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1.
This paper is a review of research works concerning the nutrient transportation, transformation and exchange between water, sediment and biota in the lakes from the middle and lower reaches of the Yangtze River conducted in the context of project entitled "The Processes and Mechanism of Lake Eutrophication in Middle and Lower Reaches of Yangtze River". All the lakes from this area are shallow lakes. According to the typical lake site research, the lakes from the middle and lower reaches of Yangtze River have a higher baseline of nutrition in the history. Normally the trophic status of these lakes can be categorized into medium-trophic or eutrophic. Human activities have been enhanced during the last decades, which speed up the lake eutrophic process. Lake eutrophication control needs to reduce not only the external nutrient inputs from watershed but also the internal loading from the sediments. Investigations revealed that the lake sediments in this area are considerablly high in nutrition in which at most about 30% of phosphorus exists in the form of bio-available in the sediment. The surface sediment will exert great effects on the nutrient exchange between water-sediment interface via adsorption and release of nutrient. The nutrient release from the sediment in these shallow lakes is mainly in two ways, i.e. in the undisturbed condition the nutrient is released through diffusion created by the nutrient gradient from sediment to overlying water; whereas in disturbed condition, the nutrient release is determined by the hydrodynamic forcing intensity and the sediment resuspension. Metallic elements such as the iron, manganese and aluminium and the aerobic-anaerobic ambience will affect the release of nutrients. The disturbed release will increase the total nutrients in the water column significantly in the short period. At the beginning of sediment resuspension, the dissolved nutrient concentration will increase. This increase will be damped if the ferric oxide and aluminium are rich in sediment because of the adsorption and flocculation. This means that the lakes have capability of eliminating the nutrient loadings. Investigations for the lakes from middle and down stream of Yangtze River have suggested that most lakes have the self-cleaning capability. Dredging the control of the internal loading, therefore, is only applicable to the small lakes or undisturbed bays which normally are situated nearby the city or town and rich in organic materials in the sediment. In addition, the strong reduction condition and weak aeration of these lakes and bays make these small lakes and bays release much more bio-available nutrient and without much self-eliminating capability. Moreover, eutrophication induced algal bloom in these lakes will change the pH of water, which further induces the increase in the nutrient release. In turn, the increase in nutrient release promotes the growth of phytoplankton and results in severe algal bloom. For the heavily polluted water, research suggests that the biomass of bacteria and alkaline phosphatase activity will be higher corresponding to the higher concentration of nutrients, which accelerates the nutrient recycling between water, sediment and biota. Quick recycling of nutrient, in turn, promotes the production and biomass growth of microorganism and leads to more severe eutrophication. Further research work should focus on the nutrient transformation mechanism and the effects of microbial loop on the eutrophication. 相似文献
2.
The lake sediments, especially in recent years, genuinely record human being''s activities upon the lake environment. The top 30cm sections are of significance in the process of advanced cultural eutrophication and water quality deterioration. Based on the data of 4 core sam-ples obtained in June 19-22, 1997, with VCS in northern, western and southern Taihu Lake, some preliminary results are reported. Further analyses on the physico-chemical items as well as element content may reveal more information of the accelerating cultural eutrophication. 相似文献
3.
Ash Kumar Rai 《湖泊科学》1998,10(S1):181-201
Harnessing the natural resources is one of the basis of natural economy in developing countries. The wise use of such resources is very important to sustain the balance between immediate benefits and maintenance of the ecosystem. In Phewa, Begnas and Rupa lakes of Pokhara Valley, plankton feeding fish farming in net cage,enclosure and open water stocking is one of the effective example of natural resources utilisation which sustains a number of households in surrounding lakes for economic activities. These lakes are also used for drinking water, hydroelectricity, irrigation and recreation etc. However, the understanding of trophic status of the lakes is very important for long term sustainable use of the lakes in harmony with human activities. Here, we present the trophic status of three lakes of Pokhara Valley and discuss the impacts of human and natural activities on the trophic status of the lake. The study shows that heavy rain fall in the valley during monsoon is one of the strongest natural forces which flush out the accumulated nutrients from the lakes and migrate the eutrophication processes. Recommendations for sustainable use of lake water have also been discussed. 相似文献
4.
Lake Taihu, the third largest fresh water lake in China, with a surface area of 2 338 km2, is located in the Changjiang River Delta, the most advanced economic zone in China. During the last two decades, the rapid economic development of local agriculture and industry both in the urban and rural areas of the region has made great advances. Great quantieis of pollutants have been discharged into the lake, its nutrient content has increased continuously, and phytoplankton blooms have occurred in some areas. Water quality protection in Lake Taihu is very important because of its close relation with economical development and people''s daily life. It is urgent to have comprehensive pollution control in Lake Taihu. Based on water quality monitoring data in Lake Taihu from 1987 to 1994, the dynamic variations of water quality and eutrophication trends have been analyzed, showing obvious spatial and temporal variations. The main water quality factors were compared with the standard for drinking water and indicate considerable change with the seasons. Some basic strategies to protect water quality and prevent eutrophication are discussed. 相似文献
5.
The eutrophication of Lake Taihu is becoming more serious day by day and more urgent to be comprehensively harnessed. The lake sludge is considered as a important polluting factor. To control the internal pollution source of Lake Taihu and restore its water ecological environment, this paper put forward an idea of the dredging for environmental purposes. It was on the basis of the research on the sludge storage and physical/chemical characteristics. The technical keys are sludge-dredging depth, time, method and sludge treatment. The requirements and scheme for the environmental dredging work in Lake Taihu were also analyzed in detail. 相似文献
6.
Taihu Lake is the third largest fresh water lake in China, locating in Yangtze Delta as the richest area of China. At present, eutrophication problem is severe in Taihu Lake. This paper, in view of ecological system, presents analysis of the composition structural characteristics of Taihu Lake environment regarded as a whole ecological system, energy and substances circulation between ecological factors. The Taihu Lake ecological environment is proceeding a lake evolution period, i.e. middle-eutrophic to eutrophic. Therefore the diversion water''from Yangtze River to Taihu Lake through the Wangyu River acts to change external agent function for Taihu ecological system, i.e. increasing water quantity of Taihu Lake may rise water level and speed up flow exchanging. Moreover, with harnessing measures for pollution sources to reduce input of nutrients, natural evolution procedure of Taihu ecological environment may slow down to subsequently improve Taihu ecological environment. 相似文献
7.
Contributions of phosphatase and microbial activity to internal phosphorus loading and their relation to lake eutrophication 总被引：3，自引：2，他引：3
Phosphatase may accelerate the process of lake eutrophication through improving phosphorus bioavailability. This mechanism was studied in three Chinese eutrophic shallow lakes (Lake Taihu, Lake Longyang and Lake Lianhua). Phosphatase activity was related to the concentration of soluble reactive phosphorus (SRP) and chlorophyll a. Stability of dissolved phosphatase in reverse micelles may be attributed to molecular size, conformation and active residues of the enzyme. At the site with Microcystis bloomed in Lake Taihu, dissolved phosphatase activity was higher and more stable in micelles, SRP concentrations were lower in interstitial water, the contents of different forms of phosphorus and the amounts of aerobic bacteria were lower while respiration efficiency was higher in sediments. Phosphobacteria, both inorganic and organic and other microorganisms were abundant in surface water but rare in sediments. Therefore, internal phosphorus may substantially flux into water column by enzymatic hydrolysis and anaerobic release, together with mobility of bacteria, thereby initiating the bloom. In short, biological mechanism may act in concert with physical and chemical factors to drive the internal phosphorus release and accelerate lake eutrophication. 相似文献
8.
Macrophytes play important roles in maintaining ecosystem health and stability of shallow lakes. Better understanding of their long-term dynamics has important theoretical and practical significance for both lake ecosystem restoration and eutrophication control. However, the knowledge about the historical status and changing patterns of macrophytes in China's shallow lakes is still controversial and lacks systematic research. Here, we reviewed and synthesized the published records of submerged macrophytes from 14 typical shallow lakes in the eastern plain covering the past 100 years. The results suggest that submerged macrophytes have experienced three clear stages of change: rare period(the 1900 s–the 1950 s), growth period(the1950 s–the 1980 s), and recession period(the 1980 s–now). This finding is different from the traditional understanding that submerged macrophytes were abundant in the early 20 th century and have been degrading since then. On this basis, we proposed the possible evolution pattern(less-more-less) of submerged macrophytes in the eastern plain lake region over the past 100 years,which provides new perspectives about the long-term evolution process of macrophytes in shallow lakes. Furthermore, we found that the decline of submerged macrophytes during the regime shift shows a gradual process at the interdecadal scale; this finding contradicts the classical regime shift theory that macrophytes decline sharply during the critical transition. This study has important theoretical value for the restoration of the eastern plain lakes in China from "turbid lake" to "clear lake", especially for establishing the historical reference condition and restoration path of macrophytes. 相似文献
9.
The long term systematic investigations of ion composition components (bicarbonates, chlorides, sulphates, magnesium, calcium, sodium, potassium) and trophic status components (suspension, chlorophyll-a, mineral and organic forms phosphorus and nitrogen, carbon, silica) of water from the lake proper, its tributaries and atmospheric precipitation, which make up the main share of substance supply in to the lake, as well as the Angara river, being the source of substance discharge allowed the lake recent state to be evaluated in terms of both chemical pollution and possible eutrophication of its water. The similar (in terms of river runojf) periods of 50-ies and 80-ies have been compared. It was revealed that as a result of industrial activity 409 thousand tons of mineral substances (27.2 thousand tons of chlorides, 162 thousand tons of sulphates and over 200 thousand tons of organic substances) are supplied in the lake annually. The supply of substances of the anthropogenic origin is higher for the South Baikal than that for the North and Middle Baikal (the sum of mineral substances in 3.6 times; sulphates in 5 times, organic substances, including hydrocarbons in 7 times).The absence of abundant phytoplankton in the period studied when the ratio of silica to phosphorus is optimum (over 100), as well as a revers correlation between winter nitrogen content and spring of chlorophyll-a concentration in the Baikal water and revers dependence between the suspension and chlorophyll-a along the Selenga river valley lead to the conclusion that Baikal water contains toxicants. It is verified by the presence of polychlorbiphenyls (PCB), poly-chlordibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) for the whole food web with the maximum PCDD/PCDF (TEQ to 175 P g · g-1) concentration in the seal blubber. The levels are comparable with those reported for ringed seal (phoca hispida), living in the Baltic sea and Bar-row Strait Inlet in the Canadian Arctic. 相似文献
10.
太湖富营养化问题及其综合控制对策 总被引：1，自引：1，他引：0
On the basis of nine-time current situation investigation for eutrophication of Taihu Lake during 1991-1995, this paper evaluated the trophic levels in the different periods and analyzed the development of the main nutrient content in the nearest 35 years. The results show that the trophic level of Taihu Lake is in the transition state from meso-eutrophic to eutrophic. The eutrophhic and hypereutrophic waters account for 10% or so. The limiting nutrient, P, rises most rapidly, which causes the ratio of N:P to decrease. The increase of P content is still one of the main factors giving rise to the eutrophication of Taihu. LakeSome proposals of comprehensive countermeasure for the eutrophication are put forward. They include the pollution source control of the basin, the littoral multiple management, optimal dispatch of water conservancy facilities, the engineering of helping Taihu Lake with diversion of the Changjiang River, and as well as the setting of the water quality protection and legal system. 相似文献
11.
太湖富营养化现状及原因分析 总被引：110，自引：24，他引：86
根据2005-2006年太湖湖泊生态系统研究站的监测结果,结合历史监测记录,评价了近5年来太湖富营养化的趋势.结果显示,从2000年以来,太湖的富营养化状况有加重趋势.主要表现在:1)与历史监测资料对比,近5年来无论梅梁湾还是湖心区,夏季水体TN、TP含量均呈增高趋势,如1992-2001年,太湖湖心区夏季(6-8月份)水体TN的平均值为1.706 mg/L (范围1.238-2.266mg/L),而2002-2006这5年间该平均值为2.344mg/L(范围1.924-2.717mg/L),明显高于前10年(p=0.005),另外,同期湖心区夏季的水体透明度则明显下降(1992—2001年夏季平均值为0.63 m,而2002-2006年则为0.34 m,p=0.003); 2)从野外调查看,太湖夏季水华暴发的范围越来越大,从2000年以前的梅梁湾、竺山湾及部分湖西区为主,发展到2006年的整个西太湖,夏季暴发水华的面积占太湖总面积的一半以上,且一年中出现水华的时间越来越长,水华出现的频率越来越高,微囊藻水华为特征的藻型生态系统在大太湖似乎越来越稳定;3)近年来太湖沉水植物分布区的面积有所下降.研究表明,太湖近年来富营养化的现状不容乐观,原因可能与近几年异常的气候和水文条件有关,也可能与水草区的不断破坏而减弱了微囊藻水华的生态竞争有关,应引起有关部门重视. 相似文献
12.
官厅水库水体营养状况分析 总被引：19，自引：4，他引：19
2001-2002年的调研结果显示,官厅水库为富营养型湖泊.初级生产力为浮游藻类与大型水生高等植物混合型.浮游藻类细胞密度为1126.54×104cells/L,其中蓝藻占53.4%,绿藻占32.1%.优势种为水华微囊藻(Microcystisflos-aquae)和铜绿微囊藻(M.aeruginosa).7-10月库区水体出现大面积的微囊藻水华.TN、TP分别为1.182mg/L和0.045mg/L,水体已达富营养.官厅水库TN和TP的质量浓度比大于7,Chla与TP存在显著的正相关.磷是水体中初级生产力增长的限制性营养盐.官厅水库的污染物主要来自点源,其次是面源和内源.应以点源为主进行综合防治,恢复其饮用水源地功能,以缓解北京市淡水资源的紧缺状态. 相似文献
13.
环境因子对乌梁素海水体营养状态的影响:基于2013-2018年监测数据的分析 总被引：1，自引：0，他引：1
为探明寒旱区浅水型湖泊乌梁素海水环境因子对水体营养状态的影响程度，以2013—2018年1月和7月湖泊水环境监测数据为基础，对具有典型代表性监测点的水体营养状态与水环境因子（盐度、pH值和水深）之间建立向量自回归模型（VAR）模型，通过方差分解方法分析水环境因子对水体营养状态的贡献水平，同时界定出水体营养状态处于最佳水平条件下的水环境因子的适宜范围.结果表明：水环境因子对水体营养状态的方差贡献初期表现显著而后趋于稳定，且盐度、pH值和水深指标的综合方差贡献率最高可达66.62%；并以全湖94.4%的水体面积不呈现富营养化状态作为标准界定出乌梁素海水体处于最佳营养状态水平条件下盐度、pH值和水深指标的适宜范围，分别为0.06~2.68 g/L、7.50~8.63和1.76~3.50 m，且湖泊在此营养水平条件下全湖盐度、pH值和水深指标的均值分别为1.55 g/L、8.15和2.33 m.因此，可以通过人类活动调控湖泊水环境因子值，并实施以水养湖的策略来推动湖泊水体营养状态向良性发展. 相似文献
14.
从西太湖梅梁湾分离出野生水华微囊藻,得到水华微囊藻在半固体培养基上的纯藻株。研究太湖水华微囊藻在室内不同氮,磷浓度下的生长特征,发现在氮浓度在１７ｍｇ．Ｌ＾－１,磷逍度为１．７ｍｇ．Ｌ＾－１左右进,微囊藻日增长率最大。比较自然状态和室内培养条件下微囊藻的生长情况,可知野生微囊藻一般能形成较大的群体,室内液体培养基的营养盐浓度远高于野外,却难以得到大群体微微藻,从此实验结果来看,营养盐浓度与微囊藻在 相似文献
15.
2006-2017年乌梁素海夏季水体营养状态及影响因子 总被引：1，自引：0，他引：1
为探明草型湖泊乌梁素海水体营养状态及演变趋势，明确水体富营养化的关键影响因子，本文采用2006-2017年每年7月份湖泊水质监测数据，利用综合营养指数法评价了湖泊不同区域监测点的水体营养状态，模拟分析了湖泊水体营养状态的演变过程及趋势特征，定性分析了湖泊富营养的关键影响因子.研究结果表明：乌梁素海湖区北部、西部和南部监测点处于轻度富营养状态的极限概率分别为0.588、0.633和0.329，而湖泊的中部和东部监测点处于中营养状态的极限概率分别为0.810和0.536，说明乌梁素海湖区北部、西部和南部区域夏季水体营养状态将呈现向轻度富营养化演变的趋势，而湖区中部和东部区域则呈现向中营养化演变的趋势.水环境因子中水体理化指标对湖泊富营养化起决定性作用，且盐度指标响应概率高达55%，是水体理化指标中第1位影响因子，同时pH值与水深指标也是影响乌梁素海水体富营养化程度的重要因子. 相似文献
16.
三峡水库神农溪2008年夏季铜绿微囊藻(Microcystis aeruginosa)水华暴发特性 总被引：2，自引：0，他引：2
对三峡水库一级支流神农溪2008年夏季蓝藻水华进行调查,结果表明神农溪蓝藻水华优势种是铜绿微囊藻(Microcystis aeruginosa),暴发水域面积约0.2 km2,持续时间约50 d.本次水华暴发与水体总磷浓度呈正相关,温度、降雨、光照和营养盐等对水华暴发具有重要影响.研究发现尽管神龙溪水域总体处于中-富营养状态,但局部水域由于水流缓慢、水体滞留时间长、营养稀释扩散速率小,在夏季出现富营养化状态,这是蓝藻水华暴发的根本原因.建议开展包括流域综合治理在内的环境整治,确保神农溪水体生态环境的稳定. 相似文献
17.
“十三五”时期，长江流域水环境质量改善明显，但湖泊水质和富营养化状况改善滞后. 长江中游作为我国淡水湖泊集中分布区域之一，部分湖泊存在水环境质量恶化和富营养化加重问题. 本文以长江中游区域国家开展监测的洪湖、斧头湖、梁子湖、大通湖、洞庭湖和鄱阳湖这6个典型湖泊为研究对象，科学评价其2016—2020年水质和富营养化时空变化特征及关键驱动因素，探讨其成因及治理对策. 结果表明，“十三五”时期长江中游湖泊水质和富营养化程度存在较大差异，与2016年相比，2020年大通湖水质改善最为明显，梁子湖水质变差，总磷是影响长江中游湖泊水质类别的主要因子; 洪湖富营养程度恶化最为严重，斧头湖次之，TLI(SD)对长江中游湖泊富营养化评价贡献最大. 目前长江中游湖泊呈有机污染加重和叶绿素a浓度升高现象，洪湖、斧头湖和梁子湖主要与氮、磷营养盐浓度升高有关，而大通湖、洞庭湖和鄱阳湖受水文过程、流域纳污量和湖泊管理等非营养盐因素影响较大. 总氮和总磷仍然是影响“十三五”时期长江中游湖泊水质和富营养化的最主要驱动力，且各湖泊总氮和总磷浓度变化均具有较强正相关性，建议开展河湖氮、磷标准衔接工作，提出河湖氮、磷标准限值或考核目标，以完善河湖水环境质量标准和生态健康影响评价技术规范. 同时，建议长江中游湖泊在开展截污控源、内源控制和生态修复的同时，进一步深化流域管理，特别是对洞庭湖、鄱阳湖、梁子湖和斧头湖等跨行政区湖泊，以提高湖泊治理与修复的系统性和整体性. 相似文献
18.
19.
湖北长湖富营养化状况及时空变化(2012-2013年) 总被引：4，自引：1，他引：3
为评估长湖水体富营养化程度,2012-2013年分4个季度对全湖区20个采样点的物理、化学和生物要素进行监测,在评价水质现状的基础上采用综合营养状况指数法和浮游植物细胞丰度指数法综合评价水体营养状况,并应用典型相关分析(CCA)方法揭示水体富营养化状况与湖泊理化要素之间的典型相关性.结果显示:4个季节长湖全湖区的水质均处于地表水IV类~劣V类水标准;综合营养状态指数值在49.54~82.55之间,浮游植物细胞丰度在2.88×106~61.73×106cells/L之间,均显示其处于富营养化状态;长湖富营养化状况的分布呈现一定的时空差异性;CCA分析显示,长湖理化要素变量可解释68.6%的水体富营养化状况变量的变异,影响其富营养化状况的主要理化因素有水体总磷、总氮、溶解氧、亚硝态氮、硝态氮浓度,水深和沉积物总磷、总氮含量.长湖水体富营养化主要是由于外源的磷污染,其次是氮污染,富营养化最严重的夏、秋季浮游植物的生长主要受氮营养限制,而冬、春季则部分受磷营养限制,部分属于过渡类型.因此,建议大力削减围网/围栏养殖量,同时考虑结合水生植物栽种等生态工程建设措施以降低长湖水体发生严重富营养化的风险,并进一步改善长湖的水质现状. 相似文献