Collaborative Research: Hypoxia in Marine Ecosystems: Implications for Neritic Copepods

合作研究：海洋生态系统缺氧：对浅海桡足类的影响

• 批准号: 0961942
• 负责人: James Pierson
• 金额: $ 111.47万
• 依托单位: University of Maryland Center for Environmental Sciences
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-03-01 至 2015-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0961942&HistoricalAwards=false
• 关键词: Collaborative; Research; Hypoxia; Marine; Ecosystems

The occurrence of low-oxygen waters, often called "dead zones" in coastal ecosystems throughout the world is increasing. Despite these increases, the pelagic food-web consequences of low-oxygen waters remain poorly understood. Laboratory research has demonstrated that hypoxic water ( 2 mg l-1) can result in mortality, reduced fitness and lower egg production of planktonic copepods, a major link in food webs supporting pelagic fish. Observations in the sea indicate that hypoxic bottom waters usually have depressed abundances of copepods compared to normoxic waters ( 2 mg l-1). The gradient of declining oxygen concentration with respect to depth (oxycline) can be a critical interface in coastal pelagic ecosystems by altering the migratory behavior and depth distribution of copepods and their spatial coherence with potential predators and prey. This project will result in a mechanistic understanding of how behavior and fitness of copepods are affected by hypoxia. The PIs will compare bottom-up and top-down controls on the ecology of copepods in Chesapeake Bay waters experiencing seasonal hypoxia and those that are normoxic. Specific objectives of this project are to: 1) analyze changes in migratory behavior and fine-scale (meter) distribution of copepods across the oxycline over hourly and diel time scales while simultaneously examining the distribution and abundance of their food (phytoplankton and microzooplankton) and predators (fish, gelatinous zooplankton); 2) estimate effects of hypoxia on the "fitness" of copepods using a suite of measurements (length/weight ratios, feeding, egg production, and egg hatching success) to develop condition indices of copepods captured at different times and depths in hypoxic and normoxic waters; and 3) evaluate effects of hypoxia on copepod mortality by hypoxia-induced, stage-specific copepod mortality in hypoxic bottom waters and by changes in top-down control of copepods from predation by fish and gelatinous zooplankton.Oxyclines may be a barrier to vertical migration of copepods and thus disruptive to predator avoidance behavior. Faced with increased predation risk from fish and jellyfish, copepods may seek refuge in hypoxic waters for part of the day and/or make short-term vertical excursions between hypoxic and normoxic waters. By regulating vertical migrations, copepods may increase utilization of microzooplankton prey concentrated in the oxycline. Hypoxic waters may elevate consumption of copepods by jellyfish and depress consumption by pelagic fish. This project will evaluate copepod distribution and migration behavior, individual fitness and stage-specific mortality in hypoxic and normoxic waters. It will examine food-web consequences of increased or decreased spatial coherence of copepods and their predators and prey in regions with hypoxic bottom waters and will contribute to fundamental understanding of food-web processes in eutrophic coastal ecosystems.Broader Impacts: As hypoxia becomes more prevalent in estuarine and shelf waters, increased understanding of its effects on planktonic food-webs becomes essential for effective, ecosystem-based management. The effects of eutrophication and hypoxia are areas of research emphasized in the JSOST Ocean Research Priorities Plan. Information gained from this project will be critical for food-web modeling in development of fisheries ecosystem plans for Chesapeake Bay. In a broader sense, the research is needed to achieve goals in the Chesapeake Bay Program's "Chesapeake 2000" Agreement. The proposed research will support two graduate students and a postdoc. In addition, the Horn Point Laboratory is part of the mid-Atlantic NSF-COSEE program and this project will support the participation of two summer teacher interns. The Horn Point Laboratory also participates in the NSF Research Experience for Undergraduates (REU) program. REU undergraduate students will be involved in the proposed research. Dissemination of results to the public and environmental managers will be facilitated by the infrastructure of University of Maryland Center for Environmental Science's Integration and Application Network (www.ian.umces.com).

低氧水域的发生，在世界各地的沿海生态系统中通常被称为“死区”。尽管有这些增加，低氧水域的上层食品 - 网络的后果仍然鲜为人知。实验室研究表明，低氧水（2 mg L-1）可导致死亡率，健身降低并降低浮游生物pepods的卵产量，这是支撑上层鱼类的食物网中的主要联系。海洋的观察结果表明，与常氧水域相比，低氧底部水通常具有抑郁症（2 mg l-1）。氧气浓度相对于深度（Oxycline）下降的梯度可以通过改变copepods的迁移行为和深度分布及其与潜在的捕食者和猎物的空间相干性，从而成为沿海上层生态系统中的关键界面。 该项目将导致机械理解CopePods的行为和适应性如何受到缺氧的影响。 PI将对Chesapeake Bay Waters的Copepods生态学的自下而上的控制和自上而下的控制进行比较，患有季节性缺氧和常氧的生态。该项目的具体目标是：1）分析迁移行为的变化以及copepods在小时和DIEL时间尺度上的copepods的分布，同时研究其食物的分布和丰度（Phytoplankton和Microzooplankton）和捕食者（Fish，Fish，Gelatiendiouns浮游生物）； 2）使用一套测量值（长度/重量比，进食，喂养，产量和卵子孵化成功）估计缺氧对copepods的“适应性”的影响，以开发在不同时间和低氧和正态氧气中捕获的copepods的条件指标；和3）评估缺氧对缺氧底部水中缺氧特异性的copepod死亡率的影响以及通过鱼类和凝胶状浮游生物从捕食捕食中的copepods的变化变化的影响，氧气可能是cop的障碍，可能是cop的垂直迁移到垂直迁移到垂直迁移的，从而破坏了这种偏向于尊敬的行为。面对鱼类和水母的捕食风险增加，Copepods可能在一天中的一部分中寻求低氧水域的避难所和/或在低氧和常氧水域之间进行短期垂直游览。通过调节垂直迁移，copepods可能会增加集中在氧气中的微Zooplankton猎物的利用。低氧水域可能会通过水母来提升copepods的消耗，并降低骨膜鱼的消耗。该项目将评估低氧和常氧水域中的CopePod分布和迁移行为，个人适应性以及特定阶段的死亡率。它将检查食物 - 网络的后果增加或降低copepods及其捕食者和捕食者的空间连贯性和缺氧底部水域的猎物，并将有助于对富营营养的沿海生态系统的食品 - 网络过程的基本理解，因为在eStuarine和sheref waters上的效果变得更加有效，因此，由于缺氧的影响更加普遍，因此，它变得更加普遍。基于生态系统的管理。 富营养化和缺氧的影响是JSOST海洋研究优先级计划中强调的研究领域。从该项目中获得的信息对于切萨皮克湾渔业生态系统计划的开发中的食品WEB建模至关重要。从更广泛的意义上讲，需要研究以实现切萨皮克湾计划的“ Chesapeake 2000”协议。拟议的研究将支持两名研究生和一个博士后。此外，Horn Point实验室是中大西洋NSF-Cosee计划的一部分，该项目将支持两个夏季教师实习生的参与。 Horn Point实验室还参加了本科生（REU）计划的NSF研究经验。 REU本科生将参与拟议的研究。马里兰州环境科学中心的集成与应用程序网络（www.ian.umces.com）的基础设施将促进向公共和环境经理传播结果。