Assessing the Fidelity of Foraminiferal Mg/Ca- d18O to Estimate Seawater d18Or: A Multispecies Calibration-Validation Study

这个项目将校准和验证贝壳得出的d18O海水估计值，这些估算是通过对浮游有孔虫中的镁/钙和d18O与热带太平洋、大西洋和非洲西北部边缘三个经向岩心断面观测到的d18O海水梯度的配对分析得出的。此外，将使用最近在葡萄牙和非洲西北部边缘取心巡航期间收集的浮游生物TOW和D18O海水表层水样进行现场d18O海水校准。这项研究将检验一种假设，即他在一系列58个岩芯顶部样本中观察到的“过量镁/钙”及其与盐度的明显联系，可以在更大的(亚)热带海洋区域内分离和量化。这项研究还将检查有孔虫壳体形态、重量和壳体镁/钙不均质性的系统变化，这些变化与“过量的镁/钙”端元样本有关。该项目更广泛的影响部分包括对博士生的支持，本科生对研究内容的参与和指导，以及对变革性问题的研究，这是许多正在进行的古海洋学研究计划的基本组成部分。

This project will calibrate and validate shell-derived d18Oseawater estimates that have been derived from paired analyses of Mg/Ca and d18O in planktonic foraminifera against observed d18Oseawater gradients for three meridional coretop transects in the (sub)tropical Pacific, Atlantic, and NW African margin. In addition, an in situ d18Oseawater calibration will be conducted using plankton tow and d18Oseawater surface water samples collected during a recent coring cruise off the Portuguese and NW African margins. The research will test the hypothesis that the "excess Mg/Ca" that he has observed in a series of 58 coretop samples, and its apparent link to salinity, can be isolated and quantified over a larger (sub)tropical ocean domain. This research will also examine systematic changes in foraminifera shell morphology, weight, and shell Mg/Ca heterogeneity associated with "excess Mg/Ca" endmember samples. The Broader Impacts component of this project include support of a PhD student, involvement and mentoring of undergraduate students in elements of the research, and the study of a transformative-level problem that is a fundamental component of many ongoing paleoceanographic research programs.