OCE-PRF: Windows into Cretaceous diatom paleobiology: Seasonal responses in laminated sediments and survivability and response to the Cretaceous-Paleogene extinction event

OCE-PRF：白垩纪硅藻古生物学的窗口：层状沉积物的季节性响应以及生存能力和对白垩纪-古近纪灭绝事件的响应

• 批准号: 2205996
• 负责人: Jason Coenen
• 金额: $ 32.97万
• 依托单位: University of Nebraska-Lincoln
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2205996&HistoricalAwards=false
• 关键词: OCE; PRF; Windows; into; Cretaceous

Diatoms are photosynthetic algae that are an essential part of the biosphere and Earth’s climate system. While Cenozoic records indicate their impact on primary biological and chemical cycles, there is a lack of descriptive and applied research on Cretaceous diatoms. This lack of descriptive work limits their application for understanding ancient global ecosystems such as the Cretaceous greenhouse climates. Therefore, developing a better understanding of how diatoms responded to significant environmental perturbations during the end-Cretaceous mass extinction event and their response to seasonal changes in the early Cretaceous; is critical for understanding how Earth’s climate system has evolved through geologic time and helps constrain future climate variability. The unifying research theme is to better understand the controls on diatom responses to paleoenvironmental changes and improve their utility as tools for Cretaceous geological studies. PI Coenen will study modern and ancient laminated sediments to better understand Ocean Drilling Project Site 693 paleoenvironments and diatom taxonomy. This work will provide a critical understanding of early Cretaceous climate variability on a seasonal timescale, which will aid in the understanding of Earth’s climate system in a greenhouse world. Additionally, PI Coenen will study diatoms and silicoflagellates both before and after the Cretaceous-Paleogene (K/Pg) mass extinction to see how siliceous microfossils respond to environmental perturbations and understand what factors led to survivability in diatoms through this mass extinction event. As an NSF Postdoctoral Researcher, PI Coenen will mentor undergraduate student projects and learn how to mentor graduate level projects and run a research lab with Dr. Harwood. Additionally, PI Coenen will develop modules for an online Antarctic Geosciences course and a Paleogene and Cretaceous siliceous microfossil biostratigraphy workshop. PI Coenen will also host outreach activities at local libraries and k-12 schools and work closely with UNL to foster efforts to broaden participation in the geosciences.The proposed research seeks to develop new information on diatom paleobiology and paleoecology from two locations in the Southern Hemisphere, ranging in time from the early Cretaceous through the K/Pg mass extinction event. PI Coenen will evaluate whether modern ecological approaches can be applied to ancient paleontological records. The central hypothesis is that Cretaceous diatoms shared many life strategies with modern diatoms, allowing for the application of ‘biological uniformitarianism’ to interpret fossil diatom records. This research will be conducted at the University of Nebraska-Lincoln, where Dr. Harwood will mentor PI Coenen on Cretaceous diatom systematics, biostratigraphy, and paleoecology. Drs. Harwood and Coenen will collaborate with Dr. Leventer to provide Coenen training on modern diatom-bearing laminated sediments from the East Antarctic margin to build his skill set to interpret early Cretaceous diatom seasonal changes from ODP Site 693 laminations. This work will provide a rare opportunity to study high-resolution ocean-atmospheric forcing during early Cretaceous greenhouse climates. Additionally, siliceous microfossils from Seymour and Vega islands, Antarctic Peninsula, will be documented across a precursor extinction recognized in the macrofauna ~150 kyr prior to the K/Pg mass extinction event, as well as document the post-event recovery. The response of both silicoflagellates and diatoms to extreme environmental perturbations will be studied in detail to document silicoflagellate retrograde evolution and better understand how diatoms survived the K/Pg extinction that decimated other fossil phytoplankton. Study of diatom assemblages, with a focus on abundance and volume changes of diatom resting spores across a potential precursor extinction related to the Deccan Traps will provide data to resolve these questions. Additionally, this research on the newly forming Southern Ocean has important implications for understanding late Cretaceous paleoclimate and paleoceanography. Both proposed studies have the potential to constrain modeling efforts and provide a better sense of paleoenvironments in these respective intervals.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.

硅藻是光合藻类，是生物圈和地球气候系统的重要组成部分。虽然新生代记录表明它们对原发性生物学和化学周期的影响，但缺乏对白垩纪硅藻的描述性和应用研究。缺乏描述性工作限制了他们了解古老的全球生态系统（例如白垩纪温室气候）的应用。因此，对最终白垩纪质量扩展事件期间硅藻的反应如何及其对早期白垩纪早期季节性变化的反应，对硅藻如何应对硅藻的反应有更好的理解；对于了解地球气候系统如何通过地质时间演变而有助于限制未来的气候变异性至关重要。统一的研究主题是更好地了解对硅藻环境变化的硅藻反应的控制，并改善其作为白垩纪地质研究工具的效用。 Pi Coenen将研究现代和古老的层压沉积物，以更好地了解海洋钻井项目现场693古环境和硅藻分类学。这项工作将对季节性时间范围的早期白垩纪气候变异性提供批判性的理解，这将有助于理解温室世界中的地球气候系统。此外，Pi Coenen将研究硅藻和白垩纪 - 甲基果仁（K/PG）质量灭绝之前和之后的硅藻，以查看二氧化硅微化石如何响应环境扰动，并了解哪些因素导致了这一质量扩展事件导致硅藻的存活。作为NSF博士后研究员，Pi Coenen将精神本科生项目项目，学习如何进行心理研究生级项目并与Harwood博士一起经营研究实验室。此外，Pi Coenen将开发用于在线南极地球科学课程的模块，以及古生元和白垩纪二氧化硅微化石生物学研讨会。 Pi Coenen还将在当地图书馆和K-12学校举办外展活动，并与促进地球科学参与的努力紧密合作。拟议的研究旨在从南半球的两个地方开发有关硅藻生态学和古生物学的新信息，并从南半球的两个地方及时从早期的杂货店进行K/PG Massemens speartimens speartimens speartimens。 Pi Coenen将评估现代生态方法是否可以应用于古代古生物学记录。中心假设是白垩纪硅藻与现代硅藻共享了许多生命策略，从而使“生物统一主义”的应用来解释化石硅藻的记录。这项研究将在内布拉斯加州林肯大学进行，Harwood博士将在那里指导Pi Coenen关于白垩纪硅藻系统，生物学学和古生态学。博士。 Harwood和Coenen将与Leventer博士合作，提供有关现代硅藻层压沉积物的Coenen培训，该沉积物从东方东部的边缘开始，以建立他的技能，以解释ODP 693层压的早期白垩纪硅藻季节性变化。这项工作将为难得的机会学习在白垩纪早期温室气候期间研究高分辨率海洋大气强迫。此外，将在巨福纳（Macrofauna）在k/pg质量扩展事件之前识别的前体延伸中记录了来自西摩和维加岛的硅质化石，南极半岛，并记录了事后恢复。将详细研究硅藻液和硅藻对极端环境扰动的反应，以记录硅垂直逆行的进化，并更好地了解硅藻在决定其他化石浮游植物的K/PG扩展中如何幸存。研究硅藻组合，重点是抽象和体积变化与Deccan陷阱相关的潜在前体延伸的硅藻静脉孢子的变化，将提供数据以解决这些问题。此外，这项对新成立的南大洋的研究对了解晚白垩纪古气候和古群学具有重要意义。两项拟议的研究都有可能在这些相对间隔中限制建模工作，并提供更好的古环境感。该奖项反映了NSF的法定任务，并使用基金会的知识分子和更广泛的影响审查标准，通过评估来诚实地支持支持。