Abstract Benthic foraminifera Mg/Ca is a well-established bottom water temperature (BWT) proxy used in paleoclimate studies. The relationship between Mg/Ca and BWT for numerous species has been determined using core-top and culturing studies. However, the scarcity of calcareous microfossils in Antarctic shelf sediments and poorly defined calibrations at low temperatures has limited the use of the foraminiferal Mg/Ca paleothermometer in ice proximal Antarctic sediments. Here we present paired ocean temperature and modern benthic foraminifera Mg/Ca data for three species, Trifarina angulosa, Bulimina aculeata, and Globocassidulina subglobosa, but with a particular focus on Trifarina angulosa. The core-top data from several Antarctic sectors span a BWT range of -1.7 to 1.2˚C and constrain the relationship between Mg/Ca and cold temperatures. We compare our results to published lower-latitude core-top data for species in the same or related genera, and in the case of Trifarina angulosa, produce a regional calibration. The resulting regional equation for Trifarina angulosa is Temperature (°C) = (Mg/Ca -1.14±0.035)/0.069±0.033). Addition of our Trifarina angulosa data to the previously published Uvigerina spp. dataset provides and alternative global calibration, although some data points appear to be offset from this relationship and are discussed. Mg-temperature relationships for Bulimina aculeata and Globocassidulina subglobosa are also combined with previously published data to produce calibration equations of Temperature (°C) = (Mg/Ca-1.04±0.07)/0.099±0.01 and Temperature (°C) = (Mg/Ca-0.99±0.03)/0.087±0.01, respectively. These refined calibrations highlight the potential utility of benthic foraminifera Mg/Ca-paleothermometry for reconstructing past BWT in Antarctic margin settings, although further work is required before they are routinely used.

中文翻译：

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用于重建南极大陆架底部水温的极地底栖有孔虫物种的镁/钙温度校准

摘要 底栖有孔虫 Mg/Ca 是古气候研究中使用的成熟的底水温度 (BWT) 代理。许多物种的 Mg/Ca 和 BWT 之间的关系已使用核心顶部和培养研究确定。然而，南极大陆架沉积物中钙质微化石的稀缺性和低温下定义不明确的校准限制了有孔虫 Mg/Ca 古温度计在南极冰附近沉积物中的使用。在这里，我们展示了三个物种的配对海洋温度和现代底栖有孔虫 Mg/Ca 数据，Trifarina angulosa、Bulimina aculeata 和 Globocassidulina subglobosa，但特别关注 Trifarina angulosa。来自几个南极地区的核心顶部数据跨越 -1.7 至 1.2˚C 的 BWT 范围，并限制了 Mg/Ca 与低温之间的关系。我们将我们的结果与已发表的相同或相关属物种的低纬度核心顶部数据进行比较，并且在 Trifarina angulosa 的情况下，产生区域校准。由此产生的三角藻的区域方程是温度 (°C) = (Mg/Ca -1.14±0.035)/0.069±0.033)。将我们的 Trifarina angulosa 数据添加到之前发布的 Uvigerina spp。数据集提供了另一种全局校准，尽管一些数据点似乎与这种关系有偏差并被讨论。Bulimina aculeata 和 Globocassidulina subglobosa 的 Mg-温度关系也与先前公布的数据相结合，以产生温度 (°C) = (Mg/Ca-1.04±0.07)/0.099±0.01 和温度 (°C) = (Mg /Ca-0.99±0.03)/0.087±0.01，分别。