Collaborative Research: US GEOTRACES GP17-OCE: Size-Fractionated Particle Collection and Analysis from Ultra-Oligotrophic to Antarctic Waters

合作研究：US GEOTRACES GP17-OCE：从超贫营养到南极水域的尺寸分级颗粒收集和分析

• 批准号: 2049297
• 负责人: Phoebe Lam
• 金额: $ 27.82万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2049297&HistoricalAwards=false
• 关键词: Collaborative; Research; US; GEOTRACES; GP17

GEOTRACES is an ongoing international effort to study and understand how low-abundance (“trace”) elements and isotopes are distributed in the world’s oceans. Trace elements include both naturally occurring and human-influenced chemical components of seawater. They have several important roles in the functioning of the Earth that make them a focus of study: 1) their rarity is known to limit the growth of microscopic plants which are the base of ocean food webs; 2) the distributions of trace elements in remote parts of the world show how Earth’s atmosphere, ocean, crust, and ecosystems work together on large, planetary scales; 3) knowledge of these trace components is difficult to acquire but is also an important component to improving computer models of Earth’s climate in a rapidly changing world. The Pacific Ocean covers nearly a third of the planet, and the rarely sampled South Pacific Ocean at the focus of this project includes approximately a quarter of the world’s ocean volume. As part of a GEOTRACES expedition to this remote region, this project has three main goals: 1) to provide the sampling equipment and personnel to collect large volumes of particles from the ocean, because many chemical components in seawater are in particle forms; 2) to document and distribute ocean particle samples to collaborators of many GEOTRACES laboratories; 3) to analyze ocean particles for abundances of approximately two dozen trace elements at laboratories in Savannah, GA and Santa Cruz, CA. A post-doctoral scholar and two graduate students will participate in both field and laboratory aspects of the research.The GP-17 OCE research expedition to the South Pacific Ocean is planned for two months in late 2022 into early 2023. It comprises two transects: a southward transect along approximately 150ºW between French Polynesia and the Southern Ocean which will sample large biological and geochemical gradients from the low-dust, low-biomass oligotrophic sub-tropical gyre, though more productive regions of complex regions of watermass formation and frontal mixing, and into the Southern Ocean. An eastward transect along 67ºS and into Chile will sample the high-opal and Antarctic-influenced Southern Ocean, deep-water hydrothermal influences, and across the South American continental margin. The investigators will use large-volume in-situ pumps to collect size-fractionated particles from the water column which will be distributed to multiple collaborators; and they will operate and maintain particle-sensitive optical equipment to be deployed on the expedition. The research aims to address three main hypotheses: 1) that the large biological gradients from pico-plankton dominated gyre through frontal regions into opal- and Phaeocystis-dominated polar waters will present large gradients in particle export, particle composition, scavenging of trace elements and isotopes (TEIs), and remineralization length-scales of both carbon and TEIs; 2) that particulate iron is dominated by lithogenic (crustally-derived) phases throughout most of the water column, with the exception of regions of strong hydrothermal influence, and that lithogenic particle origins will reflect inputs of external aerosol dust, sediments, hydrothermal sources, and continental inputs as evident via TEI ratios determined after total digestion; 3) that the optical ratio of turbidity to beam attenuation coefficient is sensitive to iron-oxyhydroxide abundances thus acting as a high-resolution indicator of iron-rich authigenic and lithogenic particle inputs.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.

Geotraces是一项持续的国际努力，旨在研究和了解在世界海洋中分布较低的元素和同位素。痕量元素包括天然发生的海水和人为影响的化学成分。他们在地球的功能中具有多个重要作用，使它们成为研究的重点：1）已知它们的稀有性限制了微观植物的生长，这是海洋食品网的基础； 2）世界偏远地区的微量元素的分布表明，地球大气，海洋，地壳和生态系统如何在大型行星尺度上共同工作； 3）对这些痕量组件的了解很难获得，但在快速变化的世界中改善地球气候的计算机模型也是重要组成部分。太平洋覆盖了地球几乎三分之一，而在该项目的重点，很少采样的南太平洋包括世界海洋量的大约四分之一。作为前往该偏远地区的地理位置探险的一部分，该项目具有三个主要目标：1）提供采样设备和人员，以从海洋中收集大量颗粒，因为海水中的许多化学成分都是粒子形式的； 2）将海洋粒子样品记录并分发给许多地理位置实验室的合作者； 3）分析海洋颗粒在佐治亚州萨凡纳和加利福尼亚州圣克鲁斯的实验室中抽象大约二十个微量元素。 A post-doctoral science and two graduate students will participate in both field and laboratory aspects of the research.The GP-17 OCE research expedition to the South Pacific Ocean is planned for two months in late 2022 into early 2023. It comprises two transects: a southward transect along approximately 150ºW between French Polynesia and the Southern Ocean Which will sample large biologic and geochemical gradients from the low-dust, low-biomass贫营养的亚热带回旋，虽然是水物形成和额叶混合的复杂区域的生产力，并进入了南大洋。沿着67ºS并进入智利的向东样品将采样由南大洋，深水水热影响以及整个南美大陆边缘的高空和南极影响的样品。研究人员将使用大批量的原位泵从水柱中收集尺寸分级的颗粒，该颗粒将分配给多个合作者；他们将操作并维护对探险队部署的粒子敏感的光学设备。该研究旨在解决三个主要假设：1）从pico-plankton统治的大型生物学梯度通过额叶区域占主导地位，直达蛋白石和磷脂主导的极性水域将在粒子出口，粒子组成，痕量元素和痕量元素和同位素（teis）以及同位素（teis）以及carscalesses and carcascaliss of Carccares and Carccares and carcares and carccareport，清除粒子组成中的较大梯度; 2）颗粒铁在整个水柱中以岩性（地壳衍生的）相位为主，除了强烈的水热影响区域外，岩性颗粒的起源将反映出外部气溶胶粉尘，沉积物，沉积物，水热来源的投入，以及通过总探测后的TEI比率作为大陆投入作为证据。 3) that the optical ratio of turbidity to beam attenuation coefficient is sensitive to iron-oxyhydroxide abstractions thus acting as a high-resolution indicator of iron-rich authigenic and lithogenic particle inputs.This award reflects NSF's statutory mission and has been deemed precious of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.