| 盐沼植物对沉积物间隙水营养盐分布的影响 |
| 摘要点击 2389 全文点击 1697 投稿时间：2008-12-23 修订日期：2009-03-11 |
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| 中文关键词 盐沼植物 间隙水 营养盐 分子扩散通量 崇明东滩 |
| 英文关键词 salt marsh plant pore water nutrients molecule diffusive flux Chongming Dongtan |
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| 中文摘要 |
| 通过2007年8月～2008年5月对长江口崇明东滩中部潮间带4个不同植被带沉积物间隙水营养盐进行季节观测来研究盐沼植物对沉积物间隙水营养盐分布的影响．结果表明，大型植物生长带间隙水的ＮＨ+4-Ｎ、ＰＯ3-4-Ｐ浓度低于光滩，尤其是夏、秋两季ＮＨ+4-Ｎ的浓度比光滩低1个数量级以上．在植物生长季节，间隙水各种营养盐含量要明显高于冬季，且植物生物量与间隙水氮、磷有明显的相关关系．氮盐受植物的影响最明显，ＮＨ+4-Ｎ在互花米草与芦苇带分别是44.21、 74.38 μmol·Ｌ-1，明显低于光滩与海三棱草带(分别是340.14、 291.87 μmol·Ｌ-1)；NO-x-N的浓度比ＮＨ+4-Ｎ低1～2个数量级，但以芦苇带最高(5.94 μmol·Ｌ-1)．沉积物-水界面分子扩散通量结果表明，潮滩沉积物是上覆水中SiO2-3-Si、ＮＨ+4-Ｎ、ＰＯ3-4-Ｐ的源, NO-x-N (NO-3-N、NO-2-N的总和)的汇，其中NO-x-N从上覆水向沉积物的扩散通量［16.23 μmol·（m2·h）-1］大于ＮＨ+4-Ｎ从沉积物向上覆水的扩散通量［15.53 μmol·（m2·h）-1］．植物的生长还通过影响沉积物-水界面的物质交换与间隙水中营养盐比值及其与上覆水间营养盐比值，对毗邻富营养化河口生态系统营养盐结构起到调节作用． |
| 英文摘要 |
| The variations of nutrients in pore water of salt marsh sediment were surveyed in the middle intertidal zone of Chongming Dongtan during August 2007 to May 2008 to identify plant impact on nutrients distribution. The results show that ＮＨ+4-Ｎ and ＰＯ3-4-Ｐ concentrations are lower in pore water of Spartina alterniflora and Phragmites australis zones than in bare flat, and specially, ＮＨ+4-Ｎ concentrations in summer and autumn decrease by one more orders of magnitude. Compared to winter, nutrients concentrations are obviously higher during the period of plant growth, and plant biomass is clearly correlative to nitrogen and phosphorus. Vegetation growth influences nitrogen content intensively. ＮＨ+4-Ｎ concentrations in Spartina alterniflora and Phragmites australis zones are 44.21 and 74.38 μmol·L-1 respectively, distinctly lower than that in bare flat and Scirpus mariquete zone (340.14 and 291.87 μmol·Ｌ-1 respectively). Moreover,NO-x-N concentration is one to two order(s) of magnitude lower than ＮＨ+4-Ｎ, and its highest value exists in Phragmites australis zone (5.94 μmol·Ｌ-1). The results of molecule diffusive flux of nutrients in the surface sediment-overlying water interface indicate that marsh sediment is the source for SiO2-3-Si, ＮＨ+4-Ｎ and ＰＯ3-4-Ｐ, and the rank for NO-x-N (NO-3-N+NO-2-N), and NO-x-N flux from overlying water to sediment ［16.23 μmol·（m2·h）-1］ is higher than ＮＨ+4-Ｎ flux from sediment to overlying water ［15.53 μmol·（m2·h）-1］. Vegetation growth accommodates nutrient structure of the estuarine ecosystem by affecting sediment-water interface mass flux and nutrient ratios in pore water and overlying water. |
