Ostracode Mg/Ca Paleothermometry in the Arctic Ocean: A Calibration Study

0223097德怀尔首席调查员将进行岩心-顶部校准研究，以提高介形码镁/钙(镁/钙)古测温法的适用性、准确性和精密度，以重建北冰洋及邻近海域晚第四纪的温度历史。现有的岩心顶层校准仅限于一个属的成体贝壳，并包括不太可能是现代的沉积岩心顶层。这些因素，加上北冰洋Krithe成虫贝壳的空间和时间丰度的变化，导致北冰洋介形虫古温度计的准确性、精密度(1至20摄氏度，取决于可用的贝壳数量)和适用性降低。然而，研究表明，北极其他常见属的成虫贝壳也可用于镁/钙古温度测定，而且，最年长的幼虫贝壳对镁的摄取与成虫贝壳相同，具有温度依赖性。如果是这样的话，将幼年/成人校准和来自多个属的校准结合起来，可能会提供必要的改进，以便更准确和准确地量化北冰洋和邻近海域的温度历史。为了验证这一假设，将从北极、大西洋和太平洋盆地现有的高质量沉积物岩心顶部(箱形岩心和多岩心)的广泛收集中，分析水温从-1到120摄氏度的北极常见属Krithe和Cytheropteron的现代成体和幼体贝壳。这些岩心顶端的一部分已用于底栖有孔虫镁/钙刻度研究。这项研究将首次对可用于古海洋学和古气候研究的两个最有希望的深海古温度计进行全面校准和比较。

0223097 DwyerThe Principal Investigator will undertake core-top calibration studies to improve the applicability, accuracy, and precision of ostracode magnesium/calcium (Mg/Ca) paleothermometry to reconstruct the late Quaternary temperature history of the Arctic Ocean and adjacent seas. The existing core-top calibration is limited to adult shells of one genus, Krithe, and includes sediment core tops that are not likely to be of modern age. These factors, along with variations in the spatial and temporal abundance of adult shells of Krithe in the Arctic, contribute to diminish the accuracy, precision (1 to 20C, depending on number of shells available), and applicability of ostracode paleothermometry in the Arctic Ocean. However, studies suggest that the adult shells of other common Arctic genera may also be used for Mg/Ca paleothermometry, and, furthermore, that eldest juvenile shells display thermodependent uptake of magnesium identical to that of adult shells. If so, the combination of juvenile/adult calibrations and calibrations from multiple genera may provide the improvements necessary to more accurately and precisely quantify the temperature history of the Arctic Ocean and adjacent seas. To test this hypothesis, modern adult and juvenile shells of common Arctic genera Krithe and Cytheropteron will be analyzed from an extensive collection of existing, high-quality sediment core tops (box cores and multicores) from Arctic, Atlantic, and Pacific ocean basins at water temperatures ranging from -1 to 120C. A subset of these core tops have been used for benthic foraminifer Mg/Ca calibration studies. The research will provide for the first comprehensive calibration-comparison of the two most promising deep-sea paleothermometers available for paleoceanographic and paleoclimate studies.