How Do Phytoplankton Adapt to Fluctuating Light? Response of the Photosynthetic Apparatus to Intermittent Exposure to Bright Light

研究表明，在任何给定的辐照度下，光合作用速率在很大程度上取决于在几分钟到几小时甚至几天的时间尺度上的光史。然而，这些研究未能提供对可变光下光合作用的预测性理解。新技术使研究光合作用、光保护和光抑制过程在控制光合作用瞬时速率中的作用成为可能。该技术包括用于检测光保护、光抑制和光合作用的快速重复率（FRR）荧光，以及用于测量光下总光合作用和氧循环速率的18O质谱。在实验室中，本研究将校正基于FRR荧光的总光合作用估计与从18O2交换中获得的总光合作用测量速率，并量化光保护和光抑制在控制光合作用速率中的作用。在野外研究中，原位FRR荧光测量将用于建立光化学和非光化学猝灭系数的二维（即深度和时间）描述，计算光合作用的瞬时速率，并研究光保护和光抑制在控制浮游植物原位光合作用中的作用。

Studies have demonstrated that photosynthesis rates at any given irradiance depend critically on the light history over time scales of minutes to hours and days. However, these studies have failed to provide a predictive understanding of photosynthesis in variable light. New technology makes it possible to examine the roles of photosynthetic, photoprotective and photoinhibitory processes in controlling the instantaneous rate of photosynthesis. This technology includes fast repetition rate (FRR) fluorescence for examining photoprotection, photoinhibition and photosynthesis, and 18O mass spectrometry for measuring the rate gross photosynthesis and oxygen cycling in the light. In the laboratory, this study will calibrate FRR fluorescence-based estimate of gross photosynthesis against measured rates of gross photosynthesis obtained from 18O2 exchange and quantify the roles of photoprotection and photoinhibition in controlling the rate of photosynthesis. In field research, in situ FRR fluorescence measurements will be used to establish a two-dimensional (i.e. depth and time) description of the photochemical and non- photochemical quenching coefficients, calculate the instantaneous rate of photosynthesis and examine the roles of the photoprotection and photoinhibition in controlling phytoplankton photosynthesis in situ.