鄱阳湖氮磷营养盐变化特征及潜在性富营养化评价

Inorganic nitrogen and phosphate and potential eutrophication assessment in Lake Poyang

根据2008-10至2009-07之间4次的记录资料,阐述了鄱阳湖区氮磷营养盐的时间以及空间变化特征,并对硝氮、氨氮、磷酸盐和pH进行了相关分析,对鄱阳湖区进行了潜在性富营养化评价.结果表明:该湖区氮磷营养盐随时间和空间的不同呈现不同的变化规律,湖区水质受河流径流以及浮游植物的影响较大.在时间分布上表现出4月份的N/P比值最小,说明该季节正是浮游植物生长和繁殖最主要时期.在空间分布上表现出鄱阳湖的上游污染物浓度远小于下游污染值,湖区向出湖口浓度有增高趋势.N/P值从10月份的7.8上升至1月份的31.2,随后下降到4月份的7.4,在7月份又上升至8.9.氮磷营养盐和pH表现出不同的相关关系,如在4月份无机氮和pH的相关系数达0.5.综合各项因子的分析可以得出,潜在性富营养化评价结果是鄱阳湖在调查期间为磷污染比较严重.

According to field data from October in 2008 to July in 2009,variation feature of nitrogen and phosphate in Lake Poyang was analyzed.Regression analyses of NO-3-N,NH＋4-N,and TP versus pH were carried out,and potential eutrophication of Lake Poyang was also assessed.It showed that inorganic nitrogen and phosphate in Lake Poyang varied in different months and different locations.Inorganic nitrogen and phosphate of lake areas were mainly affected by rivers and phytoplankton.April had the smallest N/P ratio,indicating that the mean-flow period was the major period on the growth and reproduction of phytoplankton.The upper reaches of Lake Poyang pollution was far less than the lower reaches and there was an increasing trend through lake area and the area out of the lake.Ratio of inorganic nitrogen to phosphate rose to 31.2 from 7.8 in October,then dropped to 7.4 in April,and rose to 8.9 in July.Inorganic nitrogen and phosphate versus pH show different correlation.For example,the correlation coefficient of inorganic nitrogen and pH even reached 0.5.Comprehensive analysis of the factors can be drawn.Potential eutrophication assessment indicates that during the survey period Lake Poyang can be classified as a phosphate-pollution nutrient area.