Active and passive vertical motion of zooplankton in a lake
Active and passive vertical motion of zooplankton in a lake
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DOI：
10.4319/lo.2011.56.2.0695
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发表时间：
2011-03-01
影响因子：
4.5
通讯作者：
Lorke, Andreas
中科院分区：
文献类型：
--
作者：
Huber, Andrea M. R.;Peeters, Frank;Lorke, Andreas
根据康斯坦茨湖 7 个月的声学反向散射强度数据，在从几分钟到几天的时间尺度上分析了垂直浮游动物分布的时间变化。与净样本的比较表明，观察到的体积反向散射强度的大部分变化与大型水蚤丰度的变化有关。浮游动物的昼夜垂直迁移（DVM）在整个观测期间是一个持续的特征，而幅度、每日迁移时间和迁移速度随季节变化。浮游动物的这种活跃运动在广泛的时间尺度上受到内波的影响。在春季，DVM 的最大深度遵循与长波长、盆地尺度内波相关的等温深度的变化。具有可比幅度的传播的短波长内波会影响浮游动物在分钟时间尺度上的垂直分布。对浮游动物丰度、温度和海流速度的光谱分析揭示了光谱峰值和斜率的紧密对应关系，表明在数天的时间尺度内，生物过程主导被动运输的唯一时间尺度与 DVM 相关。水平运输在长时间内占主导地位，而垂直运输仅在短时间内发生。
Temporal variability of vertical zooplankton distributions is analyzed on timescales from minutes to days based on 7 months of acoustic backscatter strength data in Lake Constance. A comparison with net samples reveals that most of the observed variability in volume backscatter strength is associated with variations in the abundance of large Daphnia. Diel vertical migration (DVM) of zooplankton was a persistent feature throughout the entire period of observation, while amplitude, daily migration timing, and migration speed varied with season. This active motion of zooplankton was affected by internal waves on a broad range of timescales. In spring, the maximum depth of DVM follows variations in isothermal depths associated with long-wavelength, basin-scale internal waves. Propagating, short-wavelength, internal waves with comparable amplitudes affect vertical zooplankton distributions on timescales of minutes. Spectral analyses of zooplankton abundance, temperature, and current velocity reveal close correspondence of spectral peaks and slopes, indicating that up to timescales of several days, the only temporal scale at which biological processes dominate over passive transport is associated with DVM. Whereas horizontal transport dominates at long periods, vertical transport occurs only at short timescales.