PHOTOSYNTHETIC CHARACTERISTICS OF PHYTOPLANKTON IN THE DAYA BAY
大亚湾浮游植物光合作用特征

Photosynthetic capacity,rapid light curves and NPQ of phytoplankton in the Daya Bay were measured using pulse-amplitude-modulation(PAM) fluorometry.Phytoplankton dynamics and environmental parameters were also investigated with the purpose of assessing the coupling between photosynthetic capacity and phytoplankton distribution.During the investigation periods,multi-cellular diatoms were dominant,and their maximum quantum yields were up to 0.72.Our results revealed that acclimation of phytoplankton in the Daya Bay to high irradiance allowed saturated electron transport to occur at PAR of 1000μmol/(m2.s).The development of non-photochemical quenching and xanthophylls cycle activity could protect the photosynthesis apparatus once PAR was elevated to 1500μmol/(m2.s).The PAR of 1700μmol/(m2.s) triggered biophysical alterations in photosynthesis apparatus,resulting in the declined effective quantum yield and electron transport rate.The accumulation to extensive temperature range and high photosynthetic activity are in favor of the worldwide distribution of multi-cellular diatoms in the natural environments.