In Situ and Theoretical Analysis of Zooplankton Patch Dynamics

浮游动物斑块动力学的原位和理论分析

• 批准号: 9818661
• 负责人: Cabell Davis
• 金额: $ 44万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-03-01 至 2003-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9818661&HistoricalAwards=false
• 关键词: Situ; Theoretical; Analysis; Zooplankton; Patch

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.

Davis 9818661浮游动物斑块动态的原位和理论分析浮游动物斑块是一种众所周知的现象。尽管斑块的空间结构及其与环境变化的相关性已被很好地描述，并已提出了理论解释，但由于技术限制，迄今为止还不可能直接测量斑块的形成和持续。调查人员将进行重点领域和建模研究，以量化结构，动力学和控制机制的密集桡足类补丁在东开普省鳕鱼湾。通过结合数值模拟、高分辨率生物和物理制图以及原位生物学观察，他们将直接检验斑块形成过程分为三步的假设：1）向上游动增强近地表丰度，2）地表辐合连同向上游动速率的增加进一步增强丰度，以及3）会聚区中的高丰度增加了导致增加的聚集行为的邻居间检测率。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收敛而形成的斑块。收敛消散后的补丁持久性的测量将指示生物聚集行为在维持补丁的作用。桡足类游泳行为的各个组成部分的直接原位观测将与环境（CTD，荧光，衰减，下行光）和流体速度数据一起使用，以确定斑块形成模型的参数值。将使用两种方法的组合对会聚流中的斑块形成进行建模：1）该区域的高分辨率三维数值模型，以量化潮汐和潮下流和会聚，以及2）包含会聚流的斑块形成和群集的过程模型。这些计算将与实际测量的3-D补丁结构如何随时间变化进行比较。这项工作将为浮游动物斑块形成和维持的机制提供新的思路。