OCE-RIG: Improving Climate Records Through a Mechanistic Understanding of Sub-Micron Proxy Heterogeneity in Spinose Foraminifera

浮游生物和底栖有孔虫的方解石壳在生长过程中会将周围水中的矿物质和稳定同位素吸收到它们的壳中，因此这些壳提供了这些生物生活的环境条件的记录。这些贝壳通常被保存在沉积物中，用来估计古气候。然而，有孔虫壳组成与环境条件之间的关系仍然存在许多基本问题。更好地了解有孔虫的生物钙化作用，特别是不断变化的环境条件与碳酸盐壳中微量元素和微量元素的结合之间的关系，将使科学家能够更准确地解释古海洋学记录。该奖项将支持PI和一名研究生的工作，该研究生将在亚微米尺度上研究有孔虫壳的生物矿化。该学生还将参加华盛顿大学的COOL项目：实验室之外的化学海洋学，这是一项面向中学生的科学推广计划。这项关于生物矿化基本机制的研究也可能对材料科学领域和与骨生长相关的医学应用有用。研究人员将使用新的原位分析方法，如SIMS、nanoSIMS、激光烧蚀ICP-MS和具有先进元素定位功能的新一代EPMA，在亚微米尺度上研究有孔虫壳的非均质生物矿化，包括有孔虫测试中Mg/Ca和Na/Ca带的明显日循环。对有孔虫亚微米空间尺度元素分配机制的理解将提高我们在古海洋重建背景下解释这些元素代用物的能力。

Calcite shells of planktonic and benthic foraminifera incorporate minerals and stable isotopes from the surrounding water into their shells as they grow, so the shells provide records of the environmental conditions in which the organisms lived. These shells are often preserved in sediments and are used to provide estimates of paleoclimates. However, many basic questions still remain about the relationship between foraminiferal shell composition and environmental conditions. A better understanding of foraminiferal biocalcification, in particular the relation between changing environmental conditions and the incorporation of trace and minor elements in the carbonate shells, will allow scientists to interpret paleoceanographic records more accurately. This award will support the work of the PI and a graduate student who will investigate biomineralization of foraminiferal shells at a sub-micron scale. The student will also participate in the University of Washington's Project COOL: Chemical Oceanography Outside the Laboratory, a science outreach program for middle school students. This research on the basic mechanics of biomineralization may also be useful for the field of material sciences and for medical applications related to bone growth. Researchers will use new in situ analytical approaches such as SIMS, nanoSIMS, laser-ablation ICP-MS, and new-generation EPMA with advanced element-mapping capabilities to investigate heterogeneous biomineralization of foraminiferal shells at a submicron scale, including apparent diurnal cycles in the Mg/Ca and Na/Ca banding within foraminifera tests. A mechanistic understanding of submicron-spatial scale elemental partitioning within foraminifera should improve our ability to interpret these elemental proxies in the context of paleoceanographic reconstruction.