沉积物-水界面中可交换态氮对不同菹草密度的响应

Effects of different densities of Potamogeton crispus L. on exchangeable nitrogen at sediment-water interface

为了认清沉水植物对富营养化浅水湖泊沉积物-水界面可可交换态氮的影响,通过模拟试验,利用连续流动注射分析仪测定了NO-3-N、NH3-N等指标,并结合其他环境指标,研究了沉积物-水界面中TN、NO-3-N、NH3-N对不同菹草量(0 g、150 g、300 g)的响应。结果表明,菹草的存在增加了间隙水氧化还原电位(Eh),降低了p H,且菹草量越大,间隙水中Eh、p H值变化越明显;利用单因素方差分析,得出300 g菹草组与对照组的间隙水TN质量浓度有显著差异(P<0.05);菹草量越大,间隙水中TN、NO-3-N和NH3-N以及表层沉积物中固定态铵、有机氮、NH3-N和NO-3-N的去除效果越好。

In order to investigate the effects of submerged plants on the exchangeable nitrogen across the lntertaces between sediments and water in eutrophic shallow lakes, the concentrations of NO3-N and NH3-N were detected with the continuous flow-injection analyzer through simulation experiments. With other environmental indicators taken into account, the effects of different densities of Potamogeton crispus L. （0 g, 150 g, and 300 g, respectively） on TN, NO^-N, and NH3-N at the sediment-water interface were examined. The experimental results show that Patamogeton crispus L. increased the oxidation-reduction potential （Eh） and decreased the pH of the interstitial water. Moreover, the higher the density of Patamogeton crispus L. was, the more significantly the Eh and pH in the interstitial water changed. According to the results of one-way analysis of variance, there was a significant difference （p〈0. 05 ） in TN in the interstitial water with 0g and 300g of Patamogeton crispus L. The higher the density of Patamogeton crispus L. was, the greater the amounts of TN, NO3-N, and NH3-N in the interstitial water, and the greater the amounts of fixed ammonium, organic nitrogen, NH3-N, and NO3-N that were removed from surface sediments.