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1.
A series of experiments and simulations were performed to ascertain the rate at which phosphorus is released using a water quality model in Saemangeum Lake, an artificially constructed lake located in an estuary. The general inflow of seawater once a day contributed to the formation of a halocline in the lake water, which caused variation in the vertical concentration of dissolved oxygen. The halocline was mainly observed in the deep downstream regions of Saemangeum Lake that are close to the op...  相似文献   

2.
三峡澎溪河回水区流速对藻类原位生长速率的影响   总被引：1，自引：1，他引：0  
为明晰不同流速水平对三峡支流回水区库湾藻类原位生长的影响,本文采用可调速的环形实验槽,选择三峡水库不同运行状态(低水位、高水位),对三峡澎溪河高阳平湖库湾藻类生物量(用叶绿素a浓度表示)变化特征进行原位受控实验.通过流速在0(对照)、0.1、0.2和0.3 m/s的实验发现,夏季低水位阶段澎溪河水域光热充足,但流速升高(0.2m/s)对藻类原位比生长速率具有一定影响.大体上,高阳平湖水域藻类原位比生长速率与流速水平呈对数关系.冬季高水位运行期间,流速的升高将可能在一定程度上促进水柱扰动,成为维持藻类在上层水体受光生长、避免下沉的主要因素.该时期,采用调节流速、流量的方法抑制藻类生长的难度相对较大.  相似文献   

3.
赵斌 《湖泊科学》1996,8(2):125-132
１９９２年１１月￣１９９３年１０月，在安徽太平湖水库，同时用藻类生长潜力测试法（ＡＧＰ试验）和外源添加营养的黑白瓶测定初级生产力法，对陵山站的水体分季度进行了分析测试。其结果表明，这两种方法对太平湖水库的营养评价均是行之有效的，而且二者的结果也能相互比较、相互验证；太平湖水库的不同季节，其主要营养限制性因子也各异。在枯水期，磷是藻类种群和密度的第一限制性营养元素；丰水期，由于各营养元素都相对缺乏，  相似文献   

4.
《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   

5.
附着藻类对太湖沉积物磷释放的影响   总被引：5，自引：0，他引：5  
张强  刘正文 《湖泊科学》2010,22(6):930-934
附着藻类是清水态浅水湖泊的重要组成部分,为了解附着藻类对湖泊沉积物磷释放的影响,在室内柱状装置中,将尼龙网所培养的附着藻类加盖到太湖沉积物上,即处理组,并设置无附着藻类加盖的对照组,进行为期13d的实验.结果表明:加附着藻类的处理组中的无机磷释放速率显著低于无附着藻类的对照组.与对照组相比,实验期间加附着藻类的处理组释放到水体中的磷,平均减少1.16mg.其中附着藻类吸收了0.81mg磷(70%),而附着藻类通过光合作用改变沉积物表面的氧环境抑制了0.35mg磷的释放(30%).研究表明,底栖附着藻类可以通过吸收磷和抑制沉积物磷释放降低水中营养盐含量.  相似文献   

6.
江西柘林水库是长江中游的大型峡谷型旅游性水库,库容79.2×10~8m~3,长115 km.2015年4月在56 km的中心库区走航和定点测量了水库表层水体浮游藻类、叶绿素a(Chl.a)浓度与溶解无机氮(DIN)浓度、溶解无机磷(DIP)浓度、溶解硅(DSi)浓度、水温、浊度和溶解氧浓度等环境因子的分布特征.结果表明:1)水库属于中营养水体,表层主要浮游藻类(细胞丰度1000 cells/L)有34种,平均生物量为0.41 mg/L.主要优势藻类(优势度≥0.02)为硅藻和蓝藻,藻类组成与DIN浓度、DIP浓度、DSi浓度和水温等环境因子关系密切,4种因子对藻类结构的解释水平达60%以上.2)水库水体Chl.a浓度具有显著的次表层叶绿素最大值(SCM)现象,SCM层深度为3~8 m,厚度为2~7 m,SCM层占整个水体的25.2%~74.1%.SCM层的藻类对营养盐吸收消耗致使DIN、DIP和DSi浓度下降,同时藻类的产氧使溶解氧浓度增加.3)水库对DSi具有显著的生物过滤器效应,中、上层约有11%~12%的DSi被生物吸收利用,从上游至下游,累积约有21%的DSi被藻类吸收沉降于库底.4)人类氮、磷排放对水库生态和水质有严重影响,毗邻县城区域水体的Chl.a和DIP浓度分别是自然河段的2.9倍和3倍左右.  相似文献   

7.
The investigation and continuous monitoring with an innovative iron oxide embedded cellulose acetate membrane (FeO/CAM) on the concentrations of biologically available phosphorus (BAP) were conducted in the Meiliang Bay of the Taihu Lake during summer in 2004. The results showed that the concentrations of dissolved (FeO-DP), particulate (FeO-PP) and total bioavailable phosphorus (FeO-P) had similar horizontal distribution. The BAP concentrations were the highest in those estuaries in the northern bay. With the decrease of the distance to the estuary or long shore, there was little difference between BAP concentrations in an open lake area. During the observation period, algal blooms occurred in most waters of the northern bay, which was reflected from the high concentrations of chlorophyll a (Chl-a). While they were not highest in the estuarine waters of those major rivers, this is the case for the BAP concentrations. The concentrations of Chl-a had a significantly positive correlation with those of bioavailable phosphorus in the open area of the Meiliang Bay. With the sediment resuspension induced by wind and wave, BAP concentrations increased in a short-term, indicating that the riverine P inputs mainly contribute to the concentrations of BAP in the estuarine water while internal P release was the major source of BAP in the open lake area. In the eutrophic shallow lake, the blooms of alga may cause pH increase and further result in internal P release. The above results showed that the new membrane of FeO/CAM can be used to monitor the concentrations of BAP and provide the scientific justifications for the control strategy of the lake eu-trophication.  相似文献   

8.
甲烷(CH4)对全球温室效应有着较大的贡献。三峡水库自2003年蓄水以来,其CH4排放问题已受到广泛关注。但三峡水库反季节的运行方式,使支流库湾CH4的产生和传输过程受到多方面的影响,进而导致其CH4排放效应尚不十分明确。本文综述了三峡水库支流CH4排放的研究进展,典型支流的CH4排放通量普遍高于干流,位于三峡水库库尾的部分支流CH4排放通量高于三峡水库库首及库中支流。大多数典型支流的CH4通量在夏季均达到全年峰值,而在冬季高水位运行期均处于相对较低的水平。同时本文主要从水环境条件、水动力条件、人类活动及气象条件4个方面阐述了三峡水库支流CH4排放的影响因素。1)水环境条件:支流水华后藻类衰亡分解过程会驱动CH4释放,且藻类的演替过程会加剧CH4的产生;温度可以直接影响CH4的生成速率和消耗速率,也能通过促进藻的生长间接影响CH4排放;支流相对较低的甲烷氧化菌丰度是其CH4通量较高的原因之一。2)水动力条件:蓄水期CH4主要以扩散的方式进行释放,支流较低的流速促进了悬浮物的沉积,上游沉积物中的CH4含量高于下游;泄水期CH4主要以冒泡的方式进行释放,下游沉积物中TOC急剧增加,但干流的入侵会削弱支流的温度分层,破坏藻类生长环境,间接影响CH4通量。3)人类活动:农业耕作使支流水体中的营养物浓度增加,甲烷氧化菌的丰富度降低,细菌群落的营养相关代谢增强;建设用地扩大、支流筑坝增加抑制了有机物的传输,增加了水体中的产CH4底物,促进了CH4的产生。4)气象条件:降雨会携带更多营养物质进入支流,同时会增加水体浊度、破坏水体的温度分层,从而对CH4的产生和传输过程造成影响。最后对未来的研究热点进行了展望,以期为三峡水库CH4排放的控制和管理提供参考。  相似文献   

9.
Spatiotemporal variations of P species and adsorption behavior in water column, interstitial water, and sediments were investigated in the large shallow eutrophic Lake Chaohu. Orthophosphate (Ortho-P) and total phosphorus (TP) concentrations were significantly higher in the western part than in the eastern part of the lake, due to different nutrient inputs from the surrounding rivers. Moreover, particulate phosphorus (PP) concentration was in a similar spatial pattern to Ortho-P and TP concentrations, and also showed significantly positive correlation with the biomass of Microcystis, indicating more uptake and store of phosphorus by Microcystis than by other algae. Increase of pH and intensive utilization of P by phytoplankton were the main factors promoting P (especially Fe-P) release from the sediment to interstitial water during the cyanobacterial blooms in Lake Chaohu. Spatial dynamics in TP concentration, P species and adsorption behavior of the sediment, coupled with the statistical analyses, suggested that the spatial heterogeneity of P contents in the sediment was influenced by various factors, e.g. human activities, soil geochemistry and mineral composition. In spite of similar TP contents in the sediments, increase in proportion of Fe-P concentration in the sediment may result in a high risk of P release.  相似文献   

10.
以自主研发的煅烧改性净水厂污泥（C-WTPS）作为污染底泥活性覆盖材料，室内静态模拟实验研究C-WTPS覆盖强度对控制底泥磷释放效果的影响，分析C-WTPS和底泥中不同形态磷含量变化，探讨C-WTPS薄层覆盖对上覆水体中pH、DO和ORP的影响.结果表明，实验历时40天，在底泥TP释放强度为6.25~10.87 mg/（m2·d）时，覆盖强度为0.25、0.50、1.00、1.50和2.00 kg/m2的C-WTPS对TP平均削减率分别为59.68%、75.71%、88.75%、92.42%和96.28%，可见覆盖强度为1.00 kg/m2以上的C-WTPS能控制底泥中90%以上TP释放.C-WTPS吸附的磷主要以无机磷（IP）中的铁铝结合态磷（NAIP）形式存在，有机磷（OP）和钙磷（AP）形式较少.C-WTPS促进了底泥中易释放形态磷迁移到C-WTPS中，并转化较为稳定的形态磷，可见C-WTP覆盖不仅控制了底泥磷释放，而且也削减了底泥磷释放风险.C-WTPS覆盖后，上覆水体中pH开始呈现下降趋势，最终维持在pH=7范围波动；C-WTPS覆盖强度越大，上覆水体pH下降也明显；C-WTPS覆盖改善上覆水体中DO和ORP环境的效果不明显.  相似文献   

11.
运河(杭州段)沉积物磷释放的模拟试验   总被引：18，自引：1，他引：18  
采用室内模拟的方法研究了扰动情况下运河（杭州段）表层沉积物磷的释放对上覆水的影响以及投加石灰、投加三气氛发化铁、连续曝气、换水清洗等措施对沉积物磷释放的控制效果，研究表明，在扰动、开放体系条件下，运河（杭州段）沉积物磷释放导致的上覆水总磷浓度在释放初期最高，随时间逐渐下降，表现出净吸附，采集于有机污染较重河段的沉积物磷释放能力显著高于总磷含量较高但以重金属污染为主的河段的沉积物，上覆水投加石灰最终导致沉积物磷释放量的增加，投加三氯化铁显著降低了上覆水总磷浓度，上覆水连续曝气降低了上覆水的平衡磷浓度、换水清洗对上覆水磷浓度的降低效果是有限的，然而上述措施均未能将上覆水总磷浓度控制在V类水的浓度限定值以下，因此，就上覆水TP的浓度指标而言，运河（杭州段）沉积物的内源释放对其影响很大。  相似文献   

12.
This study examined the phosphorus retention and release characteristics of sediments in the eutrophic Mai Po Marshes in Hong Kong. Results of chemical fractionation show that the sum of inorganic P pools exceeded 50% of the total sediment P content, with the redox-sensitive iron-bound P (Fe(OOH) approximately P) being the dominant P fraction. Given the considerable average Fe(OOH) approximately P concentration of 912 microg g(-1), Mai Po sediments demonstrated a great potential to release bioavailable P under low sediment redox potentials. This was further supported by the high mean anaerobic P flux of 31.8 mg m(-2)d(-1) recorded in Mai Po sediment cores, indicating the role of bottom sediments as a net P source. Although sediments in Mai Po had appreciable Langmuir adsorption maxima (1642-3582 mg kg(-1)), the high zero equilibrium P concentrations (0.02-0.51 mg L(-1)) obtained suggest that sediment sorption processes would contribute to sustaining the eutrophic conditions in overlying water column even with a further reduction in external P load. Concerted efforts should be made to reduce internal loading of P, especially under reducing conditions, to complement the implementation of zero discharge policy for Deep Bay for effective eutrophication abatement and long-term water quality improvement in the Mai Po Marshes.  相似文献   

13.
Macrophytes compete with planktonic algae directly for nutrients which are solved in the pelagic region and impede the planktonic algae development indirectly by increasing sedimentation in the macrophyte populations and by reducing the supply of littoral detritus into the deeper zones of the lake by whirling-up in the period of vegetation, This leads to a reduced release of nutrients from the sediment and to the promotion of the development of a coenosis in the littoral zone living on pelagic seston. Therefore, waters with an extensive macrophyte vegetation have a relatively good water quality. By the artificial removal of macrophytes the planktonic coenosis is changed as by a measure of eutrophication.  相似文献   

14.
菹草、伊乐藻对沉积物磷形态及其上覆水水质的影响   总被引：3，自引：1，他引：2  
采集武昌南湖湖水、沉积物进行沉水植物的盆栽试验,试验设置沉积物未施磷处理和施100mg/kg磷处理,分别对应沉积物低内源磷和高内源磷状态,同时种植菹草、伊乐藻,以研究沉积物中磷形态及上覆水水质的变化特点.研究从2007年9月15日开始,历时160d.结果表明,高内源磷沉积物处理后,上覆水中水溶性总磷含量在沉水植物的作用下明显降低;种植沉水植物可使水体总磷、总氮、叶绿素a含量显著降低,且伊乐藻对总磷的净化效果优于菹草;沉水植物对高内源磷沉积物的上覆水中叶绿素a的控制比对低内源磷条件下的效果更好;无论沉积物是否输入磷,在盆栽条件下,上覆水中叶绿素a随时间的变化均能较好地用一级动力学模型来描述;上覆水TDP、TP与沉积物中Ca_(10)-P之间有极显著正相关;种植菹草或伊乐藻的沉积物中Ca_(10)-P与上覆水中TDP和TP的相关系数分别为0.990(P≤0.01)和0.977(P≤0.05).  相似文献   

15.
The spatial and temporal variations of algae within a large drinking water reservoir with mesotrophy (Panjiakou Reservoir, Northern China) were investigated in relation to variations in environmental factors over a 6-month period (May to October) in 2013 and 2014. The analysis based on in-situ samples upstream to downstream (Puhekou, Jiajia’an, Yanziyu Panjiakou and Baqian) showed that three harmful algae species of Cyanophyta, Chlorophyta and Bacillariophyta prevail in the reservoir. The variations in algal concentrations presented a seasonal cycle with high values in the flood season and low values in the drought season and a spatial concentration in main water storage area of the reservoir. Compared with the environmental factors of pH value, permanganate index, ammonia nitrogen and total nitrogen, water temperature, dissolved oxygen content and total phosphorus were significant related to algae concentrations with correlation coefficients of 0.76, 0.62 and 0.85, respectively. The impact analysis of three factors on prevailing algae species indicated that Chlorophyta was the main contributor to the algal photosynthesis of the Panjiakou Reservoir. An extremely high value of algal concentrations with little variety in August 2013 revealed that pollution carried by tremendous runoff may induce algae blooms later.  相似文献   

16.
Laboratory incubation experiments were carried out on sediment cores collected from Esthwaite Water, U.K., during April 1987, when the sediments displayed a characteristic surface (1.5 to 2 cm) oxide floc. The experiments were undertaken at 10°C, in the dark, under variable redox and pH conditions for periods of ~ 720 h (30 d). In some cases, realistic amounts of decomposing lake algae were added to simulate the deposition of an algal bloom. Pore waters and overlying waters were obtained from the incubated sediment cores at various time intervals and the samples analysed for pH and dissolved Fe, Mn, Zn and Cu by AAS. The results demonstrated that trace metal concentrations at the sediment-water interface can show rapid, pulsed responses to episodic events associated with controlling factors such as algal deposition and mixing conditions. The variations in dissolved Fe and Mn concentrations could generally be explained by their well known redox behaviour. Appreciable loss of Mn from solution under conditions of well-developed anoxia was consistent with adsorption of Mn2+ by FeS. Cu and Zn were both rapidly (24 h) released into solution during incubation of sediment cores prior to the development of anoxia in the overlying waters. Their most likely sources were the reductive remobilization of Mn oxides and the decomposition of organic matter. The addition of decomposing algae to a series of cores resulted in even higher interfacial dissolved concentrations of Cu and Zn, probably through acting as a supplementary source of the metals and through increased oxide dissolution. Switching from anoxic to oxic conditions also rapidly increased dissolved Cu and Zn concentrations, possibly due to their release during the oxidation of metal sulphides. The enhanced releases of dissolved Cu and Zn were generally short-lived with removal being attributed to the formation of sulphides during anoxia and to adsorption by Fe and Mn oxides under oxic conditions.  相似文献   

17.
浅水湖泊生态系统中的沉积物—水界面是湖泊内源氮释放的重要界面,而水动力因素是改变沉积物氮释放的重要因素.三峡大坝修建以后,长江中下游通江湖泊的水动力条件发生了明显的变化.通过采集洞庭湖湖口区域的沉积物和水样,在双向环形水槽动力模拟装置内模拟湖泊水位和流速的变化,探讨湖泊沉积物氮在沉积物和水系统中的二次释放特征.结果表明,随着扰动强度的增加,上覆水悬浮物浓度增大,上覆水中总氮浓度增加,沉积物向上覆水释放氮的强度增强,水动力条件的改变所引起的沉积物内源氮释放不容忽视.在该模拟实验条件下,沉积物存在最适扰动水位(20cm),此水位下上覆水中悬浮物浓度最低,总氮浓度最小.水动力条件的改变对上覆水和沉积物—水界面处铵态氮和硝态氮浓度的影响并不明显,孔隙水中铵态氮与硝态氮之间发生形态的转化.  相似文献   

18.
富营养化对贵州红枫湖水库汞形态和分布特征的影响   总被引：6，自引：1，他引：5  
通过对贵州省红枫湖水库中各种汞形态的空间分布及季节变化的研究,探讨了富营养化对各种汞形态分布特征的影响.红枫湖湖水总汞浓度在2.5-13.9ng/L之间,平均值为6.9ng/L.红枫湖水库中汞浓度的空间分布和季节变化均严重受到人为汞污染源的干扰.水体中汞在颗粒态和溶解态之间的分配,主要受内源有机质以及氧化还原条件的影响.由于水华现象,春季后五采样点大量繁殖的藻类吸附了大量的汞,从而改变了汞在水库中的分配和迁移.藻类的生长对水体中溶解气态汞浓度分布也有显著的影响.在夏季,总甲基汞和溶解态甲基汞在水体中的垂直分布表明:在富营养化较严重的后五采样点,水体中升高的甲基汞主要是由于水体中汞的甲基化过程;而在富营养化特征不明显的大坝,水体中升高的甲基汞主要来自沉积物甲基汞的释放.红枫湖水体中各种汞形态的分布特征表明,富营养化对汞的迁移转化影响显著,尤其是汞的甲基化过程.水体富营养化为汞的甲基化提供了有利条件,给水生生态环境及人体健康带来了潜在的威胁.  相似文献   

19.
以福建泉州水源地山美水库和惠女水库的表层底泥和上覆水为研究对象,室内静态模拟试验研究了生物沸石薄层覆盖削减水源水库氮负荷的效果及可行性,探讨了上覆水体溶解氧(DO)浓度对削减氮负荷的影响,分析了削减氮负荷的作用机理.结果表明,覆盖强度为1 kg/m~2的生物沸石覆盖(厚度约1 mm)对上覆水中总氮的削减率为58.89%~65.75%,对底泥中总氮的削减率为10.39%~13.08%,对底泥中铵态氮的削减率为32.35%~44.56%,对底泥中有机氮的削减率为8.41%~11.04%;对于以硝态氮为主要形态氮的上覆水体,DO浓度越低,越有利于高效菌脱氮;可见,生物沸石薄层覆盖能有效削减水源水库氮负荷,利用生物沸石薄层覆盖技术削减水源水库氮负荷是可行的,但需要进一步研究水源水库底泥生物沸石薄层覆盖修复过程中氮的迁移转化机制.  相似文献   

20.
The Orbetello lagoon (Tyrrhenian coast, Italy) receives treated urban and land based fishfarms wastewater. The development of severe eutrophication imposed the three main activity adoption focuses on (1) macroalgae harvesting; (2) pumping of water from the sea; (3) confining wastewater to phytotreatment ponds. The responses to these interventions were rapid and macroalgal reduction growth and seagrass return were recorded. Since 1999, a new macroalgal development was recorded. The aim of this research was to discover whether the recent macroalgal growth can be attributed to the continuing wastewater influx from the remaining persistent anthropic sources (PAS) or from the sediment nutrient release. A monitoring programme was carried out between August 1999 and July 2000 in order to measure dissolved inorganic nitrogen and phosphorus in the wastewaters entering into the lagoon and in central lagoon areas, seaweed and seagrass distribution and lagoon N, P annual budgets. The results showed higher N and P values close to PAS. The distribution of the macroalgal species confirms that the available P comes almost entirely from these remaining PAS. In conclusion, the environmental measures adopted produced a significant reduction in algal biomass development in the lagoon; the macroalgal harvesting activities produced a sediment disturbance with following oxidize conditions, which make P unavailable in the lagoon water, excepting close the PAS.  相似文献   

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