Ecological Conditions of Diatom Water Bloom Formulation in the Middle and Lower Reach of the Hanjiang River and Strategy for Water Bloom Control

The present paper reported the time,place,range,duration,the highest density of phytoplankton and community structure characteristics of 5 diatom water blooms in the middle and lower reach of the Hanjiang River.The results indicated that there is a worse trend for the occurrence of diatom water blooms from 1992-2000 in the middle and lower reaches of the Hanjiang River.After 2000,the range of diatom water bloom was smaller but the frequency was significantly higher.Based on the analysis of meteorological,hydraulic,nutritional and biological conditions for diatom water bloom occurrence,strategies for controlling diatom water bloom in the middle and lower reaches of the Hanjiang River was put forwarded from different aspects of water pollution control in the Hangjiang River,early warning and ecological water transition.