广东大亚湾藻类水华的动力学分析Ⅰ.藻类水华的生消过程及其与环境因子的关系

Dynamic analysises on several algal bloom events in Daya Bay of Guangdong Ⅰ.Process of algal bloom and its relationship with environmental factors

1998年广东大亚湾澳头海域先后发生日本星杆藻 (Asterionellajaponica)水华 (0 1 2 4～ 0 2 2 3)、细弱海链藻 (Thalathiosirasubtilis)水华 (0 4 0 8～ 0 4 2 0 )、裸甲藻 (Gymnodiniumspp .)水华 (0 4 2 9～ 0 5 0 8)、角毛藻(Chaetocerosspp .)水华 (0 5 11～ 0 5 2 0 )。本文研究了水华期间藻类的生消过程及其动态变化 ,并分析环境因子在水华形成和消亡过程中的作用和机制。研究结果显示 :稳定、适宜的水温是水华形成的必要条件 ,水温的急剧改变是水华消散的重要原因。海水盐度的大幅度波动与水华的消散密切相关。连续的低光照对藻类有诱导作用 ,而不同的藻类对光照强度的需求和反应并不完全相同。

Investigation on the phytoplankton of Daya Bay in Aotou, Guangdong province, which were collected from six stations once every three days, were carried out by Olympus BH2 and Olympus CH30 from January to December 1998. Water temperature, salinity, irradiance of light, pH, DO, Chlorophyll a, COD Mn , turbidity and nutrient elements were determined synchronized with phtoplankton from April to June, once a month in other months. Four algal bloom events occurred successively in Daya Bay of Guangdong province in 1998. The causative organisms were Asterionella japonica , Thalathiosira subtilis , Gymnodinium spp. and Chaetoceros spp. respectively. The processes and dynamics of these blooms were studied, and the functions and mechanisms of the environmental factors in the processes of the blooms in area scale were analysed. The studies revealed: Steady and appropriate water temperature is the necessary condition for the occurrence of the blooms, its rapid change is the key factor in the vanishing blooms. Substantial fluctuation in salinity is a key factor linked with the vanishing of algal blooms. Continuous low irradiance of light has induced action to algal, stimulates algal to proliferate quickly. However, the requirement and reaction of different algal to the reeadiance are not the same.