Paleogeochemical and oxygenation history of the Eastern Pacific Ocean

东太平洋的古地球化学和氧化历史

• 批准号: 628-2006
• 负责人: Pedersen, Thomas
• 金额: $ 4.89万
• 依托单位: University of Victoria
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2007
• 资助国家: 加拿大
• 起止时间: 2007-01-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=365802
• 关键词: Paleogeochemical; oxygenation; history; Eastern; Pacific

The western continental slopes of North and South America are bathed at intermediate water depths by large pools of oxygen-poor water that are thought to play a significant role in global climate modulation by limiting the nitrate content of the world's oceans. Because nitrate is a key nutrient for phytoplankton, its biochemically-mediated loss from the low oxygen water constrains the productivity of the sea. We have been investigating controls, both biological and physical, on the intensity of such oxygen depletion through time, focusing on the NE subtropical and subarctic Pacific. We propose to expand this work through a focus on several of 22 giant-piston cores raised from the western margin of North America in 2002. Cores from the Vancouver Island, Oregon, and northern California margins, as well as the Gulf of California are the initial targets in this project.  Our objective is to reconstruct marine production and intermediate water circulation across a broad swath of the North Pacific over the last 100,000 or so years. The research includes a focus on the distribution of silver in continental margin sediments. Our new data show that the sedimentary silver content increases with water depth, while water-column measurements we have made indicate scavenging of silver from solution in upper North Pacific intermediate waters. These phenomena--for which no explanations currently exist--will receive particular attention in the proposed research. Finally, we shall explore the history of productivity in the Galapagos Archipelago and its link to El Niño over the last 10,000-20,000 years through intensive study of a sediment core to be collected during a research cruise to the eastern equatorial Pacific proposed for 2007. We anticipate that this research program will contribute to an improved understanding of both climate history and oceanographic processes that influence and respond to climate changes on Earth.

北美的西部连续懒惰被大量的氧气水池沐浴在中等水深的中间水深，这些水被认为通过限制世界海洋的硝酸盐含量，在全球气候调节中发挥了重要作用。由于硝酸盐是浮游植物的关键营养素，因此其生物化学介导的低氧水损失限制了海洋的生产力。我们一直在调查生物学和物理的对照，以随着时间的推移这种氧气耗尽的强度，重点关注NE亚热带和亚北极太平洋。我们建议通过重点关注2002年从北美西部边缘筹集的22个巨型活塞核心中的几个。我们的目标是在过去的100,000年左右的时间里重建海洋生产和中间水循环。该研究包括关注连续边缘沉积物中银的分布。我们的新数据表明，沉积银含量随水深度的增加而增加，而我们进行的水柱测量值表明在北太平洋上层中间水域清除了溶液中的银。这些现象 - 目前尚无解释 - 在拟议的研究中会特别关注。最后，我们将通过对在2007年东部Qualitorious Pacific提议的研究期间收集的沉积物核心的深入研究，探索加拉帕戈斯群岛及其与厄尔尼尼诺的生产率及其与厄尔尼诺现象的联系。我们预计，这项研究计划将有助于对两个气候历史和海洋学的了解，从而有助于对这两种情况的了解，从而有助于对地球造成的变化和响应的变化。