Forced Convection Effects on Gas Flux in Benthic Cnidarians

许多无根的海洋无脊椎动物依靠海水的强制对流来输送颗粒食物、溶解的营养物质和呼吸气体。先前对被动悬浮喂养刺胞生物的研究表明，生物边界层的流动状态是粒子和气体通量的最重要决定因素。传质理论在分析水生无脊椎动物对流介导的气体通量方面一直没有得到充分的利用。我建议通过使用气体微电极、循环流动呼吸测量法、细胞层生物类似物、加热模式生物类似物和场形态测量法的实验来研究流动如何调节几种北方和温带刺胞动物的交换过程。本研究的目标包括：(1)了解生物体大小、几何形状和间距对舍伍德/雷诺数关系的影响；(2)测量了浅海潮下实际湍流中扩散边界层限制和湍流增强效应的频率(3)测试了扩散相似模型作为理解刺胞体多几何异速的一种方案；(4)研究微电极扩散边界层映射作为面积交换系数的生理探针及其与动物结构和动量边界层的关系。这项气体交换研究的结果还将深入了解DOM的吸收和渗透调节的某些方面，并将对有兴趣估计海洋栖息地次级生产力的工作者有用。这项工作将应用于污染群落、珊瑚礁生态学和近岸底栖生物过程的研究。

Many sessile marine invertebrates depend on forced convection of seawater to deliver particulate food, dissolved nutrients, and respiratory gases. Previous work with passive suspension feeding cnidarians has shown that the state of flow in the boundary layer over the organism is the most important determinant of particle and gas flux. The theory of mass transfer has been under-utilized in the analysis of convection mediated gas flux in aquatic invertebrates. I propose to investigate how flow modulates exchange processes in several species of boreal and temperate cnidarians through experiments using gas microelectrodes, recirculating flow respirometry, cell layer organism analogs, heated model organism analogs, and field morphometry. The goals of this study include: (1) an understanding of the effects of organism size, geometry, and spacing on the Sherwood/Reynolds number relationship, (2) measurement of the frequency of diffusional boundary layer limitation and turbulent enhancement effects in real turbulent flows in shallow subtidal hibitats (3) testing of diffusional similarity models as a scheme for understanding the allometry of polypal geometry in cnidarians, and (4) investigation of microelectrode diffusional boundary layer mapping as a physiological probe of areal exchange coefficients and their relationship with animal structure and the momentum boundary layer. The results of this gas exhanges study will also give insights into uptake of DOM and some aspects of osmoregulation, and will be useful to workers interested in estimating secondary productivity in marine habitats. This work will have application to the study of fouling communities, coral reef ecology, and near-shore benthic processes.