长江口及邻近海域赤潮藻种演替过程中营养盐特征

Nutrient characteristics in red-tide algal succession in Changjiang Estuary and adjacent sea areas

根据2010年4～10月份四个航次典型断面的调查数据,分析了长江口及邻近海域赤潮爆发过程中藻种演替现象、营养盐含量及结构变化,并初步分析了营养盐特征对赤潮藻种演替的作用。结果表明:在4月、5月、7月三个航次"硅藻→甲藻→硅藻"的演替过程中,发现不同藻种对营养盐的需求不同,较高浓度的DIN、磷酸盐和硅酸盐以及低的DIN/P、Si/DIN、Si/P比值更有利于硅藻的生长,而甲藻在低浓度的DIN、磷酸盐和硅酸盐以及高的DIN/P、Si/DIN、Si/P比值条件下生长速度较快;至10月份,硅藻和甲藻赤潮结束,营养盐基本恢复至赤潮爆发前的状态;不同时期长江口及其邻近海域水体中营养盐的改变,使得竞争能力强的藻种逐渐成长为优势藻种,从而导致了藻种的季节演替现象。

Four comprehensive surveys were conducted in the Changjiang Estuary and adjacent sea areas from Apr. to Oct. 2010. Based on the analysis of the variation of nutrients and its structures in the typical sections, the nutrient effects on dominant red-tide algal suc- cession were discussed. The results showed that a high concentration of DIN, phosphate and silicate and low DIN/P, Si/DIN, Si/P rati- os were more advantageous to the growth of the Diatom. To the contrary, Dinoflagellat grew faster in low concentration of DIN, phos-phate and silicate and high DIN/P, Si/DIN, Si/P ratios condition. The variation of nutrients resulted up and down of population of a red-tide algal species, and lead to the seasonal succession of phytoplankton predominant species.