Collaborative Research: Diel physiological rhythms in a tropical oceanic copepod

合作研究：热带海洋桡足类的昼夜生理节律

• 批准号: 1829378
• 负责人: Ann Tarrant
• 金额: $ 22.7万
• 依托单位: Woods Hole Oceanographic Institution
• 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: 2018-10-01 至 2021-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1829378&HistoricalAwards=false
• 关键词: Collaborative; Research; Diel; physiological; rhythms

The daily vertical migration (DMV) of zooplankton and fish across hundreds of meters between shallow and deep waters is a predominant pattern in pelagic ecosystems. This migration has consequences for biogeochemical cycling as it moves a substantial portion of fixed carbon and nitrogen (an estimated 15 to 40 % of the total global organic export) from the surface directly to depth where it feeds the midwater food chain and sequesters nutrients away from atmospheric mixing. Estimates and predictions of these fluxes are, however, poorly understood at present. New observations have shown that one source of uncertainty is due to the assumption that metabolic rates and processes do not vary over the course of the day, except based on changes in temperature and oxygen availability. Rates are, however, also driven by differences in feeding, swimming behavior, and underlying circadian cycles. The objective of this project is to improve the ability of scientists to understand and predict zooplankton contributions to the movement of carbon and nitrogen in the ocean by detailing daily changes in physiological processes of these organisms. By producing a set of respiration and excretion measurements over a daily time series, paired with simultaneously collected gene and protein expression patterns for an abundant vertically migratory species, the investigators will provide unprecedented and predictive insight into how changes in the environment affect the contribution of zooplankton to biogeochemical fluxes. The sampling design of the project will advance discovery and understanding by providing hands-on training opportunities to at least two undergraduate researchers. The project will broaden dissemination of the research via development of an educational module, focusing on rhythms in the ocean. The module will initially be piloted with the Bermuda Institute of Ocean Sciences (BIOS) summer camp students and then disseminated through the BIOS Explorer program, the Teacher Resources Page on the BIOS website, and published in a peer-reviewed educational journal.This project will characterize the metabolic consequences of daily physiological rhythms and DVM for a model zooplankton species, the abundant subtropical copepod Pleuromamma xiphias. Flux processes (oxygen consumption, carbon dioxide production, production of ammonium and fecal pellet production) will be interrogated using directed experiments testing the effects of temperature, feeding and circadian cycle. Circadian cycling will further be examined using transcriptomic and proteomic profiling. These experiments will be related to field samples taken at 6-h intervals over the course of the diel migration using an integrated suite of molecular and organismal metrics. Combined organismal, transcriptomic and proteomic profiles will provide an understanding of which metabolic pathways and associated flux products vary in relation to particular environmental variables (food, light cycle, temperature). Diel variation in metabolic rates will also be assessed across seasons and species using other important migratory groups (pteropod, euphausiid, and another copepod). The metabolic data will then be contextualized with abundance estimates from archived depth-stratified tows to allow scaling to community-level patterns and will be used to improve calculations of zooplankton contribution to particulate organic carbon, nitrogen and respiratory active flux. The results of this study will both improve our flux estimates and provide predictive insight into how various environmental variables influence the underlying physiological pathways generating carbon and nitrogen flux.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.

浮游动物和鱼类在浅水和深水之间跨越数百米的每日垂直迁徙是远洋生态系统中的一种主要模式。这种迁移对生物地球化学循环产生了影响，因为它将相当大一部分固定碳和氮(估计占全球有机出口总量的15%至40%)从表层直接转移到深海，在那里它喂养中水食物链，并从大气混合中隔离营养物质。然而，目前人们对这些通量的估计和预测知之甚少。新的观察表明，不确定性的一个来源是假设代谢率和代谢过程在一天中不会改变，除非基于温度和氧气供应的变化。然而，摄食、游泳行为和潜在的昼夜节律的不同也决定了这种比率。该项目的目标是通过详细描述浮游动物的生理过程的日常变化，提高科学家了解和预测浮游动物对海洋中碳和氮运动的贡献的能力。通过产生一套每日时间序列的呼吸和排泄测量，并结合同时收集的大量垂直迁徙物种的基因和蛋白质表达模式，研究人员将提供前所未有的和预测性的洞察，了解环境变化如何影响浮游动物对生物地球化学通量的贡献。该项目的抽样设计将通过为至少两名本科生研究人员提供实践培训机会来促进发现和理解。该项目将通过开发一个侧重于海洋节律的教育模块来扩大研究的传播。该模块最初将在百慕大海洋科学研究所(BIOS)夏令营的学生中试行，然后通过BIOS探索者计划、BIOS网站上的教师资源页面进行传播，并发表在同行评议的教育期刊上。该项目将描述浮游动物模型物种--丰富的亚热带桡足类--Pleuromama xiphias的日常生理节律和DVM的新陈代谢结果。通量过程(氧气消耗、二氧化碳生产、氨生产和粪便颗粒生产)将通过测试温度、进食和昼夜循环的影响的直接实验来询问。将使用转录和蛋白质组学分析进一步研究昼夜节律循环。这些实验将与在Diel迁移过程中每隔6小时采集一次的现场样本有关，使用一套完整的分子和生物指标。结合生物体、转录组和蛋白质组学将提供对哪些代谢途径和相关的通量产物与特定环境变量(食物、光周期、温度)相关的变化的理解。代谢率的昼夜变化也将使用其他重要的迁徙类群(翼足类、真足类和另一种桡足类)来评估不同季节和物种。然后，代谢数据将与存档的深度分层拖网的丰度估计联系起来，以便能够调整到群落水平的模式，并将用于改进浮游动物对颗粒有机碳、氮和呼吸活动通量的贡献的计算。这项研究的结果将改善我们的通量估计，并为各种环境变量如何影响产生碳和氮通量的潜在生理途径提供预测性洞察。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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

Small copepods could play a big role in the marine carbon cycle

小型桡足类动物可能在海洋碳循环中发挥重要作用

• DOI: 10.1002/bies.202000267
• 发表时间: 2020
• 期刊: BioEssays
• 影响因子: 4
• 作者: Tarrant, Ann M.

Diel metabolic patterns in a migratory oceanic copepod

迁徙的海洋桡足类动物的昼夜代谢模式

• DOI: 10.1016/j.jembe.2021.151643
• 发表时间: 2021
• 期刊: Journal of Experimental Marine Biology and Ecology
• 影响因子: 2
• 作者: Tarrant, Ann M.;McNamara-Bordewick, Nora;Blanco-Bercial, Leocadio;Miccoli, Andrea;Maas, Amy E.
• 通讯作者: Maas, Amy E.