Foraminifera are commonly used in paleoclimate reconstructions as they occur throughout the world's oceans and are often abundantly preserved in the sediments. Traditionally, foraminifera‐based proxies like δ¹⁸O and Mg/Ca are analyzed on pooled specimens of a single species. Analysis of single specimens of foraminifera allows reconstructing climate variability on timescales related to El Niño–Southern Oscillation or seasonality. However, quantitative calibrations between the statistics of individual foraminifera analyses (IFA) and climate variability are still missing. We performed Mg/Ca and δ¹⁸O measurements on single specimens from core top sediments from different settings to better understand the signal recorded by individual foraminifera. We used three species of planktic foraminifera (Globigerinoides ruber (s.s.), T. sacculifer, and N. dutertrei) from the Indo‐Pacific Warm Pool and one species (G. ruber (pink)) from the Gulf of Mexico. Mean values for the different species of Mg/Ca versus calculated δ¹⁸O temperatures agree with published calibration equations. IFA statistics (both mean and standard deviation) of Mg/Ca and δ¹⁸O between the different sites show a strong relationship indicating that both proxies are influenced by a common factor, most likely temperature variations during calcification. This strongly supports the use of IFA to reconstruct climate variability. However, our combined IFA data for the different species only show a weak relationship to seasonal and interannual temperature changes, especially when seasonal variability increases at a location. This suggests that the season and depth habitat of the foraminifera strongly affect IFA variability, such that ecology needs to be considered when reconstructing past climate variability.

中文翻译：

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破译个别有孔虫的镁/钙和稳定氧同位素的变异性。

有孔虫普遍用于古气候重建，因为它们遍布世界各地的海洋，并且经常大量保存在沉积物中。传统上，基于有孔虫的替代物（例如 δ ¹⁸ O 和 Mg/Ca）是在单个物种的汇集样本上进行分析的。对单个有孔虫标本的分析可以重建与厄尔尼诺-南方涛动或季节性相关的时间尺度上的气候变化。然而，个体有孔虫分析（IFA）的统计数据与气候变化之间的定量校准仍然缺失。我们对来自不同环境的岩心顶部沉积物的单个样本进行了 Mg/Ca 和 δ ^{18 O 测量，以更好地了解单个有孔虫记录的信号。}我们使用了来自印度太平洋暖池的三种浮游有孔虫（Globigerinoides ruber (ss)、T . sacculifer和N. dutertrei ）和来自墨西哥湾的一种浮游有孔虫（ G. ruber （粉红色））。不同种类 Mg/Ca 的平均值与计算的 δ ¹⁸ O 温度的关系与已发布的校准方程一致。不同位点之间Mg/Ca 和 δ ¹⁸ O的 IFA 统计数据（均值和标准差）显示出很强的关系，表明这两个代理均受到共同因素的影响，最有可能是钙化过程中的温度变化。这有力地支持了使用 IFA 来重建气候变化。然而，我们对不同物种的综合 IFA 数据仅显示出与季节和年际温度变化的微弱关系，特别是当某个地点的季节变化增加时。这表明有孔虫的季节和深度栖息地强烈影响IFA的变化，因此在重建过去的气候变化时需要考虑生态学。