Temperature-Dependent Ocean-Atmosphere Equilibration of Carbon Isotopes in Atlantic Thermocline and Surface Waters

大西洋温跃层和地表水中碳同位素与温度相关的海洋-大气平衡

基本信息

批准号：
1459563
负责人：
Jean Lynch-Stieglitz
金额：
$ 29.82万
依托单位：
Georgia Tech Research Corporation
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2015
资助国家：
美国
起止时间：
2015-03-15 至 2019-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1459563&HistoricalAwards=false
关键词：
Temperature Dependent Ocean Atmosphere Equilibration

项目摘要

The stable isotopes of carbon can provide clues about the processes by which carbon moves through the earth system. Researchers at Georgia Institute of Technology will use carbon isotope and nutrient reconstructions in the upper ocean, in combination with existing atmospheric carbon isotope reconstructions from ice cores, to better understand why and how atmospheric carbon dioxide rose at the end of the last ice age. This work will help further the understanding of the controls and feedbacks on atmospheric carbon dioxide concentrations. The possibility of reconstructing past surface ocean temperatures from the air-sea carbon isotope difference will also be explored. The investigators will assess whether the upper ocean carbon isotope changes seen over the deglaciation in the North Atlantic primarily reflect biological cycling or air sea exchange processes. A detailed record of seawater cadmium (Cd, related to the nutrient phosphate in today's ocean) from Cd/Ca measurements in benthic foraminifera will be constructed. These measurements will help to pinpoint what mechanism was responsible for the transition to a less efficient biological carbon pump over the deglaciation. The investigators will also reconstruct the carbon isotopic composition of well equilibrated, low nutrient surface waters in the North Atlantic using carbon isotopic measurements on large planktonic foraminifera. The carbon isotope ratio in these waters will reflect the changes in the atmospheric ratio and the temperature of equilibration, potentially providing information on past surface ocean temperature changes. In addition to the societal relevance of better understanding the relationship between carbon dioxide and climate, this grant will support the training of several students from under-represented groups. The data will be made available to the community and will be contributed to an international effort to synthesize and interpret carbon isotope records over the deglaciation.

碳的稳定同位素可以提供有关碳通过地球系统移动的过程的线索。佐治亚理工学院的研究人员将在上海上使用碳同位素和营养重建，并结合现有的大气碳同位素重建，从冰芯中更好地了解为什么在最后一个冰河时代结束时，二氧化碳的原因以及大气中的二氧化碳是如何上升的。这项工作将有助于进一步理解对大气二氧化碳浓度的控制和反馈。还将探索从空气碳同位素差异重建过去海洋温度的可能性。研究人员将评估海洋碳同位素的变化是北大西洋的脱气而主要反映生物循环还是空中海洋交换过程。将构建底栖有孔虫中CD/CA测量结果的海水镉（CD，与当今海洋中的磷酸营养磷酸盐有关）的详细记录。这些测量结果将有助于确定哪种机制是导致在脱胶中过渡到效率较低的生物碳泵的原因。研究人员还将使用大型浮游有孔虫上的碳同位素测量值重建北大西洋中良好平衡，低营养的地表水的碳同位素组成。这些水域中的碳同位素比将反映大气比和平衡温度的变化，有可能提供有关过去表面海洋温度变化的信息。除了更好地了解二氧化碳与气候之间的关系的社会相关性外，该赠款还将支持对代表不足群体的几名学生的培训。这些数据将提供给社区，并将为国际努力做出贡献，以综合和解释碳同位素记录。