洋河水库水华优势种演替的原因分析

Analysis of succession of dominant algal species in water bloom of Yanghe Reservoir

针对鱼腥藻和微囊藻这2种洋河水库水华暴发常见优势藻,研究了其在不同温度及硝态氮浓度下的生长情况。结果表明,在温度15～25℃,硝态氮浓度0.05～10 mg/L的范围内,温度的升高、硝态氮浓度的增加,对鱼腥藻的生长影响不明显,却能够明显地促进微囊藻的增长。15℃或0.05 mg/L硝氮条件下,鱼腥藻的比增长速率高于微囊藻,而25℃或10 mg/L硝氮时,微囊藻的比增长速率分别达到了0.425 d-1和0.466 d-1,明显超过鱼腥藻。洋河水库逐年升高的硝态氮浓度以及夏秋季节比较适宜的温度促进了微囊藻的增长,可能是洋河水库水华优势种由螺旋鱼腥藻向微囊藻转变的重要因素。

Anabaena sp.and Microcystis sp.are the two common dominant algal species in the water bloom occurs in Yanghe Reservoir.Study on the growth of the above two dominant algal species was conducted under different conditions of temperature and nitrate nitrogen concentration.The results showed that no significant impact is caused by the increase of temperature and nitrate nitrogen concentration on the growth of Anabaena sp.,when the temperature ranged from 15 ℃ to 25 ℃ and the nitrate nitrogen concentration ranged from 0.05 mg/L to 10 mg/L,while bringing with obvious promotion of Microcystis sp.growth.Under the condition of 15 ℃ or 0.05 mg/L nitrate nitrogen concentration,the specific growth rate of Anabaena sp.is higher than that of Microcystis sp..However,the specific growth rates of Microcystis sp.could reach 0.425 and 0.466 d-1 separately under 25 ℃ or 10 mg/L nitrate nitrogen concentration,being obviously higher than that of Anabaena sp.The yearly increasing nitrate nitrogen concentration and suitable temperature in summer and autumn have stimulated the growth of Microcystis sp.,which becomes the significant potential factor causing the succession of dominant algal species in the water bloom of Yanghe Reservoir from Anabaena sp.to Microcystis sp.