Collaborative Research: Mesoscale variability in nitrogen sources and food-web dynamics supporting larval southern bluefin tuna in the eastern Indian Ocean

合作研究：支持东印度洋南部蓝鳍金枪鱼幼体的氮源和食物网动态的中尺度变化

• 批准号: 1851347
• 负责人: Sven Kranz
• 金额: $ 52.78万
• 依托单位: Florida State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1851347&HistoricalAwards=false
• 关键词: Collaborative; Research; Mesoscale; variability; nitrogen

The small area between NW Australia and Indonesia in the eastern Indian Ocean (IO) is the only known spawning ground of Southern Bluefin Tuna (SBT), a critically endangered top marine predator. Adult SBT migrate thousands of miles each year from high latitude feeding areas to lay their eggs in these tropical waters, where food concentrations on average are below levels that can support optimal feeding and growth of their larvae. Many critical aspects of this habitat are poorly known, such as the main source of nitrogen nutrient that sustains system productivity, how the planktonic food web operates to produce the unusual types of zooplankton prey that tuna larvae prefer, and how environmental differences in habitat quality associated with ocean fronts and eddies might be utilized by adult spawning tuna to give their larvae a greater chance for rapid growth and survival success. This project investigates these questions on a 38-day expedition in early 2021, during the peak time of SBT spawning. This project is a US contribution to the 2nd International Indian Ocean Expedition (IIOE-2) that advances understanding of biogeochemical and ecological dynamics in the poorly studied eastern IO. This is the first detailed study of nitrogen and carbon cycling in the region linking Pacific and IO waters. The shared dietary preferences of SBT larvae with those of other large tuna and billfish species may also make the insights gained broadly applicable to understanding larval recruitment issues for top consumers in other marine ecosystems. New information from the study will enhance international management efforts for SBT. The shared larval dietary preferences of large tuna and billfish species may also extend the insights gained broadly to many other marine top consumers, including Atlantic bluefin tuna that spawn in US waters of the Gulf of Mexico. The end-to-end study approach, highlights connections among physical environmental variability, biogeochemistry, and plankton food webs leading to charismatic and economically valuable fish production, is the theme for developing educational tools and modules through the ?scientists-in-the-schools? program of the Center for Ocean-Atmospheric Prediction Studies at Florida State University, through a program for enhancing STEM learning pathways for underrepresented students in Hawaii, and through public outreach products for display at the Birch Aquarium in San Diego. The study also aims to support an immersive field experience to introduce talented high school students to marine research, with the goal of developing a sustainable marine-related educational program for underrepresented students in rural northwestern Florida.Southern Bluefin Tuna (SBT) migrate long distances from high-latitude feeding grounds to spawn exclusively in a small oligotrophic area of the tropical eastern Indian Ocean (IO) that is rich in mesoscale structures, driven by complex currents and seasonally reversing monsoonal winds. To survive, SBT larvae must feed and grow rapidly under environmental conditions that challenge conventional understanding of food-web structure and functional relationships in poor open-ocean systems. The preferred prey of SBT larvae, cladocerans and Corycaeidae copepods, are poorly studied and have widely different implications for trophic transfer efficiencies to larvae. Differences in nitrogen sources - N fixation vs deep nitrate of Pacific origin - to sustain new production in the region also has implications for conditions that may select for prey types (notably cladocerans) that enhance transfer efficiency and growth rates of SBT larvae. The relative importance of these N sources for the IO ecosystem may affect SBT resiliency to projected increased ocean stratification. This research expedition investigates how mesoscale variability in new production, food-web structure and trophic fluxes affects feeding and growth conditions for SBT larvae. Sampling across mesoscale features tests hypothesized relationships linking variability in SBT larval feeding and prey preferences (gut contents), growth rates (otolith analyses) and trophic positions (TP) to the environmental conditions of waters selected by adult spawners. Trophic Positions of larvae and their prey are determined using Compound-Specific Isotope Analyses of Amino Acids (CSIA-AA). Lagrangian experiments investigate underlying process rates and relationships through measurements of water-column 14C productivity, N2 fixation, 15NO3- uptake and nitrification; community biomass and composition (flow cytometry, pigments, microscopy, in situ imaging, genetic analyses); and trophic fluxes through micro- and mesozooplankton grazing, remineralization and export. Biogeochemical and food web elements of the study are linked by CSIA-AA (N source, TP), 15N-constrained budgets and modeling. The project elements comprise an end-to-end coupled biogeochemistry-trophic study as has not been done previously for any pelagic ecosystem.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.

澳大利亚西北部和印度洋东部印度尼西亚（IO）之间的小区域是南部蓝鳍金枪鱼（SBT）唯一已知的产卵地，这是一种濒临灭绝的顶级海洋捕食者。 成年SBT每年从高纬度喂养区迁移数千英里，以在这些热带水域中产卵，在这些热带水域中，食物浓度平均低于水平，可以支持其幼虫的最佳喂养和生长。 该栖息地的许多关键方面是鲜为人知的，例如，维持系统生产力的氮营养素的主要来源，浮游食品网络如何运作，以产生金枪鱼幼虫更喜欢的多种浮游动物群的异常类型，以及与栖息地质量相关的环境差异如何与成年的Spak and Specs and Specive相关的栖息地质量以及如何利用他们的生存机会，以使他们能够促进他们的成功率和较大的机会。 该项目在SBT产卵的高峰时段对2021年初的38天探险进行了调查。 该项目是美国对第二届国际印度洋探险队（IIOE-2）的贡献，该项目在研究不佳的IO中对生物地球化学和生态动态的理解提高了。 这是与太平洋和IO水域联系的地区的氮和碳循环的首次详细研究。 SBT幼虫与其他大型金枪鱼和Billfish物种的饮食偏好也可能使人们广泛适用于了解其他海洋生态系统中顶级消费者的幼体招募问题。 该研究的新信息将增强SBT的国际管理工作。 大金枪鱼和Billfish物种的共同幼体饮食偏好也可能扩展到许多其他海洋顶级消费者，包括在墨西哥湾美国水域产卵的大西洋蓝鳍金枪鱼。 端到端的研究方法突出了物理环境变异性，生物地球化学和浮游生物食品网之间的联系，从而导致具有超凡魅力和经济有价值的鱼类生产，这是否是通过“科学家”在学科中开发教育工具和模块的主题？佛罗里达州立大学海洋 - 大气预测中心计划，通过一项计划，以增强夏威夷代表性不足的学生的STEM学习途径，并通过公共外展产品在圣地亚哥的桦木水族馆展出。 The study also aims to support an immersive field experience to introduce talented high school students to marine research, with the goal of developing a sustainable marine-related educational program for underrepresented students in rural northwestern Florida.Southern Bluefin Tuna (SBT) migrate long distances from high-latitude feeding grounds to spawn exclusively in a small oligotrophic area of​​ the tropical eastern Indian Ocean (IO) that is富含中尺度结构，由复杂的电流和季节性逆转季风风驱动。 为了生存，SBT幼虫必须在环境条件下迅速喂食和生长，这挑战了贫困开放海洋系统中食品 - web结构和功能关系的常规理解。 SBT幼虫，cladocerans和corycaeidae copepods的首选猎物的研究很差，并且对对幼虫的营养转移效率的影响很大。 氮源的差异 - N固定与太平洋的深硝酸盐的差异 - 维持该地区的新产量也对可能选择猎物类型（尤其是Cladocerans）的条件有影响，从而提高了SBT幼虫的转移效率和增长率。 这些N来源对IO生态系统的相对重要性可能会影响SBT的弹性对预计的海洋分层增加。 这项研究探险调查了新生产，食品 - 野生型结构和营养通量中的中尺度变异性如何影响SBT幼虫的喂养和生长条件。 在中尺度跨尺度特征进行的采样测试，假设的关系将SBT幼体喂养和猎物偏好（肠含量），生长速率（耳梯分析）和营养位置（TP）与成人生成生成量选择的潮流的环境条件联系起来。 使用氨基酸（CSIA-AA）的化合物特异性同位素分析确定幼虫及其猎物的营养位置。 Lagrangian实验通过测量水列14C生产率，N2固定，15NO3-摄取和硝化来研究基本的过程率和关系；社区生物量和组成（流式细胞仪，色素，显微镜，原位成像，遗传分析）；以及通过微观和中龙兰克顿放牧，回忆和出口的营养通量。 该研究的生物地球化学和食物网元素由CSIA-AA（N来源，TP），15N受限的预算和建模联系在一起。 该项目元素包括一项端到端耦合生物地球化学研究研究，以前尚未针对任何层状生态系统进行。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛的审查标准通过评估来通过评估来支持的。

项目成果

LATERAL ADVECTION OF PARTICULATE ORGANIC MATTER IN THE EASTERN INDIAN OCEAN

• DOI: 10.1029/2023jc019723
• 发表时间: 2023-05
• 期刊: Journal of Geophysical Research: Oceans
• 作者: Opeyemi Kehinde;M. Bourassa;S. Kranz;M. Landry;T. Kelly;M. Stukel

Sinking carbon, nitrogen, and pigment flux within and beneath the euphotic zone in the oligotrophic, open-ocean Gulf of Mexico

• DOI: 10.1093/plankt/fbab001
• 发表时间: 2021-02
• 期刊: Journal of Plankton Research
• 影响因子: 2.1
• 作者: M. Stukel;T. Kelly;M. Landry;K. Selph;R. Swalethorp

Constraining the sources of nitrogen fueling export production in the Gulf of Mexico using nitrogen isotope budgets

• DOI: 10.1093/plankt/fbab049
• 发表时间: 2021-08
• 期刊: Journal of Plankton Research
• 影响因子: 2.1
• 作者: A. Knapp;Rachel K. Thomas;M. Stukel;T. Kelly;M. Landry;K. Selph;E. Malca;T. Gerard;J. Lamkin

Microbial food web dynamics in the oceanic Gulf of Mexico

墨西哥湾海洋微生物食物网动态

• DOI: 10.1093/plankt/fbab021
• 发表时间: 2021
• 期刊: Journal of Plankton Research
• 影响因子: 2.1
• 作者: Landry, Michael R;Selph, Karen E;Stukel, Michael R;Swalethorp, Rasmus;Kelly, Thomas B;Beatty, Jennifer L;Quackenbush, Cameron R
• 通讯作者: Quackenbush, Cameron R

Phytoplankton community composition and biomass in the oligotrophic Gulf of Mexico

墨西哥湾贫营养浮游植物群落组成和生物量

• DOI: 10.1093/plankt/fbab006
• 发表时间: 2021
• 期刊: Journal of Plankton Research
• 影响因子: 2.1
• 作者: E Selph, Karen;Swalethorp, Rasmus;R Stukel, Michael;B Kelly, Thomas;N Knapp, Angela;Fleming, Kelsey;Hernandez, Tabitha;R Landry, Michael
• 通讯作者: R Landry, Michael