Suspension Regulation in Positively Buoyant Marine Diatoms

这项研究计划将确定内部的作用 离子调节在维持大的正浮力 海洋硅藻，Rhizolenia，使用联合实验室和 现场程序 以前的研究表明， 属Rhizolenia是积极的浮力，这种浮力， 可以用细胞液的大小依赖函数来描述 密度和硅化。 该计划将遵循 正浮力硅藻对光的浮力反应， 养分（N、P、Si）调控。 的产生的变化 运动的方向和速度将与 细胞液离子组成和内源性 营养库 昼夜研究将测量时间变化 以确定其对垂直方向的潜在影响 与生命周期现象相关的细胞定位。 的 潜在的垂直迁移在这些硅藻利用 深硝酸盐池将具体解决， 实验室和现场实验。 这项工作代表了第一个 重点分析硅藻中的正浮力，一类 以前认为不能向上定向的浮游生物 在真光层的运动。

This research program will determine the role of internal ionic regulation in maintaining the positive buoyancy of large oceanic diatoms, Rhizosolenia, using a combined laboratory and field program. Previous work has shown that diatoms of the genus Rhizosolenia are positively buoyant, and that this buoyancy can be described by a size- dependant function of cell sap density and silicification. This program will follow the buoyancy response of positively buoyant diatoms to light and nutrient (N, P, Si) manipulations. The resulting changes in direction and rate of movement will be related to variations in the cell sap ionic composition and concentration of internal nutrient pools. Diel studies will measure the temporal variation in buoyancy to determine its potential effect on the vertical positioning of cells in relation to life-cycle phenomenon. The potential for vertical migration in these diatoms for utilization of deep nitrate pools will be specifically addressed in laboratory and field experiments. This work represents the first focused analysis of positive buoyancy in diatoms, a class of plankton previously assumed to be incapable of directed upward movement in the euphotic zone.