The technique of DGT (diffusive gradients in thin films) was applied to obtain high-resolution vertical profiles of dissolved reactive phosphorus (DRP) in sediment porewater of Lake Chaohu, a shallow eutrophication la...The technique of DGT (diffusive gradients in thin films) was applied to obtain high-resolution vertical profiles of dissolved reactive phosphorus (DRP) in sediment porewater of Lake Chaohu, a shallow eutrophication lake. Three kinds of DGT probes (with three thicknesses of diffusive gel: 0.38 mm, 0.78 mm and 1.18 mm) measured vertical concentration and induced flux from solid to solution phase which had intricate variations with depth. The results indicated that higher concentrations and induced fluxes of DRP were achieved by using DGT probe with thicker diffusion layer (CDGT1.18 > CDGT0.78 > CDGT0.38) and relatively stable DRP concentration profiles using DGT probes with 0.78 mm diffusive gel were obtained in each sediment core. The DRP concentrations displayed a clear gradient from Core C1 to Core C3 in sediment porewaters due to different sources and exchange degrees of reactive phosphorus. Compared to the concentrations obtained by the centrifugation technique, the concentrations of DRP resulting from the DGT technique were higher because some dissolved reactive phosphorus compounds have always been neglected using conventional centrifugation method.展开更多
A diffusive gradients in thin films （DGT） technique based on hydrous zirconium oxide （Zr-oxide） has been recently developed for the measurement of dissolved reactive phosphate （DRP）. In this study, the detailed ...A diffusive gradients in thin films （DGT） technique based on hydrous zirconium oxide （Zr-oxide） has been recently developed for the measurement of dissolved reactive phosphate （DRP）. In this study, the detailed performance of the DGT technique is reported. Spiking experiments revealed that several orthophosphate monoester compounds contributed to the Zr-oxide DGT measurements of DRP. However, such a phenomenon is unlikely to occur during field conditions due to the low concentration of organic P in typical natural waters. The presence of Cl- （up to 106 g/L）, SO42- （up to 16 g/L）, HCO3- （up to 817 g/L）, and AsO2- and AsO 3 4 （both up to 1 mg As/L） in solutions had negligible effects on the measurement of DRP. The threshold concentrations of Cl-, SO42- and HCO3- have been increased from previous reports for the measurements of DRP using other adsorbent-based DGT techniques. The capacity for DGT measurements of DRP decreased with increasing solution pH （4.2-9.2）. The lowest capacity （95 μg P/m2 at pH 9.2） was still greater than that of other DGT techniques that are usually used for the measurement of DRP （2-12 μg P/cm2 ）. The Zr-oxide binding gel could be stored for up to 2 years without any aging effect. This period of validity was considerably longer than the ferrihydrite binding gel that is commonly used in present DGT devices （6 months）. The field application revealed that the concentrations of DRP measured in three fresh water samples using the Zr-oxide DGT technique were in agreement with those of the traditional colorimetric method.展开更多
薄膜扩散梯度技术（diffusive gradients in thin films technique,DGT）是近年来广泛应用于水体、沉积物和土壤中有效态元素生物有效性研究的一种新技术,为确定测定土壤磷素生物有效性的DGT最佳测试条件以及肥料磷在土壤中迁移特性,采...薄膜扩散梯度技术（diffusive gradients in thin films technique,DGT）是近年来广泛应用于水体、沉积物和土壤中有效态元素生物有效性研究的一种新技术,为确定测定土壤磷素生物有效性的DGT最佳测试条件以及肥料磷在土壤中迁移特性,采用盆栽试验,分析了土壤与DGT作用时间、环境温度、土壤相对含水量对DGT测定的磷素生物有效性影响,并利用DGT测定肥料磷在表面撒施和滴施（4种土壤类型：潮土、灌淤土、灰漠土和草甸土）方式下土壤剖面的迁移规律。结果表明：DGT-P随土壤与DGT作用时间（0-24 h）的增加而增加,在24 h后趋于稳定;DGT-P随土壤相对含水量（20%-100%）的增加而增加,在含水量为80%-100%时最大,当相对含水量增加到120%时,DGT-P则降低;DGT-P随环境温度的增加而增加,在25℃后趋于稳定。与表面撒施处理相比,滴施可以增加5-15 cm肥料磷的分布。而滴施处理的磷的移动性也受到土壤类型和质地的影响,在草甸土（71%砂粒）上运移性较大,在潮土（46.65%砂粒）上运移性较小。总之,DGT测定的土壤磷素生物有效性最佳测试条件为土壤与DGT作用时间在24 h,土壤相对含水量为80%-100%,环境温度25℃,磷肥滴施优于表面撒施,滴施的磷肥能够迁移到更深的土层。展开更多
Macrophytes are usually chosen for phytoremediation tools to remove P in eutrophic aquatic ecosystems,but the lack of test methods hinders the understanding of removal mechanism and application.In this study,we used t...Macrophytes are usually chosen for phytoremediation tools to remove P in eutrophic aquatic ecosystems,but the lack of test methods hinders the understanding of removal mechanism and application.In this study,we used the novel technologies combined of Diffusive gradients in thin films(DGT),Planar optode(PO),and Non-invasive micro-test technology(NMT)to explore P dynamics in water-sediment continuum and rhizosphere of Potamogeton crispus over time.Results of the high-resolution in situ measurement showed that labile P(LPDGT)fluxes at the surficial sediment significantly decreased from approximate 120,140,and 200 pg/(cm^(2)·sec)via 30 days incubation period to 17,40,and 56 pg/(cm2•sec)via that of 15 days.Obvious synchronous increase of LPDGT was not detected in overlying water,suggesting the intense assimilation of dissolve reactive P via root over time.PO measurement indicated that O_(2)concentration around the rhizosphere remarkably increased and radially diffused into deeper sediment until 100%saturation along with the root stretch downwards.NMT detection of roots showed the obvious O_(2)inflow into root tissue with the uppermost flux of 30 pmol/(cm2•sec)from surroundings via aerenchyma on different treatment conditions.Different from previous reports,gradually saturating O_(2)concentrations around the rhizosphere was principally driven by O_(2)penetration through interspace attributing to root stretch downward rather than root O_(2)leakage.Increased O_(2)concentrations in deep sediment over time finally induced the oxidization of labile Fe(II)into Fe(III)bound P and local P immobilization.展开更多
The synergistic effect of vermiculite and the submerged macrophytes Vallisneria spiralis and Hydrilla verticillata on lake sediment was studied using diffusive gradients in thin films(DGT)technology.The dynamics of ph...The synergistic effect of vermiculite and the submerged macrophytes Vallisneria spiralis and Hydrilla verticillata on lake sediment was studied using diffusive gradients in thin films(DGT)technology.The dynamics of phosphorus(P)fractions in sediment,the labile-P and labile-S in the water-sediment continuum,and the microbial community in the rhizosphere were studied.Vermiculite effectively promoted reproduction of microorganisms in the sediments Microbial abundance in treatments containing V.spiralis with sediments containing 10%added vermiculite,and H.verticillata containing 50%added vermiculite being 1.7 and 3.5 times higher than the controls which contained no added vermiculite.Acidobacteria and Proteobacteria populations,which are both beneficial for the sediment microenvironment,were higher in treatment groups containing vermiculite.The bioavailable-P in treatment groups containing added vermiculite was lower at the sediment-water interface,with a correlating decrease of TP by between 63%and 91%in the overlying water.This suggests that vermiculite can affect the release of labile P and facilitate the assimilation of nutrients by macrophyte roots.Additionally,vermiculite can improve the Oxidation-Reduction potential and further reduce sulfide toxicity to plants.These results provide theoretical guidance and technical support for the application of vermiculite combined with submerged plants for the remediation of eutrophic lakes.展开更多
文摘The technique of DGT (diffusive gradients in thin films) was applied to obtain high-resolution vertical profiles of dissolved reactive phosphorus (DRP) in sediment porewater of Lake Chaohu, a shallow eutrophication lake. Three kinds of DGT probes (with three thicknesses of diffusive gel: 0.38 mm, 0.78 mm and 1.18 mm) measured vertical concentration and induced flux from solid to solution phase which had intricate variations with depth. The results indicated that higher concentrations and induced fluxes of DRP were achieved by using DGT probe with thicker diffusion layer (CDGT1.18 > CDGT0.78 > CDGT0.38) and relatively stable DRP concentration profiles using DGT probes with 0.78 mm diffusive gel were obtained in each sediment core. The DRP concentrations displayed a clear gradient from Core C1 to Core C3 in sediment porewaters due to different sources and exchange degrees of reactive phosphorus. Compared to the concentrations obtained by the centrifugation technique, the concentrations of DRP resulting from the DGT technique were higher because some dissolved reactive phosphorus compounds have always been neglected using conventional centrifugation method.
基金sponsored by the National Natural Scientific Foundation of China (No. 41001334, 41001325)the Project of Knowledge Innovation for the 3rd period, the Chinese Academy of Sciences (No. KZCX2-YW-JS304)the Natural Scientific Foundation of Jiangsu Province, China (No. BK2010606)
文摘A diffusive gradients in thin films （DGT） technique based on hydrous zirconium oxide （Zr-oxide） has been recently developed for the measurement of dissolved reactive phosphate （DRP）. In this study, the detailed performance of the DGT technique is reported. Spiking experiments revealed that several orthophosphate monoester compounds contributed to the Zr-oxide DGT measurements of DRP. However, such a phenomenon is unlikely to occur during field conditions due to the low concentration of organic P in typical natural waters. The presence of Cl- （up to 106 g/L）, SO42- （up to 16 g/L）, HCO3- （up to 817 g/L）, and AsO2- and AsO 3 4 （both up to 1 mg As/L） in solutions had negligible effects on the measurement of DRP. The threshold concentrations of Cl-, SO42- and HCO3- have been increased from previous reports for the measurements of DRP using other adsorbent-based DGT techniques. The capacity for DGT measurements of DRP decreased with increasing solution pH （4.2-9.2）. The lowest capacity （95 μg P/m2 at pH 9.2） was still greater than that of other DGT techniques that are usually used for the measurement of DRP （2-12 μg P/cm2 ）. The Zr-oxide binding gel could be stored for up to 2 years without any aging effect. This period of validity was considerably longer than the ferrihydrite binding gel that is commonly used in present DGT devices （6 months）. The field application revealed that the concentrations of DRP measured in three fresh water samples using the Zr-oxide DGT technique were in agreement with those of the traditional colorimetric method.
文摘薄膜扩散梯度技术（diffusive gradients in thin films technique,DGT）是近年来广泛应用于水体、沉积物和土壤中有效态元素生物有效性研究的一种新技术,为确定测定土壤磷素生物有效性的DGT最佳测试条件以及肥料磷在土壤中迁移特性,采用盆栽试验,分析了土壤与DGT作用时间、环境温度、土壤相对含水量对DGT测定的磷素生物有效性影响,并利用DGT测定肥料磷在表面撒施和滴施（4种土壤类型：潮土、灌淤土、灰漠土和草甸土）方式下土壤剖面的迁移规律。结果表明：DGT-P随土壤与DGT作用时间（0-24 h）的增加而增加,在24 h后趋于稳定;DGT-P随土壤相对含水量（20%-100%）的增加而增加,在含水量为80%-100%时最大,当相对含水量增加到120%时,DGT-P则降低;DGT-P随环境温度的增加而增加,在25℃后趋于稳定。与表面撒施处理相比,滴施可以增加5-15 cm肥料磷的分布。而滴施处理的磷的移动性也受到土壤类型和质地的影响,在草甸土（71%砂粒）上运移性较大,在潮土（46.65%砂粒）上运移性较小。总之,DGT测定的土壤磷素生物有效性最佳测试条件为土壤与DGT作用时间在24 h,土壤相对含水量为80%-100%,环境温度25℃,磷肥滴施优于表面撒施,滴施的磷肥能够迁移到更深的土层。
基金supported by National Natural Science Foundation of China(Nos.41503099,31971476)the CAS Interdisciplinary Innovation Team(No.JCTD-2018-16)the Key Research Program of Frontier Sciences,CAS(No.ZDBS-LYDQC018).
文摘Macrophytes are usually chosen for phytoremediation tools to remove P in eutrophic aquatic ecosystems,but the lack of test methods hinders the understanding of removal mechanism and application.In this study,we used the novel technologies combined of Diffusive gradients in thin films(DGT),Planar optode(PO),and Non-invasive micro-test technology(NMT)to explore P dynamics in water-sediment continuum and rhizosphere of Potamogeton crispus over time.Results of the high-resolution in situ measurement showed that labile P(LPDGT)fluxes at the surficial sediment significantly decreased from approximate 120,140,and 200 pg/(cm^(2)·sec)via 30 days incubation period to 17,40,and 56 pg/(cm2•sec)via that of 15 days.Obvious synchronous increase of LPDGT was not detected in overlying water,suggesting the intense assimilation of dissolve reactive P via root over time.PO measurement indicated that O_(2)concentration around the rhizosphere remarkably increased and radially diffused into deeper sediment until 100%saturation along with the root stretch downwards.NMT detection of roots showed the obvious O_(2)inflow into root tissue with the uppermost flux of 30 pmol/(cm2•sec)from surroundings via aerenchyma on different treatment conditions.Different from previous reports,gradually saturating O_(2)concentrations around the rhizosphere was principally driven by O_(2)penetration through interspace attributing to root stretch downward rather than root O_(2)leakage.Increased O_(2)concentrations in deep sediment over time finally induced the oxidization of labile Fe(II)into Fe(III)bound P and local P immobilization.
基金This work was financially supported by the National Natural Science Foundation of China(No.31830013,32201384)Youth Innovation Promotion Association,Chinese Academy of Sciences(No.2020335)+2 种基金National Science&Technology Fundamental Resources Investigation Program of China(2019FY100600)Key Research and Development Program of Hubei Province,China(2020BCA073,2022BCA066)Special Research Assistant Project Chinese Academy of Sciences.
文摘The synergistic effect of vermiculite and the submerged macrophytes Vallisneria spiralis and Hydrilla verticillata on lake sediment was studied using diffusive gradients in thin films(DGT)technology.The dynamics of phosphorus(P)fractions in sediment,the labile-P and labile-S in the water-sediment continuum,and the microbial community in the rhizosphere were studied.Vermiculite effectively promoted reproduction of microorganisms in the sediments Microbial abundance in treatments containing V.spiralis with sediments containing 10%added vermiculite,and H.verticillata containing 50%added vermiculite being 1.7 and 3.5 times higher than the controls which contained no added vermiculite.Acidobacteria and Proteobacteria populations,which are both beneficial for the sediment microenvironment,were higher in treatment groups containing vermiculite.The bioavailable-P in treatment groups containing added vermiculite was lower at the sediment-water interface,with a correlating decrease of TP by between 63%and 91%in the overlying water.This suggests that vermiculite can affect the release of labile P and facilitate the assimilation of nutrients by macrophyte roots.Additionally,vermiculite can improve the Oxidation-Reduction potential and further reduce sulfide toxicity to plants.These results provide theoretical guidance and technical support for the application of vermiculite combined with submerged plants for the remediation of eutrophic lakes.
