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.

该研究计划的目的是通过从沉积记录中存档的古环境指标重建过去的海洋条件来探索海洋循环，海洋生产率和碳（C）骑自行车之间的联系。提出了将遵循相同方法的三个互补项目：新的生物通量，海面温度和模式 - 水代理数据将在太平洋（SE）太平洋的深海核心上生成，以其对研究问题的战略重要性及其在当前知识中填补空白的能力。这些新数据将放置在正在进行的全球生物通量数据综合的背景下，该数据综合了C累积变化和海洋浮游植物丰度的七个指标，以重建海洋生产率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灵敏度实验，其中已经实施了海冰覆盖，铁皮，上升强度和淡水强迫的变化。将生产率的模拟变化与观察到的冰期重建进行比较，以评估哪些过程为以下项目提供了最佳匹配：项目1探讨了海冰覆盖物和灰尘对二氧化硅和C循环的影响。 项目2研究了南半球循环发生变化的影响（例如西风，海洋阵线，北极二种模式水的形成）对生产力。 项目3调查了从上一个冰河时代到今天的过渡期间极地表面新鲜度和相关循环变化对海洋生产力的潜在影响。 拟议的研究将在上一个冰河时代为太平洋的过去海洋状况提供新的重建。 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型，从而使地球系统科学领域受益。结果将有助于我们当前对冰河时代海洋C周期的了解，从而确定了导致大气二氧化碳变化的海洋机制。