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-始新世最热事件 (PETM) 是一次强烈的变暖事件，发生于 5500 万年前，是由当时海洋和大气中二氧化碳大量增加造成的。该项目将量化 PETM 二氧化碳。该研究将探讨地球系统如何响应气候扰动，包括地质记录中显示的响应速率和机制。因此，这项研究将为现代气候变化和未来气候提供有价值的比较，包括支持研究生和本科生研究人员创建 YouTube。用于本科课程的视频内容。本研究将利用 Ca 同位素作为 PETM 恢复区间内底水方解石饱和状态随时间演化的记录器，与开始阶段和海洋酸化阶段相比，这一区间受到的关注较少。恢复区间的动态至关重要，因为这是硅酸盐风化对气候变暖的反应表现出来的时间，主要表现为碱度“超调”。该区间是研究的有利焦点，因为它比强烈的区间更有可能。在海洋沉积物中记录和保存碳酸盐溶解的补充数值模拟方法——反应输运（RTM）和中等复杂性地球系统（cGENIE）建模——以及海洋溶解无机碳的现有重建。 （DIC）将用于阐明（i）输入到海洋-大气系统的碳量，以及（ii）硅酸盐风化响应。这种方法的一个显着优点是解释框架不受碳酸盐速率的影响。碳注入（即最有可能的注入时间尺度为 10 ka），消除了重建碳注入质量的显着不确定性。地球系统从高温中恢复的速度主要取决于碳注入的速度。尽管这些知识很重要，但几乎没有任何限制可以最大限度地减少不确定性。该奖项是 NSF 的法定使命，并且通过使用基金会的智力价值和更广泛的影响进行评估，被认为值得支持。审查标准。