Collaborative Research: Investigation of pCO2 Changes Since the Pliocene Based on Alkenone Carbon Isotopes

合作研究：基于烯酮碳同位素研究上新世以来的 pCO2 变化

• 批准号: 0726572
• 负责人: Ana Ravelo
• 金额: $ 1.72万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-08-01 至 2009-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0726572&HistoricalAwards=false
• 关键词: Collaborative; Research; Investigation; pCO2; Changes; Collaborative; Research; Investigation; pCO2; Changes

Collaborative Research: Investigation of pCO2 Changes Since the Pliocene Based on Alkenone Carbon IsotopesMark Pagani/A. Christina RaveloYale University/UC Santa CruzAbstractThis proposal seeks to reconstruct atmospheric pCO2 across the Pliocene/Pleistocene climate transition of the last 5 million years, which will provide a framework to test possible causes of the Plio-Pleistocene climatic transition. The primary objective of this proposal is to test the hypothesis that the pattern of warming during the early Pliocene warm period, as well as the subsequent cooling, was forced by a corresponding increase and decrease in pCO2. The PI's will evaluate pCO2 changes by reconstructing records of the total carbon isotopic fractionation that occurs during algal photosynthesis (Ep). The approach will be to extract and determine the carbon isotopic (d13C) values of haptophyte-derived long-chain ketone biomarkers (alkenones) obtained from a globally distributed set of DSDP and ODP cores. In addition, the carbon isotopic and Mg/Ca composition of one or more species of planktonic foraminifers will be analyzed from the same sample to constrain changes in the carbon isotopic composition of seawater and surface temperatures respectively. The difference between the d13C of alkenones and of the coeval near-surface dwelling planktonic foraminifera represents the approximate carbon isotopic fractionation that occurs during photosynthetic carbon fixation specific to alkenone-producing haptophyte algae. This technique has been used to reconstruct the magnitude of pCO2 change during the Cenozoic and is considered one of the most reliable paleo- pCO2 proxies presently available. Broader impacts include the bi-coastal collaboration between two major U.S. institutions, participation in the project by two undergraduates and a post-doc, and PI Pagani's participatetion in a middle and high school education program that will incorporate the results of this study into presentations to students and interns in the program.

协作研究：基于烯酮碳同位素标记Pagani/A以来PCO2变化的研究。克里斯蒂娜·拉维亚尔大学（Christina Raveloyale University）/加州大学圣克鲁萨克拉特（UC Santa Cruzabstract）提案旨在重建过去500万年的上新世/更新世气候过渡的大气PCO2，这将提供一个框架，以测试造成复杂新世纪气候过渡的可能原因。该提案的主要目的是检验以下假设：上新世热时期的变暖模式以及随后的冷却，这是由于PCO2的相应增加和减少而强迫的。 PI将通过重建藻类光合作用（EP）期间发生的总碳同位素分馏记录来评估PCO2的变化。该方法将是提取和确定从全球分布的DSDP和ODP核心获得的触发型长链酮生物标志物（烯烃）的碳同位素（D13C）值。此外，将分别从相同的样品分析一种或多种浮游有孔虫的碳同位素和Mg/ca组成，以约束海水和表面温度的碳同位素组成的变化。烷酮的D13C和二层近表面植物有孔虫的差异代表了在光合碳烯酮产生的光合碳固定过程中发生的近似碳同位素分馏。该技术已用于重建新生代期间PCO2变化的幅度，被认为是目前可用的最可靠的古PCO2代理之一。更广泛的影响包括两家美国主要机构之间的双层合作，由两名本科生和一名大多学生参与该项目，以及Pi Pagani参与中学和高中教育计划的参与，该计划将将这项研究的结果纳入该计划的学生和实习生。