嘉陵江下游江段春季浮游藻类特征及污染现状

CHARACTERISTICS OF.PHYTOPLANKTON AND WATER POLLUTION IN LOWER REACHES OF JIALING RIVER IN SPRING

2006年春季,通过水质分析和浮游藻类调查,应用污生谱分析法及生物多样性指数法,对嘉陵江下游江段春季浮游藻类特征及污染现状进行了研究。结果发现,该江段共有浮游藻类7门42属85种(包括变种);优势种群并不单一,以黄藻、绿藻和硅藻占优势,优势种为黄藻门中的黄丝藻,绿藻门中的小球藻和硅藻门中的小环藻。5月份藻类的种类和个数均比4月份有所减少,可能与5月份降雨量比4月份多有关;流速最快的石门大桥具有最低的藻类细胞密度,流速最慢的化龙桥具有较高的藻类细胞密度,说明流速对浮游藻类种类和数量产生一定的影响。嘉陵江下游沿岸一带的氨氮含量都很高,氨氮已经形成全江段水系的主要污染,磷酸盐含量也较高,均超过水体富营养化的氮、磷含量最低限制标准,该江段水质污染较严重。污生谱分析法及生物多样性指数法的评价结果表明,该江段整体污染状况为中度污染,农业和工业污染不容忽视。

Water quality and the distribution of phytoplankton were investigated in lower reach of Jialing River in the spring of 2006,to analyze the characteristics of phytoplankton and water pollution. The results showed that there were 42 genera and 98 species （including varieties） of phytoplankton belonging to 7 phyla. Xanthophyta and Chlorophyta had high abundance,and became dominant groups together with Bacillariophyta. The dominant species are Tribonema vulgate of Xanthophyta,Chlorella of Chlorophyta and Cyclotella of Bacillariophyta. In May the algae species and abundance were both lower than that of in April because of more rain in May. At Shimen Bridge the water flow was fast,the algal density was the lowest at Hualongqiao the water flow was slow,the algal density was the highest, indicating that water velocity contributed some effects of phytoplankton species and abundance. At each sampling site ammonia contents were very high,so ammonia pollution was the main pollution of the Jialing River. And the phosphate contents were also high, nutrient contents all transcended the lowest limited standard of water eutrophication, the water pollution was serious in the Jialing River. Water pollution was evaluated by saprobiologic analysis and algae diversity index. The pollution belonged to medium type and the agriculture and industrial pollution could not be neglected.