摘要
根据2016年长江源和怒江源区现场调查获取的水质监测资料,分析了长江源和怒江源区河湖水体的基本理化参数、氮磷含量和形态指标,并利用氮磷化学计量比(m(TN)∶m(TP),氮磷质量比)特征评估了江源地区河湖水体的氮磷养分限制状态。结果表明:长江源和怒江源区河湖水体的总氮含量介于0.475~0.956 mg/L,满足地表水Ⅱ—Ⅲ类水质标准;总磷含量介于0.006~0.017 mg/L,满足地表水Ⅰ—Ⅱ类水质标准;硝态氮占总氮含量的43.5%~85.5%,是河湖水体氮素的主要组成部分,对江源地区水体总氮污染的贡献更大;氮磷比介于33.7~79.3,磷素是江源区河湖水体中浮游植物生长的限制性营养因子。研究成果可为揭示江源地区河湖水体的富营养化进程和水生态环境保护提供数据支撑。
According to the water quality monitoring data obtained from our field survey in the source regions of the Yangtze River and Nujiang River in 2016, we analyzed the physicochemical parameters, nitrogen and phosphorus content and form in water body of rivers and lakes in the source regions, and evaluated the nutrient limitations of nitrogen and phosphorus in rivers and lakes using stoichiometric approach. Results demonstrated that the total nitrogen(TN) content in water body of rivers and lakes in the study area ranged from 0.475 to 0.956 mg/L, ranking between class II and III of surface water quality standard; the total phosphorus(TP) content ranged from 0.006 to 0.017 mg/L, ranking between class Ⅰand II of surface water quality standard. Nitrate nitrogen(NO_3~--N) which accounted for 43.5%-85.5% of TN was the main component of nitrogen in water body of rivers and lakes and contributed more to TN pollution in the source regions of the Yangtze River and Nujiang River. The stoichiometric ratio of nitrogen and phosphorus(m(TN)∶m(TP)) in water body of rivers and lakes of the Yangtze River and Nujiang River was between 33.7 and 79.3, indicating that phosphorus was the limiting nutrient for the growth of phytoplankton in water body of rivers and lakes in the source regions of the Yangtze River and Nujiang River. The research findings offer data support for revealing the eutrophication process and water eco-environment protection in the water body of rivers and lakes in the source regions in the Qinghai-Tibet Plateau.
引文
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