为评估蠡湖水环境治理工程措施对蠡湖水体营养状况的影响,于2012年4月及10月对蠡湖湖区及环湖河口共64个采样点进行了采样及分析,探讨了水体及表层沉积物中各形态氮的空间分布特征及其影响因素.结果表明:蠡湖上覆水中ρ(TN)为0.82 ～ 3.20 mg/L,平均值为1.35 mg/L；间隙水中ρ(DTN)为1.28 ～5.36 mg/L,平均值为2.51 mg/L.上覆水和间隙水分布趋势均为自西向东递增,并且环湖河口ρ(TN)显著高于湖区.研究期间蠡湖NH4+-N平均扩散通量为4.80 mg/(m2·d),并且NH4+-N扩散通量与表层沉积物中w(TN)和w(E-NH4+-N)呈显著正相关.2003年以来,经过一系列水环境治理工程后,蠡湖水质改善较为明显,但仍未从根本上解决蠡湖的富营养化问题,因此在外源污染得到严格控制的情况下,需加强对蠡湖水体沉水植物的恢复,优化调控蠡湖目前的生态系统结构.%To assess the impact of the Water Environment Governance Engineering on the nutritional status of water in Lihu Lake, this paper explored the spatial distribution characteristics of Nitrogen fractions and its influencing factors of the water and surface sediments in Lihu Lake by investigating totally 64 locations in the lake and the lake estuaries in April and October, 2012. The results showed that the p(TN) contents in the overlying water in Lihu Lake ranged from 0. 82 to 3. 20 mg/L with the mean value of 1. 35 mg/L, while p( DTN) in the interstitial water was 1. 28 to 5. 36 mg/L with the mean value of 2. 51 mg/L. Both of the two parameters increased from the west to the east. Meanwhile, the ρ(TN) was higher in the estuaries than in the lake. Average diffusion flux of NH4 +-N during the study period is 4. 80 mg/( m2 . d) and there is a significant positive correlation of the diffusion fluxes of NH4 +-N and the concentration of ω(E-NH4 +-N) and ω(TN) in the surface sediment. The eutrophication problem has not been completely solved yet. As exogenous pollution had been controlled, although the water quality of Lihu Lake has been significantly improved by a series of water treatment projects launched in 2003. More attention should be paid to the recuperation of the submerged plant and the optimization of the ecosystem structure of Lihu Lake.
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