[Temporal variation of trophic status in drawdown area of Hanfeng Lake in the storage period of Three Gorges Reservoir in China].
In order to explore the temporal variations of nutrient and biomass in drawdown area of Hanfeng Lake of the Three Gorges Reservoir region, this paper continuously observed the water quality in the storage period of 2013 October to 2014 February. And the concentrations of nutrients, water physical parameters and chlorophyll were determined. The results showed that the concentrations of nutrients and chlorophyll increased, and the nutrition degree increased after the flooding. The concentrations of TN, TP, permanganate index and Chl-a in water in February 2014 were 4.7 times, 1.0 time, 0.2 times and 3.27 times the amount in October 2013. It should be noticed that the concentrations of TN and TP were above the algae growth limit value, which would be easy to cause water eutrophication with prolonged residence time. The single-factor evaluation of Chl-a reflected that the water quality was changed from poor nutrient to eutrophic. The results of N/P showed that TN in Han Feng Lake was a factor limiting the growth of algae in different period. In October to December 2013 and February 2014, TN limited the growth of algae. In January 2014, TP limited the growth of algae. The Chl-a had a significant positive correlation to pH, DO, NH4(+) -N, NO3(-) -N, TN, permanganate index and TP, but significant negative correlations were observed with SD and TEMP. The water quality was influenced by the same source of pollution during the storage period. The result of factor analysis showed that the water quality in riparian zone of Hanfeng Lake was mainly affected by pH, DO, NO3(-)-N, TN, while Chl-a, TP, NH4(+) -N and aerobic organics pollution could not be ignored. The water had self-purification capacity in the early phase of the storage period, the eutrophication aggravated with the increase of retention time, and it should be controlled. During the storage period of the Three Gorges Reservoir, the nutrition levels of south river and east river were relatively high, and the management should be strengthened.
Qi
Q
Huang
Bing-Hui
BH
He
Xiu-Lan
XL
Zhao
Yu-Fei
YF
Wang
D018533:Biomass; D002681:China; D002734:Chlorophyll / Q000032:analysis; D004784:Environmental Monitoring; D005068:Eutrophication; D005618:Fresh Water / Q000737:chemistry; D060106:Lakes / Q000737:chemistry*; D009584:Nitrogen / Q000032:analysis; D010758:Phosphorus / Q000032:analysis; D045483:Rivers; D060753:Water Quality
D002734:Chlorophyll; D010758:Phosphorus; D009584:Nitrogen