Collaborative Research: Atmospheric CO2 and the Relationship to Millennial Changes in Atmospheric and Oceanic Circulation in the Eastern Equatorial Pacific Ocean over the Past 100

合作研究：大气CO2及其与过去100年东赤道太平洋大气和海洋环流千年变化的关系

• 批准号: 1803933
• 负责人: Matthew Schmidt
• 金额: $ 27.44万
• 依托单位: Old Dominion University Research Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-06-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1803933&HistoricalAwards=false
• 关键词: Collaborative; Research; Atmospheric; CO2; Relationship

To understand future climate change, we must know how climate varied in the past. One of the biggest unknowns about past climate is the origin of atmospheric carbon dioxide (CO2) variability over global warm-cold cycles. This project will address potential causes of the varying atmospheric carbon dioxide by focusing on changes in the efficiency of fertilization of the surface ocean, and how, and if, that is related to changes in the deep-ocean. Furthermore, the research will investigate both the "how" of varying carbon dioxide with the "where", namely the Eastern Equatorial Pacific (EEP), an important region of the world ocean where, today, significant CO2 is exhaled to the atmosphere and the greatest rates of phytoplankton growth are found. The project will contribute to an improved understanding of global climate change and important Earth systems connected to the tropical Pacific Ocean. On the broadest of levels, understanding the past dynamics of Earth's carbon cycle is of fundamental importance to inform and guide societal policy-making in an increasing CO2 world. The project will support the educational and professional development of graduate and undergraduate students and results will be incorporated into the curriculum of undergraduate and graduate classes. In addition, a series of YouTube videos will be developed that are aimed at communicating the importance of how past climate variability informs us about climate's future variability and its potential impact on our lives.The project seeks to answer questions related to: 1) where and how atmospheric carbon dioxide was sequestered from the atmosphere, or ventilated from the ocean, on millennial timescales, and 2) how these carbon dynamics are related to both changes in atmospheric and oceanic circulation over the last glacial period and into the deglacial and Holocene. To address these objectives, an integrated suite of multiple proxies will be measured in two high accumulation rate sediment cores previously collected from the EEP. These proxies include: authigenic uranium as a proxy for bottom water oxygenation and radiocarbon ages of benthic foraminifera as a proxy for changes in the age of deep water in the EEP, 231Pa/230Th ratios and excess Ba fluxes as proxies for productivity, excess 230Th-derived 232Th flux as a proxy for dust flux, B/Ca ratios in planktonic foraminifera as a proxy for carbonate ion concentration of surface water, and Nd and Pb isotope ratios as a proxy for the provenance of the dust source of the detrital component of the sediment and, therefore, an index of Intertropical Convergence Zone migration. By investigating the storage of a respired carbon pool in the deep ocean during cold periods of the last glacial period (i.e., from ~71,000 to 14,000 years ago), in conjunction with probing how this storage relates to changes in export production and potential iron fertilization, the research will shed light on the mechanistic links between ocean (stratification/ventilation) and atmospheric (wind belt shifts) circulation and the modification of atmospheric CO2 levels.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

要了解未来的气候变化，我们必须知道过去气候如何变化。 关于过去气候的最大未知数之一是全球暖冷周期中大气二氧化碳（CO2）变异性的起源。该项目将通过专注于地表海施肥效率的变化以及与深度海洋的变化有关的方式来解决不同大气二氧化碳的潜在原因。此外，该研究将研究与“地点”（即东赤道太平洋（EEP））不同的“二氧化碳”的“如何”，即世界海洋的一个重要地区，如今，在其中发现了重要的二氧化碳，并且发现了大气和最大的浮游植物增长率。该项目将有助于改善对全球气候变化和与热带太平洋相关的重要地球系统的了解。从最广泛的角度来看，了解地球碳循环的过去动态对于在不断增长的二氧化碳世界中提供和指导社会决策至关重要。该项目将支持研究生和本科生的教育和专业发展，结果将纳入本科和研究生班的课程中。此外，还将开发一系列YouTube视频，旨在传达过去气候变异性如何告知我们气候的未来可变性及其对生活的潜在影响。该项目试图回答与：1）与以下位置相关的问题：1）在何处以及如何与大气中的大气隔离，或对大气中的大气以及对海洋的各种态度以及2）的动力以及2），以及这些习惯于这些习惯于这些。在最后的冰川时期循环，进入冰川和全新世。为了解决这些目标，将以先前从EEP收集的两个高积累速率核心进行多个代理的集成套件。这些代理包括：底栖有孔虫的底水氧合和放射性碳年龄的代理，作为EEP中深水年龄的变化的代理，第231 ppa/230的比率和多余的ba量作为生产力，超过230th tux car/ca有孔虫作为地表水的碳酸盐离子浓度的代理，ND和Pb同位素比是沉积物碎屑成分的粉尘来源的代理，因此是间接收敛区迁移的指数。通过调查在最后一个冰川时期的寒冷时期（即，从〜71,000到14，000年前）在深海中的储存，以及探测该存储与出口产量的变化和潜在的铁受精的变化，研究将揭示出循环范围（分类/通风式的循环范围）（旋转层次）的循环范围（分层）循环（分层）的变化（反映了NSF的法定任务，并使用基金会的知识分子优点和更广泛的影响审查标准来评估值得支持。