Zarkogiannis Stergios D, Rae James W B, Shipley Benjamin R, Mortyn P Graham
Department of Earth Sciences, University of Oxford, Oxford, UK.
School of Earth and Environmental Sciences, University of St Andrews, St Andrews, UK.
Commun Earth Environ. 2025;6(1):605. doi: 10.1038/s43247-025-02558-w. Epub 2025 Jul 31.
Planktonic foraminifera are key contributors to the oceanic carbon cycle. In pelagic environments, carbonate production by planktonic biomineralizers regulates ocean-atmosphere carbon dioxide exchange and exports surface carbon to the deep ocean. Here we compare shell traits of three planktonic foraminifera species from the central Atlantic with a suite of environmental parameters to discern the factors underlying their variations. Our analysis revealed that calcification in foraminifera is associated with seawater density and depends on species habitat depth, whereas foraminifera bulk shell densities may serve as a seawater density proxy, regardless of species. We observe that their shell weights increased with habitat depth, enabling the living cells to adjust their overall density to match that of the surrounding liquid. This suggests that calcification in nonmotile organisms has a buoyancy regulatory function and will respond to the anthropogenically driven reductions in ocean density (oceanic rarefication), with potential consequences for the carbon cycle.
浮游有孔虫是海洋碳循环的关键贡献者。在远洋环境中，浮游生物矿化者进行的碳酸盐生产调节着海洋与大气之间的二氧化碳交换，并将表层碳输送到深海。在此，我们将来自大西洋中部的三种浮游有孔虫物种的壳体特征与一系列环境参数进行比较，以识别其变化背后的因素。我们的分析表明，有孔虫的钙化作用与海水密度相关，并且取决于物种的栖息深度，而有孔虫壳体的总体密度可能可作为海水密度的替代指标，与物种无关。我们观察到它们的壳体重量随着栖息深度的增加而增加，使活细胞能够调节其整体密度以与周围液体的密度相匹配。这表明非移动生物的钙化作用具有浮力调节功能，并且会对人为驱动的海洋密度降低（海洋贫化）做出反应，这可能会对碳循环产生影响。
