不同水动力条件下沉水植物在生长期对上覆水和沉积物磷迁移的影响
Influence of Submerged Macrophytes on Phosphorus Transference Between Overlying Water and Sediment in the Growth Period under Different Hydrodynamic Conditions
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摘要: 通过室内静水和动水实验,研究苦草(Vallisneria natans)和黑藻(Hydrilla verticillata)在生长期上覆水和沉积物中各形态磷含量、沉水植物生物量和环境因子的变化,探讨在不同水动力条件下沉水植物对上覆水和沉积物中各形态磷迁移规律。实验结果表明:在静水(v=0m/s)和动水(v=0.10m/s)条件下,沉水植物生长期均能降低上覆水中各形态磷含量,实验结束时静水实验组和动水实验组上覆水总磷(TP)含量分别保持在0.05~0.11mg/L和0.02~0.17mg/L。在静水条件下沉水植物以降低上覆水中溶解性总磷(DTP)为主,动水条件下以减少DTP和颗粒磷(PP)为主。沉水植物苦草和黑藻均能显著降低沉积物中TP、无机磷(IP)和NaOH提取磷(NaOH-P)含量,在实验结束时实验组沉积物从轻度污染逐步转为未受污染。相比黑藻,苦草能够有效抑制沉积物表层磷释放。在动水实验中HCl提取磷(HCl-P)与NaOH-P呈显著负相关(苦草组P<0.01;黑藻组P<0.05)。沉水植物生物量迅速增加(苦草组70~511g;黑藻组30~510g)引起上覆水溶解氧(DO)和pH提高(静水组DO 2.5~6.2mg/L,pH 7.3~9.3;动水组DO 2.4~8.1 mg/L,pH 7.4~8.9),从而间接影响沉积物磷向上覆水的释放。本研究结果分析了静水、动水条件下沉水植物对上覆水和沉积物中各形态磷的影响,可为沉水植物修复湖泊和河流生态系统提供参考依据。Abstract: In order to clarify the process of phosphorus transference in overlying water and sediment under different hydrodynamic conditions, changes of phosphorus concentrations in overlying water and sediment, biomass of submerged macrophytes and environmental factors were studied during the growth of Vallisneria natans and Hydrilla verticillata by indoor experiment. The results showed that submerged macrophytes could reduce the contents of various phosphorus fractions in overlying water during the growing period under hydrostatic(v=0 m/s) and hydrodynamic conditions(v=0.10 m/s), and total P (TP) contents in overlying water in hydrostatic experimental groups and hydrodynamic experimental groups ranged from 0.05 to 0.11mg/L and 0.02 to 0.17mg/L, respectively at the end of the experiment. In the hydrostatic experimental group, dissolved total P (DTP)contents were mainly decreased, while concentrations of DTP and particulate P (PP) were mainly decreased in the hydrodynamic experimental group. Compared with the control replicates, TP, inorganic P (IP) and NaOH-extracted P (NaOH-P) concentrations in the sediment of experimental groups were significantly decreased. At the end of the study, the sediment in the experimental group gradually changed from slightly polluted to unpolluted . There is a significant negative correlation between HCl-extracted P (HCl-P) and NaOH-P under hydrodynamic conditions.(Vallisneria natans group P<0.05; Hydrilla verticillate group P<0.01).The biomass of submerged macrophytes increased rapidly (Vallisneria natans group 70~511g; Hydrilla verticillate group 30~510g) caused the increase of dissolved oxygen (DO) and pH in overlying water (hydrostatic experimental group DO 2.5~6.2mg/L, pH 7.3~9.3; hydrodynamic experimental group DO 2.4~8.1 mg/L, pH 7.4~8.9), which indirectly affected the release of phosphorus from sediment to overlying water. Compared with Hydrilla verticillata, Vallisneria natans can effectively prevent phosphorus releasing from surface sediment. The results of this study supplemented the effects of submerging macrophytes on various phosphorus forms in overlying water and sediment under hydrodynamic conditions and provided a reference for the restoration of lakes and rivers by in situ phytoremediation.
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Key words:
- hydrodynamic /
- submerged macrophytes /
- overlying water /
- sediment /
- phosphorous
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