Coupling of Silicon Isotope Distributions to Meridional Overturning Circulation of the North Atlantic

硅同位素分布与北大西洋经向翻转环流的耦合

• 批准号: 1129227
• 负责人: Mark Brzezinski
• 金额: $ 24.87万
• 依托单位: University of California-Santa Barbara
• 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: 2011-09-15 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1129227&HistoricalAwards=false
• 关键词: Coupling; Silicon; Isotope; Distributions; Meridional

The silicon (Si) isotope proxy is increasingly being used to assess the role of diatoms and silicic acid in past shifts in ocean productivity and their implication for climate; however, before it can be successfully used, we need to understand the mechanisms that control the spatial and temporal variability of the Si isotope composition in ventilating water masses. A scientist from the University of California, Santa Barbara put forth the hypothesis that the Si isotope distribution is a function of the coupling of fractionation during silica production and during silica dissolution to the biological pump and the meridional overturning circulation (MOC). To test the hypothesis, the researcher plans to measure Si isotopes within the major water masses of the North Atlantic, a key end member within the MOC (i.e., surface and mode waters, the southward flowing North Atlantic Deep Water, and its northward flowing counterparts: Antarctic Intermediate Water and Antarctic Bottom Water). In addition, because the samples for the Si isotope work are being collected as part of the 2011 GEOTRACES North Atlantic zonal section, the scientist has the opportunity to collaborate with researchers working on nitrogen (N) isotopes to determine the controls on N and Si isotope dynamics and create the first numerical model that includes both isotopes, as well as incorporates Si isotope fractionation during silica dissolution. In terms of the broader impacts, data generated will be submitted to the GEOTRACES databases and thereby be readily available to the science community. Two undergraduate students will be supported and trained as part of this project.

硅（Si）同位素代理越来越多地用于评估硅藻和硅酸在过去海洋生产力变化中的作用及其对气候的影响；然而，在成功使用它之前，我们需要了解控制通风水团中硅同位素组成的空间和时间变化的机制。 加州大学圣塔芭芭拉分校的一位科学家提出了这样的假设：硅同位素分布是二氧化硅生产过程中和二氧化硅溶解过程中分馏与生物泵和经向翻转循环（MOC）耦合的函数。 为了验证这一假设，研究人员计划测量北大西洋主要水团中的硅同位素，北大西洋是 MOC 内的一个关键终端成员（即地表水和模式水、向南流动的北大西洋深水及其向北流动的对应部分） ：南极中层水和南极底层水）。 此外，由于硅同位素工作的样本是作为 2011 GEOTRACES 北大西洋分区的一部分收集的，因此科学家有机会与从事氮 (N) 同位素研究的研究人员合作，以确定对 N 和 Si 同位素的控制动力学并创建了第一个包含两种同位素以及二氧化硅溶解过程中硅同位素分馏的数值模型。就更广泛的影响而言，生成的数据将提交给 GEOTRACES 数据库，从而可供科学界轻松使用。 作为该项目的一部分，两名本科生将得到支持和培训。