太湖不同湖湾中铜锈环棱螺(Bellamya aeruginosa)的氮稳定同位素特征

Characteristic of nitrogen stable isotope in Bellamya aeruginosa in different bays of Lake Taihu,China

进入湖泊中不同氮源氮稳定同位素值(δ15N)的差异和生物对氮稳定同位素的记忆作用,可以反映流域人类活动输入的污染物对生态系统的影响程度.本文调查了太湖4个湖湾(梅梁湾、贡湖湾、竺山湾和东太湖)中铜锈环棱螺(Bel-lamya aeruginosa)的δ15N值,结果表明环棱螺δ15N值的变幅为6.9‰～18.1‰,平均值为11.2‰,不同湖湾中环棱螺δ15N值差异极显著,从高到低依次为梅梁湾(17.7‰)、贡湖湾(13.2‰)、东太湖(10.2‰)和竺山湾(7.8‰).分析认为,梅梁湾和贡湖湾接纳较多的人类活动产生的污染物,其周边城市如无锡、常州等地的污水处理效率有待提高;竺山湾水体氮素主要来自于农业面源污染,需降低农田化肥的使用量.

Nitrogen discharged into lake ecosystems typically has different nitrogen stable isotope ratios（δ15N） and measurement of δ15N in organisms can be useful indicators of anthropogenic impacts from the watershed.The δ15N values of Bellamya aeruginosa were investigated in four bays of Lake Taihu.Results showed that δ15N values in snail ranged from 6.9‰ to 18.1‰,with an average of 11.2‰.Snail δ15N values displayed a significant variation among four bays.The highest average value was found in Meiliang Bay（17.7‰）,followed by Gonghu Bay（13.2‰）,East Taihu（10.2‰） and Zhushan Bay（7.8‰）.Our investigation suggested that both Meiliang Bay and Gonghu Bay have received tremendous amount of domestic sewage derived from increasing human activities.Therefore,it＇s necessary to promote investment of sewage treatment plants in surrounding cities including Wuxi and Changzhou.Our research also indicated that Zhushan Bay,which is located in northwest part of Lake Taihu is mainly affected by agriculture non-point source pollution.So it＇s necessary to reduce the use of fertilizers to improve the water quality of that bay.