| 摘要: |
| 沉水植物光合作用形成的微环境有利于水体中钙和磷形成CaCO3-P共沉淀，但在不同水环境因子下水体中钙和磷形成CaCO3-P共沉淀的能力不同。本研究以菹草（Potamogeton crispus）为研究对象，研究不同钙浓度(0、20、35、50、65 mg·L-1)、碱度(0、100、200、300、400 mg·L-1 CaCO3）、磷浓度(0、0.1、0.2、0.3、0.4 mg·L-1)和温度(11、14、17、20℃）对菹草削减水体磷的能力及对CaCO3-P共沉淀产生的差异，并通过分析无植物对照组培养液的饱和指数变化趋势，揭示植物介导下CaCO3-P的发生规律，为湖泊生态修复中沉水植物的选择提供理论依据。结果表明：①在菹草培养组中，总磷(TP)和溶解性磷酸盐(SRP)浓度显著下降，并且不同处理组之间存在显著差异。随着钙浓度的增加，各处理组的TP和SRP浓度均呈减小趋势，而添加钙浓度导致减幅进一步提高。相比之下，在无菹草对照组中，TP和SRP浓度没有显著变化。这表明菹草的引入促进了水中磷的去除效率。②各处理组CaCO3-P共沉淀量随碱度的增加而增加，碱度为400 mg·L-1 CaCO3时，产生最大CaCO3-P共沉淀量，说明菹草在碱性水环境中更有利于产生CaCO3-P共沉淀。共沉淀在中等磷水平（0.2 mg·L-1）产生量最高，每株菹草每天平均产生23.12 mg共沉淀量。实验验证了自然水体磷浓度对菹草叶面CaCO3-P共沉淀量的产生差异较小，共沉淀在中等温度水平（17℃）含量最高，每株菹草每天平均产生16.61 mg共沉淀量，说明菹草在适宜温度下产生共沉淀的差异不大。以上结果表明碱度相较于磷浓度及温度对菹草的CaCO3-P共沉淀量影响更大。③在水环境因子相同的情况下，无菹草对照组碳酸钙饱和指数（方解石和霰石饱和指数）均大于0，说明有结晶趋势，但在实验期间并未产生沉淀，而添加菹草的处理组产生了不等量的CaCO3-P共沉淀，表明沉水植物也可通过共沉淀的方式削减水体磷负荷，为湖泊富营养化的治理提供理论支撑。 |
| 关键词: 沉水植物 钙 磷 CaCO3-P共沉淀 菹草 |
| DOI： |
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| 基金项目:中国科学院南京地理与湖泊研究所自主部署科研项目（NIGLAS2022GS03）与美丽中国生态文明建设科技工程（XDA23020403）联合资助 |
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| Analysis of key factors influencing the production of CaCO3-P precipitation on the leaf surface of Potamogeton crispus |
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Tao Yifan,Huang Wei,Yu Cheng,Chen kaining,Li Ziwei
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School of Geographic Science and Surveying Engineering, Suzhou University of Science and Technology
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| Abstract: |
| Abstract: The microenvironment formed by photosynthesis of submerged macrophytes is favourable for the formation of CaCO3-P co-precipitation of calcium and phosphorus in the water column, but the ability of calcium and phosphorus to form CaCO3-P co-precipitation in the water column varies under different water environmental factors. In the present study, Potamogeton crispus was used to investigate different calcium concentrations (0, 20, 35, 50, and 65 mg·L-1), alkalinity (0, 100, 200, 300, and 400 mg·L-1 CaCO3), phosphorus concentrations (0, 0.1, 0.2, 0.3, and 0.4 mg·L-1), and temperatures (11, 14, 17, 20 ℃) on the ability of P. crispus to cut water body phosphorus and the difference on the production of CaCO3-P co-precipitation, and by analysing the trend of the saturation index of the culture solution of the no-plant control group, to reveal the law of plant-mediated CaCO3-P occurrence, and to provide a theoretical basis for the selection of submerged macrophytes in the ecological restoration of lakes. The results showed that: In the P. crispus culture group, the total phosphorus (TP) and soluble reactive phosphorus (SRP) concentrations decreased significantly, and there were significant differences between different treatment groups. TP and SRP concentrations tended to decrease in all treatment groups as calcium concentration increased, while the addition of calcium concentration resulted in a further increase in the rate of decrease. In contrast, there were no significant changes in TP and SRP concentrations in the no P. crispus culture group. This suggests that the introduction of P. crispus facilitated the removal efficiency of phosphorus from the water. CaCO3-P co-precipitation increased with increasing alkalinity in each treatment group, with maximum CaCO3-P co-precipitation produced at an alkalinity level of 400 mg·L-1 CaCO3, suggesting that P. crispus is more conducive to CaCO3-P co-precipitation in an alkaline water environment. Co-precipitation was highest at moderate phosphorus levels (0.2 mg·L-1), with an average of 23.12 mg co-precipitation per day per P. crispus. The experiments verified that the natural water body phosphorus concentration has less difference on the production of CaCO3-P co-precipitation in the leaves of P. crispus, and the co-precipitation was highest at the medium temperature level (17°C), with an average of 16.61 mg co-precipitation per P. crispus per day, which indicates that there is not much difference in the production of co-precipitation by P. crispus at the appropriate temperatures. The above results indicate that alkalinity has a greater effect on the amount of CaCO3-P co-precipitation in P. crispus compared to phosphorus concentration and temperature. Under the same water environment factors, the calcium carbonate saturation indices (calcite and aragonite saturation indices) of the control group without P. crispus were greater than 0, indicating a crystallisation tendency, but no precipitation was produced during the experimental period, whereas the treatment group with added P. crispus produced unequal amounts of CaCO3-P co-precipitation, which suggests that submerged macrophytes can also reduce the phosphorus loading of the water body by co-precipitation, providing theoretical support for the management of lake eutrophication. |
| Key words: Submerged macrophyte calcium phosphorus CaCO3-P co-precipitation Potamogeton crispus |
