Vertical Migration of Pelagic Tunicates: Role of Feeding and Reproduction

本研究的重点是昼夜垂直迁移， 百慕大大西洋附近的海鞘（远洋被囊动物） 时间序列站。 海鞘是高效的食草动物， 浮游植物和其他颗粒物;它们分布广泛 有时会在密集的人群中发生。 几个物种 垂直迁移，有些高达800米，而另一些则 仅限于地表沃茨。 最近在亚北极的工作 太平洋和百慕大附近发现了有趣的新特征， 这些移民，似乎不符合传统的 移民优势的理论。 太平洋的海鞘 进行浅水迁移，但在水面时停止进食 在夜里。 这种行为被认为主要与 产卵和受精 最近有人观察到海鞘 在一天的不同时间出现在地表 - 早上，下午和晚上。 这种明显的迁移也是 与通常的解释不一致。 Madin博士和他的合作者将调查 这一极其重要的浮游食草动物群体的起源。 他们 将测试两个非排他性的假设， 观察到的模式：1）迁移优化了食物丰富的摄食 或在时间上将食物划分为空间上共同的食物。 发生的物种; 2）迁移集中在 表层和底层产卵和受精。 的 调查涉及适应和生态学的基本问题 在浮游动物迁徙，生殖生理的樽海鞘， 竞争和利基分离。 它们也是至关重要的， 海鞘的放牧和迁移作用的计算 颗粒和溶解营养盐的垂直通量。

This investigation focuses on diel vertical migration by salps (pelagic tunicates) in the vicinity of the Bermuda Atlantic Time Series Station. Salps are efficient grazers on phytoplankton and other particulates; they are widely distributed and sometimes occur in dense populations. Several species migrate vertically, some as far as 800 m, while others are restricted to surface waters. Recent work in the Subarctic Pacific and near Bermuda has revealed intriguing new features to these migrations, which do not seem consistent with traditional theories for the advantages of migration. Salps in the Pacific make shallow migrations, but stop feeding while at the surface during the night. This behavior is believed to relate mainly to spawning and fertilization. Recently salps have been observed to consistently appeared at the surface at different times of day - morning, afternoon and night. This apparent migration is also inconsistent with the usual explanations. Dr. Madin and collaborators will investigate the behavior of this extremely important group of pelagic herbivores. They will test two, non-exclusive hypotheses for the migratory patterns observed: 1) migration optimizes feeding at food-rich depths, or temporally partitions food among spatially co- occurring species; 2) migration concentrates salps at the surface and synchronizes spawning and fertilization. The investigations address basic questions of adaptation and ecology in migrating zooplankton, reproductive physiology of salps, and competition and niche separation. They are also critical for calculations of the role of grazing and migration by salps on vertical fluxes of particulate and dissolved nutrients.