Abstract: To understand the diel vertical distribution patterns of Raphidiopsis raciborskii in Dashahe Reservoir,we carried outa survey on September 20-21 (wet season) and December 31 (dry season) of 2018. The distribution patterns of R. raciborskii population were examined with Morisita’s index and mean retention depth, and the differences of which were tested with a oneway ANOVA. A multiple regression model was used to analyze the effects of environmental variables on diel vertical distribution. The results showed that R. raciborskii clumped in water column in wet season, mainly distributed in the depth from 0.5 to 2 m, with a mean retention at 1.5 m. They were randomly distributed in dry season. R. raciborskii did not show vertical migration in both wet and dry seasons. Thermal stratification was the key factor driving diel vertical distribution of R. raciborskii in the reservoir.

Key words: Miscanthus, phytoremediation., soil amelioration, heavy metal, energy plant