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1.
通常认为,磷是湖泊富营养化的主要限制因子,因此控制湖泊磷浓度和水平被认为是湖泊治理的关键.在外源磷输入得到有效控制之后,湖泊富营养化仍可持续几十年,这主要归咎于内源磷的释放.底泥原位化学钝化控磷技术因其操作性强、控磷效果明显,而被广泛作为湖泊内源磷的控制技术之一,而钝化材料的研发和应用是本项技术的核心.在世界范围内,研...  相似文献   

2.
甘磊  钟萍  苏玲  刘正文 《湖泊科学》2019,31(5):1219-1228
分析湖泊沉积物磷形态的变化是揭示控制沉积物磷释放机理的关键.本研究分析了暨南大学南湖加镧改性膨润土前后水体磷浓度和沉积物磷形态变化,以探讨镧改性膨润土对削减水体磷浓度的效果.结果显示,镧改性膨润土添加后,上覆水磷浓度波动较大,总体呈下降趋势;至60 d时,水体总磷、颗粒态磷、总溶解磷和溶解性反应磷分别比添加前下降了45.1%、44.1%、48.2%和85.3%;沉积物中的弱结合态磷和氧化还原敏感性磷含量减少,更稳定的磷灰石结合态磷和残渣磷含量增加,而金属氧化物磷和有机磷含量变化较小.本研究表明镧改性膨润土能改变沉积物磷形态,使活性磷转化为稳定的磷形态,从而提高沉积物对磷的滞留能力、降低湖水磷含量,改善水质.  相似文献   

3.
浅水湖泊内源磷负荷季节变化的生物驱动机制   总被引:14,自引:5,他引:14  
谢平 《中国科学D辑》2005,35(Z2):11-23
由于磷是重要的生源要素,过量的磷促进浮游植物(包括有毒蓝藻)的生长而使水质恶化,水-泥界面的磷交换机制受到广泛关注.一般认为沉积物的磷释放模式在浅水湖泊和深水湖泊之间有很大的差异.在探讨沉积物中磷释放机制时,人们一直最关注的要素为铁和氧及其相关的环境因子(如扰动、分解),但是浅水湖泊中磷含量变化的大部分结果仍然无法解释.通过对欧洲温带浅水湖泊和亚热带气候的长江中下游浅水湖泊中有关沉积物磷释放模式的野外和实验研究结果的分析,认为在浅水湖泊内源磷负荷季节变动模式的驱动因子中,pH可能比溶氧更为重要,即浮游藻类的光合作用增强时导致水体pH值的上升,这又可改变沉积物表面的pH,从而促进沉积物中磷(特别是铁磷)的释放并基于藻类水华对沉积物中磷的泵吸作用,首次提出了浅水湖泊中内源磷负荷的季节波动与营养水平密切相关主要是由于藻类光合作用驱动的新的观点.此外,浅水湖泊中藻类水华对沉积物磷的选择性泵吸作用,一方面圆满地解释了为何在超富营养的武汉东湖通过非经典的生物操纵于20世纪80年代中期消除了东湖的蓝藻水华后水柱中总磷和活性磷含量均显著下降,另一方面也解释了为何在许多欧洲湖泊的群落季节演替过程中出现的春季浮游植物较少的清水期或通过经典的生物操纵降低浮游植物的现存量均可显著地降低湖水中的磷含量.相对于深水湖泊来说,浅水湖泊生态系统结构的改变引发的浮游植物的兴衰,能对水-泥界面磷的交换能产生更显著的影响.也就是说,生物的生命活动同样可以驱动沉积物中营养盐的释放,而且在浮游植物丰富的富营养化浅水湖泊中,这种静态释放作用更为明显.  相似文献   

4.
采用室内培养的方法,以富营养化湖泊太湖为例,研究了沉积物有机质矿化过程中碳、氮、磷的迁移特征.结果表明,在沉积物中的有机质矿化过程中,碳以溶解性无机碳释放至水中,同时以CH4和CO2形式释放至大气中,培养结束时,CH4和CO2累积排放含量分别为1492.21和498.96 mg/g(dw),其中CH4占气态碳的89.16%(以C质量计);此外,大量的氮、磷营养盐释放至上覆水体,水中总氮、总磷和铵态氮的最高浓度分别是初始浓度的62.16、28.16和139.45倍,而硝态氮浓度在整个培养过程中逐渐下降,培养末期浓度是初期的0.21倍;厌氧条件下,沉积物有机质的矿化,不仅可以生成大量的CH4、CO2气体,还能够促使沉积物中铵态氮和磷的释放;而沉积物有机质矿化释放的碳、氮、磷营养元素又能加剧湖泊富营养化程度,促进湖泊水体的初级生产力,从而增加湖泊沉积物有机质输入.这样的循环方式可能是湖泊富营养化自维持的重要机制之一.  相似文献   

5.
太湖水体氮素污染状况研究进展   总被引:33,自引:15,他引:18       下载免费PDF全文
氮是引起湖泊富营养化的关键要素之一.传统观点认为氮缺乏时,湖泊生态系统可以通过生物固氮作用从大气中获取氮来满足自身的需求,因此认为淡水湖泊水体的生产力主要受磷限制.但随着进一步的研究,发现氮限制与氮和磷共同限制更为普遍,且氮的限制常常伴随着水体的富营养化,因此了解富营养化湖泊水体的氮素污染状况具有重要意义.本文介绍了太湖水体氮素的污染状况及其发展趋势,从外源、内源两大方面介绍了太湖水体中氮素的来源,着重分析和比较了河道输入、大气输入以及沉积物释放不同污染源的输入比例.太湖水体氮素污染存在很大的空间差异,其中西部和北部污染较重而东南部相对较轻,入湖河道输入的外源污染是造成太湖水质空间分布差异的主要原因,其中农业面源污染及生活污染在太湖外源污染中占据了相当的比重;湖泊底泥所造成的内源释放也是氮素污染的一个重要原因,但目前对释放量的估算主要是基于底泥悬浮引起的总量估算,关于这些释放量能有多少比例可以被浮游植物利用还不清楚,尤其是有机颗粒物在水体中停留期间的矿化再生值得进一步研究;在氮素的生物转化过程中,生物固氮目前对太湖氮素输入的贡献很小,反硝化作用是太湖水体氮素自净的主要途径.  相似文献   

6.
季节性缺氧导致夏季沉积物内源磷强烈释放,加剧水体富营养化,是我国西南地区深水湖泊(水库)面临的重要挑战.有效增加夏季缺氧期深水沉积物-水界面的含氧量,是减少内源磷释放的关键.现有的深水增氧技术由于缺乏对沉积物-水界面增氧的针对性,因此治理效果有限.近年来,纳米气泡已被证实具有的稳定性好、氧传质速率高和环境风险低等优点,为新型深水增氧技术研发提供了巨大潜力.本文以天然矿物材料白云母、绢云母、硅藻土和沸石为基底,负载纳米气泡,研发纳米气泡改性矿物颗粒技术,开展湖泊沉积物-水界面增氧模拟实验研究,运用平面光电极技术评估其界面增氧效果.结果表明,纳米气泡改性矿物颗粒对沉积物-水界面具有比较明显的增氧效果.其中,改性白云母、绢云母和沸石的界面持续增氧时间可达7天以上,增氧后的界面最大溶解氧(DO)浓度达4.40 mg/L,而改性硅藻土不具有增氧能力.其次,矿物粒度对改性颗粒的增氧效果有一定影响:粒度越细,界面的最大增氧浓度越高,且持续增氧时间越长.纳米气泡改性矿物颗粒技术有望成为夏季缺氧期深水沉积物-水界面精准增氧和内源污染控制的有效技术手段.  相似文献   

7.
氧化还原条件对红枫湖沉积物磷释放影响的微尺度分析   总被引:7,自引:0,他引:7  
选取贵州红枫湖为研究对象,在实验室条件下模拟了自然、好氧和厌氧条件下沉积物内源磷的释放过程,联合应用微电极技术和沉积物磷形态分析对沉积物—水界面开展了微尺度观测与研究.结果表明,厌氧条件下红枫湖沉积物总磷含量显著降低,且主要是NaOH提取态磷(NaOH-P)和残渣态磷(rest-P)含量降低所致,厌氧条件下沉积物孔隙水中磷酸盐浓度明显升高,而好氧条件下沉积物孔隙水磷酸盐浓度显著降低,反映厌氧条件显著促进了红枫湖沉积物磷释放.厌氧条件下沉积物内部溶解氧浓度下降、硫还原活动增强可能是导致NaOH-P释放的主要原因.O_2浓度的降低加速了沉积物还原作用并产生大量H2S,进而与二价铁离子形成硫化亚铁沉淀,最终导致NaOH-P(Fe-P)释放到孔隙水中.好氧条件向厌氧条件的转换可通过改变沉积物内部pH值分布和微生物活动促使rest-P释放:厌氧条件下,厌氧微生物不仅可以消耗硫酸根产生H_2S,导致pH值降低,还可消耗有机质,将有机磷转变为无机磷.上述研究结果表明,沉积物—水界面氧化还原环境可影响沉积物氧渗透深度、pH值分布、微生物活动、硫循环以及有机质降解过程,进而控制沉积物磷的形态转化与释放.联合应用微电极技术和沉积物磷形态分析对湖泊沉积物—水界面开展微尺度观测研究是揭示沉积物内源磷释放机制与控制因素的有效途径.  相似文献   

8.
环太湖河流进出湖水量及污染负荷(2000-2002年)   总被引:22,自引:5,他引:22  
翟淑华  张红举 《湖泊科学》2006,18(3):225-230
天然水域,尤其是富营养的浅水湖泊,沉积物中磷的释放是蓝藻水华发生、形成和持续生长的重要因素.分析沉积物中磷的赋存形态转化及其潜在生态效应,有助于理解沉积物中磷的迁移转化过程及其与湖泊富营养化之间的关系.本文综述国内湖泊水域中磷的主要形态、来源和转化过程以及其生物有效性的研究进展.重点讨论了近5年来中国东部浅水湖泊沉积物磷的形态分析、转化和生物有效性评估的现状,以及沉积物中磷形态与浅水湖泊富营养化之间的潜在联系.  相似文献   

9.
通过对大型浅水富营养化湖泊--巢湖湖水、间隙水以及沉积物中磷形态及吸附行为时空变化的研究发现,富营养化较为严重的巢湖西区湖水、间隙水中的正磷酸盐(orthophosphate,Ortho-P)、总磷(total phosphorus,TP)显著高于东湖区,这与西湖区有大量的营养物质通过入湖河道输入有密切关系;此外水柱中颗粒态磷(particulate phosphorus,PP)亦有同样的空间分布规律,且PP的含量与微囊藻的生物量呈显著正相关关系,表明微囊藻在吸收与储藏磷方面比其它藻类更具优势.夏季浮游藻类爆发性增长引起湖水pH的升高以及对磷的大量需求是促使沉积物中的磷(特别是Fe-P)向间隙水中释放的关键因子.沉积物TP、磷形态及吸附行为的空间变化及统计分析的结果表明,沉积物中磷含量的空间异质性与人类活动、土壤地球化学背景及矿物组成等的差异有密切关系.此外,即使沉积物磷含量相同,Fe-P含量的增加将会带来更高的磷释放风险.  相似文献   

10.
夏季梅梁湾水体中生物有效磷的分布及来源   总被引:8,自引:1,他引:8  
2004年夏季在太湖梅梁湾应用一种新型氧化铁/醋酸纤维素复合膜(FeO/CAM)对水体生物有效磷浓度(FeO-P)进行了调查和连续监测. 发现水体溶解态(FeO-DP)、颗粒态(FeO-PP-)生物有效磷浓度与其总浓度在空间上有着相似的平面分布. 在梅梁湾北部入湖河口附近生物有效磷浓度最高, 随离河口或湖岸距离的增加逐渐减小, 湖心区域的水体生物有效磷浓度差异不大. 在观测期间, 梅梁湾北部多数水域的叶绿素a含量较高, 出现藻类水华现象. 但在几个主要入湖河口附近叶绿素a含量并不是最高, 尽管其水体生物有效磷浓度最高. 在受河流输入影响较小的梅梁湾开阔水域, 叶绿素a含量与生物有效磷浓度呈显著正相关性. 在风浪引起的沉积物再悬浮过程中, 水体生物有效磷浓度会出现短促的升高. 结果表明, 河流磷输入对河口水体生物有效磷浓度起主要贡献作用, 而内源磷释放则是开阔水域生物有效磷的主要来源. 在富营养的浅水湖泊中, 蓝藻水华暴发可以通过改变pH值引发内源磷的释放. 所研制的FeO/CAM膜材料能够用来监测水体生物有效磷浓度变化规律, 并为湖泊富营养化控制策略提供科学依据.  相似文献   

11.
Strzeszynskie Lake was formerly a slightly eutrophic (meso-eutrophic) water body. The aim of the current research was to define variables on both spatial and seasonal internal phosphorus loading from bottom sediments at five stations located in zones varying in depth, oxygenation, macrophyte presence, and uses of the neighboring catchment area. Ex situ experiments done with the use of intact bottom sediment cores have shown that the highest phosphorus release occurred in the deepest part of the lake and reached 3.6?mg?P/m2d under anoxic conditions during summer thermal stratification. In turn, the internal loading from littoral sediments, which were well aerated all year round, was clearly lower. Furthermore, phosphorus accumulation in the bottom sediment was observed to reach a maximum of 1.45?mg?P/m2 d in autumn. A comparison of the internal loading intensity in lake zones with different land uses of the neighboring catchment area has shown slightly higher values at stations adjacent to the forest catchment area than those used for recreation. Changes in the land use of the catchment area of Strzeszynskie Lake, especially the increase in impermeable surfaces, have led to an increased inflow of external loads after heavy rains, resulting in deterioration in water quality and a delayed increase in internal loading.  相似文献   

12.
Phosphorus(P) species in surface sediments from a shallow,hypertrophic lake,Lake Dianchi,China,were investigated by P fractionation and ~(31)P nuclear magnetic resonance(NMR) spectroscopy during a regional algal bloom.In addition,their potential contributions to the overlying water were also evaluated.Labile fractions of P extracted by NH_4C1,bicarbonate dithionite and NaOH ranged from 340.6 to 1,725.8 mg kg~(-1),accounting for20.5%-67.2%of the total P.A two-step extraction method refinement of P recovery was performed before the~(31)P NMR analysis.Recovery rates of sedimentary TP and organic P,by combining EDTA pretreatment and NaOH or mixed reagents,ranged from 31.8%to 69.3%and from19.8%to 51.7%.~(31)P NMR results showed that ortho-P and monoester-P were the most abundant P components in the sediment extractable P of sediments,followed by diester-P and pyro-P.Spatial distribution of the sum of ortho-P,diester-P and pyro-P detected by P NMR corresponded well with the labile P concentration determined by fractionation.Both exhibited a significant positive correlation with the total P in the water column,suggesting that internal loading may be an important source of P for the lake ecosystem.Biogenic P other than ortho-P may contribute to phytoplankton growth,with the relative proportion being 4.4%-18.7%.The release of labile P fractions fueled algal bloom,and the decay of organic matter,following the bloom events,consumed oxygen and elevated the pH value.This co-dependence might lead to a vicious cycle.Transformation mechanisms of various P species remain ambiguous and are worthy of further investigation.  相似文献   

13.
太湖水华成因及控制途径初探   总被引:45,自引:12,他引:45  
杨清心 《湖泊科学》1996,8(1):67-74
1990年8~12月对太湖水华9次调查表明,水华主要由漂浮性蓝藻—微囊藻组成,夏季SE风时其漂移集聚是西北湖区形成严重水华的主要原因。这种漂移使得藻类所含营养物逆吞吐流方向传输,形成了一种“生物营养滤器”,加速了太湖尤其是西北湖区的富营养化进程。太湖外源N、P负荷量分别为12.0和0.85g/(m~2·a),足以引起富营养化;表层5cm底泥中含丰富的N、P,其释放也成为湖水中部分营养的来源。因2~8月藻类总生物量的增长基本遵守Logistic方程dN/dt=N·r(1—N/K),故对藻类控制可从N、r入手,即通过收获藻类达到控制藻类总量和营养输出的双重功效;提高水位增加非光合层厚度,有效地降低水柱中藻类生产力;建立有水生植被的水质保护区也是一种局部藻类控制方法。  相似文献   

14.
The internal source, especially resuspension process of the sediments in lakes and its environ- mental effect has been paid shining attention in the West as well as in China[1—6] although the influence of external source is important to water environment[7]. S鴑dergaard et al. compared the releases of soluble reactive phosphorus (SRP) in the surface sediments of Lake Arres before and after disturbance and they found that disturbing can increase the release by 20—30 times[3]. Robarts and ot…  相似文献   

15.
《国际泥沙研究》2020,35(2):146-156
Many of the dams built in estuaries in the last century have difficulty with water quality management.Numerous factors have affected the estuary lake water,most importantly external loadings,tidal currents,and increases in the phosphorus(P) release from sediment,so that most water quality characteristics in the estuary are highly interactive and dynamic.In the current study,water quality measurements were made in the laboratory and field,and a series of phosphorus release experiments was done to understand the behavior of P in an estuary lake.The concentrations of chemical oxygen demand(COD),chlorophyll-a(Chl-a),and total P(TP) showed an increasing trend when the pollutant loading of the influent stream water was high.The measurements showed increasing trends,which indicates the constituents are produced in the internal environment of the lake.When a large amount of freshwater flowed in from the upper watershed,density stratification was observed,which forms strongly because of the salinity of seawater.During the period of stratification,a hypoxic layer formed,which can accelerate P release.Comparing the open and dosed conditions of the release experiments,the P release rate was much higher under the closed condition than under the open condition.The maximum P release rates from the sediment collected from the five main sites of the lake were more than 2.5 times the P loading from the inflowing streams in April.Spatially,the release rate was higher mid-reservoir than down-reservoir where a halocline was evident The pollutant load discharged from the tributary watershed was deposited on the bottom mid-reservoir,whereas it was washed out downreservoir because of the density stratification and strong tide in that area.To sustainably manage water quality and decrease lake eutrophication in brackish environments formed by freshwater from streams mixing with seawater entering through sluice dikes,different measures than those applied in strictly freshwater environments are required.Considering the spatial characteristics of an estuary lake,these measures include 1) blocking settleable particles discharged from the rivers upstream,2) controlling hypoxia to avoid P release from the sediment and inhibiting algae growth mid-reservoir,and 3)decreasing stratification caused by the halocline down-reservoir.  相似文献   

16.
Because of the obvious importance of P as a nutrient that often accelerates growth of phytoplankton (including toxic cyanobacteria) and therefore worsens water quality, much interest has been devoted to P exchange across the sediment-water interface. Generally, the release mode of P from the sediment differed greatly between shallow and deep lakes, and much of the effort has been focused on iron and oxygen, and also on the relevant environmental factors, for example, turbulence and decomposition, but a large part of the P variation in shallow lakes remains unexplained. This paper reviews experimental and field studies on the mechanisms of P release from the sediment in the shallow temperate (in Europe) and subtropical (in the middle and lower reaches of the Yangtze River in China) lakes, and it is suggested that pH rather than DO might be more important in driving the seasonal dynamics of internal P loading in these shallow lakes, i.e., intense photosynthesis of phytoplankton increases pH of the lake water and thus may increase pH of the surface sediment, leading to enhanced release of P (especially iron-bound P) from the sediment. Based on the selective pump of P (but not N) from the sediment by algal blooms, it is concluded that photosynthesis which is closely related to eutrophication level is the driving force for the seasonal variation of internal P loading in shallow lakes. This is a new finding. Additionally, the selective pump of P from the sediment by algal blooms not only explains satisfactorily why both TP and PO4-P in the hypereutrophic Lake Donghu declined significantly since the mid-1980s when heavy cyanobacterial blooms were eliminated by the nontraditional biomanipulation (massive stocking of the filter-feeding silver and bighead carps), but also explains why TP in European lakes decreased remarkably in the spring clear-water phase with less phytoplankton during the seasonal succession of aquatic communities or when phytoplankton biomass was decreased by traditional biomanipulation. Compared with deep lakes, wax and wane of phytoplankton due to alternations in the ecosystem structure is also able to exert significant influences on the P exchange at the sediment-water interface in shallow lakes. In other words, biological activities are also able to drive P release from sediments, and such a static P release process is especially more prominent in eutrophic shallow lakes with dense phytoplankton.  相似文献   

17.
Because of the obvious importance of P as a nutrient that often accelerates growth of phytoplankton (including toxic cyanobacteria) and therefore worsens water quality, much interest has been devoted to P exchange across the sediment-water interface. Generally, the release mode of P from the sediment differed greatly between shallow and deep lakes, and much of the effort has been focused on iron and oxygen, and also on the relevant environmental factors, for example, turbulence and decomposition, but a large part of the P variation in shallow lakes remains unexplained. This paper reviews experimental and field studies on the mechanisms of P release from the sediment in the shallow temperate (in Europe) and subtropical (in the middle and lower reaches of the Yangtze River in China) lakes, and it is suggested that pH rather than DO might be more important in driving the seasonal dynamics of internal P loading in these shallow lakes, i.e., intense photosynthesis of phytoplankton increases pH of the lake water and thus may increase pH of the surface sediment, leading to enhanced release of P (especially iron-bound P) from the sediment. Based on the selective pump of P (but not N) from the sediment by algal blooms, it is concluded that photosynthesis which is closely related to eutrophication level is the driving force for the seasonal variation of internal P loading in shallow lakes. This is a new finding. Additionally, the selective pump of P from the sediment by algal blooms not only explains satisfactorily why both TP and PO4-P in the hypereutrophic Lake Donghu declined significantly since the mid-1980s when heavy cyanobacterial blooms were eliminated by the nontraditional biomanipulation (massive stocking of the filter-feeding silver and bighead carps), but also explains why TP in European lakes decreased remarkably in the spring clear-water phase with less phytoplankton during the seasonal succession of aquatic communities or when phytoplankton biomass was decreased by traditional biomanipulation. Compared with deep lakes, wax and wane of phytoplankton due to alternations in the ecosystem structure is also able to exert significant influences on the P exchange at the sediment-water interface in shallow lakes. In other words, biological activities are also able to drive P release from sediments, and such a static P release process is especially more prominent in eutrophic shallow lakes with dense phytoplankton.  相似文献   

18.
Phosphorus (P) loading, exports and concentrations of the four lakes of the Yahara chain (Wisconsin, USA) were compared under four load-reduction plans using a model calibrated with 29–33 years of annual data. P mitigation goals must balance reductions in P concentrations in the four lakes and the export from the lake chain to downstream waters. Lake Mendota, the uppermost lake, is most responsive to P load reductions, and benefits diminish downstream. Nonetheless, the greatest reductions in export from the lake chain to downstream waters derive from P load reductions to lakes lower in the chain. The effective grazer Daphnia pulicaria causes large improvements in water quality. Management to maintain populations of D. pulicaria has substantial benefits that augment those from reductions in P loading. Model projections show high variability in water quality and exports under all load-reduction plans. This variability is driven by inter-annual variation in runoff. Thus lake managers and the public should expect ongoing year-to-year variability in water quality, even though P load mitigation will improve water quality on average. Because of high variability from year to year, ongoing monitoring is essential to assess the effects of management of this chain of lakes.  相似文献   

19.
长江中下游浅水湖泊富营养化发生机制与控制途径初探   总被引:191,自引:22,他引:169  
秦伯强 《湖泊科学》2002,14(3):193-202
长江中下游地区是我国淡水湖泊比较集中的地区。该地区绝大多数湖泊为浅水湖泊,所有的城郊湖泊都已经富营养化,其他湖泊的营养状况均为中营养-富营养,处于富营养化的发展中,这些湖泊富营养化的原因同流域上的人类活动有很大的关系。一方面,工业,农业和城市生活污水正源源不断地向湖泊中排放。另一方面,人类通过湖泊围垦、湖岸忖砌,水产养殖等破坏自然生态环境,减少营养盐输出途径。国际上对于浅水湖泊富营养化治理的经验表明,即使流域上的外源污染排放降到历史最低点,湖泊富营养化问题依然突出,其原因与浅水湖泊底泥所造成的内源污染有关。动力作用导致底泥悬浮,,影响底泥中营养盐的释放,也影响水下光照和初级生产力。控制浅水湖泊富营养化,除了进行外源性营养盐控制之外,还必须进行湖内内源营养盐的治理。治理内源营养盐的有效途径是恢复水生植被,控制底泥动力悬浮与营养盐释放。而要进行水生植被恢复,必须进行湖泊生态系统退化机制及生态修复的实验研究。  相似文献   

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