The Hydrodynamics of Phytoplankton Removal in Benthic Boundary Layers by Filter-Feeding Bivalves

本文对悬浮物投喂双壳贝类去除湍流边界层中颗粒的流体力学进行了实验研究。这项研究的动机是需要在各种流动条件下获得这些动物从水柱中去除浮游植物生物量的速度的准确估计。目前还不清楚，给定种群的双壳类的颗粒去除率应该如何与实验室实验中测量的单个动物的泵送速率有关，或者甚至是在与自然条件不同的条件下测量的种群的颗粒去除率之间的关系。斯坦福大学工程学院将提供补充资金，以促进复杂水槽的建设。在实验室水槽中，对“模型软体动物”(不同的抽水装置)上的速度和浓度(溶质和颗粒)场的广泛测量将被用来检验两个相互关联的假设：(1)近床面流体动力学影响悬浮颗粒(包括浮游植物)从水柱到水柱的通量。滤食型双壳类，从而确定滤食性双壳类能否控制上覆水体中的浮游植物生物量。(2)双壳类摄食电流改变了河床附近的流动特性，特别是颗粒的垂直混合速率，从而在决定底栖滤食者何时能够控制浮游植物种群方面发挥了作用。为了确保拟议工作与河口系统的直接相关性，将与美国地质调查局科学家5密切合作，研究居住在旧金山湾的悬浮喂食型双壳软体动物。

This is an experimental study of the fluid mechanics of particle removal in turbulent boundary layer by suspension feeding bivalve mollusks. The study is motivated by the need to obtain, for a variety of flow conditions, accurate estimates of the rate at which these animals remove phytoplankton biomass from the water column. It is not clear at present how particle removal rates of a given population of bivalves should be related to pumping rates measured for single animals in laboratory experiments, or even particle removal rates measured for populations under conditions different from those found in nature. Stanford's School of Engineering will provide supplemental funds to facilitate the construction of the sophisticated flume. Extensive measurements of velocity and concentration (solutes and particles) fields over "model mollusks" (various pumping arrangements) in the laboratory flume will be used to test two interrelated hypotheses: (1) Near-bed hydrodynamics influence the flux of suspended particles (including phytoplankton) from the water column to filter-feeding bivalves, and thereby determine whether or not filter-feeding bivalves can control phytoplankton biomass in the overlying water column. (2) Bivalve feeding currents modify flow properties near the bed, particularly rates of vertical mixing of particles, and thereby play a role in determining when benthic filter feeders can control phytoplankton populations. In order to assure the direct relevance of the proposed work to estuarine systems, the experimental program will be carried out in close collaboration with USGS scientistsV studying suspension-feeding bivalve mollusks resident in San Francisco Bay.