Biogeochemical linkages between Ice Age climate, ocean productivity, and carbon cycling

冰河时代气候、海洋生产力和碳循环之间的生物地球化学联系

• 批准号: 342251-2013
• 负责人: Kohfeld, Karen
• 金额: $ 1.97万
• 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: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=572475
• 关键词: Biogeochemical; linkages; between; Ice; Age

The goal of this research program is to explore the linkages between ocean circulation, marine productivity, and carbon (C) cycling by reconstructing past ocean conditions from paleo-environmental indicators archived in the sedimentary record. Three complementary projects are proposed that will follow the same approach: New biogenic flux, sea-surface temperature, and mode-water proxy data will be generated on deep-sea cores from the southeast (SE) Pacific Ocean, selected for their strategic importance to the research questions and their ability to fill a gap in current knowledge. These new data will be placed within the context of an ongoing global biogenic flux data synthesis that incorporates information on seven indicators of changes in C accumulation and marine phytoplankton abundance, to reconstruct the relative timing of changes in different components of marine productivity. Finally, these data will be used to evaluate carefully designed model sensitivity experiments in which changes in sea-ice cover, iron fertilization, upwelling intensity, and freshwater forcing have been imposed. Simulated changes in productivity will be compared with observed ice age reconstructions to assess which processes provide the best match to the data for the following projects: PROJECT 1 explores the influence of sea-ice cover and dust on silica and C cycling. PROJECT 2 examines the influence of changed Southern Hemisphere circulation (e.g., westerly winds, oceanic fronts, Subantarctic Mode Water formation) on productivity. PROJECT 3 investigates the potential influence of polar surface freshening and associated circulation changes on marine productivity during the transition from the last Ice Age to today. The proposed research will provide new reconstructions of past oceanic conditions in the SE Pacific Ocean during the last Ice Age. The global paleo-environmental datasets benefit the field of Earth System science by providing extensive and highly novel evaluation tools for analyzing ocean biogeochemistry model simulations. The results will contribute to our current knowledge of the ice age ocean C cycle, identifying oceanic mechanisms responsible for ice-age changes in atmospheric carbon dioxide.

该研究计划的目标是通过沉积记录中存档的古环境指标重建过去的海洋状况，探索海洋环流、海洋生产力和碳（C）循环之间的联系。提议的三个互补项目将遵循相同的方法：将在东南太平洋的深海核心上生成新的生物通量、海面温度和模式水代理数据，这些数据因其战略重要性而被选择研究问题及其填补当前知识空白的能力。这些新数据将置于正在进行的全球生物通量数据合成的背景下，该数据合成包含有关碳积累和海洋浮游植物丰度变化的七个指标的信息，以重建海洋生产力不同组成部分变化的相对时间。最后，这些数据将用于评估精心设计的模型敏感性实验，其中施加了海冰覆盖、铁肥化、上升流强度和淡水强迫的变化。模拟的生产力变化将与观察到的冰河时代重建进行比较，以评估哪些过程与以下项目的数据最匹配：项目 1 探讨海冰覆盖和灰尘对二氧化硅和碳循环的影响。 项目 2 研究南半球环流变化（例如西风、海洋锋、亚南极模式水的形成）对生产力的影响。 项目 3 研究从上一个冰河时代到今天的过渡期间极地表面清新和相关环流变化对海洋生产力的潜在影响。 拟议的研究将对上一个冰河时期东南太平洋过去的海洋状况进行新的重建。 全球古环境数据集通过提供广泛且高度新颖的评估工具来分析海洋生物地球化学模型模拟，从而使地球系统科学领域受益。这些结果将有助于我们目前对冰河时代海洋碳循环的了解，确定导致冰河时代大气二氧化碳变化的海洋机制。