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: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=683695
• 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二氧化碳含量较低以来，他们一直在提出理论来理解其中的原因。许多研究都研究了各个机制在海洋中封存二氧化碳的作用，还有一些研究仔细研究了二氧化碳在冰河时代末期如何离开海洋。由于地球系统模型尚未模拟整个冰期-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，也可以评估模型识别最重要变化的能力。冰川气候变化的重要机制。 ******我的研究项目重点关注地球进入冰河时代时海洋的命运，以及不同的反馈如何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种古海洋学证据，以更完整地了解当地球进入冰川循环时海洋如何变化，并利用这种综合来测试哪些海洋学过程是最重要的贡献者封存大气中的二氧化碳。我的研究计划中的三个项目旨在重建冰期不同阶段的海洋物理学和生物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。我的方法将把全球环境数据汇编（提供多行数据的新颖和创新的空间和时间比较）与对海洋沉积物样本的新分析结合起来，以填补有关海洋变化的知识的现有空白。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，并明确关注早期和中期的变化。以前从未研究过的冰川时期。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（例如加拿大的 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，当这些项目汇集在一起​​时，将对假设进行全面的检验，以检验大规模气候波动期间海洋环流的变化如何与海冰覆盖、灰尘中的铁肥化、海洋生产力和海洋碳封存的变化联系起来。