Fluorescence-Based Diagnostic of Iron Limitation for Analysis of Natural Phytoplankton Communities

这个项目的总体目标是使用新发现的荧光诊断技术来调查海洋浮游植物中的铁限制。该项目包括实验室和实地部分。实验室研究的目的是解决荧光诊断铁限制的生理机制(S)，并测试其在主要浮游植物分类区系中的表达。这些研究是基于连续培养实验，并将包括测量。(1)可变的荧光参数，(2)荧光发射光谱，(3)皮秒荧光寿命，(4)光系统的化学计量组成。实验室研究将解决以下问题：(1)荧光诊断是由于铁限制对状态转变的荧光特征的影响，还是由于电子从高度还原的质醌池向光系统II上的主要受体的反向转移？(2)在铁限制条件下，荧光诊断在所有分类中是平等表达的，还是仅限于原核光自养生物？将进行适度的现场成分来探索这项技术在自然界中的应用。

The overall objective of this project is to investigate iron limitation in marine phytoplankton using the newly discovered fluorescence diagnostic technique. The project encompasses both laboratory and field components. The laboratory studies are aimed at resolving the physiological mechanism(s) for the fluorescence diagnostic of iron limitation and testing for its expression across major phytoplankton taxonomic divisions. These studies are based on continuous culture experiments and will include measurements of. (1) variable fluorescence parameters, (2) fluorescence emission spectra, (3) picosecond fluorescence lifetimes, and (4) the stoichiometric composition of the photosystems. The laboratory studies will address the following questions:(1) Does the fluorescence diagnostic result from an effect of iron limitation on the fluorescence signature of state transitions or the back-transfer of electrons from a highly reduced plastoquinone pool to the primary acceptor on Photosystem II?(2) Is the fluorescence diagnostic equally expressed in all taxonomic divisions under iron limiting conditions or is it restricted to prokaryotic photoautotrophs?The modest field component will be conducted to explore the utility of this technique in nature.