基于生物光学剖面漂流浮标（Bio-Argo)现场观测的南海浮游植物季节性变化及其光适应性研究

影响南海物理-生物地球化学耦合的不同时间尺度海洋-大气过程中，季节性反转的东亚季风是重要影响因子。浮游植物具有明显的季节变化特征，冬季含量最高。浮游植物能调整细胞内叶绿素a浓度以适应光照及营养盐的变化，在光照降低、营养盐充足时增大chl-a.含量增大以提高光合作用效率。同一海区浮游植物chl-a与其碳生物量的比值在不同生理状态下的变动范围可超过一个数量级，浮游植物的生物光学参数比chl-a能更好地反映其生物量。Bio-Argo是集成多种生物光学与生物地球化学传感器的新型自持式剖面漂流浮标，它极大地弥补了传统船基现场观测时空分辨率低和遥感无法观测深层海洋的不足。本项目利用投放在南海的Bio-Argo，结合现场和遥感观测，利用多平台资料分析南海生物光学关系，浮游植物的光适应性及其季节变化特点。这对深入理解南海海洋生物地球化学循环、海洋物理与生态过程的耦合机制都具有重要意义。

The physical-biogeochemical coupling in the South China Sea (SCS) is sensitive to ocean-atmosphere forcing at different time scales. Among them the seasonally reversing East Asian Monsoon exerts a major control mechanism, consequently phytoplankton presents a remarkable seasonal variability with the feature of blooming in winter. Phytoplankton can adjust their intracellular chlorophyll-a content in response to ambient light and nutrient. When incident irradiance decreases and nutrients remain replete, phytoplankton increase their chl-a content to enhance their photosynthesis efficiency. The physiological adaptation can introduce more than a ten-fold variation in chl-a to carbon biomass ratio. It is argued that bio-optical properties can be used as a better proxy of phytoplankton biomass than chl-a concentration. As a new type autonomous platform, Argo floats integrated with multiple bio-optical and biogeochemical sensors (Bio-Argo) provide data with very high temporal and vertical resolution. This overcomes the disadvantages of both field shipborne and satellite remote sensing observations. The proposed work will utilize multi-platforms (Bio-Argo floats combined with field cruise and and remote sensing) to analyze the bio-optical properties, photo-acclimation of phytoplankton, and their seasonal variability in SCS. This work will be beneficial to further understand the biogeochemical cycles, physical-biological coupling mechanism in SCS.