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.

六千六百万年前，在白垩纪-古近纪边界 (KPB)，尤卡坦半岛发生小行星撞击，导致地球上约 75% 的物种灭绝，这是历史上最近、有据可查的快速大规模灭绝。地球历史、KPB 灭绝的研究对于了解气候变化对生物多样性的影响是理想的选择，但是，KPB 灭绝的原因仍然不确定，该项目将结合新颖的气候模型模拟和地质记录。探索与小行星撞击相关的气候变化和杀伤机制，测量整个 KPB 的各种地质​​记录将限制小行星撞击造成的排放类型和强度，然后将这些排放估算用于气候模型模拟，以确定地球系统。项目结果将提供对 KPB 灭绝的机制理解，从而改善对这一时期许多记录的解释，提供对生态系统崩溃和恢复的见解，并导致有价值的气候模型开发。 . 外展活动包括创建 KPB 展览、开发地球化学高中项目、招募三名代表性不足的本科生实习生，以及让学生研究人员参与德克萨斯大学里奥格兰德河谷分校（一所西班牙裔占多数的大学）以确定各种过程的相对重要性。这可能导致 KPB 灭绝和随后的环境恢复，PI 将使用地球系统模型进行 KPB 模拟，模拟小行星撞击产生的强迫，该模型包含明确的气溶胶解析方案和高层大气，此外，海洋生物地球化学模块的开发和实施将能够与整个 KPB 的古生物学、化学和同位素记录进行直接比较。用于限制和验证 KPB 模拟的生物标记记录将对烟灰和多环芳烃进行分析，以测试小行星撞击火灾假设并为模拟提供精确的烟灰排放数据。影响后温度变化的估计将由磷酸盐微化石和生物标记物产生，这些记录将提供亚千禧年到千禧年尺度的温度限制，并与模拟和烟尘估计相结合，最终消除与影响相关的二氧化碳排放。 ，高分辨率生物标志物工作将揭示海洋浮游生物的恢复率，并将其与海洋生物地球化学模拟进行比较。该奖项反映了 NSF 的法定使命，并通过使用评估被认为值得支持基金会的智力价值和更广泛的影响审查标准。