EAGER: Characteristic Disruptions of the Marine Carbon Cycle

地球的碳循环包括消耗和产生二氧化碳的过程。地质记录表明，消费和生产之间的平衡经历了多次破坏，持续了数千年或更长时间。这个项目的重点是产生异常高的二氧化碳水平和全球变暖的破坏。先前的研究将这些事件与在适当的气候条件下从特定来源释放的碳联系起来。然而，最近的研究表明，这些事件以一种独立于长期气候趋势的典型方式发生。该项目提出，这种特征中断是碳循环中始终活跃的机制的自然后果。该项目将量化海洋沉积物记录中这种行为的证据。它还将开发数学模型来显示这种破坏是如何产生的。为了让更多的人了解这一主题，该项目将在reddit网站的“IAmA”（问我任何问题）网站上举行公开问答环节。它还将举办2019年HBO纪录片《冰雪之火》的公开放映，该片以相关主题为主题。该项目还将产生新的教育资源，支持研究生的培训，并在新闻媒体上宣传其工作。该项目的总体目标是了解导致长期碳循环中断的机制。该项目假设通过非线性放大过程发生特征中断。它建议在古气候时间序列中探测这些过程的特征，并通过构建新模式来解释这些观测结果。过去的工作强调了特定沉积碳储层在产生某些个别事件中的作用。然而，它也表明，更普遍的破坏途径可能在不同的气候制度下持续存在。该项目旨在确定与海洋碳循环内在非线性动力学相关的这种持续现象的类别。该项目将建立数学模型，展示这是如何工作的，并将从过去碳同位素数据的波动中寻找其预测的证据。这样的理解可能会导致对特定压力源（如火山活动增强或甲烷释放）作为主要变暖事件驱动因素的作用的新解释。研究结果还将为人类对现代碳循环的扰动带来的长期风险提供洞见。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Earth's carbon cycle consists of processes that consume and produce carbon dioxide. The geologic record shows that the balance between consumption and production has undergone many disruptions lasting thousands of years or more. This project focuses on disruptions that produce unusually high carbon dioxide levels and global warming. Previous work has related these events to carbon that is released from particular sources under the right climatic conditions. However, recent work suggests these events occur in a typical way independent of longer-term climatic trends. This project proposes that such characteristic disruptions are natural consequences of mechanisms in the carbon cycle that are always active. The project will quantify the evidence of such behavior in records from marine sediments. It will also develop mathematical models to show how such disruptions could arise. To bring this subject to a wide audience, the project will hold public question-and-answer sessions on reddit.com's “IAmA” “Ask me anything” website. It will also host a public screening of the 2019 HBO documentary Ice on Fire, which features related themes. The project will also produce new educational resources, support the training of a graduate student, and publicize its work in the news media.The project's overall goal is to understand mechanisms responsible for disruption of the long-term carbon cycle. The project hypothesizes that characteristic disruptions occur via processes of nonlinear amplification. It proposes to detect signatures of such processes in paleoclimate time series and to explain these observations by construction of new models. Past work has emphasized the role of specific sedimentary carbon reservoirs in generating certain individual events. Yet it also indicates that more general pathways to disruption may have persisted through different climate regimes. The project seeks to identify classes of such persistent phenomena related to intrinsic nonlinear dynamics of the marine carbon cycle. The project will construct mathematical models showing how this could work and will seek evidence of their predictions in past fluctuations in carbon-isotopic data. Such understanding will likely lead to new interpretations of the role of specific stressors, such as enhanced volcanism or the release of methane, as drivers of major warming events. Results will also provide insight into the long-term risks of the human perturbation of the modern carbon cycle.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.