Siliceous Paleoceanography: (Ge/Si) OPAL-IV

海洋硅藻对Ge/Si微小生物分异的最新认识表明，在晚更新世柱状岩心和新生代钻孔岩心中测量的（Ge/Si）欧白石变化记录了整个海洋（Ge/Si）海水的变化，这是由大陆风化强度和河流入海通量的快速和大的冰期至间冰期变化驱动的。如果是这样，那么在具有成熟的18o和14c地层的岩心中制作（Ge/Si）蛋白石的高分辨率记录，以确定相对于其他气候和风化指标的海洋Ge/Si响应的形状和时间，显然是重要的。此外，为了解决面对小生物分异效应时整个海洋的变化，有必要仔细评估和去除局部记录中Ge/Si分异的影响。随着一种快速、高灵敏度的HG-ICP-MS ge方法的发展，这些问题可以得到解决，揭开海洋化学变化的原因和时间可以开始。因此，本研究旨在实现两个主要目标：(1)在含有丰富硅藻和有孔虫的岩心中，与他人在同一岩心（如87Sr/86Sr）中适当的古地球化学示踪剂的测量合作，获得高分辨率的晚更新世（Ge/Si）蛋白石记录；(2)通过硅藻培养、水文和岩心顶部样带以及汉堡海洋Ge/Si模型的运行，提供测试以完善Ge/Si生物分选的效果。此外，还将继续开展南极（向南太平洋和北太平洋扩展）的蛋白石古生产力研究和其他辅助项目。

9508072 Froelich Recent advance in our understanding of minor biological fractionation of Ge/Si by oceanic diatoms suggest that (Ge/Si) opal variations measured in late Pleistocene piston cores and Cenozoic drill cores are recording whole ocean (Ge/Si) seawater variations driven by rapid and large glacial to interglacial changes in continental weathering intensity and river fluxes to the sea. If so, then it is clearly important to produce high resolution records of (Ge/Si) opal in cores with well-established 18 O and 14 C stratigraphies across transitions to establish the shape and timing of the oceanic Ge/Si response relative to other climate and weathering indicators. In addition, in order to resolve whole ocean changes in the face of small biological fractionation effects, it is necessary to carefully evaluate and remove the effects of Ge/Si fractionation in local records. With the development of a rapid and highly- sensitive HG-ICP-MS Ge-method, these problems can be addressed and unraveling the causes and timing and ocean chemical variations can begin. As a result, this is aimed at accomplishing two major goals: (1) Produce high resolutions late Pleistocene (Ge/Si) opal records in cores that contain abundant diatoms and forams in collaboration with others' measurements of the appropriate paleogeochemical tracer in the same cores (e.g. 87Sr/86Sr); and (2) Provide tests to refine the effects of Ge/Si biological fractionation with diatom cultures, hydrographic and core top transects, and runs of the Hamburg ocean Ge/Si model. In addition, opal paleoproductivity work in the Antarctic (expanding into the North and South Pacific Oceans), and other ancillary programs will be continued.