不同光强下小球藻纵向沉降及悬浮特性研究

Chlorella vulgaris vertical migration characteristics in different light intensity

通过用自制沉降柱研究小球藻（Chlorella vulgaris）在表层不同光强作用下纵向沉降特性以及分布规律,为进一步了解水库中小球藻的纵向分布提供参考。实验室培养的小球藻按其直径可分为小于4.5μm、4.5-5.5μm、大于5.5μm 3个等级,不同粒径的小球藻在不同光强的作用下沉速不同；实验条件下小球藻的沉速分布在0.1-468.2μm/s,均值为32.8μm/s；小球藻的沉降速度随沉降柱表层光强增强而降低,无光状态下时沉速是表层光强为10000 lx的2-3倍；小球藻直径大小与沉速呈正相关,直径4.5-5.5μm的小球藻沉速是3.5-4.5μm的5-6倍；沉降稳定后实验柱中小球藻从表层至底层粒径逐渐变大,除底层外小球藻在纵向峰值随光强增加而向下延伸,如实验柱表层光强为1000 lx和4000 lx时小球藻峰值出现实验柱表层,而表层光强为7000 lx和10000 lx的实验峰值分别出现在水下300 mm和600 mm处。

Vertical migration and distribution law in Chlorella vulgaris were observed and determined in inducing effect of different light intensity by homemade settling column, which provided support for comprehending longitudinal distribution of the reservoir C.vulgaris. C.vulgaris cultured in the laboratory was divided into three level in according with the particle diameter size： 〈 4.5 μm, 4.5-5.5 μm and 〉 5.5 μm . The settling velocity range of C.vulgaris which had different particle size was different in inducing effect of different light intensity. The settling velocity range of C.vulgaris was 0.1-468.2 μm/s with an average value of 32.8 μm/s under the experimental conditions. Settling velocity was getting slower with increase of light intensity. When light intensity reaches 10000 lx, the settling velocity and matt stated a difference of about 2 to 3 times. The particle size of C.vulgaris were positively correlated with settling velocity. The settling velocity of 4.5-5.5μm group was 5 to 6 times higher than 3.5-4.5μm groupbig;After settlement, The particle size distribution from the surface to the bottom became bigger gradually. The longitudinal peak of C.vulgaris are stretching downward with light intensity enhance except the bottom. For example, the maximum value was obtained at the surface when the light intensity was 1000 and 4000 lx., while maximum value was obtained 300 and 600 mm below the surface when the light intensity was 7000 and 10000 lx, respectively.