Investigation On Plankton And Water Quality Of The Reservoir In Liaohe River

There are many reservoirs around Liaohe River. In order to understand the plankton and water environment conditions, the water quality assessment and the plankton investigation in 28 reservoirs were conducted in this paper.Qualitative and quantitative analysis of zooplankton and phytoplankton were processed. What’s more, biodiversity Margalef index of the phytoplankton was calculated. Eight indexes: the total nitrogen(TN), total phosphorus(TP), ammonia(NH3-N), chemical oxygen demand(COD), dissolved oxygen(DO), suspension(TSS), conductivity and PH, selected from the People’s Republic of China Quality Evaluation "Surface Water Environmental Quality Standards", were used to evaluate the quality. The Principal Component Analysis was conducted among TN, TP, NH3-N, COD and DO.The result of zooplankton survey showed that the number of zooplankton vary seasonally(from maximum to minimum): the early summer, the late fall, the late summer and the spring. Rotifera and copepods were common, cladocerans was rare.The result of phytoplankton survey showed that the number of phytoplankton was largest when closed to winter, decreased through the spring and the early summer, increased until the late fall. The average of Margalef indexes in four periods ranged from high to low: the late fall, the late summer, the early summer and the spring, which suggested that comparing to the time of spring and summer, the condition of reservoirs was better in the fall.Results of the Principal Component Analysis showed that comparing to the spring, the late summer, the early fall, and in front of and after the fall, the Principal Component Analysis score of samples was lower in the early summer and the late fall, which indicated the water quality in reservoirs around Liaohe river in the summer and near fall was better than in the spring and the fall. The results showed that the quality of majority Liaohe River Reservoir was in poor condition, water of a great part of the reservoir was belong Ⅴ class. The results showed that the the PH of water was the highest during late autumn, while lowest in the spring. The TSS of water was lower in the spring and summer than at other seasons, indicating that the water of reservoirs was relatively clear in the spring and summer. In addition, the conductivity of reservoirs was strongest in the late fall, which was accorded with the PH value.