Collaborative Research: Chemical Orientation in Turbulent Environments Above Natural Stream Substrates: The Role of Bed Roughness and Turbulence Structure on Search Mechanisms

这项合作提案描述了将流流体动力学、气味信号的湍流传输以及小龙虾Orconectes rusticus的感觉生态学和行为联系起来的研究。小龙虾利用水中的化学信号（“气味羽状物”）作为定位食物、洞穴或配偶以及躲避捕食者的导航线索。气味羽流的时空变异性（“结构”）的性质取决于水动力条件，而水动力条件又取决于水流的物理特性。这项研究的目的是了解小龙虾是如何利用气味羽状物来定位水下物体的。特别是，我们计划研究在不同的水动力条件下（与不同类型的溪流基质材料相关）小龙虾的导航行为是如何变化的。通过将我们的注意力集中在不同基质类型的气味结构和相关取向行为的变化上，我们希望能够深入了解动物使用的特定算法和信息线索。最终，从拟议的研究中获得的知识可用于设计机器人车辆，以搜索危险的水下物体，或保护受管理的生态系统中的小龙虾栖息地。在环境方面，小龙虾是许多河流栖息地的关键物种，了解影响其行为的物理、生物和化学因素将有助于更广泛地了解河流生态学和人类对河流生态学的影响。特别是，关于河流栖息地如何影响化学物质分布的详细知识将不仅为了解小龙虾和河流生态提供必要的信息，而且将有助于阐明河流中污染运输背后的物理机制及其对河流生态系统的可能影响。本提案中概述的工作是生物学家和工程师之间的合作努力，将导致研究生和本科生的跨学科培训。此外，新的技术进步将通过开发高速和精细尺度的三维测量不同自然流动状态下的化学浓度来实现。这些技术的发展和量化将有利于从海洋学到环境工程的广泛领域。

This collaborative proposal describes research that links stream hydrodynamics, turbulent transport of odor signals, and the sensory ecology and behavior of the crayfish Orconectes rusticus. Crayfish use water-borne chemical signals ("odor plumes") as navigational cues for locating food, burrows, or mates, and for avoiding predators. The nature of the spatial and temporal variability ("structure") of the odor plumes depends on the hydrodynamic conditions, which, in turn, depends on the physical characteristics of the stream. The goal of the proposed research is to understand how crayfish use odor plumes to locate underwater objects. In particular, we plan to investigate how the crayfish navigational behavior varies under different hydrodynamic conditions (associated with different types of stream substrate materials). By focusing our attention to the changes in odorant structure and associated orientation behavior over different substrate types, we hope to gain insight into the specific algorithms and information cues used by the animals. Ultimately, the knowledge gained from the proposed study could be used to design robotic vehicles to search for dangerous underwater objects, or to protect crayfish habitat in managed ecosystems. Environmentally, crayfish are keystone species for many stream habitats and understanding the physical, biological, and chemical factors that influence their behavior will lead to a broader understanding of stream ecology and the human impact on stream ecology. In particular, detailed knowledge of how stream habitats influence the distribution of chemicals will provide the information necessary to understand not only crayfish and stream ecology, but will help elucidate the physical mechanisms behind pollution transportation in streams and their possible impact on stream ecosystems.The work outlined in this proposal is a collaborative effort between a biologist and engineer that will lead to cross-disciplinary training of both graduate and undergraduate students. In addition, new technical advances will be achieved through the development of high-speed and fine-scale three-dimensional measurements of chemical concentrations in different natural flow regimes. The development and quantification of these techniques will benefit a wide array of fields from oceanography to environmental engineering.