Collaborative Research: Studying Carbon Injection and the Silicate Weathering Feedback over the Paleocene Eocene Thermal Maximum Using Ca Isotopes and Modeling

合作研究：利用 Ca 同位素和模拟研究古新世始新世热最大值期间的碳注入和硅酸盐风化反馈

• 批准号: 2233962
• 负责人: Sandra Turner
• 金额: $ 5.61万
• 依托单位: University of California-Riverside
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-05-01 至 2026-04-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2233962&HistoricalAwards=false
• 关键词: Collaborative; Research; Studying; Carbon; Injection

The Paleocene-Eocene Thermal Maximum (PETM) was a strong warming event that took place 55 million years ago. The PETM was driven by a large addition of carbon dioxide to the ocean and atmosphere at that time. This project will quantify the PETM carbon dioxide addition and document the response of the Earth’s carbon cycle to that addition. The study will explore how the Earth system responds to climatic perturbations, including the rates and mechanisms of that response. Events in the geologic record show the climatic, hydrological, and geochemical evolution of the Earth in response to rapid warming. Thus, this study will provide a valuable comparison with modern climate change and future climate. The project broader impacts include support for a graduate student and undergraduate researchers. The project will also create YouTube video content for use in undergraduate courses.This study will utilize Ca isotopes as recorders of the temporal evolution of bottom water calcite saturation state over the recovery interval of the PETM, an interval that has received less attention in comparison to the onset and ocean acidification phases. Understanding the dynamics of the recovery interval is critical because this is the time during which the silicate weathering response to climatic warming is expressed, primarily as an alkalinity 'overshoot'. This interval is a favorable focus for study because it is more likely than the interval of intense carbonate dissolution to be recorded, and preserved, in marine sediments. Complementary numerical modeling approaches – reactive transport (RTM) and intermediate complexity Earth System (cGENIE) modeling – and existing reconstructions of oceanic dissolved inorganic carbon (DIC) will be used to elucidate (i) the amount of C input to the ocean-atmosphere system, and (ii) the silicate weathering response. A significant advantage of this approach is that the interpretive framework is not impacted by the rate of carbon injection (i.e., for the most likely injection time scales 10 ka), removing a significant uncertainty in reconstructing the mass of carbon injection. The rate at which the Earth System recovers from hyperthermals depends critically on the rate at which the silicate weathering feedback operates and the strength of the feedback. Despite the significance of this knowledge, there are few constraints available to minimize uncertainties.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

古新世 - 新世热最大（PETM）是5500万年前发生的强烈变暖事件。当时，PETM是由大量二氧化碳加入海洋和大气的驱动。该项目将量化PETM二氧化碳的添加，并记录地球碳循环对该添加的响应。该研究将探讨地球系统如何对气候扰动的反应，包括该反应的速率和机制。地质记录中的事件显示了响应快速变暖的地球的气候，水文和地球化学演变。这是这项研究将与现代气候变化和未来气候提供宝贵的比较。该项目更广泛的影响包括对研究生和本科研究人员的支持。该项目还将创建YouTube视频内容，以用于本科课程。这项研究将利用CA同位素作为PETM恢复间隔的底部水钙饱和状态暂时演变的记录，与发作和海洋酸化阶段相比，该间隔较少。理解恢复间隔的动力学至关重要，因为这是硅酮对杂交变暖的反应的时间，主要是碱度“过冲”。此间隔是研究的一个有利的重点，因为它比在海洋沉积物中记录并保留的强烈碳酸盐溶解的间隔更有可能。互补的数值建模方法 - 反应性传输（RTM）和中间复杂性地球系统（CGENIE）建模 - 以及海洋溶解的无机碳（DIC）的现有重建将阐明（i）（i）对海洋 - 大气系统的COUPT量，以及（II）（II）（II）硅胶响应。这种方法的一个重要优点是，解释性框架不受碳注入速度的影响（即，对于最可能的注射时间尺度10 ka），消除了重建碳注入质量的显着不确定性。地球系统从高温群体中恢复的速率严重取决于有机硅风化反馈的速度和反馈的强度。尽管这些知识具有重要意义，但很少有限制因素可最大程度地减少不确定性。该奖项反映了NSF的法定任务，并且使用基金会的知识分子优点和更广泛的影响审查标准，通过评估来诚实地获得支持。