Glacial-Interglacial Changes in Oxygen Minimum Zones Using Deep-Dwelling, Low-Oxygen Planktic Foraminifera

利用深海低氧浮游有孔虫研究冰期-间冰期最低含氧带的变化

• 批准号: 2154081
• 负责人: Catherine Davis
• 金额: $ 19.52万
• 依托单位: North Carolina State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-10-01 至 2023-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2154081&HistoricalAwards=false
• 关键词: Glacial; Interglacial; Changes; Oxygen; Minimum

Oxygen minimum zones (OMZs) are naturally occurring regions of low oxygen found across large swaths of the ocean at depths of 100 to 1000 meters below the surface. OMZs play an important role in biogeochemical cycling and ecosystem function and any change in the expanse of their low oxygen waters can have far reaching implications for marine life and valuable fisheries resources. Marine oxygenation is variable on multiple timescales in response to global climate change, with recent observations showing that OMZs have expanded over the past half century. This project will explore promising new geochemical and morphologic proxies applicable to low-oxygen environments in the planktic foraminifer Globorotaloides hexagonus, a unicellular calcifying organism whose fossil record in seafloor sediments is well suited to reconstructing past low-oxygen environments in the water column. The project will focus on the extensive OMZ of the eastern tropical Pacific. The first goal is to evaluate and calibrate the targeted measurements for modern G. hexagonus collected live in plankton tows. The second goal is to apply these proxies to fossil specimens in sediment cores to generate records of glacial-Holocene change. The outcomes will be useable proxies for generating records of the OMZ environment, and a better understanding of how a major regional OMZ changed during the most recent period of rapid climate change. Both outcomes represent important progress towards understanding natural oscillations in the OMZ as well as modeling and planning for a changing OMZ in the face of global climate perturbations. The project will provide opportunities for undergraduate researchers as well as support a female early career researcher.The marine sedimentary record is the most promising archive from which to reconstruct long term marine oxygenation. However, significant limitations exist in the available proxies for low oxygen marine environments. This project aims to address this need by evaluating and applying a range of promising geochemical (trace element and stable isotope) and morphologic (area-density and porosity) proxies relevant to low oxygen environments in the planktic foraminifer Globorotaloides hexagonus. The project will develop viable proxies based on the morphology and geochemistry of G. hexagonus shells previously collected in depth-distributed MOCNESS (Multiple Opening/Closing Net and Environmental Sensing System) tows from the eastern Pacific. The results from this proxy development in modern shells will then be ground-truthed and applied to two already well characterized sediment cores from the Mexican Margin and Panama Basin that span from the Last Glacial Maximum through the Holocene. The sediment records will be used to reconstruct past conditions in the eastern tropical Pacific OMZ, where significant questions about glacial-interglacial oxygenation persist. This research will lead to a more mechanistic understanding of how OMZs respond to climate more broadly.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.

氧最小区域（OMZ）是自然存在的，在大海的大部分大部分地区的低氧区域天然存在，深度为100至1000米以下的深度。 OMZ在生物地球化学和生态系统功能中起着重要作用，其低氧水域的任何变化都可能对海洋生物和有价值的渔业资源具有很大的影响。响应全球气候变化的多个时间尺度上，海洋氧合变化是可变的，最近的观察结果表明，OMZ在过去半个世纪中有所扩展。该项目将探索有希望的新的地球化学和形态代理，适用于浮游有孔虫环境中的低氧环境Globorotaloides Hexagonus，这是一种单细胞钙化有机体，其化石在海底沉积物中的化石记录非常适合重建过去的低氧环境中的低氧环境。该项目将集中于东部热带太平洋的广泛OMZ。第一个目标是评估和校准现代收集的现代G. hexagonus的目标测量现场现场直播。第二个目标是将这些代理应用于沉积物芯中的化石标本，以产生冰川 - 半新世变化的记录。结果将是可用的代理，以产生OMZ环境的记录，并更好地理解主要的区域性OMZ在最近的快速气候变化期间如何变化。这两种结果都代表着了解OMZ中自然振荡的重要进展，以及面对全球气候扰动的OMZ的建模和计划。该项目将为本科研究人员提供机会，并支持一位女性早期职业研究员。海洋沉积记录是重建长期海洋氧合的最有希望的档案。但是，对于低氧海洋环境的可用代理中存在显着局限性。该项目旨在通过评估和应用一系列有希望的地球化学（痕量元素和稳定同位素）和形态学（面积密度和孔隙率）代理来满足这一需求。该项目将根据先前以深度分布的MOC（多个开放/闭合网络和环境传感系统）从东太平洋地区收集的G. hexagonus壳的形态和地球化学发展可行的代理。然后，现代贝壳中这种代理发展的结果将经过经过经验，并将其应用于两个已经具有良好特征的沉积物核心，从墨西哥边缘和巴拿马盆地跨越了从最后一个冰川到全新世。沉积物记录将用于重建东部热带太平洋OMZ的过去条件，在那里，有关冰川间 - 冰川氧合的重大问题持续存在。这项研究将使对OMZ如何更广泛地对气候的反应有了更大的理解。该奖项反映了NSF的法定使命，并使用基金会的知识分子优点和更广泛的影响审查标准，被认为值得通过评估来获得支持。

项目成果

Planktic foraminifera iodine/calcium ratios from plankton tows

浮游生物丝束中的浮游有孔虫碘/钙比率

• DOI: 10.3389/fmars.2023.1095570
• 发表时间: 2023
• 期刊: Frontiers in Marine Science
• 影响因子: 3.7
• 作者: Winkelbauer, Helge A.;Hoogakker, Babette A.;Chance, Rosie J.;Davis, Catherine V.;Anthony, Christopher J.;Bischoff, Juliane;Carpenter, Lucy J.;Chenery, Simon R.;Hamilton, Elliott M.;Holdship, Philip
• 通讯作者: Holdship, Philip

Trace element composition of modern planktic foraminifera from an oxygen minimum zone: Potential proxies for an enigmatic environment

• DOI: 10.3389/fmars.2023.1145756
• 发表时间: 2023-03
• 作者: C. V. Davis;S. Doherty;J. Fehrenbacher;K. Wishner

Deglacial restructuring of the Eastern equatorial Pacific oxygen minimum zone

赤道东太平洋含氧最低区的冰消重建

• DOI: 10.1038/s43247-022-00477-8
• 发表时间: 2022
• 期刊: Communications Earth & Environment
• 影响因子: 7.9
• 作者: Davis, Catherine V.

Vertical distribution of planktic foraminifera through an oxygen minimum zone: how assemblages and test morphology reflect oxygen concentrations

• DOI: 10.5194/bg-18-977-2021
• 发表时间: 2021-02-10
• 期刊: BIOGEOSCIENCES
• 影响因子: 4.9
• 作者: Davis, Catherine, V;Wishner, Karen;Hull, Pincelli M.
• 通讯作者: Hull, Pincelli M.