Understanding ocean carbon uptake mechanisms during glacial-interglacial cycles

了解冰期-间冰期循环期间海洋碳吸收机制

• 批准号: RGPIN-2018-04201
• 负责人: Kohfeld, Karen
• 金额: $ 2.19万
• 依托单位: Simon Fraser University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=712773
• 关键词: Understanding; ocean; carbon; uptake; mechanisms

Ever since scientists first discovered that carbon dioxide levels were low during ice ages, they have been proposing theories to understand why. Many studies have examined the role of individual mechanisms in sequestering carbon dioxide in the ocean, and others have closely examined how carbon dioxide exits the ocean at the end of an ice age. As Earth system models have yet to simulate carbon dioxide changes over a full glacial-interglacial cycle, it becomes increasingly important to bring together new data, both to quantify environmental changes of the ocean, as well as to evaluate how well models can identify the most important mechanisms in glacial climate change. My research program focuses on the fate of the ocean as the Earth enters an ice age, and how different feedbacks play dominant roles during different stages of a glacial cycle. My long-term objective is to bring together multiple lines of paleo-oceanographic evidence to create a more complete picture of how the ocean changes as the Earth enters a glacial cycle, and to use this synthesis to test which oceanographic processes are the most important contributors to the sequestration of atmospheric carbon dioxide. The three projects in my research program are designed to reconstruct different aspects of ocean physics and biogeochemistry during different stages of a glacial period; these aspects include dust deposition, ocean productivity, sea ice cover, and deep-ocean temperatures. My approach will combine global environmental data compilation - to provide novel and innovative spatial and temporal comparisons of multiple lines of data - with new analyses on marine sediment samples - to fill existing gaps in knowledge about how the ocean is changing. The projects will provide important interdisciplinary training to two doctoral, one Masters, and five undergraduate students. One key outcome of this research is that it will provide multiple benchmark datasets of changes in ocean temperature, marine productivity, dust deposition, and Southern Ocean sea-ice cover, with explicit focus on the early- and mid-glacial time periods that have not previously been studied. These data will benefit climate modelers who wish to evaluate the skill of Earth system models, such as Canada's UVic Earth System Model, in simulating carbon-climate feedbacks during past time periods when the Earth experienced different boundary conditions. Furthermore, when brought together, these projects will provide a comprehensive test of hypotheses examining how the ocean circulation changes during large-scale climate fluctuations are linked with changes in sea ice cover, iron fertilization from dust, marine productivity, and ocean carbon sequestration.

自从科学家首次发现冰河时期的二氧化碳含量很低以来，他们一直在提出理论来解释原因。许多研究已经研究了在海洋中封存二氧化碳的单个机制的作用，其他研究则仔细研究了二氧化碳在冰河时代结束时如何离开海洋。由于地球系统模型尚未模拟整个冰川-间冰期循环中的二氧化碳变化，因此汇集新数据变得越来越重要，既可以量化海洋环境变化，也可以评估模型如何确定冰川气候变化中最重要的机制。 我的研究项目侧重于海洋的命运，因为地球进入冰河时代，以及如何不同的反馈在冰川周期的不同阶段发挥主导作用。我的长期目标是汇集多条古海洋学证据，以创建一个更完整的海洋变化的图片，因为地球进入一个冰川周期，并使用这种合成来测试海洋过程是最重要的贡献者大气二氧化碳的封存。我的研究计划中的三个项目旨在重建冰川时期不同阶段的海洋物理学和海洋地球化学的不同方面;这些方面包括灰尘沉积，海洋生产力，海冰覆盖和深海温度。我的方法将联合收割机全球环境数据汇编--提供多条数据线的新颖和创新的空间和时间比较--与海洋沉积物样本的新分析--结合起来，填补有关海洋如何变化的现有知识空白。这些项目将为两名博士生，一名硕士生和五名本科生提供重要的跨学科培训。 这项研究的一个关键成果是，它将提供海洋温度、海洋生产力、尘埃沉积和南大洋海冰覆盖变化的多个基准数据集，并明确关注以前从未研究过的冰期早期和中期。这些数据将使气候建模者受益，他们希望评估地球系统模型（如加拿大的UVic地球系统模型）在模拟地球经历不同边界条件的过去时期的碳气候反馈方面的技能。此外，当这些项目结合在一起时，将提供一个全面的假设测试，研究在大规模气候波动期间海洋环流的变化如何与海冰覆盖、灰尘铁肥化、海洋生产力和海洋碳固存的变化相联系。