CAREER: Nitrogen Biogeochemistry during Oceanic Anoxic Events

职业生涯：海洋缺氧事件期间的氮生物地球化学雪城大学克里斯托弗·朱尼姆，地球和生命如何随着时间的推移相互作用对我们理解地球系统是至关重要的，特别是在大规模灭绝和气候快速变化间隔等重大转变期间。海洋缺氧事件是由温室气体浓度迅速增加引起的对地球气候和生态平衡的异常扰动。地球系统对快速变暖的反应是将增加的二氧化碳隔离为沉积在缺氧海洋环境中的富含有机碳的页岩。温室气体导致的手生产力变暖之间的关键联系是营养物质，特别是氮、磷和生物限制痕量金属在海洋环境中如何循环和重新分配。事实上，我们所知道的关于海洋生态环境中N和P循环的反应清楚地表明，与地球历史上的大部分时间相比，海洋生态环境中的营养循环是截然不同的。在接下来的几个世纪里，由于气候变暖和农业养分径流增加，海洋缺氧的程度可能会扩大。通过研究过去的时间间隔，最好地限制海洋缺氧的未来轨迹，例如OAEs，在那里，变暖和缺氧的扩大联系在一起，海洋中的生命受到直接影响。这项研究将通过开发和应用氮和碳同位素技术来应对这一研究挑战，重点是以白垩纪、塞诺马尼亚-图罗尼亚OAE 2和锡拉丘兹地区缺氧湖为主要研究区域。该项目的教育部分将让来自传统上代表性不足的群体的本科生在STEM教育的早期阶段进行实地研究。实践研究的机会超过了在地球科学课堂上所能完成的，并增加了学生继续从事STEM领域的可能性。这一职业项目将致力于解决关于海洋生产力和海洋缺氧事件如何联系的悬而未决的问题。这项研究的主要问题是：为什么在显生界海洋环境事件期间，氮同位素值异常低？海洋食物网和生态如何对快速变暖和水体缺氧的扩张做出反应？缺氧/缺氧过渡(化跃层)的深度如何影响海洋群落的生态？这项工作将通过分析海洋大型无脊椎动物贝壳中微量有机成分的稳定碳、氮同位素组成，有孔虫和有机微体化石的测试来实现。实地研究和教育将集中在非凡的、美丽的费耶特维尔绿湖，距离锡拉丘兹大学校园只有几英里远。通过与州北部路易斯·斯托克斯少数民族参与联盟和奥农达加社区学院的合作，我们将在整个项目期间接待暑期研究实习生，并将为奥农达加社区学院的STEM学生开设一个专注于费耶特维尔绿湖地球化学的短期课程。

CAREER: Nitrogen Biogeochemistry During Oceanic Anoxic Events Christopher Junium, Syracuse University How the Earth and life have interacted through time is central to our understanding of the Earth system, particularly during significant transitions such as mass extinctions and intervals of rapid climate change. Oceanic Anoxic Events (OAEs) were extraordinary disturbances in Earth's climatic and ecological balance, initiated by rapid increases in the concentrations of greenhouse gases. The Earth system responded to rapid warming by sequestering added carbon dioxide as organic carbon rich shales deposited in anoxic marine environments. The key link between greenhouse gas induced warming hand productivity is in how nutrients, particularly nitrogen, phosphorus and biolimiting trace metals, are cycled and redistributed in marine environments. Indeed, what we know about how the N and P cycles respond during OAEs makes it clear that nutrient cycling was drastically different during OAEs than for much of Earth's history. Over the course of the coming centuries the extent of marine anoxia is likely to expand as a direct result of warming and increased agricultural nutrient runoff. The future trajectory of marine anoxia is best constrained by examining intervals of the past, such as OAEs, where warming and the expansion of anoxia are linked and life in the ocean was directly impacted. This study will address this research challenge through development and application of nitrogen and carbon isotope techniques focused on the Cretaceous, Cenomanian-Turonian OAE 2 and Syracuse-region anoxic lakes as principal study areas. The educational component of this project will involve undergraduate students from traditionally underrepresented groups in field research during the early stages of their STEM education. Opportunities for hands-on research transcend what can be accomplished in the Earth science classroom, and increases the likelihood that students will continue in STEM fields. This CAREER project will aim to resolve outstanding issues that remain regarding how marine productivity and Oceanic Anoxic Events are linked. The primary questions addressed in this study are: Why are nitrogen isotope values anomalously low during Phanoerozoic OAEs' How do marine food webs and ecology respond to rapid warming and expansion of water-column anoxia? How does the depth of the oxic/anoxic transition (the chemocline) affect the ecology of marine communities? This work will be achieved by analyzing stable carbon and nitrogen isotopic composition of trace organic constituents in the shells of marine macroinvertebrates, the tests of foraminifera and organic microfossils. Field research and education will be focused on the extraordinary, meromictic Fayetteville Green Lake, just a few miles from the Syracuse University campus. Through collaboration with the Upstate Louis Stokes Alliance for Minority Participation and Onondaga Community College we will host summer research interns through the duration of the project and will run a short course that focuses on the geochemistry of Fayetteville Green Lake for STEM students from Onondaga Community College.