Form, Function and Flow in the Plankton: Jet Propulsion and Filtration by Pelagic Tunicates

海鞘是远洋的，桶形的，喷射式的游泳者，对小颗粒（1米-1毫米）的过滤率几乎比任何其他的浮游食草动物都高。大多数的salp物种都发现在海洋的热带和亚热带沃茨，在那里他们发挥了关键作用的有机物质的循环。了解它们的游泳行为和滤食机制对于梳理这些重要食草动物的生态作用至关重要。喷流推进过程中樽海鞘摄食和运动的耦合导致这两个生命过程之间的权衡。这组动物的特点是形态和游泳行为的多样性，这可能与共生物种的生态作用有关。初步数据表明，形态差异可能会导致一系列的生活方式之间的海鞘从快速游泳的形式，以较慢的游泳形式。快速游泳salps的特点是增强肌肉组织，更高的脉搏率和线性，流线型的链结构相比，较慢的，表面取向salps.This研究将研究的游泳和喂养行为的salp物种目前关闭巴拿马太平洋海岸，并使用这些信息绘制形态，游泳力学和生态角色之间的联系。该方法将结合联合收割机现场和实验室方法，从微观过滤装置到动物周围的流场。这项工作将集中在Salpa cylindrica，一种快速游泳的流线型形式，Pegea confoederata，一种较慢的游泳形式和Cyclosalpa spp.，一种缓慢游动的形式，具有轮状聚集体。该项目的具体目标是a）在野外和实验室中量化由游泳的海鞘产生的水的流量，并检查流量和进料效率之间的联系，B）用三维视频描述整个过滤网的形式和运动，以及c）显微镜下测量过滤网参数，以描述过滤的小尺度力学。有越来越多的知识，大量运输的物质海洋深处的内部凝胶食草动物，但我们缺乏有关生态功能和个别物种的关系的信息。新技术的应用将提供一个机械的基础上的变化，在过滤速率和粒子的保留效率之间的salp物种。这项工作将增强我们对海鞘中存在的形式的进化多样性的理解，以及它如何更广泛地与其他浮游食草动物的共存相关。拟议工作的更广泛影响包括培训一名研究生（博士）和两个本科生研究生将培养显微镜，流体力学和脆弱的浮游生物的工作方法的技能。本科生将获得在现场和实验室的研究经验。在原始环境中对大型凝胶动物群的研究将吸引公众，我们已经联系了WHOI海洋杂志的编辑，讨论发表我们的发现。该杂志的网络版每月有30 000次点击，每期分发6 500份印刷本。

Salps are pelagic, barrel-shaped, jet-propelled swimmers that have higher filtering rates of small particles (1 m- 1 mm) than almost any other planktonic grazer. The majority of salp species are found in oceanic tropical and subtropical waters where they play a critical role in cycling of organic material. An understanding of their swimming behavior and filter feeding mechanics is critical to teasing out the ecological roles of these important grazers. The coupling of feeding and locomotion by salps during jet propulsion results in trade-offs between these two life processes. This group of animals is characterized by a diversity of morphology and swimming behaviors, that likely relate to ecological roles of co-occuring species. Preliminary data indicate that morphological differences may account for a range of lifestyles among salps from fast swimming forms to slower swimming forms. Fast swimming salps are characterized by enhanced musculature, higher pulse rates and linear, streamlined chain structures compared to slower, surface oriented salps.This study will examine the swimming and feeding behavior of salp species present off the Pacific Coast of Panama and use this information to draw linkages between morphology, swimming mechanics and ecological roles. The approach will combine field and laboratory methods that span scales from the microscopic filtering apparatus to the flow field around the animal. The work will focus on Salpa cylindrica, a fast-swimming, streamlined form, Pegea confoederata, a slower swimming form and Cyclosalpa spp., a slow swimming form with wheel shaped aggregates. The specific goals of this project are to a) quantify the flow of water produced by swimming salps in the field and in the lab and examine the connection between flow and feeding efficiency, b) describe the form and movement of the entire filtering mesh with 3-dimensional video and, c) measure filtering mesh parameters microscopically in order to describe the small-scale mechanics of filtration. There is increasing knowledge of the substantial transport of material to the ocean's deep interior by gelatinous grazers but we lack information about the ecological function and relationships of individual species. The application of new techniques will provide a mechanistic basis for variations in filtering rates and particle retention efficiencies among salp species. This work will enhance our understanding of the evolutionary diversity of form present in salps and how it relates more broadly to the coexistence of other planktonic grazers.Broader impacts of the proposed work include the training of one graduate student (Ph.D.) and two undergraduate students. The graduate student will develop skills in microscopy, fluid mechanics and methods for working with fragile planktonic organisms. Undergraduate students will gain research experience both in the field and the laboratory. The study of large gelatinous fauna in a pristine setting will be appealing to the public and we have already contacted the editors of WHOI's Oceanus magazine about publishing our findings. The online version of the magazine receives 30,000 hits each month and 6,500 print copies of each issue are distributed.