Collaborative Research: Isotopic Indicators for Mechanisms of Organic Matter Degradation in the Northeast Pacific (EXPORTS)

合作研究：东北太平洋有机物降解机制的同位素指标（出口）

• 批准号: 1830016
• 负责人: Hilary Close
• 金额: $ 48.84万
• 依托单位: University of Miami
• 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: 2018-08-15 至 2023-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1830016&HistoricalAwards=false
• 关键词: Collaborative; Research; Isotopic; Indicators; Mechanisms

The biological pump is largely responsible for the vertical transport of organic carbon from the surface to the ocean interior. However, only a small fraction of organic material produced in surface waters is sequestered in the deep ocean. The rest is consumed, or respired, by bacteria and larger organisms. The overarching goal of the proposed work is to characterize the relative influences of bacteria versus larger organisms on the degradation of organic material with depth. Guided by recent results from the subtropical Pacific, the investigators will use measurements of stable isotopes of nitrogen in different amino acids (compound-specific isotopic analysis of amino acids, known as AA-CSIA), along with measurements of the abundances of different forms of amino acids, and other parameters derived from these analyses to identify how the partitioning and flux of large and small particles are affected by different degradation processes. By improving the interpretive power of the AA-CSIA technique the investigators propose to determine: 1) the relative importance of microbial and zooplankton consumption on the efficiency of the biological carbon pump in the subarctic northeast Pacific, and 2) how much microbially-altered small particles fuel the metabolisms of mid-water zooplankton. This work capitalizes on an existing, comprehensive field program (NASA EXPORTS) specifically focused on building a predictive framework relating surface ocean properties to the vertical flux of organic carbon. The tremendous amount of data to be collected on all aspects of the biological pump as part of the EXPORTS program will aid the development and interpretation of the investigators' amino acid isotopic tool. Results will be broadly communicated via production and distribution of several episodes of Voice of the Sea, a local television program that will air in Hawaii and across many Pacific islands. Episodes also will be posted online and publicized through social media to the south Florida community. This project will support a Ph.D. student and an undergraduate student at University of Miami, which serves a 25% Hispanic population, and an M.S. student and an undergraduate student at University of Hawaii, which is a designated minority-serving institution.The proposed work introduces a new geochemical framework to distinguish microbial versus zooplankton alteration of marine organic matter. Piloted on samples from the subtropical Pacific, this approach interrogates unamended sinking material directly, using amino acid compound-specific isotopic analysis (AA-CSIA) to determine the progressive, cumulative impact of microbial and zooplankton degradative pathways. The proposed work (1) will extend this interpretive framework to explicitly define end-member signatures such as fecal pellets and will apply this refined method to a study site in the subarctic northeast Pacific to (2) determine the vertical progression of degradative mechanisms in an oceanographic location with contrasting productivity and vertical length scales of flux attenuation and (3) determine whether microbially- degraded biomass is important for fueling midwater metazoans under contrasting carbon flux conditions. The proposed work will be conducted in collaboration with the NASA EXPORTS program at the Ocean Station Papa time-series site. Teaming with this program presents a unique opportunity to refine AA-CSIA interpretation in parallel with intensive data collection defining productivity, particle size distribution and flux, and numerous biological parameters. In comparing subtropical and subarctic Pacific locations, the proposed work will test how differences in productivity and plankton community structure influence vertical patterns of consumption and alteration of phytodetritus by microbes and zooplankton, from surface to mesopelagic depths.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.

生物泵在很大程度上是有机碳从表面到海洋内部垂直运输的原因。但是，在深海中只有一小部分在地表水中产生的有机材料。其余的被细菌和较大的生物消耗或呼吸。拟议工作的总体目标是表征细菌与大生物对有机材料降解的相对影响。在亚热带太平洋的最新结果的指导下，研究人员将在不同氨基酸（化合物特异性的同位素分析氨基酸（称为AA-CSIA）中使用稳定同位素的测量，以及不同形式的丰度的测量值氨基酸以及从这些分析得出的其他参数，以确定大小颗粒的分配和通量如何受到不同降解过程的影响。通过提高研究人员提出的AA-CSIA技术的解释能力来确定：1）微生物和浮游动物消耗对亚北极亚太平洋生物碳泵的效率的相对重要性，以及2）2）微生物变化的小型小型小型小型小型小型小的小型小型小细胞颗粒为中水浮游动物的代谢燃烧。这项工作利用了现有的综合现场计划（NASA出口），专门针对建立一个预测框架，该框架与有机碳的垂直通量有关。作为出口计划的一部分，在生物泵的各个方面收集的大量数据将有助于研究人员的氨基酸同位素工具的开发和解释。结果将通过生产和发行几集《海洋之声》（Of The Sea）的生产和分发，这是一项当地电视节目，该电视节目将在夏威夷和许多太平洋岛屿上播出。情节还将在线发布，并通过社交媒体向南佛罗里达社区发布。该项目将支持博士学位。迈阿密大学的学生和一名本科生，为西班牙裔人口提供25％的人和硕士学位。夏威夷大学的学生和一名本科生，该大学是指定的少数派服务机构。拟议的工作引入了一个新的地球化学框架，以区分微生物与浮游动物有机物的变化。这种方法是在亚热带太平洋的样品中试用的，使用氨基酸化合物特异性同位素分析（AA-CSIA）直接询问未经保护的沉没材料，以确定微生物和浮游动物降解途径的渐进性，累积影响。拟议的工作（1）将将此解释性框架扩展到明确定义诸如粪便颗粒之类的最终成员的签名，并将这种精致的方法应用于亚北方太平洋亚洲太平洋的研究地点，以确定（2）确定降级机制的垂直进展海洋位置具有对比的生产率和通量衰减的垂直长度尺度，并且（3）确定微生物降解的生物量对于在对比碳通量条件下加油中的中水后生动物是否很重要。拟议的工作将与海洋站Papa Time系列网站的NASA出口计划合作进行。与该计划合作提供了一个独特的机会，可以与密集的数据收集以及定义生产力，粒度分布和通量以及许多生物学参数并行的AA-CSIA解释。在比较亚热带和亚北极太平洋地区时，拟议的工作将测试生产力和浮游生物群落结构的差异如何影响垂直的消费模式，并通过微生物和浮游动物的植物质量变化，从地表到中质深度。认为值得通过基金会的智力优点和更广泛影响的评论标准来评估值得支持。

项目成果

An operational overview of the EXport Processes in the Ocean from RemoTe Sensing (EXPORTS) Northeast Pacific field deployment

• DOI: 10.1525/elementa.2020.00107
• 发表时间: 2021
• 期刊: Elementa: Science of the Anthropocene
• 作者: David A. Siegel;I. Cetinić;Jason R. Graff;Craig M. Lee;N. Nelson;M. Perry;I. S. Ramos;D. Steinberg-D.

Deconvolving mechanisms of particle flux attenuation using nitrogen isotope analyses of amino acids

使用氨基酸氮同位素分析的粒子通量衰减去卷积机制

• DOI: 10.1002/lno.12398
• 发表时间: 2023
• 期刊: Limnology and Oceanography
• 影响因子: 4.5
• 作者: Wojtal, Paul K.;Doherty, Shannon C.;Shea, Connor H.;Popp, Brian N.;Benitez‐Nelson, Claudia R.;Buesseler, Ken O.;Estapa, Margaret L.;Roca‐Martí, Montserrat;Close, Hilary G.
• 通讯作者: Close, Hilary G.

Small particles and heterotrophic protists support the mesopelagic zooplankton food web in the subarctic northeast Pacific Ocean

小颗粒和异养原生生物支持亚北极东北太平洋中层浮游动物食物网

• DOI: 10.1002/lno.12397
• 发表时间: 2023
• 期刊: Limnology and Oceanography
• 影响因子: 4.5
• 作者: Shea, Connor H.;Wojtal, Paul K.;Close, Hilary G.;Maas, Amy E.;Stamieszkin, Karen;Cope, Joseph S.;Steinberg, Deborah K.;Wallsgrove, Natalie;Popp, Brian N.
• 通讯作者: Popp, Brian N.