Quantifying Upper Ocean Export and Remineralization of Bioactive and Particle Reactive Trace Elements along the US GEOTRACES Tahiti to Alaska Transect

量化美国 GEOTRACES 塔希提岛至阿拉斯加断面沿线生物活性和粒子反应性微量元素的上层海洋出口和再矿化

• 批准号: 1735445
• 负责人: Ken Buesseler
• 金额: $ 60.35万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-01 至 2021-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1735445&HistoricalAwards=false
• 关键词: Quantifying; Upper; Ocean; Export; Remineralization

The goal of the international GEOTRACES program is to understand the distributions of trace chemical elements and their isotopes in the oceans. A core approach of GEOTRACES involves coordinated expeditions that measure multiple trace elements and isotopes (TEIs) across key gradients in the ocean, such as changes in productivity, redox/oxygen, boundary scavenging intensity, and hydrothermal activity. However, trace elemental distributions are not enough to meet the GEOTRACES goal to "identify processes and quantify fluxes that control the distribution of TEIs in the ocean and to establish the sensitivity of these changing distributions to environmental conditions." To measure rates of processes requires the use of other measurements, such as natural ly occurring radioactive isotopes. This project involves the measurement of two isotopes of the element thorium on a U.S. GEOTRACES expedition in the Pacific Ocean, from Alaska to Tahiti. Thorium has a tendency to become associated with particles in the oceans, and therefore it can be used to measure the sinking of other elements out of the ocean surface. Thorium isotopes with short half-lives can be used to track processes that occur on faster timescales (weeks or seasons), such as those related to biology in the surface waters of the ocean, while isotopes with longer half-lives are useful for studying processes that occur on longer time scales like that of ocean circulation. This project would use measurements of thorium-234 and thorium-228, with half-lives of 24.1 days and 1.9 years, respectively, to estimate sinking rates of thorium and other elements in the upper ocean.The proposal is broken down into four main activities: 1) Use short-lived Th-234 to estimate particle export and remineralization rates; 2) use ratios of Th-234 to major biogenic phases (e.g., carbon, nitrogen, biogenic silica) and trace elements (e.g. iron, manganese, etc.) to derive flux profiles of other major and trace elements; 3) extend the export and remineralization rates in time/depth using Th-228; 4) examine how changes in #1-3 are related to expected gradients in particle concentration and type, plankton community shifts, net community production, aerosol inputs/dust, physical forcing (e.g. upwelling), hydrothermal plumes, and other features along this GEOTRACES transect. Profiles of total Th-234:U-238 provide quantitative estimates of Th-234 flux vs. depth, which along with parallel size-fractionated particulate profiles of Th-234 and TEIs allow us to empirically calculate the vertical profile of net particle export for any TEI. With high resolution vertical and spatial sampling, the application of Th-234 can be extended below the zone of net removal in the surface ocean to include quantification of particle export and remineralization in the upper several hundred meters. Based upon prior studies, the Th-234 flux model will need to be adjusted for physical transport, especially upwelling across the equator. Selected Th-228 profiles can extend these flux and remineralization estimates even further with depth and over longer time scales. The project will support a Ph.D. student.

国际地理计划计划的目标是了解痕量化学元件及其同位素在海洋中的分布。地理位置的核心方法涉及协调的探险，这些探险探险测量了海洋主要梯度的多个痕量元素和同位素（TEI），例如生产力，氧化还原/氧气的变化，边界清除强度和热液活性。但是，痕量元素分布不足以满足地理位置目标，即“识别和量化控制TEI在海洋中分布的过程并确定这些不断变化的分布对环境条件的敏感性”。为了衡量过程的速率，需要使用其他测量值，例如自然存在的放射性同位素。该项目涉及测量从阿拉斯加到大溪地的太平洋的美国地理探险中的两个元素thorium的同位素。 thor倾向于与海洋中的颗粒相关联，因此可以用来测量其他元素从海面的下沉。具有短半衰期的畸形同位素可用于跟踪在更快的时间尺度（几周或季节）上发生的过程，例如与生物学相关的海洋地表水域中发生的过程，而具有更长半衰期的同位素对于研究在像海洋循环的较长时间尺度上发生的过程有用。该项目将使用Thor-234和Thorium-228的测量结果，分别为24.1天和1。9年，以估计上海中or和其他元素的下沉率，该提议分为四个主要活动：1）使用短期寿命的TH-234来估计粒子的粒子出口和回忆率； 2）使用TH-234与主要生物阶段（例如碳，氮，生物二氧化硅）和微量元素（例如铁，锰等）的比率来得出其他主要和微量元素的通量谱； 3）使用TH-228扩大时间/深度的出口和回忆率； 4）检查＃1-3中的变化与颗粒浓度和类型，浮游生物社区变化，净社区生产，气溶胶输入/灰尘，物理强迫（例如上升流动），水热羽流以及该geotraces沿该区域的其他特征有关。 TH-234：U-238的概况提供了TH-​​234通量与深度的定量估计，并与Th-234和TEIS的平行尺寸分级的颗粒曲线以及TEIS的平行尺寸分级型号一起，使我们能够在任何TEI中统计地计算净粒子导出的垂直谱图。使用高分辨率的垂直和空间采样，可以将TH-234的应用扩展到地表海中的净去除区以下，以包括在几百米的上部定量粒子出口和回忆性。基于先前的研究，需要调整TH-234通量模型，以进行物理运输，尤其是在赤道横跨赤道的上升。选定的TH-228轮廓可以随着深度和更长的时间尺度进一步扩展这些通量和回忆性估计。该项目将支持博士学位。学生。

项目成果

The GEOTRACES Intermediate Data Product 2017

• DOI: 10.1016/j.chemgeo.2018.05.040
• 发表时间: 2018-08
• 期刊: Chemical Geology
• 影响因子: 3.9
• 作者: R. Schlitzer;R. Anderson;Elena Masferrer Dodas;M. Lohan;W. Geibert;A. Tagliabue;A. Bowie;C. Jeandel;M. T. Maldonado;W. Landing;Donna Cockwell;Cyril Abadie;W. Abouchami;E. Achterberg;A. Agather;Ana Aguliar-Islas;H. V. Aken;M. B. Andersen;C. Archer;M. Auro;H. Baar;O. Baars;A. Baker;K. Bakker;C. Basak;M. Baskaran;N. Bates;D. Bauch;P. Beek;M. Behrens;Erin E. Black;K. Bluhm;L. Bopp;H. Bouman;K. Bowman;J. Bown;P. Boyd;M. Boyé;E. Boyle;Pierre Branellec;Luke Bridgestock;G. Brissebrat;T. Browning;K. Bruland;H. Brumsack;M. Brzezinski;C. Buck;K. Buck;K. Buesseler;Abby Bull;E. Butler;P. Cai;P. Mor;D. Cardinal;C. Carlson;Gonzalo Carrasco;N. Casacuberta;K. Casciotti;M. Castrillejo;E. Chamizo;R. Chance;M. Charette;J. Chaves;Hai-Lan Cheng;F. Chever;M. Christl;T. Church;I. Closset;A. Colman;T. Conway;D. Cossa;P. Croot;J. Cullen;G. Cutter;C. Daniels;F. Dehairs;Feifei Deng;Huong Thi Dieu;B. Duggan;G. Dulaquais;C. Dumousseaud;Yolanda Echegoyen-Sanz;R. Edwards;M. Ellwood;E. Fahrbach;J. Fitzsimmons;A. Flegal;M. Fleisher;T. Flierdt;M. Frank;J. Friedrich;F. Fripiat;H. Fröllje;S. Galer;T. Gamo;R. Ganeshram;J. García-Orellana;E. Garcia-Solsona;M. Gault‐Ringold;E. George;L. Gerringa;M. Gilbert;J. Godoy;S. Goldstein;S. R. Gonzalez;K. Grissom;C. R. Hammerschmidt;A. E. Hartman;C. Hassler;E. Hathorne;M. Hatta;N. Hawco;C. T. Hayes;L. Heimbürger;Joshua Helgoe;M. Heller;G. Henderson;P. Henderson;S. Heuven;Peng Ho;T. Horner;Y. Hsieh;Kuo‐Fang Huang;M. Humphreys;K. Isshiki;Jeremy E. Jacquot;D. J. Janssen;W. Jenkins;S. John;E. Jones;Janice L. Jones;D. Kadko;Rick Kayser;T. Kenna;R. Khondoker;Taejin Kim;L. Kipp;J. Klar;M. Klunder;S. Kretschmer;Y. Kumamoto;P. Laan;M. Labatut;F. Lacan;P. Lam;M. Lambelet;C. Lamborg;F. L. Moigne;E. L. Roy;O. Lechtenfeld;Jong‐Mi Lee;P. Lherminier;S. Little;M. López-Lora;Yanbin Lu;P. Masqué;Edward Mawji;C. McClain;C. Measures;S. Mehic;J. M. Barraqueta;P. Merwe;R. Middag;S. Mieruch;A. Milne;Tomoharu Minami;J. Moffett;G. Moncoiffe;W. Moore;P. Morris;P. Morton;Y. Nakaguchi;N. Nakayama;J. Niedermiller;J. Nishioka;Akira Nishiuchi;A. Noble;H. Obata;S. Ober;D. Ohnemus;J. Ooijen;J. O'Sullivan;S. Owens;K. Pahnke;M. Paul;F. Pavia;L. Pena;B. Peters;F. Planchon;H. Planquette;C. Pradoux;Viena Puigcorbé;P. Quay;F. Quéroué;A. Radic;S. Rauschenberg;M. Rehkämper;R. Rember;T. Remenyi;J. Resing;J. Rickli;S. Rigaud;M. Rijkenberg;S. Rintoul;L. Robinson;M. Roca-Martí;V. Rodellas;Tobias Roeske;J. Rolison;M. Rosenberg;S. Roshan;M. Loeff;E. Ryabenko;M. Saito;L. Salt;V. Sanial;G. Sarthou;Christina Schallenberg;U. Schauer;H. Scher;C. Schlosser;B. Schnetger;Peter Scott;P. Sedwick;I. Semiletov;R. Shelley;R. Sherrell;A. Shiller;D. Sigman;Sunil Kumar Singh;H. Slagter;Emma Slater;W. Smethie;H. Snaith;Y. Sohrin;B. Sohst;J. Sonke;S. Speich;R. Steinfeldt;G. Stewart;T. Stichel;C. Stirling;J. Stutsman;G. Swarr;J. Swift;Alexander L. Thomas;K. Thorne;Claire P. Till;Ralph Till;A. Townsend;Emily Townsend;R. Tuerena;B. Twining;D. Vance;Sue Velazquez;C. Venchiarutti;M. Villa-Alfageme;Sebastián M. Vivancos;A. Voelker;B. Wake;M. Warner;R. Watson;E. V. Weerlee;M. A. Weigand;Y. Weinstein;D. Weiss;A. Wisotzki;E. Woodward;Jingfeng Wu;Yingzhe Wu;K. Wuttig;N. Wyatt;Yang Xiang;R. Xie;Z. Xue;Hisayuki Yoshikawa;Jing Zhang;Pu Zhang;Ye Zhao;Linjie Zheng;Xin-Yuan Zheng;M. Zieringer;L. Zimmer;P. Ziveri;P. Zunino;C. Zurbrick

Flux of Particulate Elements in the North Atlantic Ocean Constrained by Multiple Radionuclides

受多种放射性核素约束的北大西洋颗粒元素通量

• DOI: 10.1029/2018gb005994
• 发表时间: 2018
• 期刊: Global Biogeochemical Cycles
• 影响因子: 5.2
• 作者: Hayes, Christopher T.;Black, Erin E.;Anderson, Robert F.;Baskaran, Mark;Buesseler, Ken O.;Charette, Matthew A.;Cheng, Hai;Cochran, J. Kirk;Edwards, R. Lawrence;Fitzgerald, Patrick
• 通讯作者: Fitzgerald, Patrick