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: 1851558
• 负责人: Michael Landry
• 金额: $ 66.83万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 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 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1851558&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.

在东印度洋（IO）的西北澳大利亚和印度尼西亚之间的小区域是唯一已知的南蓝鳍金枪鱼（SBT）的产卵地，南蓝鳍金枪鱼是一种极度濒危的顶级海洋捕食者。成年SBT每年从高纬度觅食区迁徙数千英里到这些热带水域产卵，那里的食物浓度平均低于支持其幼虫最佳觅食和生长的水平。这个栖息地的许多关键方面都鲜为人知，例如维持系统生产力的氮营养的主要来源，浮游食物网如何运作以产生金枪鱼幼虫喜欢的不寻常类型的浮游动物猎物，以及成年产卵金枪鱼如何利用与海洋锋面和漩涡相关的栖息地质量的环境差异来给它们的幼虫更大的快速生长和生存成功的机会。该项目于2021年初在SBT产卵高峰期进行了为期38天的考察，调查了这些问题。该项目是美国对第二次国际印度洋考察（IIOE-2）的贡献，旨在促进对研究较少的印度洋东部生物地球化学和生态动力学的理解。这是第一次详细研究连接太平洋和印度洋水域的氮和碳循环。SBT幼虫与其他大型金枪鱼和长嘴鱼物种的幼虫共同的饮食偏好也可能使所获得的见解广泛适用于了解其他海洋生态系统中顶级消费者的幼虫招募问题。这项研究的新资料将加强国际上对SBT的管理工作。大型金枪鱼和长嘴鱼的幼虫共同的饮食偏好也可能将我们对其他海洋顶级消费者的认识广泛地扩展到其他海洋顶级消费者，包括在美国墨西哥湾水域产卵的大西洋蓝鳍金枪鱼。端到端的研究方法强调了物理环境变化、生物地球化学和浮游生物食物网之间的联系，从而产生了具有魅力和经济价值的鱼类生产，这是通过“学校科学家”开发教育工具和模块的主题。佛罗里达州立大学海洋-大气预测研究中心的项目，通过一个为夏威夷代表性不足的学生加强STEM学习途径的项目，以及通过在圣地亚哥伯奇水族馆展示的公共宣传产品。该研究还旨在支持身临其境的实地体验，向有才华的高中生介绍海洋研究，目标是为佛罗里达州西北部农村地区代表性不足的学生开发一个可持续的海洋相关教育项目。南蓝鳍金枪鱼（SBT）从高纬度的觅食地长途迁徙，只在热带东印度洋（IO）的一个小的少营养区域产卵，该区域具有丰富的中尺度结构，受复杂的洋流和季节性逆转的季风的驱动。为了生存，SBT幼虫必须在环境条件下快速进食和生长，这些环境条件挑战了对贫瘠的开放海洋系统中食物网结构和功能关系的传统理解。枝海动物和羽科桡足动物是SBT幼虫的首选猎物，对它们的研究很少，对幼虫的营养转移效率有不同的影响。维持该地区新产量的氮源（固氮与源自太平洋的深层硝酸盐）的差异，也影响了可能选择猎物类型（特别是枝海洋动物）的条件，从而提高SBT幼虫的转移效率和生长速度。这些氮源对IO生态系统的相对重要性可能会影响SBT对预计增加的海洋分层的恢复能力。本次研究考察了新产量、食物网结构和营养通量的中尺度变化如何影响SBT幼虫的摄食和生长条件。跨中尺度取样的特点是测试假设的关系，这些关系将SBT幼虫的摄食和猎物偏好（肠道内容物）、生长速度（耳石分析）和营养位置（TP）与成年产卵者选择的水域环境条件联系起来。利用氨基酸化合物特异性同位素分析（CSIA-AA）确定了幼虫及其猎物的营养位置。拉格朗日实验通过测量水柱14C生产力、N2固定、15NO3-吸收和硝化作用来研究潜在的过程速率和关系；群落生物量和组成（流式细胞术、色素、显微镜、原位成像、遗传分析）；以及通过微、中浮游动物放牧、再矿化和输出的营养通量。通过CSIA-AA （N来源，TP）、15n约束预算和模型将研究的生物地球化学和食物网要素联系起来。项目要素包括端到端的耦合生物地球化学-营养研究，这是以前从未对任何远洋生态系统进行过的研究。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

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

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

Microbial community biomass, production and grazing along 110°E in the eastern Indian Ocean

东印度洋110°E沿岸微生物群落生物量、生产和放牧

• DOI: 10.1016/j.dsr2.2022.105134
• 发表时间: 2022
• 期刊: Deep Sea Research Part II: Topical Studies in Oceanography
• 作者: Landry, Michael R.;Hood, Raleigh R.;Davies, Claire H.;Selph, Karen E.;Antoine, David;Carl, Mika C.;Beckley, Lynnath E.
• 通讯作者: Beckley, Lynnath E.

Active prey selection in developing larvae of Atlantic bluefin tuna ( Thunnus thynnus ) in spawning grounds of the Gulf of Mexico

墨西哥湾产卵场大西洋蓝鳍金枪鱼幼体发育中的主动猎物选择

• DOI: 10.1093/plankt/fbab020
• 发表时间: 2021
• 期刊: Journal of Plankton Research
• 影响因子: 2.1
• 作者: Shiroza, Akihiro;Malca, Estrella;Lamkin, John T.;Gerard, Trika;Landry, Michael R.;Stukel, Michael R.;Laiz-Carrión, Raúl;Swalethorp, Rasmus;Dolan, ed., John
• 通讯作者: Dolan, ed., John

Bluefin Larvae in Oligotrophic Ocean Foodwebs, investigations of nutrients to zooplankton: overview of the BLOOFINZ-Gulf of Mexico program

寡营养海洋食物网中的蓝鳍金枪鱼幼虫，浮游动物营养物质的调查：BLOOFINZ-墨西哥湾计划概述

• DOI: 10.1093/plankt/fbac038
• 发表时间: 2022
• 期刊: Journal of Plankton Research
• 影响因子: 2.1
• 作者: Gerard, Trika;Lamkin, John T.;Kelly, Thomas B.;Knapp, Angela N.;Laiz-Carrión, RaÚl;Malca, Estrella;Selph, Karen E.;Shiroza, Akihiro;Shropshire, Taylor A.;Stukel, Michael R.
• 通讯作者: Stukel, Michael R.