广西北仑河口国家级自然保护区水质特征及其富营养化研究

Research on water quality characteristics and eutrophication in a national nature reserve at Beilun estuary of Guangxi

2013年8月广西北仑河口国家级自然保护区水质监测结果表明,整个保护区近岸水域溶解无机氮(DIN)显示过剩,但溶解无机磷(DIP)表现低磷特征,高的N/P比值使得P可能成为浮游植物生长的潜在限制性因子。单因子污染指数显示,DIN和石油类是主要的超标污染因子,COD次之。有机污染指数显示,近期整个广西北仑河口国家级自然保护区近岸水质污染程度达到1级,水质较好,但局部海区开始受到轻度污染。富营养化指数结果表明,广西北仑河口国家级自然保护区近岸水域总体达到轻度富营养程度,不同区域富营养程度不同。COD对富营养化的贡献率范围为42.8%—76.7%,平均值为(64.3±9.6)%,COD是影响广西北仑河口国家级自然保护区近岸水域富营养化的重要因素。陆源污染物排放、水产养殖排污和船舶排污是广西北仑河口国家级自然保护区近岸海域的主要污染来源。

Water quality was monitored in a national nature reserve at Beilun estuary of Guangxi in August 2013. The results showed that dissolved inorganic nitrogen（DIN） rather than dissolved inorganic phosphorus（DIP） was abundant in the coastal area, and P might be the potential factor controlling growth of phytoplankton. The analysis of single factor pollution index indicated that the DIN and petroleum hydrocarbon were the prioritized pollution factors, and the chemical oxygen demand（COD） was the following pollution factor. The analysis of organic pollution index suggested that the entire investigated area attained the quality standard for GradeⅠ, which belonged to good water quality. However, some regions were lightly polluted gradually. The analysis of eutrophication index indicated that the study area attained slight level of eutrophication, and the eutrophication level was different in different regions. The range of COD contribution to the eutrophication was from 42.8% to 76.7%, and the mean value was（64.3±9.6）%. COD was a significant factor contributing to eutrophication in the study area. The discharges of terrigenous pollutants, aquaculture pollution and shipping waste were the main pollution sources inputting to the national nature reserve.