中文摘要：

通过2014年枯水、丰水两期监测,综合分析了太湖西部入湖河流与湖区水体及其沉积物的无机氮形态与同位素特征,并利用δ^15识别了太湖西部上游区氮污染来源及转化途径的生物化学作用机制.结果表明：NO_3^--N与NH_4^＋-N为研究区域入湖河流无机氮的主要形态,而NO_3^--N为西部湖区水体无机氮的主要形态;δ^15-NO_3^-的数值范围揭示了西部入湖河流在枯水季NO_3^--N主要来源于农用化肥,有少量矿化土壤有机氮,而丰水季则以生活污水为主,有少量矿化土壤有机氮及农用化肥;δ^15-NH_4^＋的数值范围说明了生活污水是河流水体NH_4^＋-N的主要来源;通过水体及沉积物样品NO_3^--N、NH_4^＋-N、δ^15-NO_3^-、δ^15-NH_4^＋的协同分析可知,湖区氮的赋存形态主要受湖区水体硝化作用及沉积物内反硝化作用的影响.

英文摘要：

The water and sediments from the river and lake in the western region of the Taihu Lake basin were sampled during the dry and wet season in 2014. The forms of inorganic nitrogen in the samples were analyzed, and the ratio δ15N was used to identify the sources of nitrogen pollution and the biochemical mechanism of nitrogen cycle in the region. The results showed that ： ①NO-3-N and NH＋4-N were the main forms of inorganic nitrogen in the rivers entering the lake, while NO-3-N was the main form of inorganic nitrogen in the lake water. ②During dry seasons, NO-3-N in the rivers were mainly from fertilizers and, to a much less extent, from mineralized soil organic nitrogen according to the 815N-NO-3 values, while during wet seasons, N came from sewage and, to a much less extend, from mineralized soil organic nitrogen and fertilizers. ③Sewage was the major source of NH＋4-N in the rivers according to the range of the 81SN-NH＋4 values. ④The occurrence of nitrogen in the lake water was mainly affected by nitrification of the lake water and denitrificatian of the sediments based on combined analyses of NO-3-N, NH＋-N, 815N-NO-3, and 815N-NH＋4 of the water and sediment samples.