| 夏季大辽河河口区水体反硝化及其影响因素 |
| 摘要点击 2384 全文点击 1396 投稿时间：2014-08-27 修订日期：2014-09-28 |
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| 中文关键词 大辽河 河口 氮 反硝化 通量 |
| 英文关键词 Daliao River estuary nitrogen denitrification flux |
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| 中文摘要 |
| 于2013年夏季对大辽河及其河口区水体反硝化过程的环境效应,包括反硝化氮损失比例、N2O产生比例等进行了研究讨论. 结果表明,夏季大辽河干流及其河口区氮、磷的主要赋存形态为溶解态. 干流营养盐浓度显著高于河口区(P<0.05). 河口区营养盐浓度降低受海水稀释和其它生物地球化学过程的共同影响. 整体上研究区域内水体溶存N2净增量(ΔN2)介于-11.01~71.37 μmol·L-1,且负值主要出现在大辽河干流水体; 表明干流水体N2的消耗量高于反硝化作用的产生量. 河口区N2O占反硝化总产物(N2O+N2)的比例为0.007%,而N2O释放通量占总通量(N2O+N2)的比例为0.04%. 本研究ΔN2与DO不相关,而与水温和盐度显著正相关,与NO3-显著负相关; 表明反硝化过程不完全受控于DO水平,且硝化-反硝化耦合作用为河口区的主要反硝化机制. 基于河口区N2净增量与水体氮浓度比例估算得到,大辽河河口区约26%的TN、37%的DIN、43%的NO3-可通过反硝化过程得以去除. |
| 英文摘要 |
| Ratios of nitrogen loss and N2O production by denitrification were observed in Daliao River and the estuary in summer 2013. The results showed that the concentrations of N and P in the main stream of Daliao River were significant higher than those in the estuary (P<0.05). Decrease of nutrients concentration in the estuary might be integrally caused by water diluting and biogeochemical processes. The net increase of dissolved N2 (ΔN2) ranged between -11.01 and 71.37 μmol·L-1, in which the negative values were mostly determined in the main stream of the river, indicating the consumption amount of N2 was higher than the production in the fresh water. The mean ratio of N2O production during the process of denitrification was about 0.007%, and the N2O flux across water-air interface was about 0.04% of the total fluxes (N2O+N2). In this study, ΔN2 was not related with DO, while exhibited a significant positive correlation with water temperature and salinity, and a negative correlation with NO3-. This suggests that denitrification was not totally regulated by DO level in the estuary, and coupled nitrification-denitrification was the main denitrification process. Finally, we estimated that 26% of the TN, 37% of the DIN, and 43% of the NO3- were removed by denitrification in the Daliao River estuary based on the ratio of ΔN2 to N concentrations. |
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