Measuring the vertical distributional variability of pelagic fauna in Monterey Bay
Measuring the vertical distributional variability of pelagic fauna in Monterey Bay
复制标题
测量蒙特利湾中上层动物群的垂直分布变化
DOI：
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
D. Barbee
中科院分区：
文献类型：
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作者：
S. Urmy;J. Horne;D. Barbee
时间变异性是水生生态系统的一个重要特征，可能难以衡量。一个固定的，面向上的科学回声测深仪被用来记录在蒙特雷湾，加利福尼亚州，18个月的水层动物的垂直分布。为了表征分布，一套指标，包括密度，丰度，位置，分散，占用，均匀度和聚集的措施，开发和测试。利用图像分析技术开发了一种检测和计数声学后向散射层数量的算法。这些指标记录了一个很强的季节性周期，总后向散射在春季上升流季节达到最小值，在秋季和冬季达到峰值。在动物的垂直分布的变异性是最大的，在长时间尺度和信号频率的功率（21.050至21.585）下降。功率谱在12小时和24小时周期有明显的峰值，对应于半日潮和昼夜垂直迁移。昼夜信号在冬末最强，在春季上升流季节最弱。主动声学是对海洋观测站的有益补充，所提出的指标提供了一套有用的工具，用以量化远洋动物的分布和时间变化。
Temporal variability is an important feature of aquatic ecosystems that can be difficult to measure. A stationary, upward-facing scientific echosounder was used to record the vertical distribution of pelagic fauna in Monterey Bay, CA, for 18 months. To characterize the distributions, a suite of metrics, including measures of density, abundance, location, dispersion, occupancy, evenness, and aggregation, was developed and tested. An algorithm to detect and count the number of acoustic backscatter layers was developed using image-analysis techniques. The metrics recorded a strong seasonal cycle, with total backscatter reaching a minimum during the spring upwelling season and peaking in autumn and winter. Variability in the vertical distribution of animals was greatest at long time-scales and decreased as a power (21.050 to 21.585) of signal frequency. There were significant peaks in the power spectrum at 12- and 24-h periods, corresponding to the semi-diurnal tide and diel vertical migration. The diel signal was strongest in late winter and weakest during the spring upwelling season. Active acoustics are a useful addition to ocean observatories, and the metrics presented provide a useful set of tools to quantify the distribution and temporal variability of pelagic fauna.