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

摘要本研究旨在探讨弱光条件下解偶联光合碳结合和硝酸盐吸收的重要性。弱光条件在光区的底部是常见的，在那里，通过混合事件的营养物质的偶发性输入可能引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和硅藻生长方面可能发挥的作用。这些相同的实验还将研究随着pH值上升和无机碳库总量缩小，硅藻生长可能受到游离二氧化碳限制的可能性。这些研究将在一系列受控的实验室实验中进行，涉及目前在首席研究员实验室培养的马尾藻海大型硅藻的分离物。这些结果将为评估大型浮游植物的生理、它们在新生产中的作用以及分子扩散对海洋食物链自养部分结构的潜在影响提供基础。

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.