US GEOTRACES PMT: the geochemistry of size-fractionated suspended particles collected by in-situ filtration

US GEOTRACES PMT：通过原位过滤收集的按尺寸分级的悬浮颗粒的地球化学

• 批准号: 1736601
• 负责人: Phoebe Lam
• 金额: $ 37.28万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-10-01 至 2023-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1736601&HistoricalAwards=false
• 关键词: US; GEOTRACES; PMT; geochemistry; size

A researcher at the University of California, Santa Cruz will analyze the chemical composition of marine particles collected from the ocean. Marine particles will be collected in two size classes, 1-51um and 51um along the U.S. GEOTRACES Pacific Meridional Transect (PMT), which will sample from Alaska to Tahiti along 152°W. The smaller particles generally remain suspended in seawater, where they can interact with dissolved elements in seawater, whereas the larger particles tend to sink which means these elements can be transported to the bottom of the ocean. We will measure a suite of trace elements (e.g. iron, aluminum, zinc, manganese, cadmium, copper, cobalt, titanium, and barium), some of which are required for life, and others that act as tracers of oceanographic processes, as well as the major biologically-produced carrier phases (e.g. particulate organic carbon and the biominerals, calcium carbonate and biogenic silica) in the size-fractionated particles collected from the US PMT section. The data will be used to assess the relative importance of particle concentration, composition, and size distribution on the cycling and removal of trace elements and their isotopes (TEIs). Results will not only contribute to the overall goal of the GEOTRACES program, but also provide critical information to other science communities interested in the role of particles in sequestering carbon from the atmosphere through a process known as the biological carbon pump. A graduate student and a postdoc will be supported and trained on this project, and undergraduate students will be involved in several aspects of this work. The results from this study will be integrated into class curricula taught by the researcher. The scientist will also work with a science journalist who will sail on the expedition to translate the process and initial results of this research to the public. Particles play essential roles in the cycling and distribution of trace elements and isotopes (TEI) in the ocean by being sources and sinks for many TEIs. The scavenging of dissolved TEIs by particles is a major removal term for many particle-associated TEIs, but is poorly understood and represents a major uncertainty in our understanding of the biogeochemical cycling of many TEIs. The scavenging of TEIs is affected by particle size, concentration, and composition, whereas the subsequent removal of particles by sinking is influenced by particle dynamics processes such as particle aggregation and disaggregation. We will measure the major (particulate organic matter, calcium carbonate, opal, lithogenic particles) and minor (particulate trace metals) phase compositions of size-fractionated particles (1-51um; 51um) collected by in-situ filtration on the the US GEOTRACES Pacific Meridional Transect (PMT). The PMT will be the first meridional section of the US GEOTRACES program and will cross many gradients in surface productivity, biological community composition, subsurface silica concentrations, and depth of the calcite saturation horizon. Therefore, the US PMT section is expected to vary dramatically in particle concentration, composition, and size distribution, allowing us to examine the factors controlling scavenging efficiency in the ocean.

加州大学圣克鲁斯分校的一名研究人员将分析从海洋收集的海洋颗粒的化学成分，这些颗粒将沿着美国 GEOTRACES 太平洋经线横断面 (PMT) 收集，分为 1-51 微米和 51 微米两个尺寸等级。将从阿拉斯加沿西经 152° 采样到塔希提岛。较小的颗粒通常保持悬浮在海水中，在那里它们可以与海水中溶解的元素相互作用，而较大的颗粒往往会下沉，这意味着这些元素可以被运输。我们将测量一系列微量元素（例如铁、铝、锌、锰、镉、铜、钴、钛和钡），其中一些是生命所必需的，另一些则充当生命所需。海洋学过程的示踪剂，以及尺寸分级颗粒中主要生物产生的载体相（例如颗粒有机碳和生物矿物质、碳酸钙和生物二氧化硅）从美国 PMT 部分收集的数据将用于评估颗粒浓度、成分和尺寸分布对微量元素及其同位素 (TEI) 循环和去除的相对重要性。结果不仅有助于实现总体目标。 GEOTRACES 计划的一部分，同时也向其他科学界提供重要信息，这些科学界对颗粒通过称为生物碳泵的过程从大气中封存碳的作用感兴趣。 ，本科生将参与这项工作的几个方面。该研究的结果将被纳入研究人员教授的课程中。该科学家还将与一名科学记者合作，该记者将在这次探险中翻译这项研究的过程和初步结果。颗粒作为许多 TEI 的源和汇，在海洋中微量元素和同位素 (TEI) 的循环和分布中发挥着重要作用。颗粒对溶解的 TEI 的清除是许多与颗粒相关的主要去除术语。 TEI，但人们对其了解甚少，并且代表了我们对许多 TEI 的生物地球化学循环的理解的主要不确定性。 TEI 的清除受到颗粒尺寸、浓度和成分的影响，而随后通过下沉去除颗粒则受到颗粒动力学的影响。我们将测量颗粒聚集和分解等过程的主要相（颗粒有机物、碳酸钙、蛋白石、成岩颗粒）和次要相（颗粒痕量金属）。通过美国 GEOTRACES 太平洋经向横断面 (PMT) 上的原位过滤收集的尺寸分级颗粒（1-51 微米；51 微米） PMT 将是美国 GEOTRACES 计划的第一个经向部分，并将跨越表面生产力的许多梯度。 、生物群落组成、地下二氧化硅浓度和方解石饱和层深度因此，预计美国 PMT 部分的颗粒浓度、组成和尺寸会发生巨大变化。分布，使我们能够研究控制海洋清除效率的因素。

项目成果

Transmitted Cross-Polarized Light Detection of Particulate Inorganic Carbon Concentrations and Fluxes in the Ocean Water Column: Ships to ARGO Floats

海洋水柱中颗粒无机碳浓度和通量的透射交叉偏振光检测：运送到 ARGO 浮标

• DOI: 10.3389/frsen.2022.837938
• 发表时间: 2022-03
• 期刊: Frontiers in Remote Sensing
• 作者: Bishop, James K.;Amaral, Vinicius J.;Lam, Phoebe J.;Wood, Todd J.;Lee, Jong;Laubach, Allison;Barnard, Andrew;Derr, Ale;Orrico, Cristina
• 通讯作者: Orrico, Cristina

Cycling Rates of Particulate Organic Carbon Along the GEOTRACES Pacific Meridional Transect GP15

GEOTRACES 太平洋经向断面 GP15 沿线颗粒有机碳的循环速率

• DOI: 10.1029/2023gb007940
• 发表时间: 2024-01
• 期刊: Global Biogeochemical Cycles
• 影响因子: 5.2
• 作者: Amaral, Vinícius J.;Lam, Phoebe J.;Marchal, Olivier;Kenyon, Jennifer A.
• 通讯作者: Kenyon, Jennifer A.

Major processes of the dissolved cobalt cycle in the North and equatorial Pacific Ocean

北太平洋和赤道太平洋溶解钴循环的主要过程

• DOI: 10.5194/bg-19-2365-2022
• 发表时间: 2022-01
• 期刊: Biogeosciences
• 影响因子: 4.9
• 作者: Chmiel, Rebecca;Lanning, Nathan;Laubach, Allison;Lee, Jong;Fitzsimmons, Jessica;Hatta, Mariko;Jenkins, William;Lam, Phoebe;McIlvin, Matthew;Tagliabue, Alessandro;et al
• 通讯作者: et al

Isotopes illustrate vertical transport of anthropogenic Pb by reversible scavenging within Pacific Ocean particle veils

同位素说明太平洋颗粒幕内人为铅通过可逆清除的垂直输送

• DOI: 10.1073/pnas.2219688120
• 发表时间: 2023-06-06
• 期刊: Proceedings of the National Academy of Sciences
• 作者: Lanning, Nathan T.;Jiang, Shuo;Amaral, Vinicius J.;Mateos, Katherine;Steffen, Janelle M.;Lam, Phoebe J.;Boyle, Edward A.;Fitzsimmons, Jessica N.
• 通讯作者: Fitzsimmons, Jessica N.