Testing the turbulence avoidance hypothesis

本计画将借由实验室实验与电脑模拟，评估桡足类对乱流之种别反应。实地研究强烈表明，海洋湍流影响桡足类的垂直位置主要是通过改变他们的行为，只有其次通过物理改变他们的位置。有待检验的假设是，细尺度湍流改变桡足类的行为，通过定向运动和游泳运动学的变化。特别设计的实验室设备，使浮游生物运动学模式的比较，以响应细尺度湍流特征。该设备创建湍流耗散率，长度尺度，速度尺度，和波动的应变率水平，是适合浮游动物的研究。三维速度测量技术的最新进展，使这是一个合适的时间来量化周围的流场自由游动浮游动物在高空间和时间分辨率。为了将特定的行为反应与特定的瞬时3D流模式相关联，必须在动物周围的3D体积中量化速度场。这些实验将有助于桡足类行为和水动力条件之间的定量相关性，并将为生物与物理强迫的平衡提供新的见解。此外，桡足类响应的规则，以空间明确的物理环境将进入一个基于个人的模型（IBM），以提供一个上下文来评估浮游动物行为的生态意义。IBM模拟将测试微尺度行为对细尺度桡足类分布的影响，从而允许避免服从性假设问题得到解决：个别桡足类反应细尺度湍流功能与物种特异性的反应，导致人口分布，不重叠的湍流区域？合作的相互作用是必不可少的生物，物理和化学过程，创造和维持精细尺度浮游生物分布格局的扩展理解。这种跨学科的努力依赖于流体力学和生物海洋学的专业知识相结合，以促进桡足类生态学和感觉系统的理解。该项目将增加我们对湍流对浮游动物分布影响的理解和建模能力。此外，这些数据将被NOAA人员用于开发作为风力产生的混合层湍流函数的二次生产的长期指数，作为NOAA FATE（渔业与环境）计划的一部分。将为一名研究生提供先进激光测量系统、桡足类机械传感系统和海洋生物物理相互作用等具体领域的培训。学生将体验丰富的跨学科研究环境，并发展技能，成为她/他的领域的领导者。该项目与正在进行的教育工作，特别是NSF IGERT和REU计划，在水生化学和水力机械信号领域进行教育。此外，研究人员计划与格鲁吉亚水族馆和亚特兰大动物园的工作人员合作，设立无脊椎动物行为和水下感知在调解行为中的作用的展览。

This project will evaluate species-specific responses of copepods to turbulence via laboratory experiments and computer simulations. Field studies strongly suggest that oceanic turbulence affects the vertical position of copepods primarily by changing their behavior, and only secondarily by physically altering their position. The hypothesis to be tested is that fine-scale turbulence alters copepod behavior via directed movements and changes in swimming kinematics. The specially-designed laboratory apparatus enables comparison of plankton kinematic patterns in response to fine-scale turbulent flow features. The apparatus creates turbulent flows with dissipation rates, length scales, velocity scales, and fluctuating strain rate levels that are appropriate for zooplankton studies. Recent advances in 3D velocity measuring techniques make this an opportune time to quantify the flow field around frees-wimming zooplankton at high spatial and temporal resolution. To correlate specific behavior responses to specific instantaneous 3D flow patterns, the velocity field must be quantified in a 3D volume surrounding the animal. The experiments will facilitate a quantitative correlation between copepod behavior and hydrodynamic conditions and will provide new insight to the balance of biological versus physical forcing. Further, the rules of copepod response to a spatially-explicit physical environment will be entered into an individual-based model (IBM) to provide a context to assess the ecological significance of zooplankton behavior. The IBM simulations will test the influence of micro-scale behavior on fine-scale copepod distributions, and hence allow the turbulence-avoidance hypothesis question to be addressed: Do individual copepods react to fine-scale turbulent features with a species-specific response that results in a population distribution that does not overlap with the turbulent region?Collaborative interactions are essential to extending understanding of the biological, physical, and chemical processes that create and maintain fine-scale plankton distribution patterns. This interdisciplinary effort relies on combining expertise in fluid mechanics and biological oceanography to advance understanding of copepod ecology and sensory systems. This project will increase our understanding and ability to model the effects of turbulence on zooplankton distributions. Further, the data will be used by NOAA personnel towards developing long-term indices of secondary production as a function of wind-generated mixed-layer turbulence as part of NOAA's FATE (Fisheries And The Environment) program. Training will be provided for a graduate student in the specific areas of advanced laser measurement systems, copepod mechanosensory systems, and biological-physical interactions in the ocean. The student will experience a rich interdisciplinary research environment and develop skills to be a leader in her/his field. The project connects well with on-going educational efforts, in particular NSF IGERT and REU programs to educate in the area of aquatic chemical and hydromechanical signaling. Further, the investigators plan to work with staff members at the Georgia Aquarium and Zoo Atlanta to set up exhibits of invertebrate behavior and the role of underwater perception in mediating behavior.