Undisturbed sediment cores from four sites in Meiliang Bay were collected from north to south of Lake Taihu, then incubated by flow-through technique in the laboratory. The denitrification and anaerobic ammonium oxidation (anammox) rates were measured by stable isotope tracing technique, isotope nitrogen product measurement and isotope pairing technique. The results showed that denitrification and anammox rate were from 46.36±13.26 to 16.34±22.74μmol/(m~2·h) in the Meiliang Bay and from7.50±2.21 to 2.05±2.90μmol/(m~2·h) on the open lake areas out of the bay, respectively. Denitrification rates were significantly higher in the north of the Meiliang Bay than in the south and open lake areas. The dominated nitrogen removal process was uncoupled nitrification-denitrification(D_w) which utilizing nitrate in overlying water as substrate in north Meiliang Bay, and coupled denitrification(D_n) was dominate process in the open lake area. The concentration of NO_3~- and O_2 penetration depths were main factors affecting the distribution of D_n and D_w. The anammox proportion of the total nitrogen removal ratio was 12%-14% in the Meiliang Bay, and 11% out of the bay, which was correlated with the denitification rate and influenced by the intermediate product (nitrite) of denitrification.%运用无扰动芯样实验室内流动培养、稳定同位素示踪、同位紊气态产物测定及同位素配对技术,对太湖梅梁湾北部到南部的4个梯度样点的水土界面反硝化和厌氧氨氧化速率进行研究.结果表明,梅梁湾内及湾外开敞湖区4个样点的水土界面反硝化脱氮速率为(46.36±13.26)-(16.34±22,74)μmol/(m~2·h),厌氧氨氧化脱氮速率为(7.50±2.21)-(2.05±2.90)～mol/(m~2.b).梅梁湾北部河口区水土界面总脱氮能力明显高于梅梁湾南部及开敞湖区.通过对脱氮过程的进一步研究发现.北部脱氮过程主要以上覆水硝酸盐为底物的非耦合反硝化过程(D_w)为优势过程,而梅梁湾外开敞湖区则以沉积物硝化过程耦合控制的反硝化(D_n)为主.影响D_n、D_w在反硝化中比重的主要因素是沉积物溶氧侵蚀深度和上覆水NO_3~-.浓度的差异;梅梁湾厌氧氨氧化脱氮比例占总脱氮比例为12%-14%,湾外开敞湖区则占11%,影响其比例差异的主要因子是反硝化强度的大小及其反硝化中间产物--亚硝酸盐含量的差异.
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