In situ twilight grazing rhythm during diel vertical migrations of a scattering layer of Calanus finmarchicus1
In situ twilight grazing rhythm during diel vertical migrations of a scattering layer of Calanus finmarchicus1
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芬马奇库斯1散射层昼间垂直迁移过程中的原位黄昏放牧节奏
DOI：
10.4319/lo.1985.30.3.0598
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
L. Legendre
中科院分区：
文献类型：
--
作者：
Y. Simard;G. Lacroix;L. Legendre
散射层的Calanusjnmarchicus采样每90分钟在48小时内在较低的圣劳伦斯河口。放牧活动（浮游植物色素在肠道）和最近和nonrecently喂养桡足类（从观察食物在肠道）的百分比进行了监测，在两个层（O-30米和30-100米）。浮游植物仅限于上层。观察到一个双峰的黄昏放牧节律：第一个进食期，在上层，日落后开始;其次是“午夜下沉”在较深的层（2-3小时），在此期间，肠道内容物被疏散;在此之后，动物返回到上层的第二餐，黎明下降之前。在这两次迁移中，两个地层之间的个体动态交换，掩盖了所有桡足类都迁移到上层的事实，以及实际发生的黎明上升。在温暖的表层水中，摄食时间很短。即使浮游植物浓度很低，摄食也会迅速停止。大量增加的移民人数并没有改变喂养模式。结果支持了C. jinmarchicus在中央阶段的垂直迁移在夏末是密切相关的在原地放牧节奏。
A scattering layer of Calanusjnmarchicus was sampled every 90 min during 48 h in the lower St. Lawrence estuary. Grazing activity (phytoplankton pigments in the gut) and the percentage of recently and nonrecently fed copepods (from observation of food in the gut) were monitored in two strata (O-30 m and 30-100 m). Phytoplankton was restricted to the upper stratum. A bimodal twilight grazing rhythm was observed: the first feeding period, in the upper stratum, begins after sunset; it is followed by the “midnight sinking” in the deeper stratum (2-3 h), during which the gut content is evacuated; after this, the animals return to the upper stratum for a second meal, before the dawn descent. In both migrations, there was a dynamic interchange of individuals between the two strata, which masked the fact that all the copepods migrated to the upper stratum and that a dawn rise actually happened. The feeding time in the warmer surface water was very short. Feeding ceased rapidly even if phytoplankton concentration was low. A large increase in the number of migrants did not change the feeding patterns. Results support the hypothesis that the behavior of C. jinmarchicus during the central phase of vertical migrations in late summer is closely linked to an in situ grazing rhythm.