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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碳在地球系统中移动过程的线索。格鲁吉亚理工学院的研究人员将利用海洋上层的碳同位素和营养物质重建，结合现有的来自冰芯的大气碳同位素重建，以更好地了解上一个冰河时代结束时大气二氧化碳为何以及如何上升。这项工作将有助于进一步了解大气二氧化碳浓度的控制和反馈。还将探讨是否有可能根据海气碳同位素差异重建过去的海洋表面温度。研究人员将评估北大西洋冰川消退期间上层海洋碳同位素的变化是否主要反映了生物循环或海气交换过程。通过对底栖有孔虫中Cd/Ca的测量，建立了海水镉（Cd，与当今海洋中的营养盐磷酸盐有关）的详细记录。这些测量将有助于确定是什么机制导致了冰川消退期间生物碳泵效率降低。研究人员还将利用对大型浮游有孔虫的碳同位素测量，重建北大西洋平衡良好、营养物含量低的表层沃茨的碳同位素组成。这些沃茨中的碳同位素比率将反映大气比率和平衡温度的变化，可能提供过去海洋表面温度变化的信息。除了更好地了解二氧化碳和气候之间的关系的社会意义，这笔赠款将支持来自代表性不足群体的几名学生的培训。这些数据将提供给社区，并将有助于综合和解释冰川消退期间碳同位素记录的国际努力。