SGER: Controls on Li/Ca Uptake in Planktic Foraminifera Determined by Live Culturing

SGER：活体培养对浮游有孔虫中 Li/Ca 吸收的控制

• 批准号: 0509180
• 负责人: Mark Pagani
• 金额: $ 5万
• 依托单位: Yale University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-02-15 至 2005-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0509180&HistoricalAwards=false
• 关键词: SGER; Controls; Li; Ca; Uptake

Controls on Li/Ca uptake in planktic foraminifera determined by live culturingBeing able to correlate changes in seawater chemistry and climate allows us to read the record of climate changes and rates of change back through time. This research focuses on the development of a new geochemical proxy that will link the Li/Ca ratio on the calcareous tests of planktonic foaminifera with the concentration of carbonate ion in seawater. If the primary hypotheses that are to be tested hold, the tool and techniques developed will extend significantly our ability to track changes in the carbonate ion in seawater, hence atmospheric CO2 concentrations, back through time. It will also allow us to monitor changes in the flux and source of Li in the oceans over time, providing a means for measuring how sources of oceanic lithium (hydrothermal circulation through the ocean crust versus continental weathering) have changed with time. This research will use laboratory culturing experiments on a common unicellular marine organism, Orbulina universa, that precipitates a hard calcareous carapace (i.e., test) to determine if uptake of Li into the test is controlled strictly by the carbonate ion concentration of seawater. To test this hypotheses, controlled culturing experiments on Orbulina universa will be carried out to examine the effect of carbonate ion concentration, lithium concentration, salinity, and temperature on the Li/Ca ratio of the foram test. From the previous work of one of the PIs (Hall), it is already known that lithium does not significantly participate in the biological cycle, and so its concentration in the test will not be affected by changes in nutrients or biological productivity. Lithium also has a relatively long residence time in the ocean, compared to the bioactive element, zinc, which is presently used as a carbonate ion proxy. Culturing work will be carried out at the Hebrew University of Jerusalem field station in Eilat, Israel in collaboration with Dr. Jonathon Erez who is an expert in such culturing experiments and who is set up to begin culturing as early as the first week of January, 2005. Cultured specimens grown in these experiments will be subsequently cleaned at Yale University and analyzed there by inductively coupled plasma mass spectrometry.

通过活体培养确定的浮游有孔虫对Li/Ca吸收的控制能够将海水化学和气候的变化联系起来，使我们能够通过时间来阅读气候变化和变化率的记录。 本研究的重点是开发一种新的地球化学代用指标，该代用指标将把碳酸盐泡沫动物钙质测试中的Li/Ca比值与海水中碳酸盐离子的浓度联系起来。 如果要测试的主要假设成立，开发的工具和技术将大大扩展我们跟踪海水中碳酸盐离子变化的能力，从而追溯大气中的CO2浓度。 它还将使我们能够监测海洋中锂的通量和来源随时间的变化，为测量海洋锂的来源（通过海洋地壳的热液循环与大陆风化）如何随时间变化提供一种手段。 这项研究将使用一种常见的单细胞海洋生物Orbulina universa的实验室培养实验，这种生物沉淀出坚硬的钙质甲壳（即，测试），以确定进入测试的Li的吸收是否受到海水中碳酸根离子浓度的严格控制。 为了验证这一假设，控制培养实验Orbulina universa将进行检查碳酸根离子浓度，锂浓度，盐度和温度的影响上的Li/Ca比的有孔虫测试。 从其中一位PI（Hall）的先前工作中，已经知道锂不显著参与生物循环，因此其在测试中的浓度不会受到营养物质或生物生产力变化的影响。 与目前用作碳酸根离子替代物的生物活性元素锌相比，锂在海洋中的停留时间也相对较长。 培养工作将在以色列埃拉特的耶路撒冷希伯来大学野外工作站进行，并与培养实验方面的专家Jonathe Erez博士合作，他最早将于2005年1月的第一周开始培养。 在这些实验中生长的培养标本随后将在耶鲁大学进行清洁，并在那里通过电感耦合等离子体质谱法进行分析。