Second-order seasonal variability in diel vertical migration timing of euphausiids in a coastal inlet
Second-order seasonal variability in diel vertical migration timing of euphausiids in a coastal inlet
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DOI：
10.3354/meps10215
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发表时间：
2013-04
影响因子：
2.5
通讯作者：
M. Sato;J. Dower;E. Kunze;R. Dewey
中科院分区：
文献类型：
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作者：
M. Sato;J. Dower;E. Kunze;R. Dewey
利用2年的有线观测资料，对加拿大不列颠哥伦比亚省萨尼奇湾南极磷虾昼夜垂直迁移时间的变化进行了定量分析。观测的连续性和高分辨率性质允许检查相对于民用黄昏时间的迁移时间的二阶季节性变化。早黄昏上升和晚黎明下降发生在春秋季节，而晚黄昏上升和早黎明下降发生在冬季。上升的时间似乎是由（1）光的可用性在白天深度的磷虾，这是由浮游植物水华阴影调制，和（2）磷虾大小依赖的视觉捕食风险。因为（1）在黎明时不适用，所以下降时间似乎受（2）的调节。在产卵前期，较高的繁殖能量需求可能会导致更早的黄昏上升和更晚的黎明下降，以最大限度地提高能量增益，即使有更大的身体大小。而不是传统的观点昼夜垂直迁移的时间，仅与民用暮光，我们的数据表明，磷虾也适应他们的迁移时间，以适应环境的变化线索，以及他们的增长。
Variability in the diel vertical migration timing of euphausiids in Saanich Inlet, British Columbia, Canada, is quantified using 2 years of echosounder data from a cabled observatory. The continuous and high-resolution nature of the observations allows examination of second-order seasonal variability in migration timing relative to civil twilight times. Early dusk ascent and late dawn descent occur during spring–fall, while late dusk ascent and early dawn descent occur during winter. Ascent timing appears to be regulated by (1) light availability at the daytime depth of the euphausiids, which is modulated by phytoplankton bloom shadowing, and (2) euphausiid size-dependent visual predation risk. Because (1) does not apply at dawn, descent timing appears to be regulated by (2). During the pre-spawning period, higher energy demand for reproduction may cause earlier dusk ascent and later dawn descent to maximize energy gain, even with larger body size. Instead of the traditional view of diel vertical migration timing, correlated solely with civil twilight, our data suggest that euphausiids also adapt their migration timing to accommodate changes in environmental cues as well as their growth.