大亚湾亚历山大藻种群周年变动与环境因子的关系

Dynamics of Alexandrium population and environmental factors in Daya Bay,the South China Sea

于1997年7月至1998年6月,在大亚湾澳头海域设立6个监测站位,连续监测亚历山大藻(Alexandriumsp.)种群周年变动规律及其与环境因子的关系。大亚湾亚历山大藻种群的密度高峰出现在春季(4月至5月),最高密度达到20.4cells·mL-1,其它季节则密度较低。亚历山大藻密集出现的温度为22.8～30.0℃、盐度范围为25～30。在亚历山大藻种群密度高峰期里,N/P都较高,DIN含量维持较高水平,有利于亚力山藻的生长,DIP含量却很低,使得此藻比其他藻更具竞争优势。可溶性Fe含量可能成为亚历山大藻增殖的限制性因子。

Annual variation of Alexandrium population.in Daya Bay, the South China Sea, were investigated,The influences of environmental factors on the population dynamics were analyzed at six stations in Daya Bay from July 1997 to June 1998. The abundance of Alexandrium sp, was found higer in spring from April to May than those in other seasons in the area. The highest cell density was 20400 cells·L^-1. The temperature and salinity range were 22.8～30.0℃ and 25～30‰ respectively with the high cell density occurring. During the high density cell seasons of the Alexandrium population, the N/P ration was above 16. The concentration of DIN remained the high level. So the Alexandrium sp had more competitive advantages than other alga populations when the concentration of DIP was low. Fe may be the limiting factor of the population growth.