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.

摘要智力价值：主要营养物质硝酸盐和磷酸盐的高浓度是南大洋南极区的基本特征，对其在全球海洋肥力和全球碳循环中的作用至关重要。硅藻结合的有机氮的同位素组成是重建冰川周期期间极地表层水营养状况的最佳希望之一，这反过来可能解释冰河时期大气二氧化碳的减少。 PI 建议从凯尔盖朗高原的高沉降率岩心生成详细的硅藻结合氮同位素 (δ15Ndb) 记录。由于岩芯是在相对较浅的海底深度收集的，因此它们具有足够的浮游和底栖有孔虫来开发准确的年龄模型。由此产生的数据可以与南极冰芯和其他档案的气候记录进行比较，以调查与气候相关的变化，包括进入和结束冰河时代的主要步骤以及冰河时代及其结束时发生的千年规模的事件。该项目生成的记录将为冰河时期二氧化碳浓度降低的原因提供关键的假设检验。更广泛的影响：这项研究将有助于实现了解冰河时代和过去二氧化碳变化的目标，这两者都对未来的气候产生广泛的影响。本科生将进行暑期实习，并有可能将他们的工作扩展到大三项目和高级论文。此外，首席研究员还将领导两个普林斯顿中学教师项目的模块，并将接待一名教师进行为期六周的夏季研究项目。