充气和自然条件下苦草、荇菜和芦苇腐烂过程中水质指标的变化

Changes of Water Quality Indexes in Decomposition Process of Vallisneria natans,Nymphoides peltatum and Phragmites australis under Aeration and Natural Conditions

于2015年10月11日,在无锡太湖贡湖湾退圩还湖生态恢复工程区,采集苦草(Vallisneria natans)、荇菜(Nymphoides peltatum)和芦苇(Phragmites australis)样品,将样品清洗、剪段和烘干后,投入装有8 L自来水的实验池中。于2015年10月28日~2016年1月15日,分别在充气和自然条件下,对植物腐烂过程中水质指标的变化进行了研究。研究结果表明,在3种植物的腐烂过程中,水体中各项指标有明显变化。其中,水体p H始终比较稳定,化学需氧量和总磷含量在实验初期增大,而铵态氮含量、亚硝态氮含量和硝态氮含量在腐烂过程中波动变化。荇菜和苦草的腐烂过程对水质指标的影响较大;在芦苇的腐烂过程中,水质指标变化规律与对照组的基本一致。充气条件对投入芦苇的实验组水体各水质指标影响很小,对投入苦草的实验组水体各水质指标影响显著。

To explore the effects of plants decomposition on water quality indexes, we selected Vallisneria natans, Nymphoides peltatum and Phragmites australis samples on November 10, 2015 in ecological restoration area of Gonghu Lake in Taihu Lake, Wuxi. The samples were washed, cut and dried. Then the samples were put in the ponds with 8 L water. Indoor simulation experiments were carried on to study the decomposition process of three plants under the conditions of non-inflated aeration and inflated aeration. The results showed that the effects of the decomposition of the three plants on water quality had obvious phase changes. The p H of water was stable, and contents of chemical oxygen demand and total phosphorus first increased and then decreased. However, contents of ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen changed fluctuationly. The decomposition of Nymphoides peltatum and Vallisneria spiralis had a greater influence on water quality indexes. Phragmites australis had less influence on water quality indexes,the changes of water quality in the decomposition of Phragmites australis were almost the same as the blank control group. The effects of the inflated aeration conditions on the water quality indexes were different in the three different plant species. In Phragmites australis group, the difference of water quality indexes between inflated aeration condition and non-inflated aeration was slight, in the Nymphoides peltatum group the difference was larger, and in the Vallisneria spiralis group, the most significant difference was found.