High-resolution, Assemblage-specific Records of Diatom-bound N Isotopes from the Indian Sector of the Antarctic Ocean

南极洋印度区硅藻结合氮同位素的高分辨率、特定组合记录

• 批准号: 1401489
• 负责人: Daniel Sigman
• 金额: $ 49.19万
• 依托单位: Princeton University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-05-01 至 2019-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1401489&HistoricalAwards=false
• 关键词: resolution; Assemblage; specific; Records; Diatom

ABSTRACTIntellectual Merit:The high concentration of the major nutrients nitrate and phosphate is a fundamental characteristic of the Antarctic Zone in the Southern Ocean and is central to its role in global ocean fertility and the global carbon cycle. The isotopic composition of diatom-bound organic nitrogen is one of the best hopes for reconstructing the nutrient status of polar surface waters over glacial cycles, which in turn may hold the explanation for the decline in atmospheric carbon dioxide during ice ages. The PIs propose to generate detailed diatom-bound nitrogen isotope (δ15Ndb) records from high sedimentation rate cores from the Kerguelen Plateau. Because the cores were collected at relatively shallow seafloor depths, they have adequate planktonic and benthic foraminifera to develop accurate age models. The resulting data could be compared with climate records from Antarctic ice cores and other archives to investigate climate-related changes, including the major steps into and out of ice ages and the millennial-scale events that occur during ice ages and at their ends. The records generated in this project will provide a critical test of hypotheses for the cause of lower ice age CO2. Broader impacts:This study will contribute to the goal of understanding ice ages and past CO2 changes, which both have broad implications for future climate. Undergraduates will undertake summer internships, with the possibility of extending their work into junior year projects and senior theses. In addition, the PI will lead modules for two Princeton programs for middle school teachers and will host a teacher for a six-week summer research project.

抽象智能优点：主要营养素的硝酸盐和磷酸盐的高浓度是南大洋南极区的基本特征，并且是其在全球海洋生育能力和全球碳循环中作用的核心。硅藻结合有机氮的同位素组成是重建冰川周期上极地地表水的营养状况的最佳希望之一，这反过来又可能对冰期期间大气中的二氧化碳二氧化碳的下降构成解释。 PI提议从Kerguelen Plateau的高沉积率核心产生详细的硅藻结合的氮同位素（＆＃948; 15nDB）记录。由于岩心是在相对较浅的海底深处收集的，因此它们具有足够的浮游生物和底栖有孔虫以开发准确的年龄模型。可以将所得数据与来自南极冰芯和其他档案馆的气候记录进行比较，以研究与气候相关的变化，包括进入冰河时代和冰河时期内发生的千禧年尺度事件的主要步骤。该项目中产生的记录将为较低的冰河时代二氧化碳原因提供批判性测试。更广泛的影响：这项研究将有助于了解冰年龄和过去的二氧化碳变化，这两者都对未来的气候具有广泛的影响。本科生将进行暑期实习，并有可能将其工作扩展到大三的项目和高级论文。此外，PI将为中学教师提供两个普林斯顿计划的模块，并将为一个为期六周的夏季研究项目主持一名老师。