Collaborative Research: RUI: "CSI Devonian" - testing Late Devonian ocean anoxia proxies across different paleoenvironments

合作研究：RUI：“CSI Devonian” - 测试不同古环境中的晚泥盆世海洋缺氧代理

• 批准号: 2044222
• 负责人: Sarah Carmichael
• 金额: $ 46万
• 依托单位: Appalachian State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-11-01 至 2024-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2044222&HistoricalAwards=false
• 关键词: Collaborative; Research; RUI; CSI; Devonian

How do scientists determine the cause of a mass extinction? Long before the dinosaurs, marine animals that lived during the Late Devonian time period (383-359 million years ago) were affected by a series of catastrophic events, including some of the most severe and widespread die-offs in Earth’s history. Unlike all of the other major mass extinctions in Earth's history, the reasons for this series of biological crises still remain unclear. Most scientists think that these extinction events were due to loss of oxygen from the oceans, but the severity of oxygen loss can be hard to decipher in the rock record. The tools we typically use to recognize oxygen loss in marine environments (trace fossils, microfossils, sediment type, and chemical signatures) were developed for rock types where oxygen loss is both easy to preserve and to recognize. But do these tools also work in places where oxygen loss is not as easy to preserve or recognize in the rock record? This project seeks to determine if the most commonly used methods for determining ancient ocean oxygen levels work across all marine environments, or only a subset of them. Through this process, the investigators will develop a comprehensive set of best practices for assessing oxygen loss in marine sediments (regardless of geologic setting), which in turn will help fine-tune the causes of the Late Devonian extinction pulses. This project will involve faculty and undergraduate researchers across three undergraduate institutions and will create online learning modules (primarily videos with accompanying data sets and teacher training materials) aligned with Next Generation Science Standards for both in-person and remote learning for grades 6-12. This online dissemination model (called “CSI: Devonian”) not only expands the geographic reach of this project, but can be used in flipped classroom teaching environments, homeschooling, and periods of remote learning. Late Devonian extinction events at the 372 Ma Frasnian-Famennian (F-F) boundary and 359 Ma Devonian-Carboniferous (D-C) boundary are some of the most severe mass extinctions in Earth's history. Despite 150 studies of ocean anoxia across the Kellwasser Events and Hangenberg Black Shale Event using a variety of geochemical and trace fossil proxies, Late Devonian ocean anoxia is still a mystery and considerable sample bias, both in terms of paleogeography and paleoenvironment, hinders this work. We seek funding to form an internally consistent dataset for rocks that span disparate paleoenvironments and paleogeographic locations, in order to both calibrate and validate the utility of the most commonly used ocean anoxia proxies. We propose to develop a comprehensive set of best practices for evaluating oxygen loss in ancient marine environments using the same anoxia proxy methodology (total organic carbon, organic walled microfossils, δ34SPY, δ34SCAS, δ13Ccarb, δ13Corg, trace element geochemistry, pyrite framboid distributions, and ichnofabrics) across a variety of sites and existing sample sets so that proxy utility can be assessed in different paleoenvironments and sedimentary regimes. The sample range will include baseline pre-anoxic conditions, anoxic conditions, and post-anoxic/extinction rebound conditions. In addition to determining the best practices for proxy application (regardless of time period, anoxic event, or depositional environment), our resulting dataset will help inform reconstructions of Late Devonian ocean currents, climate, tectonics, ecosystems, and extinctions. The proposed research is a cooperative effort by three universities involving multiple international and domestic collaborators and focuses heavily on undergraduate training and mentorship. The proposal also seeks to develop an interactive “CSI: Devonian” online learning module geared towards students in grades 6-12 that is aligned with the Next Generation Science Standards (NGSS), which focuses on how scientists a) collaborate on research in real life and b) use empirical evidence to derive scientific explanations of different phenomena.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.

科学家如何确定大规模灭绝的原因？早在恐龙出现之前，生活在泥盆纪晚期（383-3.59 亿年前）的海洋动物就受到了一系列灾难性事件的影响，其中包括一些最严重和最严重的事件。与地球历史上所有其他重大物种灭绝不同，这一系列生物危机的原因仍不清楚，大多数科学家认为这些灭绝事件是由于海洋氧气流失造成的。我们通常用来识别海洋环境中氧流失的工具（痕迹化石、微化石、沉积物类型和化学特征）是针对氧流失的岩石类型而开发的。但这些工具是否也适用于岩石记录中氧气流失不易保存或识别的地方？该项目旨在确定确定古代海洋氧气水平的最常用方法是否适用。所有海洋环境，或仅一部分通过这个过程，研究人员将开发一套全面的最佳实践来评估海洋沉积物中的氧气损失（无论地质环境如何），这反过来将有助于微调晚泥盆世灭绝脉冲的原因。涉及三个本科院校的教师和本科生研究人员，并将创建符合下一代科学标准的在线学习模块（主要是附带数据集的视频和教师培训材料），适用于 6-12 年级的面对面和远程学习。模型（称为“CSI：泥盆纪”）不仅扩大了该项目的地理范围，而且可用于翻转教学课堂环境、家庭教育以及 372 Ma Frasnian-Famenian (F-F) 边界的晚泥盆世灭绝事件时期。 359 Ma 泥盆纪-石炭纪 (D-C) 边界是地球历史上最严重的大规模灭绝之一，尽管有 150 项关于整个海洋缺氧的研究。 Kellwasser事件和Hangenberg黑色页岩事件使用各种地球化学和痕迹化石代理，晚泥盆世海洋缺氧仍然是一个谜，并且在古地理和古环境方面都存在相当大的样本偏差，阻碍了这项工作我们寻求资金以形成内部一致。跨越不同古环境和古地理位置的岩石数据集，以便校准和验证最常用的海洋缺氧代理的实用性。使用相同的缺氧代理方法（总有机碳、有机壁微化石、δ34SPY、δ34SCAS、δ13Ccarb、δ13Corg、微量元素地球化学、黄铁矿framboid分布和ichnofabrics）评估古代海洋环境中氧气损失的一套全面的最佳实践各种地点和现有样本集，以便可以在不同的古环境和沉积体系中评估代理效用。除了确定代理应用的最佳实践（无论时间段、缺氧事件或沉积环境）之外，样本范围还包括基线缺氧前条件、缺氧条件和缺氧/灭绝后反弹条件。将有助于重建晚泥盆世洋流、气候、构造、生态系统和灭绝。拟议的研究是三所大学与多个国际和国内合作者的合作成果，重点关注本科生培训和指导。该提案还寻求开发一个面向 6-12 年级学生的交互式“CSI：泥盆纪”在线学习模块，该模块符合下一代科学标准 (NGSS)，重点关注科学家如何 a) 在现实生活中进行研究合作b) 使用经验证据对不同现象得出科学解释。该奖项反映了 NSF 的法定使命，并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，被认为值得支持。