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.

北美和南美的西部大陆坡沐浴在中等水深的大片贫氧水池中，这些水池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着重要作用，因为硝酸盐是关键。浮游植物的营养物质，由于低氧水的生化介导的损失限制了海洋的生产力，我们一直在研究对这种氧气消耗随时间的强度的控制，无论是生物的还是物理的。我们建议重点关注东北亚热带和亚北极太平洋，重点关注 2002 年从北美西缘采集的 22 个巨型活塞核心。来自温哥华岛、俄勒冈州和加利福尼亚州北部边缘的核心，我们的目标是在过去 10 万年左右的时间里重建北太平洋广大地区的海洋生产和中间水循环。该研究的重点是大陆边缘沉积物中的银分布，我们的新数据表明，沉积物中的银含量随着水深的增加而增加，而我们所做的水柱测量表明银从北太平洋中层上部的溶液中清除。这些现象（目前尚无解释）将在拟议的研究中受到特别关注。最后，我们将探讨加拉帕戈斯群岛的生产力历史及其与厄尔尼诺现象的联系。 10,000-20,000 年，通过对 2007 年提议的东赤道太平洋研究航行期间收集的沉积物核心进行深入研究。我们预计该研究计划将有助于更好地了解影响和响应的气候历史和海洋学过程。地球气候变化。