Diffusion and Low Light Effects on the Nutrition and Growth of Large Marine Diatoms

9416012戈德曼项目摘要这项拟议的研究将调查弱光条件下光合碳结合和硝酸盐吸收解耦的重要性。弱光条件在真光区的底部很常见，在那里通过混合事件周期性地输入营养物质可能会触发大型硅藻的快速生长。此外，还将研究扩散在限制硝酸盐吸收从而限制硅藻生长方面可能发挥的作用。这些实验还将研究，随着pH升高和总无机碳库缩小，硅藻生长可能会受到游离二氧化碳的限制。这些研究将在一系列对照实验室实验中进行，这些实验涉及目前在首席调查员实验室培养的马尾藻海的大型硅藻分离物。这些结果将为评估大型浮游植物物种生理学的重要方面提供基础，它们在新的生产中的作用，以及分子扩散在构建海洋食物链自养部分的潜在影响。

9416012 Goldman PROJECT ABSTRACT The proposed research will investigate the importance of uncoupling photosynthetic carbon incorporation and nitrate uptake under low light conditions. Low light conditions are common at the base of the euphotic zone where episodic inputs of nutrients through mixing events might trigger the rapid growth of large diatoms. In addition, studies will be performed on the role that diffusion may play in the limitation of nitrate uptake and hence diatom growth. Those same experiments will also investigate the possibility that diatom growth might become limited by free CO2 as the pH rises and the total inorganic carbon pool shrinks. These studies will be performed in a series of controlled laboratory experiments involving isolates of large diatoms form the Sargasso Sea that are currently in culture in the Principal Investigator's laboratory. The results will provide a basis for assessing important aspects of the physiology of large phytoplankton species, their role in new production, and the potential impact of molecular diffusion in structuring the autotrophic portion of marine food chains.