Collaborative Research. Ontogenetic Changes in Swimming Squid: An Integrative Examination of Jet Structure and Muscular Mechanics

项目摘要合作研究。 游泳乌贼的个体发育变化：射流结构和肌肉力学的综合研究。Bartol（Old自治领大学），Joseph T.汤普森（圣约瑟夫大学）和保罗S。克鲁格（南卫理公会大学）鱿鱼是多才多艺的游泳者，有能力盘旋在一个地方，迅速改变方向或方向与明显的轻松，并上升/下降几乎垂直。 虽然鱿鱼有鳍和臂，用于不同程度的推进，稳定性和机动性，它是脉冲射流是基础的机车系统。 鱿鱼的脉冲射流不同于鱼类、水生爬行动物和水生哺乳动物更熟悉的波动运动，它是通过交替地用水填充内部地幔腔并通过可折叠的漏斗通过强大的地幔收缩喷射水而产生的。 脉冲喷射被不同大小的鱿鱼使用，从只有几毫米长的幼鱼到可能长到18米的成年鱼。 在这个宽的尺寸范围内，流体的物理学在各种射流特征的演变中起着重要作用（例如，被称为涡环的特征涡），这是推进游泳性能的核心。 这个合作项目研究了流体力学约束如何塑造不同生命史阶段的鱿鱼的游泳策略和肌肉力学，最终目标是评估推进效率如何随大小变化。 要做到这一点，射流，身体运动和肌肉特性将在两种鱿鱼，简短的鱿鱼Lolliguncula brevis和椭圆形鱿鱼Sepioteuthis lessoniana检查。 这些鱿鱼的总长度从孵化时的1厘米到成年时的15厘米不等，它们将被训练在流动池中游泳（即，一种水生的"跑步机"），其包含有在水中播种反光颗粒的水。 当充满颗粒的水从漏斗中排出时，将用激光照射并录像，以便使用称为数字粒子图像测速（DPIV）的技术确定射流速度。 这些DPIV数据将提供喷流特性和推进效率的直接测量。 在机动轨道系统上放置的多个摄像机将用于收集鱿鱼游泳时地幔和漏斗的高分辨率图像，提供有关游泳行为的宝贵数据。 由于外套膜的收缩特性随大小而变化，并对射流有直接影响，因此也将使用标准肌肉力学技术对外套膜肌的孤立束进行详细测量。 DPIV，游泳镜头和肌肉力学数据的整合有望扩大我们对喷气推进生物体推进效率的理解，特别是在对喷气机制知之甚少的低尺寸范围内，并提供对肌肉骨骼支持系统个体发育变化的深入了解。 这些数据不仅对生物学研究人员有意义，而且对合成喷气机和脉冲喷气微型飞行器等新兴技术的工程师和设计师也有意义。 这个项目将吸引本科生和研究生进行跨学科研究。 它还将通过直接参与实验或通过在当地公立学校和水族馆开展教育活动，促进少数民族学生的参与。

PROJECT ABSTRACTCollaborative Research. Ontogenetic Changes in Swimming Squid: An Integrative Examination of Jet Structure and Muscular MechanicsIan K. Bartol (Old Dominion University), Joseph T. Thompson (Saint Joseph's University), and Paul S. Krueger (Southern Methodist University)Squids are versatile swimmers, having the ability to hover in one spot, change direction or orientation rapidly with apparent ease, and ascend/descend almost vertically. Although squids have fins and arms that are used to varying degrees for propulsion, stability, and maneuverability, it is the pulsed jet that is the foundation of the locomotive system. Pulsed jets in squids, which differ from the more familiar undulatory locomotion of fishes, aquatic reptiles, and aquatic mammals, are generated by alternately filling an internal mantle cavity with water and ejecting that water by powerful mantle contractions through a maneuverable funnel. Pulsed jetting is used by squids of remarkably different sizes, from hatchlings that are only a few millimeters in length to adults that may grow as large as 18 m. Over this wide size range, the physics of fluids plays an important role in the evolution of various jet features (e.g., characteristic vortices known as vortex rings) that are central to propulsive swimming performance. This collaborative project investigates how fluid mechanical constraints shape swimming strategies and muscular mechanics in squid of different life history stages, with the ultimate goal of assessing how propulsive efficiency changes with size. To accomplish this, jet flows, body movements, and muscle properties will be examined in two species of squids, the brief squid Lolliguncula brevis and the oval squid Sepioteuthis lessoniana. These squids, which vary in total length from 1 cm as hatchlings to 15 cm as adults, will be trained to swim in a flow tank (i.e., an aquatic "treadmill") containing water seeded with light-reflective particles. As particle-laden water is expelled from the funnel, it will be illuminated with lasers and videotaped so that the jet velocity can be determined using a technique known as digital particle image velocimetry (DPIV). These DPIV data will provide direct measurements of jet features and propulsive efficiency. Multiple video cameras positioned on a motorized rail system will be used to collect high-resolution images of the mantle and funnel as the squids swim, providing valuable data on swimming behavior. Because the contractile properties of the mantle change with size and have direct effects on jet flows, detailed measurements of isolated bundles of mantle muscle also will be made using standard muscle mechanical techniques. The integration of DPIV, swimming footage, and muscle mechanical data promises to broaden our understanding of propulsive efficiency in jet-propelled organisms, especially at low size ranges where little is known about the jet mechanism, and provide insight into the evolution of ontogenetic changes in musculoskeletal support systems. These data are relevant not only for biological investigators but also for engineers and designers of emerging technologies, such as synthetic jets and pulsed-jet micro-vehicles. This project will engage undergraduate and graduate students in interdisciplinary research. It will also facilitate minority student involvement, either through direct participation in experiments or through educational development in local public schools and aquariums.