Collaborative Research: Dynamics of carbon release and sequestration: Case studies of two early Eocene hyperthermals

合作研究：碳释放和封存的动力学：两次始新世早期高温的案例研究

• 批准号: 0628719
• 负责人: James Zachos
• 金额: $ 41.95万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-15 至 2011-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0628719&HistoricalAwards=false
• 关键词: Collaborative; Research; Dynamics; carbon; release

ABSTRACTIntellectual Merit: The ocean is the largest sink for anthropogenic CO2 and has absorbed nearly 130 PgC of the 380 PgC emitted to the atmosphere since the onset of the Industrial Revolution. If emissions continue to rise unabated for the next three centuries, an additional 4000 PgC or more will be input to the atmosphere and ocean. Published model simulations of the ocean/atmosphere response to the eventual complete utilization of fossil fuels indicate that atmospheric CO2 will rise to levels that Earth likely hasn't experienced for at least 40 million years, and the surface ocean may undergo acidification to the extent that corals and other calcifying organisms will be unable to precipitate their skeletons. Confidence in and refinement of these model simulations will benefit from application to, and comparison with, analogous events in Earth history. Approximately 55 million years ago (Mya), Earth experienced a similar episode of rapid and extreme transient warming, the Paleocene-Eocene Thermal Maximum (PETM), likely the product of massive carbon release. Intense study of the PETM over the last five years has led to a far clearer understanding of the consequences of this event on climate, biota, and biogeochemical cycles. One of the more prominent advances is the documentation of evidence for widespread ocean acidification and buffering, consistent with carbon cycle theory. A related advance was the discovery of second warming and ocean acidification event at ~53 Mya. This event, known as ELMO, was less extreme than the PETM in every sense, from the carbon cycle perturbation to the magnitude of warming. These global warming events, termed hyperthermals, provide a unique opportunity to gain insight into the long-term impacts of rapidly rising CO2 levels on modern climate, ocean carbonate chemistry, and biotas. They also provide an opportunity to identify potential non-linear feedbacks, and test climate and biogeochemical model sensitivity. To this end, an interdisciplinary group of scientists with expertise in carbon cycle dynamics, sediment geochemistry, paleoceanography and paleobiology has been assembled, and will embark on a 4-year project to address critical questions regarding two hyperthermals, and their implications for understanding of the carbon cycle including: 1) what were the mass, rate, and origin of carbon released during the hyperthermals? 2) what were the rates of sequestration and recovery and what biogeochemical feedbacks came into play? and 3) how did associated extreme changes in ocean carbonate chemistry affect planktonic calcifiers? The strategy will involve integration of the observational database with numerical models. The observational database will be used to constrain and test the carbon cycle models. This includes records of biogenic carbonate production, accumulation and preservation in 3-dimensions through the PETM and ELMO. This will also require substantial refinement of age models. With a highly resolved and multifaceted data set for input, three modeling approaches will be used, each involving specific opportunities and compromises in terms of the time scales and scope of processes that can be modeled. Earth system models (GENIE and CCSM) will provide boundary conditions for the process-oriented models. Process model simulations will be designed to investigate problems identified during data/model validation of the Earth system models and to develop hypotheses to be tested with model simulations.Broader Impacts: This highly interdisciplinary project will provide important insight into the short-term and long-term fate of anthropogenic CO2 on the global carbon cycle, climate, and biota. Such information is essential to providing scientific leaders and policy makers with a better sense of the consequences of unabated anthropogenic CO2 emissions for global climate, ocean carbon chemistry and marine food chains. Moreover, the project places significant emphasis on a number of closely integrated research and educational activities that will lead to the development and circulation of educational materials related to abrupt climate change and training in how to integrate them in curricula. In addition, we will take advantage of highly successful existing programs to provide opportunities for undergraduates from under-represented groups to participate in cutting-edge, relevant, carbon-cycle research.

AbstractIntellectual功绩：海洋是人为二氧化碳的最大水槽，自工业革命开始以来，已经吸收了近130 pgc到大气中的380 pgc。如果在接下来的三个世纪中，排放量继续不断增加，则将进一步向大气和海洋输入4000 pgc或更多的pgc。对海洋/大气对化石燃料最终完全利用的反应的公开模型仿真表明，大气中的二氧化碳将至少在至少4000万年中没有经历的水平上升，并且地表海可以在珊瑚和其他钙化生物体无法沉淀骨架的程度上进行酸化。这些模型模拟的信心和完善将受益于地球历史上类似事件的应用并比较。大约5500万年前（MYA），地球经历了类似的快速和极端瞬态变暖，古新世 - 纽热最大（PETM），这可能是大量碳释放的产物。在过去的五年中，对PETM的深入研究使人们对这一事件对气候，生物群和生物地球化学周期的后果有了更清晰的了解。最突出的进步之一是证明与碳循环理论一致的广泛海洋酸化和缓冲的证据。 相关的进展是在〜53 Mya发现了第二次变暖和海洋酸化事件。从碳循环扰动到变暖的大小，这一事件被称为Elmo，比PETM不那么极端。这些全球变暖事件称为高温，为洞察二氧化碳水平快速上升对现代气候，海洋碳酸盐化学和生物群的长期影响提供了独特的机会。他们还提供了一个机会来识别潜在的非线性反馈，并测试气候和生物地球化学模型敏感性。为此，已经组装了一个跨学科的科学家小组，这些科学家在碳循环动态，沉积物地球化学，古代学和古生物学方面进行了专业知识，并将开始一个为期4年的项目，以解决有关两个高温的关键问题，以及他们对碳周期的理解的含义，包括：1）包括：1）在质量，费率和碳中释放了什么？ 2）隔离和恢复的速度是多少，哪些生物地球化学反馈发挥了作用？ 3）海洋化学的极端变化如何影响浮游钙化剂？该策略将涉及将观测数据库与数值模型集成。观察数据库将用于约束和测试碳循环模型。这包括通过PETM和Elmo在三维中产生碳酸盐，积累和保存的记录。 这还需要对年龄模型进行大量完善。通过用于输入的高度解析和多方面的数据集，将使用三种建模方法，每种模型方法都涉及特定的机会和妥协的时间尺度和可以建模的过程范围。地球系统模型（Genie和CCSM）将为以过程为导向的模型提供边界条件。过程模型模拟将旨在调查在地球系统模型的数据/模型验证期间发现的问题，并开发用于使用模型模拟测试的假设。Broader的影响：这个高度的跨学科项目将为全球碳周期，气候和Biota的人类二氧化碳的短期和长期命运提供重要的见解。此类信息对于为科学领导者和政策制定者提供了对全球气候，海洋碳化学和海洋食品链的不利人为二氧化碳排放的后果的更好理解。此外，该项目非常重视许多紧密综合的研究和教育活动，这将导致与突然的气候变化和如何将其整合到课程中有关的教育材料的发展和流通。 此外，我们将利用非常成功的现有计划，为来自代表性不足的群体的本科生提供机会，以参与尖端，相关，碳循环研究。