In Situ and Theoretical Analysis of Zooplankton Patch Dynamics

戴维斯9818661浮游动物斑块动态的现场和理论分析浮游动物斑块是一种众所周知的现象。虽然斑块的空间结构及其与环境变化的关系已经被很好地描述，并提出了理论上的解释，但由于技术的限制，迄今为止还不可能直接测量斑块的形成和持续。研究人员将进行一项重点领域和模拟研究，以量化东开普科德湾致密的桡足类斑块的结构、动力学和控制机制。利用数值模拟、高分辨率生物和物理制图以及现场行为观测相结合的方法，他们将直接检验斑块是由三个步骤形成的假设：1)向上游动增加近地表丰度，2)表面收敛和向上游动速度增加进一步增加丰度，3)汇聚带高丰度增加邻域间检测率，从而导致聚集行为增加。在现场计划期间，将在潮汐周期的不同阶段进行测量，以检查由于潮汐驱动的辐合而形成的斑块。在收敛消散后对斑块持久性的测量将指示生物聚集行为在维持斑块中的作用。对桡足类游泳行为各组成部分的直接现场观测将与环境(CTD、荧光、衰减、向下涌光)和流体速度数据一起用于确定斑块形成模型的参数值。汇流中斑块的形成将使用两种方法的组合来模拟：1)该地区的高分辨率三维数值模型，以量化潮汐和潮下流动和汇流；2)包含汇流的斑块形成和聚集的过程模型。这些计算将与3-D补丁结构随时间变化的实际测量结果进行比较。这项拟议的工作将为浮游动物斑块的形成和维持机制提供新的线索。

Davis 9818661In-situ and Theoretical Analysis of Zooplankton Patch DynamicsZooplankton patchiness is a well-known phenomenon. Although patch spatial structure and its corre-lation with environmental variation has been well described, and theoretical explanations for it have been proposed, direct measurement of how patches form and persist has not been possible to date because of technological limitations. The investigators will conduct a focused field and modeling study to quantify the struc-ture, dynamics, and controlling mechanisms of dense copepod patches in eastern Cape Cod Bay. Using a combination of numerical modeling, high resolution biological and physical mapping, and in-situ behav-ioral observations, they will directly test the hypothesis that the patches form in a three-step process: 1) upward swimming enhances near-surface abundance, 2) surface convergence together with increased up-ward swimming rate further enhances abundance, and 3) high abundance in the convergence zone increases interneighbor detection rates which lead to increased aggregation behavior. During the field program, mea-surements will be made during different phases of the tidal cycle to examine formation of the patches due to the tidally driven convergence. Measurements of patch persistence after the convergence has dissipated will be indicative of the role of biological aggregation behavior in maintaining the patches. Direct in-situ observations of various components of copepod swimming behavior will be used together with environmental (CTD, fluorescence, attenuation, downwelling light) and fluid velocity data to determine parameter values for patch formation models. Patch formation in convergent flow will be modeled using a combination of two approaches: 1) high resolution 3-D numerical models of the region to quantify tidal and subtidal flow and convergence and 2) process models of patch formation and swarming that incorporate convergent flows. These calculations will be compared with the actual measurements of how the 3-D patch structure varies over time. The proposed work will shed new light on mechanisms of patch formation and maintenance in zooplankton.