采集入贡湖亲水河原位底泥柱芯、上覆水及伊乐藻样品,搭建室内模拟实验,探究不同生态修复手段下硝氮和铵氮的脱除机制.采用15N同位素配对技术,测定分析了裸泥组A、脱氮微生物(INCB)组B、伊乐藻组C和INCB+伊乐藻组D中反硝化速率及植物吸收速率.结果表明,处理组D中反硝化速率最高,在添加15NO3-和15NH4+的处理组分别为258.6μmol/(m2·h)和156.49μmol/(m2·h).对比添加15NO3-的处理组,添加15NH4+的处理组中伊乐藻吸收速率大约是15NO3-的2倍,而添加15NO3-处理组中反硝化速率约是添加15NH4+的处理组1.5倍.沉水植物在吸收氮素的同时促进了微生物脱氮作用,与植物吸收相比,反硝化脱氮是氮素脱除的主要途径.INCB和沉水植物的联合应用,提高了河道水体氮素的去除速率,促进河道水体净化.%Undisturbed sediment cores, surface water and Elodea nuttallii were collected from Qinshui River in Gonghu Bay. And a simulation experiment in laboratory was carried out to study the effects of different ecological restoration methods on the removal mechanisms of nitrate-N and ammonia-N. The stable 15N isotope pairing technique was used to investigate the rates of denitrification and plant uptake among four different treatment groups (Treatment A: bare sediment, Treatment B: INCB, Treatment C:E. nuttallii, Treatment D:INCB+E. nuttallii). The experiment results indicated that Treatment D with 15NO3-and 15NH4+had the highest denitrification rate of 258.6μmol·(m2·h)-1 and 156.49μmol·(m2·h)-1, respectively. Compared with the group with 15NO3-added, the absorption rate of 15NH4+in E. nuttallii was about 2 times faster than that of 15NO3-, while the denitrification rate in group with 15NO3-added was about 1.5 times higher than that in 15NH4+group. In addition of absorbing nitrogen, submerged plants promote microbial nitrogen removal, and denitrification is the main pathway of nitrogen removal compared with plant absorption. The combined use of INCB and submerged macrophytes enhanced the removal rate of nitrogen in river water and promoted the purification of river water.
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