The pattern of zooplankton migration has been investigated in the water column from 120 to 1300m depth using the backscatter strength signal (Sv) provided by Acoustic Doppler Current Profilers (operating at 300kHz and 76.8kHz), from a 10-year high-frequency mooring time series (2008–2018) in the deepwater region of the western Gulf of Mexico (GoM). This analysis was complemented with in-situ thermohaline data, model derived data, as well as one-month deployment glider-derived oceanographic information.

The overall Sv time series presents a marked circadian cycle at 12 and 24h associated with the well-known Diel Vertical Migration (DVM) motion performed by the zooplankton community. The signal analysis reveals the existence of two main layers (a shallow layer between the surface to about 100m and an intermediate one from 400m to 600m), where the abundance of scatterers is the highest. Both layers exhibit a seasonal -but different- modulation of the DVM, with peaks in backscatter at ∼200m in winter but at ∼400m depth in summer; with no seasonal variability below 800 m. The migration pattern differed between depths, and relative to density, dissolved oxygen concentration, mixed layer depth and net primary production. Density plays a major role in the upper 600m limiting the depth of the different migration patterns, whereas oxygen concentration reveals to be the best single predictor of resident depth of non-migrating species in the deeper layer. A relationship was found between the migration patterns and the moon and sun position, since the migration patterns were finely tuned to the timing of sunrise and sunset. The shallowest group (0-500m) begins to descend about two hours before sunrise, and starts to rise about one hour before sunset. The amount of light penetrating the ocean when the sun altitude is greater than 35° seems to be the triggering mechanism of DVM for the mesopelagic species in the GoM. A wavelet analysis applied to the backscatter signal reveals a close relation between migratory patterns and the moon’s periodicity in the layer 1000-1200m, rather than in the upper water column. Based on previous studies of the biological community of the deepwater region of the GoM, the migration patterns likely reflect the presence of a seasonally-varying community of scatterers in the surface layer, partially-migratory and strongly migratory taxa in the mesopelagic layer, resident taxa associated with the minimum oxygen layer, and a deeper community which may migrate in response to the lunar cycle.

使用声学多普勒电流剖面仪提供的反向散射强度信号（Sv）（在300kHz和76.8kHz的频率下运行），从十年的高频系泊时间开始，研究了水深120至1300m处浮游动物的迁移模式。系列（2008-2018）在墨西哥湾西部（GoM）的深水区域。这项分析得到了原位热盐数据，模型导出数据以及为期一个月的滑翔机衍生海洋学信息的补充。

整个Sv时间序列在12和24h呈现出明显的昼夜节律周期，与浮游动物群落执行的众所周知的Diel垂直迁移（DVM）运动有关。信号分析表明存在两个主要层（表面至约100m之间的浅层和400m至600m之间的中间层），其中散射的丰度最高。这两层都表现出DVM的季节性变化，但调制方式不同，冬季的反向散射峰值位于200m，夏季的深度约为400m。在800 m以下没有季节性变化。迁移模式在深度之间有所不同，并且相对于密度，溶解氧浓度，混合层深度和净初级生产而言是不同的。密度在上限600m中起着主要作用，限制了不同迁移模式的深度，而氧浓度显示出是更深层非迁移物种驻留深度的最佳单一预测因子​​。由于迁移模式已根据日出和日落的时间进行了微调，因此发现了迁移模式与月亮和太阳位置之间的关系。最浅的组（0-500m）在日出前约两个小时开始下降，并在日落前约一小时开始上升。当太阳高度大于35°时，穿透海洋的光量似乎是GoM中中生物种的DVM触发机制。对反向散射信号进行的小波分析显示，在1000-1200m层而非上水柱中，column游模式与月球周期性之间存在密切关系。