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: 2042928
• 负责人: Catherine Davis
• 金额: $ 19.52万
• 依托单位: Yale University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-06-15 至 2021-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2042928&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.

氧最小带（OMZs）是指在海面以下100至1000米深处的大片海洋中自然出现的低氧区域。omz在生物地球化学循环和生态系统功能中发挥着重要作用，其低氧水域的任何变化都可能对海洋生物和宝贵的渔业资源产生深远的影响。由于全球气候变化，海洋氧合在多个时间尺度上是可变的，最近的观测表明，在过去的半个世纪里，海洋氧合区已经扩大。该项目将探索适用于浮游有孔虫Globorotaloides hexonus的新的地球化学和形态指标，Globorotaloides hexonus是一种单细胞钙化生物，其在海底沉积物中的化石记录非常适合重建过去的低氧水体环境。该项目将重点关注东热带太平洋广阔的OMZ。第一个目标是评估和校准在浮游生物拖曳中收集的现代六角藻的目标测量值。第二个目标是将这些代用物应用于沉积物岩心中的化石标本，以生成冰川-全新世变化的记录。这些结果将成为生成OMZ环境记录的可用代理，并更好地了解在最近的快速气候变化期间，主要区域OMZ是如何变化的。这两个结果都代表了在理解海洋空间的自然振荡以及在面对全球气候扰动时对海洋空间变化的建模和规划方面取得的重要进展。该项目将为本科研究人员提供机会，并支持一名女性早期职业研究人员。海相沉积记录是重建长期海洋氧合作用最有希望的资料。然而，低氧海洋环境的可用替代指标存在显著的局限性。本项目旨在通过评估和应用与浮游有孔虫Globorotaloides hexagonus低氧环境相关的一系列有前途的地球化学（微量元素和稳定同位素）和形态学（面积密度和孔隙度）指标来解决这一需求。该项目将根据以前在东太平洋深度分布的moness（多重开合网和环境传感系统）拖带中收集的G. hexagonus壳的形态和地球化学开发可行的代理。在现代贝壳中，这一代用发展的结果将被实地验证，并应用于墨西哥边缘和巴拿马盆地的两个已经很好表征的沉积物岩心，这些岩心从末次盛冰期跨越到全新世。沉积物记录将用于重建热带太平洋东部OMZ的过去条件，在那里关于冰期-间冰期氧化作用的重要问题仍然存在。这项研究将使人们对omz如何更广泛地响应气候有更机械的了解。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

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.