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研究报告

Experimental study on the effect of nitrate nitrogen content on denitrification in the typical area of the west of Taihu Lake

摘要：以太湖湖西为例，采用流动培养同位素添加法，分别模拟了湖西北、湖西南地区不同温度及有机碳浓度下的底泥原位反硝化作用，结果表明只有水体硝酸盐含量高的湖西北地区底泥反硝化速率受温度和有机碳影响明显，水体硝酸盐含量低的湖西南地区底泥反硝化速率受水体温度、有机碳含量影响较小.研究结果表明，太湖湖西北地区22、27、32 ℃时反硝化速率分别为（77.62±5.23）、（156.01±12.01）、（309.36±20.31） μmol·m^-2·h^-1.湖西北区域上覆水有机碳含量为0、4、10 mg·L^-1时，沉积物平均反硝化速率分别为177.39、203.48、275.85 μmol·m^-2·h^-1.根据皮尔逊相关性分析可知，太湖反硝化速率与水体硝酸盐含量呈显著相关，即水体氮素构成是影响底泥反硝化速率的最根本原因，只有硝酸盐供给充足，底泥反硝化速率才会随着温度及水体碳源的变化而变化.

Abstract：Taking the west of Taihu Lake as an example， the flow culture isotope addition method was used to simulate the in-situ denitrification rate of sediments at different temperatures and organic carbon concentrations in the northwest and southwest of the lake. The results showed that only the northwestern lake with high nitrate content in the water was significantly affected by temperature and organic carbon， while the southwest of the lake with low nitrate content in the water was less affected by water temperature and organic carbon content. The denitrification rates at 22， 27， and 32 ℃ in the northwestern region of Lake Taihu （S1） were （77.62±5.23），（156.01±12.01），（309.36±20.31） μmol·m^-2·h^-1， respectively. When the organic carbon content of the overlying water in the northwest of the lake （S1） were 0， 4 and 10 mg·L^-1， the average denitrification rate of the sediment were 177.39， 203.48 and 275.85 μmol·m^-2·h^-1， respectively. According to Pearson correlation analysis， the denitrification rate of Taihu Lake is significantly correlated with the nitrate content in the water， that is， the nitrogen composition of the water is the most fundamental reason affecting the denitrification rate of the sediment. Only when the nitrate supply is sufficient， the denitrification rate of the sediment will change with the change of temperature and carbon source of the water.