Collaborative Research: How did Terrestrial Ecosystems Rebuild Following the Cretaceous/Paleogene Mass Extinction?

合作研究：白垩纪/古近纪大规模灭绝后陆地生态系统如何重建？

• 批准号: 2317668
• 负责人: Theodore Them
• 金额: $ 28.73万
• 依托单位: College of Charleston
• 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: 2023-09-01 至 2028-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2317668&HistoricalAwards=false
• 关键词: Collaborative; Research; How; did; Terrestrial

During the Cretaceous/Paleogene (K/Pg) mass extinction (ca. 66 million years ago), ~75% of all species on Earth went extinct, notably including all non-avian dinosaurs. This event completely changed the trajectory of the evolutionary tree of life, leading ultimately to the formation of today’s mammal-dominated communities. The aftermath of the K/Pg mass extinction represents a natural laboratory in which ecosystem reorganization can be studied with high geologic resolution. Some studies have been undertaken to examine how marine ecosystems were rebuilt, but the response of terrestrial environments is poorly documented. This project will examine ecological and environmental changes that occurred on land across the K/Pg boundary in the Rocky Mountain region of the western United States. The research will involve extensive paleontological and geochemical analyses of existing fossil collections and introduce novel data that will reveal the variability in the timing and pattern of terrestrial ecosystem rebuilding after the mass extinction. This project will expand knowledge of a major turning point in the history of life on Earth that will help determine how the biodiversity of ecosystems recover at the continental scale and how modern terrestrial biota evolved. The results may also provide data for conservation biologists to predict the long-term consequences of current rapid changes in biodiversity and help inform conservation priorities to alleviate ecosystem disruptions. The project will use established programs in classrooms, museum exhibits, and outreach at the participating institutions to reach audiences of multiple ages and backgrounds.The K/Pg mass extinction completely changed the trajectory of the evolutionary tree of life and most research has focused on marine systems. Post-extinction patterns of ecosystem restructuring on land, fundamental to understanding the evolution of the modern taxa of mammals and plants, have received little attention because fossil collections, data, and high-resolution chronostratigraphic sections are relatively rare. This project will build on extensive fossil collections from three primary study areas in the Western Interior of North America, involve new fieldwork designed to augment collections and data from critical intervals, and develop diverse inorganic and organic geochemical records to characterize and identify biotic patterns, local environments, and factors involved in terrestrial ecosystem restructuring following the K/Pg extinction. To accomplish these goals, the research team will: collect and interpret megafloral, palynological, invertebrate, and vertebrate fossils and associated contextual data from three well-studied stratigraphic sections; use fossil leaf physiognomic traits and geochemical data from organic compounds to construct records of temperature, precipitation, and fire frequency; integrate ecological proxies of community structure and environmental conditions over time and space as they relate to the three study areas, to determine if there are any climatic conditions, geographic locations, or trophic interactions that enhance or impede ecosystem restructuring after the K/Pg extinction. In addition, geochemical proxies for volcanic activity will be examined to resolve the influence of the extensive basalt eruptions of the Deccan Traps on the biota within the study areas.This project is jointly funded by Frontier Research in Earth Sciences (FRES) and the Established Program to Stimulate Competitive Research (EPSCoR).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.

在白垩纪/古近纪（K/Pg）大灭绝期间（约。6600万年前），地球上约75%的物种灭绝，特别是包括所有非鸟类恐龙。这一事件彻底改变了生命进化树的轨迹，最终导致了今天哺乳动物占主导地位的社区的形成。K/Pg大灭绝的后果代表了一个天然的实验室，可以在其中以高地质分辨率研究生态系统重组。已经进行了一些研究，以审查海洋生态系统是如何重建的，但陆地环境的反应却记录甚少。 该项目将研究美国西部落基山脉地区跨越K/Pg边界的土地上发生的生态和环境变化。这项研究将涉及对现有化石收藏进行广泛的古生物学和地球化学分析，并引入新的数据，揭示大规模灭绝后陆地生态系统重建的时间和模式的变化。该项目将扩大对地球生命史上一个重大转折点的了解，这将有助于确定生态系统的生物多样性如何在大陆范围内恢复，以及现代陆地生物区系如何演变。研究结果还可以为保护生物学家提供数据，以预测目前生物多样性快速变化的长期后果，并帮助告知保护优先事项，以减轻生态系统的破坏。该项目将在课堂、博物馆展览和参与机构的外展活动中使用既定的计划，以接触多个年龄和背景的观众。K/Pg大灭绝完全改变了生命进化树的轨迹，大多数研究都集中在海洋系统上。灭绝后陆地生态系统重建模式是理解现代哺乳动物和植物类群进化的基础，但由于化石收集、数据和高分辨率年代地层剖面相对罕见，因此很少受到关注。该项目将建立在北美西部内陆三个主要研究领域的大量化石收集的基础上，涉及旨在增加关键间隔的收集和数据的新的实地工作，并开发多种无机和有机地球化学记录，以表征和识别生物模式，当地环境和K/Pg灭绝后陆地生态系统重建所涉及的因素。为了实现这些目标，研究小组将：从三个研究充分的地层剖面中收集和解释巨型植物、孢粉学、无脊椎动物和脊椎动物化石以及相关的背景数据;使用化石叶的外貌特征和有机化合物的地球化学数据来构建温度、降水和火灾频率的记录;综合与三个研究区有关的群落结构和环境条件的生态指标，以确定是否有任何气候条件，地理位置，或营养相互作用，增强或阻碍生态系统重建后，K/Pg灭绝。此外，本发明还提供了一种方法，该项目由地球科学前沿研究（FRES）和促进竞争性研究既定计划（EPSCoR）联合资助，将研究火山活动的地球化学代用指标，以解决德干圈闭大规模玄武岩喷发对研究区域内生物群的影响该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。