Ba/Ca ratios in benthic foraminifera from recent core tops

The carbon isotope ratio (delta13C) and cadmium content (Cd/Ca) of benthic foraminifera shells have been used to reconstruct deep-water circulation patterns of the glacial oceans. These tracers co-vary with phosphorus in the modern ocean because they are nearly quantitatively regenerated from sinking biological debris in the upper water column. Hence they can be used to reconstruct the distribution of labile nutrients in glacial water masses. Independent constraints on glacial deep-ocean circulation patterns could be provided by a tracer of the distribution of silica and alkalinity, the deeply regenerated constituents of planktonic hard parts. Barium shares key aspects of its behaviour with these refractory nutrients because it is removed from solution in surface waters and incorporated into sinking particles which slowly dissolve deep in the water column and in the sediments. […]

碳同位素比值（δ13C）和底栖有孔虫壳中的镉含量（Cd/Ca）已被用于重建冰川海洋的深层水流模式。这些示踪剂与现代海洋中的磷含量呈共变关系，因为它们几乎定量地来自上层水柱中沉降的生物残骸。因此，它们可以用于重建冰川水体中易变营养物质的分布。通过硅酸盐和碱度的分布示踪剂，这些深部再生的浮游生物硬质部分的成分，可以提供对冰川深层海洋环流模式的独立约束。钡与这些耐热营养素在行为上共享关键特征，因为它从表层水中去除并融入沉降颗粒中，这些颗粒在水中深层和沉积物中缓慢溶解。