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Apparatus and methods

机译：仪器和方法

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When presented with a fine-scale upwelling or downwelling shear flow in a laboratory flume, 2 tropical copepods from the Red Sea, Acartia negligens and Clausocalanus furcatus, performed a set of behaviors that resulted in apparent depth-keeping and the potential for producing patchiness. Analyses of free-swimming trajectories revealed a behavioral threshold shear deformation rate value of 0.05 s~(-1) for both species. This threshold marked the transition to a range of behaviorally relevant shear deformation rate values and triggered statistically significant changes in path kinematics (i.e. relative swimming speed and turn frequency) in the shear layer versus out-of-layer. Gross path characteristics (i.e. net-to-gross displacement ratio, NGDR, and proportional vicinity time, PVT) were also significantly different in the shear layer treatments compared to controls. The vertical net-to-gross displacement ratio (VNGDR) was introduced here to explain a spectrum of depth-keeping behaviors. The mean value of VNGDR significantly increased in the treatments and suggested that the upwelling and downwelling shear layers induced vertical transport with large net vertical displacement. However, histograms of VNGDR revealed a bimodality, which indicated that a sizable portion of the population was also displaying depth-keeping behavior (low VNGDR). Those copepod trajectories not displaying depth-keeping behavior at the scale of the observation (high VNGDR) predominately consisted of copepods attempting to swim against the flow, thereby resisting vertical advection, which is another potential depth-keeping mechanism. Preferential depth-keeping was consistent with in situ acoustic tracking studies and could improve survival by increasing residence time near fronts, which are often coincident with food and mates.
机译：当在实验室水槽中出现小规模的上升流或下降流剪切流时，来自红海的2种热带co足类动物，A螨和短尾小Claus，表现出一系列行为，导致明显的深度保持和产生斑块的可能性。自由游动轨迹的分析表明，两种物种的行为阈值剪切变形率值为0.05 s〜（-1）。该阈值标记了到一系列行为相关的剪切变形率值的转变，并触发了剪切层相对于层外的路径运动学（即相对游泳速度和转向频率）的统计显着变化。与剪切层相比，剪切层处理中的总路径特性（即净值与总值的位移比NGDR和比例邻近时间PVT）也显着不同。此处介绍了垂直净毛位移比（VNGDR），以解释一系列深度保持行为。在处理中，VNGDR的平均值显着增加，这表明上升和下降的剪切层引起垂直传输，并具有较大的净垂直位移。但是，VNGDR的直方图显示出双峰态，这表明相当一部分人口还表现出深度保持行为（低VNGDR）。那些未在观测范围内表现出深度保持行为的co足类轨迹（高VNGDR）主要由试图对流游动的thereby足类动物组成，从而抵抗了垂直对流，这是另一种潜在的深度保持机制。优先的深度保持与原位声跟踪研究相一致，并且可以通过增加前沿附近的停留时间来提高生存率，前沿通常与食物和配偶相吻合。

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    《Oceanographic Literature Review》 |2016年第2期|324-326|共3页
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