Sinking behavior of gastropod larvae (Ilyanassa obsoleta) in turbulence
Sinking behavior of gastropod larvae (Ilyanassa obsoleta) in turbulence
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DOI：
10.4319/lo.2004.49.6.1937
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发表时间：
2004-11-01
影响因子：
4.5
通讯作者：
Solow, AR
中科院分区：
文献类型：
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作者：
Fuchs, HL;Mullineaux, LS;Solow, AR
沿海腹足类的幼虫在湍流中下沉，并可能利用近岸湍流作为初始沉降的线索。我们的目标是量化之间的关系湍流和下沉幼虫的比例主管泥蜗牛面盘（Ilyanassa obsoleta）。我们将幼虫暴露于一系列与场相关的湍流条件（λ = 8.1 × 10（-3）至2.7 × 10（0）cm（2）s（-1））中，保持其他因素不变。我们用浮游生物录像机记录幼虫在静水和湍流中的运动。幼虫的轨迹和速度测量提取使用视频图像分析。我们还测量湍流速度独立，使用激光多普勒测速仪。为了解释经验测量的幼虫的行为，我们开发了一个三分量，正常的混合物模型的幼虫在湍流中的垂直速度分布。该模型被拟合到观察到的幼虫速度的最大似然法，估计下沉，盘旋，和游泳幼虫的比例。在典型沿海栖息地的湍流强度范围内，下沉幼虫的比例随着湍流消散率的对数呈指数增加（r（2）= 0.89）。当消散速率达到10（-1）cm（2）s（-1）时，幼虫的净平均行为速度由正向负转变。当它们进入湍流的浅水时，有能力的幼虫可以通过下沉来提高它们在有利的沿海栖息地定居的机会。
Larvae of coastal gastropods sink in turbulence and may use nearshore turbulence as an initial settlement cue. Our objective was to quantify the relationship between turbulence and the proportion of sinking larvae for competent mud snail veligers (Ilyanassa obsoleta). We exposed larvae to a range of field-relevant turbulence conditions (epsilon = 8.1 X 10(-3) to 2.7 X 10(0) cm(2) s(-1)) in a grid-stirred tank, holding other factors constant. We used a video plankton recorder to record larval movements in still water and in turbulence. Larval trajectories and velocity measurements were extracted using video-image analysis. We also measured turbulent flow velocities independently, using laser Doppler velocimetry. To interpret empirical measurements in terms of larval behavior, we developed a three-component, normal mixture model for vertical velocity distributions of larvae in turbulence. The model was fitted to observed larval velocities by maximum likelihood, to estimate the proportions of sinking, hovering, and swimming larvae. Over the range of turbulence intensities found in typical coastal habitats, the proportion of sinking larvae increased exponentially (r(2) = 0.89) With the log of the turbulence dissipation rate. The net mean behavioral velocity of the larvae shifted from positive to negative when the dissipation rate reached similar to10(-1) cm(2) s(-1). By sinking when they enter turbulent, shallow water, competent larvae could improve their chances of settling in favorable coastal habitats.