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

9908079/9906757 Ashijan/周巴伦支海有一个渔业，盛产商业上重要的物种，如角鱼、鳕鱼和鲱鱼。巴伦支海南部是鲱鱼的关键育苗区，它们在早期生命阶段依赖浮游动物种群，也支持食浮游的极地鳕鱼和海豚的种群。有人认为，作为北极水域的侨民，Finmarchicus可能无法成功繁殖，也无法维持其种群。挪威大西洋流和挪威沿岸流将浮游动物输送到巴伦支海南部是巴伦支海生态系统的一个重要机制。为了了解海洋浮游动物的时空分布和归宿，有必要了解平流、迁徙行为和种群动态之间的相互作用，特别是在中尺度上。这种相互作用在极地地区最为深刻，因为内部罗斯比半径约为101公里。获取中尺度涡旋中浮游生物的三维平流和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。声学仪器可以分辨这些尺度，但不能提供传统模型估计种群动态率所需的信息。光学仪器，如光学浮游生物计数器(OPC)或视频浮游生物记录器(VPR)，可以提供高垂直和时间分辨率的浮游动物大小分布信息，但尚未用于研究浮游动物的速率过程。基于尺度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利用新的高分辨率采样方法，结合新的种群动力学和客观分析数学理论，综合调查策略，为浮游动物平流、垂直迁移和种群动力学的研究提供了前所未有的定量方法。该项目将在挪威北部的Tromsoflket对这一理论和调查战略的综合进行关键测试。热带风暴是一个重要的生态系统，位于挪威大西洋流(NAC)的分叉处。在这两个分支之间的Tromsoflket中形成了一个永久的涡流。NAC向东北流动的分支似乎是浮游动物生产性陆架水在繁殖季节进一步向北输送到巴伦支海的重要机制。在Tromsoflket附近，单一物种(Calanus Finmarchicus)占5、6月份桡足类生物量的95%。8月和9月为混合种组成。这为我们的新方法提供了机会，首先在单一优势物种的简单情况下测试，然后在更复杂的混合物种的一般情况下测试。这项研究的成功结果可能有助于理解中尺度涡旋系统中的浮游动物种群动力学如何支持北极地区的高营养水平，并代表着生物海洋学的重要进步，为高分辨率测量中尺度涡旋中的浮游动物动态开辟了可能性，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.