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.

知识优势：海洋是人为二氧化碳的最大汇，自工业革命开始以来，海洋已经吸收了排放到大气中的380 PGC中的近130 PGC。如果排放量在接下来的三个世纪里继续有增无减，大气和海洋的排放量将增加4000 PGC或更多。发布的对最终完全利用化石燃料的海洋/大气响应的模型模拟表明，大气中的二氧化碳将上升到地球可能至少有4000万年没有经历过的水平，表层海洋可能会经历酸化，以至于珊瑚和其他钙化生物将无法沉淀它们的骨骼。对这些模型模拟的信心和改进将从应用于地球历史上类似的事件并与之进行比较而受益。大约5500万年前(Mya)，地球经历了类似的快速和极端的瞬变变暖，古新世-始新世最高温度(PETM)，很可能是大规模碳释放的产物。在过去的五年里，对PETM的密集研究使人们对这一事件对气候、生物群和生物地球化学循环的影响有了更清晰的理解。更突出的进展之一是记录了广泛存在的海洋酸化和缓冲的证据，这与碳循环理论一致。一个相关的进展是在53Mya发现了第二次变暖和海洋酸化事件。从碳循环扰动到气候变暖的程度，这场被称为Elmo的事件在任何意义上都没有PETM那么极端。这些被称为高温的全球变暖事件为洞察二氧化碳水平迅速上升对现代气候、海洋碳酸盐化学和生物群的长期影响提供了一个独特的机会。它们还提供了一个机会，以确定潜在的非线性反馈，并测试气候和生物地球化学模型的敏感性。为此，一个由具有碳循环动力学、沉积物地球化学、古海洋学和古生物学专长的科学家组成的跨学科小组已经组成，并将开始一个为期4年的项目，以解决关于两个高温及其对理解碳循环的影响的关键问题，包括：1)在高温期间释放的碳的质量、速率和来源是什么？2)封存和恢复的速度是多少，以及起作用的生物地球化学反馈是什么？3)海洋碳酸盐化学的相关极端变化是如何影响浮游钙化的？该战略将涉及将观测数据库与数值模式相结合。观测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3个维度上记录生物成因碳酸盐的生产、积累和保存。这还需要对年龄模型进行实质性的改进。有了一个高分辨率和多方面的输入数据集，将使用三种建模方法，每种方法都涉及到可以建模的过程的时间尺度和范围方面的具体机会和妥协。地球系统模型(GENIE和CCSM)将为面向过程的模型提供边界条件。过程模型模拟将被设计用来调查在地球系统模型的数据/模型验证过程中发现的问题，并开发要用模型模拟来检验的假设。广泛的影响：这个高度跨学科的项目将对人为二氧化碳对全球碳循环、气候和生物群的短期和长期命运提供重要的洞察。这些信息对于让科学领袖和政策制定者更好地了解人为二氧化碳排放有增无减对全球气候、海洋碳化学和海洋食物链的影响至关重要。此外，该项目非常重视一些紧密结合的研究和教育活动，这些活动将导致编写和分发与气候突然变化有关的教育材料，并就如何将其纳入课程进行培训。此外，我们将利用非常成功的现有项目，为来自代表性不足群体的本科生提供参与尖端的、相关的碳循环研究的机会。