草型和藻型湖泊间隙水营养盐特性的比较研究

2006年9月，通过营养水平和水草的差异设计了4个浅水湖泊模拟系统，对草、藻型湖泊间隙水营养盐特性的差异进行研究。2007年9月，采用平衡浓度法测定了各系统间隙水的营养盐浓度，经分析得出以下结论或认识：(1)上覆水中，各系统营养盐浓度比较均一，垂向上梯度变化不明显；与藻型系统相比，草型系统上覆水PO43--P浓度较高，NH4+-N浓度较低；(2)在泥水界面处，各系统PO43--P和NH4+-N浓度均存在极陡的浓度梯度，随泥深增加浓度迅速升高；(3)由于底泥营养负荷高等原因，间隙水中的PO43--P和NH4+-N浓度明显高于上覆水；(4)水生植物生长对间隙水中的营养盐具有“低促高抑”的特性，即降低重污染沉积物间隙水中PO43--P和NH4+-N的浓度，增加微污染沉积物间隙水中的营养盐浓度；(5)藻型系统中，NH4+-N和PO43--P浓度之间存在非常明显的线性相关关系，说明这两种成分均主要来源于有机质的厌氧分解。

Experimental comparison of nutrient characters of pore water between macrophytic and algal lakes

In order to study nutrient character differences of pore water between macrophytic and algal lake, 4 simulation systems of shallow lake were established with different nutrition level and macrophyte in September, 2006. Pore waters were sampled at 3.2cm intervals using pore water diffusion equilibrators, and then measured as soon as possible in September, 2007. Finally, some conclusions and cognitions are drawn as follows: (1) There is no gradual change of nutrient concentrations in overlying water, which is even relatively. The growth of aquatic plant increased PO43--P concentration of overlying water, while lowered NH4+-N concentration. (2) In sediment-water interface of simulation systems, there exist steep concentration gradients of NH4+-N and PO43--P, increasing rapidly with sediment depth increase. (3) Due to high nutrition load in sediment, concentrations of PO43--P and NH4+-N are higher in pore water than overlying water. (4) In pore water, aquatic plant growth can enhance concentration of PO43--P and NH4+-N when they are low, while lower their concentration when concentration of PO43--P and NH4+-N are high. (5) There exists a good positive correlativity between NH4+-N and PO43--P concentration in algal lake systems, which shows these two matters all result from anaerobic decomposition of organic matter as a result of bacterial or fungal action.