Does Turbulence Create Small-Scale Patchiness of Phytoplankton

9402910 STRICKLER本研究项目将重点研究小尺度湍流与植物营养颗粒空间分布之间的相互作用。不可压缩的，各向同性湍流的直接数值模拟（DNS）的初步结果表明，颗粒的密度类似于藻类开发非随机的空间分布，包括聚集体的峰值数密度的40倍的全球平均值时，悬浮在模拟流场。将进行实验室试验，以确定真实的湍流中的实际藻类颗粒是否形成斑块，以及它们的行为是否与数值模拟预测的一样。 一个特殊的装置，创造可再生的网格产生的湍流，并允许直接观察悬浮的藻类颗粒将被构建和校准。将评价粒度、形状、浮力密度和固有运动性（“游动”能力）对颗粒空间分布的影响。经验数据将与来自精细模型的DNS预测进行比较。结果将提供开拓性的洞察力的作用，小规模的流体动力学影响浮游植物的空间分布：这种洞察力是必不可少的了解海洋和五大湖的藻类和草食藻类相互作用的资源收购的动态。 ***

9402910 STRICKLER This research project will focus on the interaction between small- scale turbulence and the spatial distribution of phytoplanktonic particles. Preliminary results from Direct Numerical Simulations (DNS) of incompressible, isotropic turbulence have shown that particles of a density similar to that of algae develop non-random spatial distributions including aggregates at peak number densities of 40 times the global mean value when suspended in a simulated flow field. Laboratory tests to determine whether actual algal particles in real turbulent flow form patches and whether they behave as predicted from numerical simulations will be undertaken. A special apparatus which creates reproducible grid-generated turbulent flow and which allows for direct observation of suspended algal particles will be constructed and calibrated. The effect of particle size, shape, buoyant density, and inherent motility ("swimming" capacity) on particle spatial distributions will be evaluated. Empirical data will be compared to DNS predictions derived from a refined model. Results will provide pioneering insight into the role of small-scale fluid dynamics in influencing phytoplankton spatial distributions: such insight is essential for understanding the dynamics of resource acquisition by algae and herbivore-algal interactions in oceans and the Great Lakes. ***