洱海湖滨带水质的时空变化规律

对洱海全湖128km湖滨带及其外围敞水区水质进行了为期1a的调查研究.结果表明,洱海湖滨带总氮、氨氮、总磷、高锰酸盐指数年平均处于Ⅲ类水平,主要污染因子是总氮和总磷;湖滨带水质季节性变化表现为夏、秋季水质污染重于冬、春季,最重时期是11月.水质空间变化表现为北部污染重于南部,西部重于东部;临近村落、农田区湖滨带总氮、总磷、高锰酸盐指数浓度均明显高于临近林地、山地区湖滨带;强风浪水动力扰动下,湖滨带近岸(离岸0~60m范围,水深￡2.5m)区域水体总氮、总磷、高锰酸盐指数浓度均明显高于远岸(离岸70~190m范围,水深3.0~8.0m)区域,而在弱风浪下,离岸远近水质差异不明显.

Spatial and temporal changes in water quality in aquatic-terrestrial ecotone of Lake Erhai

Lake Erhai is a large, shallow freshwater plateau lake in Yunnan Province in S. W. China. The water quality of Lake Erhai was monitored along 128km aquatic-terrestrial ecotone of this lake from July 2009 to June 2010. Annual mean concentrations of total nitrogen(TN), total phosphorus(TP), and permanganate index(CODMn) in aquatic-terrestrial ecotone water were Ⅲ class level,and the major pollution resources were TN and TP.Pollution in aquatic-terrestrial ecotone water was worse in summer and autumn than in winter and spring. Pollution in north and western of aquatic-terrestrial ecotone were much higher than in southern and eastern respectively. Concentrations of TN, TP and CODMn in aquatic-terrestrial ecotone close to villages and farmlands were much higher than those near forest and mountain lands. Under strong wind-wave hydrodynamic force, concentrations of TN, TP and CODMn close to lake bank (less than 60m from lake bank,depth￡2.5m) were significantly higher than those far away from lake bank (more than 60 m from lake bank,depth from 3.0m to 8.0 m), however, under the weak wind-wave, there was no obvious differences between those two aeras.