苦草(Vallisneria natans)衰亡对水-沉积物之间磷迁移的影响

采用沉水植物苦草(Vallisneria natans)为研究对象,在其衰亡期测定群落内、外上覆水及沉积物各形态磷的含量,以探究沉水植物在其衰亡期对上覆水和沉积物中各形态磷的影响.结果表明:苦草衰亡过程中上覆水中总磷、可溶性总磷、溶解性活性磷、颗粒磷、可溶性有机磷浓度的变化相对平稳,与对照组相比无显著差异;沉积物中各形态磷含量均呈小幅度上升趋势,在实验结束时,苦草组沉积物中总磷含量为719.27 mg/kg,和初始值比增加了14.68 mg/kg,无机磷和有机磷含量分别增加了12.06和2.20 mg/kg,氢氧化钠提取磷和盐酸提取磷含量分别增加了7.05和4.29 mg/kg.总体来看,沉水植物苦草在其衰亡过程中分解速率较慢,对水-沉积物之间各形态磷含量无显著影响.

Effects of decline phase of Vallisneria natans on phosphorus transportation between water and sediment

In order to study the effects of submerged macrophytes on different forms of phosphorus during decline phase, we adopted Vallisneria natans as the study object and measured the content of phosphorus in water and sediment. Results showed that, in water, total phosphorus (TP), dissolved total phosphorus, soluble reactive phosphorus, particles phosphorus, and dissolved organic phosphorus in V. natans changed steadily, without any significant difference compared with control groups, while all forms of phosphorus in sediment had a little rising trend. At the end of the experiment, the content of TP was 719.27 mg/kg in the V. natans sediment, and was 14.68 mg/kg higher than the initial value. The inorganic phosphorus, organic phosphorus, NaOH-P, and HCl-P contents raised for 12.06, 2.20, 7.05 and 4.29 mg/kg, respectively. The results indicated that decomposition rate of V. natans was slow and there was no significant effect of V. natans decomposition on the different forms of phosphorus between water and sediment.