Unsynchronized and synchronized vertical migration of zooplankton in a high arctic fjord
Unsynchronized and synchronized vertical migration of zooplankton in a high arctic fjord
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DOI：
10.4319/lo.2006.51.6.2586
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发表时间：
2006-11-01
影响因子：
4.5
通讯作者：
Falk-Petersen, Stig
中科院分区：
文献类型：
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作者：
Cottier, Finlo R.;Tarling, Geraint A.;Falk-Petersen, Stig
2002年6月至9月期间，我们在北纬79度的北极峡湾中测量了浮游动物的垂直迁移，并将连续照明期转变为真正的昼夜，以研究光线索对行为的变化影响。用系泊的300千赫声学多普勒海流剖面仪进行的观测表明，在研究期间发生了两种垂直迁移模式。在连续光照的几周内，后向散射数据表明，在24小时内的任何时候都没有净垂直位移的人口，但垂直速度显示了一个连续的净向下移动的表层和净向上移动的深度。我们将其解释为个体的不同步垂直迁移，其向上的轨迹在接近地表时减慢，而向下的轨迹在初始阶段最快。同步迁移，被视为一个向上和向下的运动，分散层分别在黄昏和黎明，开始一旦真正的夜晚恢复到秋天。很可能光的相对变化率被用作同步迁移的近端线索。同时采集网样鉴定出芬兰哲水蚤Calanus finmarchicus和C.冰川是最有可能造成不同步迁移模式的因素。同步散射层的高后向散射表明，它们包括额外的分类群，如磷虾类Thysanoessa spp.，翼足类Limacina helicina，或超形端足类Themisto spp.
We measured vertical migration of zooplankton in an arctic fjord at 79 degrees N between June and September 2002 and transcending a period of continuous illumination to one of true day and night to investigate the changing influence of light cues on behavior. Observations made with a moored 300 kHz acoustic Doppler current profiler indicated that two modes of vertical migration occurred during the study period. During the weeks of continuous illumination, backscatter data indicated that there was no net vertical displacement of the population at any time during the 24-h period, but vertical velocity showed a continuous net downward movement in the surface layers and a net upward movement at depth. We interpreted this as unsynchronized vertical migrations by individuals with upward trajectories that slowed closer to the surface and downward trajectories that were most rapid in their initial phases. Synchronized migrations, seen as an upward and downward movement of scattering layers at dusk and dawn respectively, began once true nighttime resumed toward autumn. It is likely that the relative rate of change in light was used as the proximal cue for synchronized migrations. Concurrent net samples identified Calanus finmarchicus and C. glacialis as the most likely contributors to the unsynchronized migration patterns. The high backscatter of the synchronized scattering layers suggests that they included additional taxa such as the euphausiid Thysanoessa spp., the pteropod Limacina helicina, or the hyperiid amphipod Themisto spp.