Abstract We performed a downcore comparison of Mg/Ca ratios obtained using reductive and non-reductive cleaning methods applied to Globigerinoides ruber, Pulleniatina obliquiloculata and Globorotalia menardii picked along two nearby sediment cores retrieved at 2100 m and 3875 m in the eastern equatorial Indian Ocean. At the shallower site, our results show statistically significant discrepancies in averaged relative Mg/Ca loss induced by the reductive cleaning compared to non-reductive cleaning: G. menardii (8.5%) > G. ruber (6.2%) > P. obliquiloculata (4.4%), suggesting that reductive cleaning impact on relative Mg/Ca loss is species-specific. At the deeper site, differences between the relative Mg/Ca losses for the three species are smaller: G. menardii (3.7%), G. ruber (4.1%) and P. obliquiloculata (6.3%), suggesting the clear impact of in situ preservation state on the cleaning related Mg/Ca loss. The Mg/Ca loss in both relative (%) and absolute (mmol/mol) value of species G. ruber and G. menardii are significantly smaller at the deeper site than the shallower site, implying that these two species which have experienced intense dissolution on the sea-floor are less prone to lose further Mg during the reductive cleaning. P. obliquiloculata, however, show non-significant difference in Mg/Ca loss between the two sites, indicating that the cleaning related Mg/Ca loss in this species is somewhat insensitive to the preservation state at our two sites. Our data reveal that Mg/Ca loss results from partial dissolution induced by the reductive step. We conclude that the non-reductive cleaning approach should be preferred for building inter-laboratory homogeneous datasets of Mg/Ca-derived temperatures, whereas the reductive step should be only included when severe oxide coating is observed.

中文翻译：

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清洁方法对三种浮游有孔虫物种 Mg/Ca 的影响：沿深度横断面的下核研究

摘要 我们对使用还原性和非还原性清洁方法获得的 Mg/Ca 比率进行了下核比较，这些方法适用于在赤道印度洋东部 2100 m 和 3875 m 处取回的两个附近沉积岩心采摘的 Globigerinoides ruber、Pulleniatina biquiloculata 和 Globorotalia menardii。在较浅的地点，我们的结果显示，与非还原性清洁相比，还原性清洁引起的平均相对 Mg/Ca 损失存在统计学显着差异：G. menardii (8.5%) > G. ruber (6.2%) > P.obliquiloculata ( 4.4%)，表明还原清洗对相对 Mg/Ca 损失的影响是物种特异性的。在更深的位置，三个物种的相对 Mg/Ca 损失之间的差异较小：G. menardii (3.7%)、G. ruber (4.1%) 和 P.obliquiloculata (6.3%)，表明原位保存状态对清洁相关的 Mg/Ca 损失的明显影响。G. ruber 和 G. menardii 物种的相对 (%) 和绝对 (mmol/mol) 值的 Mg/Ca 损失在较浅的位置显着小于较浅的位置，这意味着这两个物种经历了强烈的溶解在还原清洗过程中，海底上的 Mg 不太可能进一步损失。然而，P.obliquiloculata 在两个地点之间的 Mg/Ca 损失没有显着差异，表明该物种中与清洁相关的 Mg/Ca 损失对我们两个地点的保存状态有些不敏感。我们的数据表明，Mg/Ca 损失是由还原步骤引起的部分溶解造成的。