微生物对杜塘水库沉积物氮元素释放的影响

本研究以杜塘水库大坝断面沉积物为对象，通过对上覆水-沉积物界面的好氧／厌氧连续培养模拟试验，比较灭菌与非灭菌条件下，上覆水中氨氮和硝酸盐氮的浓度变化以及沉积物中氨氮和总氮质量分数的变化，并分析培养前后沉积物中与氮循环相关微生物的变化，研究微生物对氮释放的影响．结果表明，灭菌组沉积物氨氮和硝酸盐主要通过上覆水-沉积物浓度梯度作用力进行扩散释放，较快达到平衡；而未灭菌组氨氮和硝酸盐的释放受溶解氧浓度影响，缺氧环境在微生物的作用下会促进反硝化作用以及氨氮的释放，沉积物中含有10^4CFU／g的氨化细菌和反硝化细菌，暗示着沉积物中微生物作用下的氨化作用和反硝化作用较为激烈．

Effects of Microbe on Nitrogen Release from the Sediment of Dutang Reservoir

Nitrogen release from sediments was analyzed near the Dutang Reservoir Dam Section, through parallel experiments under aerobic and anaerobic conditions. Based on a series of tests including sterilization and non-sterilization conditions in simulated water-sediment reactors, concentrations of ammonia nitrogen and nitrate in overlying water and mass fraction of ammonia nitrogen and total nitrogen in sediments were determined. In addition, the change of related microbes of nitrogen cycle before and after cultivation was analyzed. Results showed that ammonia nitrogen and nitrate in the sediments released mainly through the force caused by concentration gradient, and the balance could be achieved faster under sterilized condition. However, the release of ammonia nitrogen and nitrate would be at the same time affected by dissolved oxygen （DO） concentration under non-sterilized condition, and the denitrification and ammonia nitrogen releasing be promoted by microbes under anoxic condition. The number of ammonification and denitrifying bacteria in the sediments reaches 104CFU per gram, implying that ammonification and denitrification processes are active under influences of microbes.