Collaborative Research: Advection and Population Dynamics of Calanus Finmarchicus in Mesoscale Eddies in the Barents Sea: A Quantitative Approach Using the Biomass-Spectra Model

9908079/9906757 Ashijan/Zhou巴伦支海拥有丰富的渔业资源，其中包括具有重要商业价值的物种，如毛鳞鱼、极地鳕鱼和鲱鱼。 南部的巴伦支海是鲱鱼的重要育苗区，鲱鱼在生命早期阶段依赖于浮游动物种群，也支持了嗜食性极地鳕鱼和毛鳞鱼的种群。 有人认为，作为北极沃茨的外来者，芬兰哲水蚤可能无法成功繁殖或维持其种群。 挪威大西洋流和挪威沿岸流对巴伦支海南部浮游动物的输送是影响巴伦支海生态系统的重要机制。 要了解浮游动物在海洋中的时空分布和命运，有必要了解平流，迁移行为和种群动态之间的相互作用，特别是在中尺度。 这种相互作用在极地地区最为深刻，因为内部罗斯比半径大约为101公里。 在中尺度涡旋中获得三维平流和浮游生物原位种群动力学速率的定量测量是一项艰巨的任务。 传统的采样和实验方法不能解决中尺度的过程。 声学仪器可以解决这些尺度，但不能提供必要的信息，传统的模型来估计人口动态率。 光学仪器，如光学浮游生物计数器（OPC）或视频浮游生物记录仪（VPR），可以提供高垂直和时间分辨率的浮游动物的大小分布的信息，但还没有被用于浮游动物率过程的研究。 基于大小结构描述浮游动物速率过程的理论和模型已经存在，但尚未得到广泛应用。本项目的PI将使用新的高分辨率采样方法的调查策略与新的种群动力学数学理论和客观分析相结合，从而在前所未有的尺度上定量研究浮游动物的平流、垂直迁移和种群动力学。 该项目将在挪威北方的特罗姆索拉凯特对这一综合理论和调查战略进行严格的检验。 特罗姆瑟湖是一个重要的生态系统，位于挪威大西洋洋流（NAC）分叉处。 在这两个分支之间的特罗姆瑟湖形成了一个永久的漩涡。东北流动的分支的NAC似乎是一个重要的机制，运输浮游动物生产陆架水进一步向北进入巴伦支海在生产季节。 在附近的特罗姆瑟湖，一个单一的物种（哲水蚤finmarchicus）占95%的桡足类生物量在5月和6月。 在8月和9月发现混合物种的组成。 这提供了机会，首先在一个简单的情况下测试我们的新方法，一个单一的优势物种，然后在一个更复杂的一般情况下的混合物种。这项研究的成功结果可能会导致了解如何浮游动物种群动态中尺度涡旋系统支持高营养水平在北极地区，并代表了生物海洋学的重要进展，开辟了高分辨率测量中尺度涡旋中浮游动物动态的可能性，而不仅仅是分布。

9908079/9906757Ashijan/ZhouThe Barents Sea contains a fishery rich in commercially important species such as capelin, polar cod, and herring. The southern Barents Sea functions as a critical nursery area for the herring, which depend on zooplankton stocks during early life stages, and also supports populations of the planktivorous polar cod and capelin. It has been suggested that Calanus finmarchicus, as an expatriate in Arctic waters, may not reproduce successfully or be capable of sustaining its populations. The transport of zooplankton into the southern Barents Sea by the Norwegian Atlantic Current (NAC) and the Norwegian Coastal Current is an important mechanism to the Barents Sea ecosystem. To understand the spatiotemporal distribution and fate of zooplankton in the ocean, it is necessary to understand the interaction between advection, migration behavior, and population dynamics, especially at the mesoscale. This interaction is most profound in polar regions because the internal Rossby Radius is on the order of 101 km. Obtaining quantitative measurements of 3-dimensional advection and in situ population dynamics rates of plankton in a mesoscale eddy are daunting tasks. Traditional sampling and experimental methods cannot resolve processes at mesoscales. Acoustic instruments can resolve these scales, but cannot provide information necessary for traditional models to estimate population dynamics rates. Optical instruments, such as the Optical Plankton Counter (OPC) or Video Plankton Recorder (VPR), can provide information on the size-distribution of zooplankton at high vertical and temporal resolution but have not been used for the study of zooplankton rate processes. Theories and models describing rate processes in zooplankton based on size structure exist but have not been applied extensively.The PI's of this project have synthesized survey strategies using new high-resolution sampling methods with new mathematical theories of population dynamics and objective analysis, yielding a quantitative approach to the study of advection, vertical migration, and population dynamics of zooplankton on unprecedented scales. This project will undertake a critical test of this synthesis of theories and survey strategies in Tromsoflaket, northern Norway. Tromsoflaket is an important ecosystem located where the Norwegian Atlantic Current (NAC) bifurcates. A permanent eddy is formed in Tromsoflaket between these two branches. The northeast-flowing branch of the NAC appears to be an important mechanism for transporting zooplankton productive shelf water farther northwards into the Barents Sea during the productive season. In the vicinity of Tromsoflaket, a single species (Calanus finmarchicus) accounts for 95% of the copepod biomass in May and June. A composition of mixed species is found in August and September. This provides opportunities to test our new approach first in a simple case of a single dominant species, and then in a more complicated general case of mixed species.The successful outcome of this research could lead to an understanding of how zooplankton population dynamics in mesoscale eddy systems support high trophic levels in Arctic regions, and represent an important advance in biological oceanography, opening up the possibility of high-resolution measurements of zooplankton dynamics in mesoscale eddies, not just distributions.