Physiological response study on Aureococcus anophagefferens and Thalassiosira pseudonana underunder nitrogen limitation and recovery conditions

• 1、College of Life Science and Technology, Jinan University, GuangZhou 510532

Abstract：Aureococcus anophagefferens (Chrysophyta，Pelagophyceae) is a harmful brown tide causative organism that has a huge destructive power for ecological environment and marine aquaculture. Brown tide caused by Aureococcus anophagefferens occurred for 5 consecutive years in Qinhuangdao sea of Bohai.Now we thought that brown tide occurred after diatom blooms when inorganic deplete and massive organic nitrogen into this region.So we study on the response of Aureococcus anophagefferens and diatom under nitrogen limitation and recovery conditions,and this has great significance for understood brown tide outbreak mechanism.So what we do has great significance.We use chlorophyll fluorescence spectrometer in this paper,and we research physiological response about Aureococcus anophagefferens and Thalassiosira pseudonana under nitrogen limitation and recovery conditions. We found that Aureococcus anophagefferens has stronger endurance capacity than Thalassiosira pseudonana in nitrogen deficiency environment，and that could sustain higher biomass and population density for a long time.Aureococcus anophagefferens has higher NPQ in recovery NaNO3 group than urea group.The result showed that, Aureococcus anophagefferens has stronger endurance capacity than Thalassiosira pseudonana when nitrogen deficiency. Aureococcus anophagefferens has higher NPQ in recovery NaNO3 group.Our results could preliminary explain that why Aureococcus anophagefferens could cause brown tide after diatom blooms.

Keywords： Aureococcus anophagefferens Thalassiosira pseudonana nitrogen limitation photosynthesis