Abstract:Characteristics of temporal and spatial distribution and the environmental effect of different nitrogen forms in overlying water of Lake Erhai was analyzed by collecting the history data of total nitrogen (TN) content from 1992 to 2009 and investigating the different nitrogen forms in overlying water in 2010 month by month. The results indicated that the contents of TN ranged from 0.20 mg/L to 0.67 mg/L, and showed a rise tendency as a whole in the overlying water of Lake Erhai from 1992 to 2009. For the overlying water of Lake Erhai in 2010, the average annual content of TN DTN, NH4+-N, NO3--N, DON and PN was 0.57,0.41,0.17,0.086,0.15, 0.17 mg/L, which met Class III water body requirements. The contents of TN, DTN and DON were highest in the northern, that of NH4+-N and NO3--N were highest in the middle, and that of PN were highest in the southern. The tendency of nitrogen content in overlying water of Lake Erhai was ascend in first and descend at last within a year. The contents of TN, DON and PN reached the highest in July, DTN and NO3--N peaked in September, and NH4+-N peaked in June. For the vertical distribution, contents of TN, DTN, DON and PN were in order of bottom layer > surface layer > the thermocline, and the peak appeared at 12 cm of the thermocline in the overlying water of Lake Erhai. The temporal and spatial distribution of different nitrogen forms in the overlying water of Lake Erhai was mainly affected by exogenous nitrogen input. The endogenous nitrogen was mainly released in the form of DON and PN and greatly impacted by water body perturbation. The distribution of NH4+-N and NO3--N was greatly affected by hydrophyte. The contents of TN were one of the main factors affected the seasonal change of the algae. The nitrogen contents of the overlying water had a greater effect on the eutrophication of Lake Erhai and the exogenous nitrogen input should be controlled mainly, especially at the beginning of the rainy season in June and July, and then the “north three rivers” basin was the key control area.
赵海超, 王圣瑞, 焦立新, 杨苏文, 徐圣友. 洱海上覆水不同形态氮时空分布特征[J]. 中国环境科学, 2013, 33(5): 874-880.
ZHAO Hai-Chao, WANG Sheng-Rui, JIAO Li-Xin, YANG Su-Wen, XU Sheng-You. Space-time evolution trends of water nitrogen in Lake Erhai. CHINA ENVIRONMENTAL SCIENCECE, 2013, 33(5): 874-880.