基于连续流动培养的珠江底泥硝氮还原速率

Nitrate reduction rate in sediments from the Pearl River based on flow-through reactors

设计了层状底泥的连续流动培养实验装置,经调试后用于对珠江广州河段的沉积物样品进行连续流动培养实验.通过检测培养出水和稳定状态时硝氮还原速率和氨氮生成速率,运用Michaelis-Menten方程计算珠江底泥的潜在硝氮还原速率和氨氮生成速率,并结合氨氮生成和硝氮还原理论配比分析硝氮还原的主要途径.结果显示,珠江广州河段整体的潜在硝氮还原速率为1410 nmol.(h.mL)-1,硝氮还原动力参数为5.0 mmol.L-1;潜在氨氮生成速率为0.665 nmol.(h.mL)-1,氨氮生成动力参数为0.137 mmol.L-1;厌氧氨氧化作用和硝氮异化还原作用是珠江底泥中硝氮还原的主要途径.

Flow-through reactors （FTR） were designed and debugged for the incubation experiments ol semment shces. Mter being constructed, the FFR with sediments were run for different concentrations of nitrate-inflow incubation experiments. Time-series concentrations of nitrate and ammonium were monitored in the outflow, and the nitrate reduction rates （NRR） and ammonium production rates （APR） were calculated when reaching a equilibrium-steady state. After that, the potential maximum nitrate reduction rate and ammonium production rate were calculated out according to Michaelis-Menten equation. The conclusions are as follows： the potential NRR in Pearl River sediment was 1410 nmol. （h .mL） -~ , and the kinetic parameter of nitrate reduction was 5.0 mmol＂ L-l; the potential APR was 0. 665 nmol＂ （h＂ mL）-1, while the kentic parameter was 0. 137 mmol＇L-~. The anaerobic ammonium oxidation （Anammox） and the dissimilatory nitrate reduction to ammonium（DNRA） are likely to be the two principle pathways for nitrate reduction in river sediments.