Collaborative Research: Evaluating Climate Change and Kill Mechanisms Associated with the End-Cretaceous Mass Extinction: A Model-Data Comparison Approach

合作研究：评估与白垩纪末大规模灭绝相关的气候变化和杀灭机制：模型数据比较方法

• 批准号: 2021262
• 负责人: Kenneth MacLeod
• 金额: $ 37.52万
• 依托单位: University of Missouri-Columbia
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-15 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2021262&HistoricalAwards=false
• 关键词: Collaborative; Research; Evaluating; Climate; Change

Sixty-six million years ago at the Cretaceous-Paleogene boundary (KPB), an asteroid impact in the Yucatán Peninsula resulted in the loss of about 75% of all species on Earth. As the most recent, well documented, and rapid mass extinction in Earth’s history, study of the KPB extinction is ideal for understanding the effects of climate change on biodiversity. However, the causes of the KPB extinctions remain uncertain. This project will use a combination of novel climate model simulations and geologic records to explore climate change and kill mechanisms associated with the asteroid impact. Measuring various geologic records from across the KPB will constrain the types and magnitudes of emissions from the asteroid impact. These emission estimates will then be used in climate model simulations to determine the Earth system responses to the asteroid impact through time. Project results will provide a mechanistic understanding of KPB extinction, which, in turn, will improve interpretation of many records from this time period, deliver insights into ecosystem collapse and recovery, and lead to valuable climate model development. Outreach activities include creation of a KPB exhibit, develop of a geochemistry high school project, recruitment of three underrepresented undergraduate interns, and engagement of student researchers at the University of Texas Rio Grande Valley, a Hispanic majority university. To determine the relative importance of various processes that could have led to the KPB extinction and subsequent environmental recovery, the PIs will use an Earth system model to perform KPB simulations that mimic forcings from the asteroid impact. The model contains an explicit aerosol resolving scheme and high-top atmosphere, both essential for capturing the processes associated with these perturbations. Further, development and implementation of an ocean biogeochemistry module will allow for direct comparison with paleontological, chemical, and isotopic records across the KPB. The PIs will also collect high resolution soot, temperature, and biomarker records to constrain and validate the KPB simulations. Samples will be analyzed for soot and polycyclic aromatic hydrocarbons to test the asteroid impact fires hypothesis and provide refined soot emission data for the simulations. New estimates of temperature change after impact will be generated from phosphatic microfossils and biomarkers. These records will provide sub-millennial to millennial scale constraints on temperature, and in combination with simulations and soot estimates, a means to backout CO2 emission associated with the impact. Finally, high resolution biomarker work will shed light on the rate of marine planktonic recovery, which will be compared with the ocean biogeochemistry simulations.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.

六六百万年前，在白垩纪 - 巴雷元边界（KPB），尤卡坦半岛的小行星影响导致地球上所有物种的约75％丧失。作为地球历史上最新的，充分记录和快速的质量扩展，对KPB扩展的研究非常适合理解气候变化对生物多样性的影响。但是，KPB扩展的原因仍然不确定。该项目将使用新型的气候模型模拟和地质记录的组合来探索气候变化并杀死与小行星影响相关的机制。测量来自KPB的各种地质​​记录将限制小行星影响的排放类型和磁性。然后，这些排放估计值将用于气候模型模拟，以确定地球系统对小行星影响的响应。项目结果将提供对KPB扩展的机械理解，反过来，这将改善对这段时期内许多记录的解释，对生态系统崩溃和恢复的见解，并导致宝贵的攀登模型开发。外展活动包括创建KPB展览，开发地球化学高中项目，招募三个代表性不足的本科实习生，以及在得克萨斯州里奥格兰德分校的西班牙裔多数大学的学生研究人员的参与。为了确定可能导致KPB扩展和随后的环境回收的各种过程的相对重要性，PI将使用地球系统模型执行KPB模拟，以模仿小行星影响。该模型包含一个明确的气溶胶解决方案和高顶气氛，这既可以捕获与这些扰动相关的过程至关重要。此外，海洋生物地球化学模块的开发和实施将允许与整个KPB的古生物学，化学和同位素记录进行直接比较。 PI还将收集高分辨率的烟灰，温度和生物标志物记录，以限制和验证KPB模拟。将分析样品中的烟灰和多环芳族烃以测试小行星撞击射击假设，并为模拟提供精制的烟灰发射数据。撞击后温度变化的新估计值将由磷酸化石和生物标志物产生。这些记录将为温度的千禧一代限制提供千年的限制，并结合模拟和烟灰估计，这是支持与影响相关的二氧化碳排放的手段。最后，高分辨率的生物标志物工作将阐明海洋浮游恢复的速度，该恢复的速度将与海洋生物地球化学模拟进行比较。该奖项反映了NSF的法定任务，并被认为是通过基金会的知识分子优点和更广泛的影响标准通过评估来获得的支持。