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CaCO_(3)-P共沉淀,但在不同水环境因子下水体中钙和磷形成CaCO_(3)-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)、碱度(0、100、200、300、400 mg/L CaCO_(3))、磷浓度(0、0.1、0.2、0.3、0.4 mg/L)和温度(11、14、17、20℃)对菹草削减水体磷的能力及对CaCO_(3)-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CaCO_(3)-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CaCO_(3)-P共沉淀量随碱度的增加而增加,碱度为400 mg/L CaCO_(3)时,产生最大CaCO_(3)-P共沉淀量,说明菹草在碱性水环境中更有利于产生CaCO_(3)-P共沉淀。共沉淀在中等磷水平(0.2 mg/L)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CaCO_(3)-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CaCO_(3)-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CaCO_(3)-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。
The microenvironment formed by photosynthesis of submerged macrophytes is favourable for the formation of CaCO_(3)-P co-precipitation of calcium and phosphorus in the water column.However,the ability of calcium and phosphorus to form CaCO_(3)-P co-precipitation in the water column varies under different water environmental factors.In this study,Potamogeton crispus was used to investigate the impacts of different calcium concentrations(0,20,35,50,and 65 mg/L),alkalinity(0,100,200,300,and 400 mg/L CaCO_(3)),phosphorus concentrations(0,0.1,0.2,0.3,and 0.4 mg/L),and temperatures(11,14,17,20℃)on the ability of P.crispus to reduce phosphorus and CaCO_(3)-P co-precipitation.By analyzing the trend of the saturation index of the culture solution of the no-plant control group,this study revealed the law of plant-mediated CaCO_(3)-P occurrence,and provided a theoretical basis for the selection of submerged macrophytes in the ecological restoration of lakes.The results showed that the total phosphorus(TP)and soluble reactive phosphorus(SRP)concentrations decreased significantly in the P.crispus culture group.There were significant differences between different treatment groups.As calcium concentration increased,TP and SRP concentrations decreased in all treatment groups,with a decreasing rate depending on the addition of calcium.In contrast,there were no significant changes in TP and SRP concentrations in the no P.crispus culture group.This suggested that P.crispus enhanced phosphorus removal.In all the treatment groups,CaCO_(3)-P co-precipitation increased with increasing alkalinity,with maximum CaCO_(3)-P co-precipitation at an alkalinity concentration of 400 mg/L CaCO_(3).This suggested that P.crispus was more conducive to CaCO_(3)-P co-precipitation in an alkaline water environment.Co-precipitation was highest at moderate phosphorus levels(0.2 mg/L),with an average of 23.12 mg co-precipitation per day for each P.crispus.The experiments verified that the natural water body phosphorus concentration has limited difference on the production of CaCO_(3)-P co-precipitation in the leaves of P.crispus.The co-precipitation was highest at the medium temperature level(17℃),with an average of 16.61 mg co-precipitation per day for each P.crispus.This suggested that there was not much difference in the production of co-precipitation by P.crispus at the appropriate temperatures.These results indicated that alkalinity has a greater effect on CaCO_(3)-P co-precipitation in P.crispus compared with phosphorus concentration and temperature.Under the same water environment,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.However,no precipitation was produced during the experimental period,whereas the treatment group with added P.crispus produced unequal amounts of CaCO_(3)-P co-precipitation,which suggested that submerged macrophytes can reduce phosphorus by co-precipitation.This study can potentially provide theoretical support for water management of lake eutrophication.
作者
陶轶凡
黄蔚
余成
陈开宁
李子威
Tao Yifan;Huang Wei;Yu Cheng;Chen Kaining;Li Ziwei(School of Environmental Science and Engineering,Suzhou University of Science and Technology,Suzhou 215009,P.R.China;State Key Laboratory of Lake Science and Environment,Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences,Nanjing 210008,P.R.China;School of Geographic Sciences and Geomatics Engineering,Suzhou University of Science and Technology,Suzhou 215009,P.R.China;Jiangsu Collaborative Innovation Center for Water Treatment Technology and Materials,Suzhou 215009,P.R.China)
出处
《湖泊科学》
EI
CAS
CSCD
北大核心
2024年第4期1060-1068,共9页
Journal of Lake Sciences
基金
中国科学院南京地理与湖泊研究所自主部署科研项目(NIGLAS2022GS03)
美丽中国生态文明建设科技工程(XDA23020403,XDA23020101)联合资助。
关键词
沉水植物
钙
磷
CaCO_(3)-P共沉淀
菹草
Submerged macrophyte
calcium
phosphorus
CaCO_(3)-P co-precipitation
Potamogeton crispus
