不同浓度蓝藻水华在好氧条件下的光合作用

Photosynthetic activities of cyanobacterial blooms of different concentrations under aerobic conditions with aeration

为研究不同浓度蓝藻水华在曝气形成的好氧条件下的光合作用,本文按叶绿素a(Chla)浓度32.5,346.8,1413.7和14250.0μg/L设4个处理组(从低到高编号依次为Ⅰ、Ⅱ、Ⅲ和Ⅳ)进行实验.结果表明,各处理Chla浓度均总体呈下降趋势,但均未出现发黑或发褐现象;各处理溶氧、pH值、NH4^+-N浓度和最大光合作用能力Fv/Fm均有一定差异(P<0.05).快速光响应曲线的特征参数α、ETRmax和Ik表明,处理Ⅰ、Ⅱ和Ⅲ中出现较高的绿藻、硅/甲藻的光能利用效率(P<0.05),而处理IV中所有藻类的光能利用效率较低(P<0.05).曝气增氧可以防止高浓度蓝藻水华形成黑水团;蓝藻水华初始Chla浓度约为32.5、346.8、1413.7μg/L时,在曝气形成的好氧条件下,蓝藻水华中会出现其它藻类如绿藻、硅/甲藻的生长,即藻类群落结构朝着多样化变化,对蓝藻水华形成控制.

An experiment was conducted to study the photosynthetic activity of different concentrations of cyanobacterial blooms under aerobic conditions formed by aeration.Four treatments(I,Ⅱ,Ⅲ and IV)were set up according to chlorophyll a(Chla)concentration,which was 32.5,346.8,1413.7 and 14250.0ug/L,respectively.The results showed that the Chla concentration of all treatments decreased,but no blackening or browning phenomenon occurred.There were some differences in DO,pH value,NH4+-N concentration and maximum photosynthetic capacity Fv/Fm among the treatments(P<0.05).The characteristic parametersα,ETRmax and Ik of the algal Rapid Response Light Curve showed that higher photosynthetic efficiency of green algae,diatom/dinoflagellate was achieved in treatments I,II and III,but lower photosynthetic efficiency of all algae in treatment IV(P<0.05).Aeration can prevent high concentration of cyanobacterial bloom from forming black bloom.When the initial Chla concentration of cyanobacterial bloom was 32.5,346.8 and 1413.7ug/L,respectively,the growth of green algae and diatom/dinoflagellate would occur in cyanobacterial bloom,showing that the algal community composition diversified under aerobic conditions,which can control the cyanobacterial blooms.