水生植物凤眼莲对水体硝化-反硝化脱氮过程的影响-jiangsuacademy.docVIP

凤眼莲及底泥对富营养化水体反硝化脱氮特征的影响研究 马涛1,2，张振华1，易能1,2，刘新红1，王岩1，严少华1*，高岩1, 江苏省农业科学研究院农业资源与环境研究所，江苏 南京 210014; 2.南京农业大学资源与环境科学学院，江苏 南京 210095 ） 摘 要：本研究利用改进的漂浮箱法，通过直接测定水体释放的N2O、N2，在模拟实验中研究种养及未种养漂浮植物凤眼莲条件下富营养化水体硝化、反硝化脱氮释放N2、N2O特征及其对消减水体氮的贡献。研究结果表明种养或未种养凤眼莲的富营养化水体硝化、反硝化脱氮的产物以N2为主。硝化、反硝化脱氮释放N2O而脱除的氮仅占水体TN损失量的0.01±0.003%。在本实验设定的水体富营养化条件下（NH4+-N浓度6.0-7.2 mg L-1、NO3--N浓度0.81~5.14 mg L-1 、TN浓度为8.9 -12.07 mg L-1），种养凤眼莲的富营养化水体（无底泥）以向大气界面累积释放N2形式损失的氮量（N2-N量，以N计）为1609.1±303.4 – 2265.2±262.6 mg，占水体氮损失量的63.2±17.0%，凤眼莲吸收的N仅占水体TN损失量的23.7±3.1%-28.7±4.8%，并不是净化水体氮的唯一途径。未种养凤眼莲的富营养化水体（无底泥）向大气界面累积释放N2形式损失的氮占整个水体N损失量的40.7±8.6%-43.6±0.8 %，是富营养化水体自净脱氮的主要途径。施加底泥进一步促进了水体通过反硝化脱氮释放N2而损失的氮量。凤眼莲与底泥对促进反硝化脱氮过程具有良好的交互作用（p0.01）。种养凤眼莲的富营养化水体向大气界面释放N2的浓度显著（p0.05）高于相应处理下未种养凤眼莲的对照水体，说明凤眼莲可能对水体反硝化脱氮过程有促进作用。 关键词：富营养化水体；凤眼莲；反硝化脱氮；N2O、N2释放 Effect of Eichhornia crassipes and sediment on characteristic of nitrogen removal from denitrification in eutrophic water Abstract: An improved floating-chamber method was developed to measure directly N2 and N2O emission from eutrophic water. The total removal of N2 and N2O from the water with or without cultivation of water hyacinth (Eichhornia crassipes) was investigated using this method. The N2,was the main gaseous product of nitrification and/or denitrification occurred in the eutrophic water; while the N loss via N2O emission only accounted for 0.01?.003% of total nitrogen (TN) loss from the water. iUnder the high concentrations of N (NH4+-N: 6.0-7.2 mg L-1; NO3--N: 0.81~5.14 mg L-1; TN 8.9 -12.07 mg L-1), the treatments with E. crassipes, but without sediment showed a total removal of 1609.1±303.4-2265.2±262.6 mg N from the water, which accounted for 63.2±17.0% of TN loss from water. However, direct uptake of N by E. crassipes only accounted for 23.7?.1%- 28.7?.8% of TN loss from the water, which indicated that the plant uptake of nitrogen was not the only way to remove N in the water. In the treatments .1without cultivation of E. crassipes and sediment, N2 emission (689.