磷酸盐对中肋骨条藻生长的影响

Effect of Different Phosphrous Concentration on the Growth of Skeletonema costatum

中肋骨条藻是一种在中国东部沿海广泛存在的广温广盐性的浮游硅藻,根据对近年来我国长江口和其他海域所发生赤潮的观测,有相当一部分是以中肋骨条藻为主(王金辉,2002;刘玉等,2002),其严重的破坏了海洋生态环境并造成了重大的国民经济损失,因此,对诱发中骨条藻爆发赤潮各种因子的研究便具有了重要的现实意义。本文应用营养盐加富的实验方法,在室内进行了中肋骨条藻的培养试验,研究了不同磷酸盐浓度条件下中肋骨条藻的生长情况,并对藻细胞内氮磷比的变化情况进行了探讨,以求对揭示中肋骨条藻赤潮的产生机制有所裨益。

The growth condition of Skeletonema costatum was studied in different phosphorus concentration by the adding-nutrients experimental method and by batch culture experiments were conducted . pH, DOC, nutrients concentration of the culture medium and the N/P ratio of the cell were measured periodically. The results showed that the phosphrous concentration determined the growth rate of Skeletonema costatum and the maximum cell density. pH of the culture medium began to decreased drastically as soon as the exponential growth period was over. It seems to be a herald to the Skeletonema costatum growth condition. The DOC concentration increased faster in the culture medium with higher cell density as the result of the addition of more phosphate, and could still keep increasing trend for a while after the exponential growth period of Skeletonema costatum ended. The N:P ratio in the Skeletonema costatum cell was about 15:1, which was close to the Redfield ratio. From the N:P ratio in the cell, we could deduce that when the Skeletonema costatum enters a new environment, it first concentrates phosphrous, and then uses it later, the initial absorption rate of phosphrous was faster than that of nitrogen.