Near-Wall Lift and its Role in the Survival of Limpets and Keyhole Limpets

所有生物体都生活在流体介质(空气或水)中，因此受到流体物理学的影响。特别是，所有的植物和动物都会遇到流体动力，这种动力可能会潜在地伤害或驱逐有机体，从而对其生存产生不利影响，在许多情况下，流体动力被认为是身体形态进化中的选择性因素。这些力的各个方面(如对底栖生物的阻力、对鸟类和昆虫翅膀的升力)已被广泛研究，我们对其机制的理解一直是解释这些群体的生态和进化的重要工具。尽管流体动力力很重要，但一种常见的力--近壁升力--却没有引起人们的注意。近壁抬升可能是许多底栖海洋动物死亡的一个重要来源。例如，帽状物和锁孔帽状物在水动力作用下移动时往往会被杀死，而近壁升力是迄今为止作用在它们身上的最大力。然而，近壁升力的机制及其与体型的相互作用从未被研究过，也没有被很好地理解。Denny博士的这些研究有三个主要目标：(1)了解近壁抬高的机制，从而为探索其作为帽状物和锁孔帽状物死亡率来源的作用提供坚实的基础。(2)测量帽状物和锁孔帽状物的强度分布，从而能够根据局部波况对死亡率进行定量预测。(3)定量预测室壁抬高的选择性优势或劣势，作为选择性死亡率的指标。因此，这项研究为探索流体动力在群落生态学、种群生物学和身体形态演变的关键联系中所起的作用提供了一个定量的实验工具。

All organisms live in a fluid medium (either air or water), and are therefore subject to the physics of fluids. In particular, all plants and animals encounter fluid-dynamic forces that can potentially injure or dislodge the organism, thereby adversely affecting its survival, and in many cases fluid-dynamic forces are thought to have acted as selective factors in the evolution of body form. Aspects of these forces (e.g., drag on benthic organisms, lift on the wings of birds and insects) have been extensively studied, and our understanding of their mechanism has been an important tool in interpreting the ecology and evolution of these groups. Despite the importance of fluid-dynamic forces, one common force, near-wall lift, has escaped notice. Near-wall lift is likely to be an important source of mortality in many benthic marine animals. For instance, limpets and keyhole limpets are often killed when dislodge by hydrodynamic forces, and near- wall lift is by far the largest force acting on them. However, the mechanism of near-wall lift and its interaction with body form have never ben examined and are not well understood. These investigations by Dr. Denny have three major goals: (1) To understand the mechanism of near-wall-lift and thereby to provide a firm basis for exploring its role as a source of mortality in limpets and keyhole limpets. (2) To measure the strength distribution of limpets and keyhole limpets, thereby allowing for the quantitative prediction of rates of mortality as a function of the local wave regime. (3) To quantitatively predict the selective advantage or disadvantage in wall lift to act as an agent of selective mortality. As such, this research provides a quantitative, experimental tool for exploring the role fluid-dynamic forces play at the crucial nexus of community ecology, population biology, and the evolution of body form.