光照度对水华鱼腥藻细胞比重与藻丝长度的影响研究

The effect of light intensity on the cell density and chain length of Anabaena flos-aquae

为深入探索可获得光资源量（light availability）与水华鱼腥藻（Anabaena flos-aquae）浮沉关键因子——细胞比重、藻丝长度,以及水华鱼腥藻沉降损失的关系,开展了纯培养试验.在温度（25±1）℃,光照度分别为100,500,1000,3000,5000lx的条件下,培养时间35d,结果显示：在1~10d内鱼腥藻细胞比重随光照度增大而增大,在10d左右达到最大值,随后各光照组下鱼腥藻细胞比重较稳定且相差不大;光照越强,水华鱼腥藻的藻丝越短,其变化趋势是先增大到最大值再减小;光照越强,水华鱼腥藻的藻丝长度越快增大到最大值;实验结束时高光照度下水华鱼腥藻沉降损失比率较小,均低于10%,低光照下水华鱼腥藻沉降性能较好,最高可达到57.3%.实验结果表明：可获得光资源量下降直接影响鱼腥藻比重和藻丝长度并进一步导致鱼腥藻的沉降损失比率增大,这为持续型垂直混合导致蓝藻消亡的原因提供了新解释.

In order to discover the relation between the light availability of Anabaena flos-aquae and the key factors in its sinking and floating which were cell density and chain length,pure culture experiments were conducted under different conditions of illumination.In addition,the relation between sinking loss ratio and light availability was also studied.With culture period of 35d,（25±1）℃,the results showed that： The cell density of Anabaena flos-aquae increased under higher light intensity,after reaching its maximum at 10th day the cell density decreased and became stable.The length of Anabaena flos-aquae decreased with the increase of light intensity,and the trend over time was that it reached the maximum then decreased.The higher the light intensity,the sooner it reached the maximum.Under high light intensity the sinking loss ratio of Anabaena flos-aquae remained very low which was under 10%,while under low light intensity it was generally higher than 20% with the maximum 57.3%.