两种海洋硅藻对生源要素N、P浓度变化的响应

Response of two marine diatoms to change nitrogen and phosphorus concentrations in medium

近年来大量废水排放导致生源要素N、P成为近海重要污染物之一，本文研究了两种海洋硅藻对培养液中生源要素N或P浓度变化的响应。结果发现：中肋骨条藻在NO3-N浓度为3．0～600mg／L、三角褐指藻在N03．N浓度为8．0～600mg／L时，都能保持旺盛的生长；相比而言，中肋骨条藻在PO4-P浓度为0．6～20mg／L的实验组生长较好，而三角褐指藻在0．6～10mg／L的实验组生长较好。实验发现PO4-P浓度过高或过低都不利于两种海洋硅藻的种群增殖。本实验结果表明两种海洋硅藻都具很强的适应高浓度NO3-N的能力，与之相比，PO4-P浓度对控制硅藻种群的增殖起着非常重要的作用。本实验结果也表明：关于N、P对海洋硅藻生长的影响，除了考虑N／P比外，N、P浓度阈值也是一个不容忽视的问题。

In recent years, nitrogen and phosphorus, the necessary nutrition of plant, have become one of the important aquatic contaminants＇due to their extreme high concentrations caused by the increasing drainage of a great deal of waste water. The objective of this study is to investigate the response of two marine diatoms to change nitrogen or phosphorus concentration in cultural medium. The results showed that Skeletonema costatum grew very well at the NO3-N concentration of 3.0 -600 mg/L, while the growth of Phaeodactylum triconutum was good at the NO3 -N concentration of 8.0 - 600 mg/L. In contrast, at the PO4-P concentration of 0.6 - 20 mg/L, the growth of S. costatum was relative good; while at the PO4-P concentration of 0.6- 10 mg/L, the P. triconutum grew very well. Both of the relative higher and lower PO4-P concentrations have adverse effects on the population growth of two marine diatoms. The results showed that two marine diatoms have adapted well to higher NO3-N concentration, while PO4-P concentration was a critical index to control the reproduce of algal population comparing with the NO3-N. The results also showed that except for the N/P ratio, the nitrogen and phosphorus concentrations are also an important index to the growth of marine diatom.