菹草伊乐藻群落对富营养化水体水质的净化效果

Purification Effect of Potamogeton crispus-Elodea nuttallii Community on Eutrophic Water Body Quality

在富营养化湖泊内的围隔中,引种菹草、伊乐藻,分别构建菹草-伊乐藻群落(围区A)与单一菹草群落(围区B),跟踪观测水草恢复生长情况,调查两类群落对水体水质的净化作用.结果发现:菹草-伊乐藻群落不仅能在春季保持对水体营养盐较高的去除效果,并能在春末初夏时有效缓解菹草死亡给水质带来的不利影响;在菹草旺盛生长期(阶段Ⅰ),与对照区(无水生高等植物)相比,菹草-伊乐藻群落对TN、NH4+-N、TP、Chla的去除率达50·7%、83·2%、32·0%、38·3%,单一菹草群落对TN、NH4+-N、TP、Chla的去除率也达到47·3%、72·5%、32·4%、45·2%;而在菹草开始衰亡后这一时期(阶段Ⅱ)菹草-伊乐藻群落对TN、NH4+-N、TP的去除率分别为47·1%、69·4%、11·2%,而围区B内TN、NH4+-N浓度则与对照区相比差异不显著(p>0·05,N=9),TP浓度甚至上升了24·3%.

Potamogeton crispus, Elodea nuttallii were introduced to the enclosures in the eutrophic pond, constructing Potamogeton crispus-Elodea nuttallii community（ enclosure A） and Potamogeton crispus community（ enclosure B） respectively. The restoration process of submerged macrophytes and the changes of water quality of two communities were investigated. The results show that Potamogeton crispus-Elodea nuttallii community could not only remain being very effective on removal of the concertration of water nutrition in spring, but also reduce bad affection caused by Potamogeton crispus＇ s death at the end of spring. Comparing with the control enclosure （non-aquatic macrophytes）, during the period Potamogeton crispus--dominated （ phase Ⅰ ）, the removal efficiencies of Potamogeton crispus-Elodea nuttallii community for TN,NH4^＋ - N ,TP,Chla were 50. 7% ,83.2% ,32, 0% ,38.3% respectively, and the removal efficiencies of Potamogeton crispus community for those were 47.3% ,72. 5% ,32.4% ,45.2%. However during the period after the death of Potamogeton crispus （phase Ⅱ ）, the removal efficiencies of Potamogeton crispus-Elodea nuttallli community for TN, NH4^＋ - N, TP were 47. 1%, 69.4%, 11.2% respectively, and the difference of TN, NH4^＋ - N between enclosure B and control enclosure was inapparent （p 〉 0. 05, N = 9）, with the concertration of TP even increasing by 24. 3%.