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: 2020380
• 负责人: Siddhartha Mitra
• 金额: $ 31.22万
• 依托单位: East Carolina University
• 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=2020380&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.

6600万年前，在尤卡坦半岛的古近纪边界（KPB），一颗小行星撞击地球，导致地球上大约75%的物种消失。作为地球历史上最新的、有据可查的、快速的大规模灭绝事件，KPB灭绝的研究对于了解气候变化对生物多样性的影响是非常理想的。然而，KPB被解雇的原因仍然不确定。该项目将使用新的气候模型模拟和地质记录相结合，以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排放的类型和幅度。这些排放量估计数随后将用于气候模型模拟，以确定地球系统对小行星撞击的长期反应。项目结果将提供对KPB灭绝的机械理解，这反过来将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。外联活动包括创建一个KPB展览，开发一个地球化学高中项目，招聘三名代表性不足的本科生实习生，并在得克萨斯州格兰德河谷大学（一所西班牙裔占多数的大学）聘请学生研究人员。为了确定可能导致KPB灭绝和随后的环境恢复的各种过程的相对重要性，PI将使用地球系统模型进行KPB模拟，模拟小行星撞击的作用力。该模型包含一个明确的气溶胶解决方案和高层大气，都是必不可少的捕捉与这些扰动相关的过程。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，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尘、温度和生物标志物记录，以约束和验证KPB模拟。将对样本进行烟灰和多环芳烃分析，以检验小行星撞击火灾假设，并为模拟提供精确的烟灰排放数据。对撞击后温度变化的新估计将从磷酸盐微体化石和生物标志物中产生。这些记录将提供对温度的千年尺度限制，并与模拟和烟尘估计相结合，这是一种取消与影响相关的二氧化碳排放的手段。最后，高分辨率生物标志物的工作将揭示出海洋生物复苏的速度，这将与海洋地球化学模拟进行比较。这一奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。