMC的Cd的极高浓度下，LBF的壳生长受到抑制，这为壳层地球化学监测提供了概念证明，目前尚无监管部门使用。