环境因子对雁鸣湖沉积物氮磷释放的影响

为探明环境因子对雁鸣湖沉积物-上覆水界面间氮磷释放的影响,通过单因子实验和响应面实验分析探究了温度、溶解氧及pH对氮磷释放通量的影响。单因子实验结果表明：雁鸣湖沉积物-上覆水界面间氮磷通量随着温度的升高而增加;随溶解氧浓度的升高而减小;当pH为中性时,氮磷通量最小,氮通量在pH=5时达到最大值,磷通量在pH=9时达到最大值。BBD模型拟合结果显示,各环境因子与氮磷通量间拟合关系均为二次多项式。响应面实验结果表明：温度和pH交互作用对TN通量影响显著;温度和溶解氧交互作用对TP通量影响显著;温度和溶解氧交互作用、温度和pH交互作用对${{rm{NH}}_4^{+}}$-N通量影响均为显著;温度和溶解氧交互作用对${{rm{PO}}_4^{3 - }}$-P通量影响极显著;雁鸣湖底泥释放的最不利条件为T=10 ℃、DO=7.87 mg·L⁻¹、pH=7.13,此时的TN交换通量为3.956 mg·(m²·h)⁻¹,TP交换通量为0.471 mg·(m²·h)⁻¹,${{rm{NH}}_4^{+}}$-N交换通量为1.469 mg·(m²·h)⁻¹,${{rm{PO}}_4^{3 - }}$-P交换通量为0.146 mg·(m²·h)⁻¹。以上研究结果可为雁鸣湖富营养化防治提供参考。

Effects of environmental factors on the release of nitrogen and phosphorus from the sediment of the Yanming Lake,China

To investigate the effect of environmental factors on the release of nitrogen and phosphorus between the sediment-overlying water interface of the Yanming Lake, the effects of temperature, dissolved oxygen and pH on the release flux of nitrogen and phosphorus were investigated by single factor test and response surface analysis. The results of single factor experiment showed that the nitrogen and phosphorus fluxes between the sediment-overlying water interface of the Yanming Lake increased with the increase of temperature, and decreased with the increase of dissolved oxygen concentration. At neutral pHs, the lowest nitrogen and phosphorus fluxes occurred. The nitrogen flux reached its maximum value at pH=5 and the phosphorus flux reached its maximum value at pH=9. The fitting results of the BBD model showed that the fitting relationships between environmental factors and the fluxes of nitrogen and phosphorus were quadratic polynomial equations. The results of response surface test showed that the interaction between temperature and pH had a significant effect on TN flux. The interaction between temperature and dissolved oxygen had a significant effect on TP flux. The interactions between temperature and dissolved oxygen, temperature and pH had a significant effect on ${rm{NH}}_4^{+}$-N flux. The interaction between temperature and dissolved oxygen had a very significant effect on the flux of ${rm{PO}}_4^{3 - }$-P; the most unfavorable conditions for the release from the Yanming Lake sediment were temperature of 10 ℃, dissolved oxygen of 7.87 mg·L−1, pH 7.13, at which the exchange flux of TN was 3.956 mg·(m2·h)−1, the exchange flux of TP was 0.471 mg·(m2·h)−1, and the exchange flux of ${rm{NH}}_4^{+}$-N was 1.469 mg·(m2·h)−1, the exchange flux of ${rm{PO}}_4^{3 - }$-P was 0.146 mg·(m2·h)−1. The research results can provide a reference for the eutrophication prevention of the Yanming Lake.