Germanium Isotope Systematics in Marine Systems

海洋系统中的锗同位素系统学

• 批准号: 1061700
• 负责人: Douglas Hammond
• 金额: $ 31.73万
• 依托单位: University of Southern California
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-03-15 至 2014-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1061700&HistoricalAwards=false
• 关键词: Germanium; Isotope; Systematics; Marine; Systems

Records of oceanic germanium:silicon (Ge:Si) preserved in diatoms show temporal variations that reflect changes in the marine Si cycle over time. These variations may be due to (1) the relative rates of Ge removal in opal and non-opal phases, (2) the ratio of weathering and/or hydrothermal Ge inputs, and (3) the internal cycling of Si in the ocean and Ge/Si fractionation by diatoms. Germanium isotopes may help constrain the influences of these factors. A scientist for the University of Southern California plans to analyze seawater from the Atlantic and Pacific Ocean, river water from selected watersheds, and sediment pore waters from iron-rich reducing sediments in the California Margin and Gulf of Mexico to address the following questions: (1) Does Ge isotope variability exist within and between ocean basins?; (2) Is there Ge isotope fractionation during low-temperature weathering?; and (3) Are Ge isotopes fractionated during sediment diagenesis? Overall, this study will determine if and where significant isotopic differences exist in the sources and sinks for inorganic Ge in the oceans and should document the utility of this tracer for unraveling the complexities of the marine Si cycle and its temporal variation. In addition, the researcher plans to analyze the isotopic composition of methyl germanium in the oceans to evaluate if its isotopic composition provides clues about its biogeochemical cycling.As regards broader impacts, one graduate and one undergraduate student would be trained and supported as part of this project.

海洋锗的记录：硅藻（GE：SI）保存在硅藻中的时间变化，反映了随着时间的推移随时间变化的海洋SI周期的变化。这些变化可能是由于（1）蛋白石和非罕见相中GE去除的相对速率，（2）风化和/或热液GE输入的比率，以及（3）SI在海洋中的SI内部循环以及硅质中的GE/SI分裂。同位素的也可能有助于限制这些因素的影响。南加州大学的科学家计划从大西洋和太平洋分析海水，来自选定流域的河水以及来自墨西哥加利福尼亚州和墨西哥湾的富铁减少沉积物的沉积物孔隙水，以解决以下问题：（1）（1）在海层之间和海洋基础之间存在地理性变异性吗？ （2）在低温风化期间是否存在GE同位素分馏？ （3）在沉积物成岩作用过程中，GE同位素是否分级？ 总体而言，这项研究将确定海洋中无机GE的来源和下沉中是否存在显着的同位素差异，并应记录该示踪剂的效用，以揭示海洋SI循环的复杂性及其时间变化。此外，研究人员计划分析海洋中甲基锗的同位素组成，以评估其同位素组合物是否提供了有关其生物地球化学循环的线索。就广泛的影响，一名毕业生和一名本科生将受到该项目的培训和支持。