Nitrogen cycle changes across the Cretacous-Paleogene mass extinction event

白垩纪-古近纪大规模灭绝事件中氮循环的变化

• 批准号: 0961914
• 负责人: Tracy Quan
• 金额: $ 34.39万
• 依托单位: Oklahoma State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-01 至 2014-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0961914&HistoricalAwards=false
• 关键词: Nitrogen; cycle; changes; across; Cretacous

The mass extinction event at the Cretaceous-Paleogene (K-Pg) boundary was one of the largest such events during the Phanerozoic and was following by a period of drastic changes in ecological and biogeochemical conditions. This research is the first to investigate changes in the nitrogen cycle across the extinction event. The PI applies a previously established a relationship between nitrogen isotopes and the oxidation state of the environment based on the predominant nitrogen reactions and their associated isotopic fractionation. They will measure the bulk, kerogen, and porphyrin d15N values across the K-Pg boundary for several cores to determine nitrogen cycling and paleoredox reactions before, during, and after the mass extinction event. The PI will test the hypothesis that the oxygen concentration in the deep waters decreased following the impact event, and that cores located in different ocean basins will record different d15N profiles as dictated by the deep water redox state at each location. The results will provide important information about the processes of global mass extinction and the subsequent recovery of biogeochemical systems. Funding supports a new female PI and a graduate student. Further broader impacts include collaboration with the COSEE-NOW (Center for Ocean Sciences Education Excellence Networked Ocean World) to develop educational products aimed at improving ocean literacy. Funding support is provided by the Marine Geology and Geophysics Program of NSF's Ocean Science Division and by the Experimental Program to Stimulate Competitive Research (EPSCoR).

白垩纪-古近纪（K-Pg）边界的大规模灭绝事件是显生宙期间最大的此类事件之一，随后是生态和生物地球化学条件发生剧烈变化的时期。这项研究是第一次调查整个灭绝事件中氮循环的变化。 PI应用先前建立的氮同位素与环境氧化态之间的关系，该关系基于主要的氮反应及其相关的同位素分馏。他们将测量几个岩心K-Pg边界上的体积、干酪根和卟啉d15 N值，以确定大灭绝事件之前、期间和之后的氮循环和古氧化还原反应。PI将检验以下假设，即撞击事件后深水沃茨中的氧浓度降低，以及位于不同海洋盆地的岩心将记录不同的d15 N剖面，这取决于每个地点的深水氧化还原状态。研究结果将为全球物种大灭绝过程和随后的地球化学系统恢复提供重要信息。资金支持一名新的女PI和一名研究生。更广泛的影响包括与COSEE-NOW（海洋科学教育卓越中心网络海洋世界）合作，开发旨在提高海洋素养的教育产品。资助由国家科学基金会海洋科学部海洋地质学和地球物理学方案以及刺激竞争性研究实验方案提供。