造流对小新月菱形藻敞开式培养的影响

Effect of Flowing on Opening Culture of Diatom Nitzschia closterium f.minutissima

将12个53 cm×72 cm×58 cm 200 L水槽分为4组,接种密度为7.0×104个/mL的小新月菱形藻,在长面距底20 cm处分别设置3、6、12 W造流泵,流量分别为2000、3000、5000 L/h,使水流角度朝向桶底与水平面呈45°,以保证造流时整个水体能混合均匀,1个对照组,用普通搅拌耙搅池,每个处理设置3个平行,研究不同功率造流下小新月菱形藻的敞开式培养效率。试验结果显示,试验开始3 d后,3个造流组内藻细胞的密度即显著高于对照组(P<0.05),至试验结束,3、6、12 W 3个造流组内藻细胞密度分别达到(116.7±4.5)×104个/mL、(133.8±4.0)×104个/mL和(144.5±3.8)×104个/mL,较对照组[(76.3±4.7)×104个/mL]分别提高53.1%、74.6%和93.1%,三者间具有显著差异(P<0.05)且均极显著高于对照组(P<0.01)。在培养过程中,造流组内藻细胞未出现颗粒状结块现象;12 W和6 W造流组在多个时间点上的温度显著高于对照组(P<0.05);3个造流组的pH自第5 d中午后始终显著高于对照组(P<0.05)。相关分析表明,对照组培养水体的pH与藻密度间的相关系数为0.923,造流组中二者的相关系数提高至0.960~0.975;利用回归分析建立了pH预测藻密度的回归模型,3个造流组预测模型的决定系数r2(0.9525~0.9685)均高于对照组(0.8588)。

Twelve 200 L(53 cm×72 cm×58 cm)water tanks with diatom Nitzschia closterium f.minutissima at initial density of 7.0×104 cells/mL were divided into 4 groups,and 3 W(group 1),6 W(group 2),or 12 W(group 3)flow pumps were disposed at 20 cm from the bottom of the long surface of the tank with flow rate of 2000 L/h,3000 L/h,and 5000 L/h with the water flow angle of 45°toward the bottom of the tank,the fourth tank(group 4)with manual agitation as control group,under natural light for 6 d to investigate the effect of different power flowing on the open culture efficiency of the diatom.The results showed that there was significantly higher microalga cell density in the three flow making groups than that in the control group(P<0.05)from the 3rd day to the end of the experiment,with(116.7±4.5)×104 cells/mL in group 1,(133.8±4.0)×104 cells/mL in group 2,and(144.5±3.8)×104 cells/mL in group 3,and 53.1%,74.6%,and 93.1%higher than that in the control group[(76.3±4.7)×104 cells/mL],significant difference among the three flow making groups(P<0.05),significantly higher than that in the control group(P<0.01).No small blockings were observed in microalga cell in making flowing groups during the diatom culture,with significantly higher temperature in group 2 and group 3 at several time(P<0.05).There was significantly higher pH value in the three flowing groups than that in the control group after the noon of the 5th day(P<0.05).Correlation analysis revealed that the correlation coefficient(R)was 0.923 between the medium pH and microalga cell density in the control group,and were ranged from 0.960 to 0.975 in the flowing groups.The regression models to predict cell density by pH was established via regression analysis,with higher determinate coefficients(r2)of the models in the flowing groups(0.9525—0.9685)than that in the control group(0.8588).