State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, No.19, Xinjiekouwai Street, Haidian District, Beijing 100875, China.
State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, No.19, Xinjiekouwai Street, Haidian District, Beijing 100875, China.
Water Res. 2012 Nov 1;46(17):5635-5644. doi: 10.1016/j.watres.2012.07.053. Epub 2012 Aug 7.
Shallow lake eutrophication has been an important issue of global water environment. Based on the simulation and field sampling experiments in Baiyangdian Lake, the largest shallow lake in North China, this study proposed a shallow lake remediation regime with Phragmites australis (reed) incorporating its opposite effects of nutrient removal and water evapotranspiration on water quality. The results of simulation experiments showed that both total nitrogen (TN) and phosphorus (TP) removal efficiencies increased with the increasing reed coverage. The TN removal efficiencies by reed aboveground uptake and rhizosphere denitrification were 11.2%, 13.8%, 22.6%, 28.4%, and 29.6% for the reed coverage of 20%, 40%, 60%, 80%, and 100%, respectively. Correspondingly, TP removal efficiencies by aboveground reed uptake were 1.4%, 2.5%, 4.4%, 7.4% and 7.9%, respectively. However, the water quality was best when the reed coverage was 60% (72 plants m(-2)). This was due to the fact that the concentration effect of reed evapotranspiration on nutrient increased with reed coverage. When the reed coverage was 100% (120 plants m(-2)), the evapotranspiration was approximately twice that without reeds. The field sampling results showed that the highest aboveground nutrient storages occurred in September. Thus, the proposed remediation regime for Baiyangdian Lake was that the reed coverage should be adjusted to 60%, and the aboveground biomass of reeds should be harvested in each September. With this remediation regime, TN and TP removal in Baiyangdian Lake were 117.8 and 4.0 g m(-2), respectively, and the corresponding removal efficiencies were estimated to be 49% and 8.5% after six years. This study suggests that reed is an effective plant for the remediation of shallow lake eutrophication, and its contrasting effects of nutrient removal and evapotranspiration on water quality should be considered for establishing the remediation regime in the future.
浅水湖泊富营养化是全球水环境的一个重要问题。本研究基于对白洋淀（中国北方最大的浅水湖泊）的模拟和野外采样实验，提出了一种利用芦苇（芦竹）的修复制度，利用芦苇对水质的养分去除和水蒸发蒸腾的相反作用来修复浅水湖泊。模拟实验结果表明，总氮（TN）和总磷（TP）的去除效率均随芦苇覆盖面积的增加而增加。芦苇地上部分吸收和根际反硝化的 TN 去除效率分别为 11.2%、13.8%、22.6%、28.4%和 29.6%，芦苇覆盖面积分别为 20%、40%、60%、80%和 100%。相应地，芦苇地上部分吸收的 TP 去除效率分别为 1.4%、2.5%、4.4%、7.4%和 7.9%。然而，当芦苇覆盖率为 60%（72 株/m2）时，水质最好。这是因为芦苇蒸发蒸腾对养分的浓度效应随芦苇覆盖率的增加而增加。当芦苇覆盖率达到 100%（120 株/m2）时，蒸发蒸腾量约为无芦苇时的两倍。野外采样结果表明，9 月地上养分储量最高。因此，对白洋淀提出的修复制度是将芦苇覆盖率调整到 60%，并在每年 9 月收割地上芦苇生物量。采用该修复制度，白洋淀 TN 和 TP 的去除量分别为 117.8 和 4.0 g/m2，六年后的去除率估计分别为 49%和 8.5%。本研究表明，芦苇是一种有效的浅水湖泊富营养化修复植物，在未来建立修复制度时，应考虑其养分去除和蒸发蒸腾对水质的相反作用。
