三峡库区大宁河藻细胞昼夜垂直迁移研究

旨在准确为三峡库区藻华预警提供基础数据,本研究于2011年7月底在三峡库区大宁河流域进行藻细胞昼夜垂直迁移试验.结果表明,大宁河在此期间,藻细胞主要以绿藻、蓝藻、硅藻和甲藻为主;藻细胞在水体中的分布不均匀,72.5%～76.2%的藻细胞集中在0.5～4.0 m水体之间,0～0.5 m处藻细胞较少,占垂直水体藻密度的7.5%～16.3%,白天藻细胞Morisita指数(MI)为1.41～1.97,夜晚MI指数为1.17～1.55,叶绿素a白天MI指数为1.31～1.59,而夜晚MI指数为1.17～1.39.藻细胞在水体中存在明显的昼夜垂直迁移现象,该现象主要发生在0.5～4.0 m水体之间.水体中的藻密度受营养盐的影响较小,与可溶解性总磷显著相关(r=0.89),藻密度主要受温度、pH值和导电率影响,藻密度与温度、pH值和导电率呈极显著相关,相关系数分别为0.96、0.97和-0.99.

Vertical Migration of Algal Cells in the Daning River Bay of the Three Gorges Reservoir

To support the basic data for forecast of algal blooms, circadian vertical migration experiment was carried out in the Daning River Bay of the Three Gorges Reservoir in July, 2011. The results were as follows: in this period, different algal species were found in the Daning River Bay, including cyanobacteria, green algae, dinoflagellates and diatoms etc; the distribution of algal cells was uneven, 72.5%-76.2% of algal cells aggregated at 0.5-4.0 m water depths from 10:00 AM to 10:00 AM next day, but 7.5%-16.3% of algal cells aggregated at 0-0.5 m. Morisita's indexes (MI) of algal cells were from 1.41 to 1.97 in day time, and from 1.17 to 1.55 at night. Morisita's indexes of chlorophyll a(Chla)were from 1.31 to 1.59 in day time, and from 1.17 to 1.39 at night. The vertical migration also occurred at 0.5-4.0 m water depths. The algal density was not significantly related with the concentrations of nutrient except that of dissolved total phosphorus (DTP) (r=0.89). The algal density was also influenced by water temperature (WT), pH and specific conductance (SPC), and the correlation coefficients were 0.96, 0.97 and -0.99, respectively.