In this paper,the artificial lake on the campus of Tibet University was taken as the research object.By detecting the water quality of the lake,the standard index method and comprehensive pollution index method were u...In this paper,the artificial lake on the campus of Tibet University was taken as the research object.By detecting the water quality of the lake,the standard index method and comprehensive pollution index method were used to understand the water quality characteristics,pollution status,and main pollutants of the Siyuan Lake.On this basis,the comprehensive nutritional status index method was used to evaluate the eutrophication status of the Siyuan Lake.The results showed that the overall water quality of the artificial lake was good,showing as still clean,with TN and TP being the main pollution factors of the artificial lake.The main nutritional indicators were TN,TP,and transparency,with a comprehensive nutritional level of middle eutropher.Based on the environmental characteristics of the artificial lake area on the campus of Tibet University,reasonable treatment measures have been proposed.It hoped to prevent and improve the water environment through these measures,and provide reference for the protection and restoration of campus landscape water body.展开更多
Lake eutrophication is recognised as a serious global challenge,and many regional legislative programmes are being made to attempt to relieve nutrient pollution and restore deteriorated lake ecological state.However,i...Lake eutrophication is recognised as a serious global challenge,and many regional legislative programmes are being made to attempt to relieve nutrient pollution and restore deteriorated lake ecological state.However,it is of primary importance to understand the degradation processes and reference conditions.The palaeolimnological approach allows us to use ecological evidences preserved in lake sediments to track the changes of lake trophic status under human impact.Diatoms,a proxy for ecological and limnological change,and pigments,a proxy for algal production and composition,were analysed on a short sediment sequence from Lake Dojran(Republic of North Macedonia and Greece),and their preservation qualities were evaluated before environmental interpretation.Good diatom preservation is inferred mainly from the consistent co-occurrence of robust,highly-silicified taxa and small taxa throughout the sequence.Pigment evaluation of the comparison between wet sediment samples in dark and cold storage and their corresponding dry sediment samples lyophilized immediately after the recovery reveals that sediment restoration conditions are critical for the accuracy of analysis.We show that the increased chlorophyll and xanthophyll pigment concentrations,particularly the siliceous-algae pigment fucoxanthin and diatoxanthin,together with the distinct increase in diatom concentration,indicate accelerated lake eutrophication and a major ecological shift linked to intensified water abstraction practice and agricultural expansion in the late 18th to early 19th century.Evidence of diatom assemblage composition is muted probably by the dominance of widely-tolerant small fragilaroid species in diatom composition and the better competitive ability of cyanobacteria and chlorophytes than diatoms for low light under eutrophic and turbid conditions.This study improves our understanding of recent human-induced environmental change and current ecological restoration target in this lake.展开更多
[ Objective] The study aimed at discussing the purification effect of constructed wetlands for treating river water flowing from phosphate mine areas into Fuxian Lake. [Method] The running parameters of the constructe...[ Objective] The study aimed at discussing the purification effect of constructed wetlands for treating river water flowing from phosphate mine areas into Fuxian Lake. [Method] The running parameters of the constructed wetlands were investigated for one year, and the purification effect of the constructed wetlands for treating the sewage from phosphate mine areas was analyzed. [Result] With the aid of the constructed wet- land, the average removal rates of total nitrogen (TN), total phosphorus (TP) and CODcr were 52%, 32% and 54%, and the removal effects were best when the designed hydraulic load was 0.67 m3/( m2 · d). Running stably for six years, the constructed wetlands had advantages of no power, low resistance and high removal rate. [ Conclusion] The constructed wetlands reduced the load of pollutants from phosphate mine areas into Fuxian Lake effectivelv, which Dlaved important roles in the Drotection of water aualitv of Fuxian Lake.展开更多
Taihu Lake, the largest freshwater shallow lake in eastern China, has suffered from severe eutrophication over the past two decades. This research developed a three-dimensional eutrophication model to investigate the ...Taihu Lake, the largest freshwater shallow lake in eastern China, has suffered from severe eutrophication over the past two decades. This research developed a three-dimensional eutrophication model to investigate the eutrophication dynamics. The model fully coupled the biological processes and hydrodynamics, and also took into account the effects of sediment release and the external loads from the tributaries. After sensitivity analyses, the key parameters were defined and then calibrated by the field observation data. The calibrated model was applied to study the seasonal primary productions and its regional differences. The comparisons between model results and field data in year 2000 indicated that the model is able to simulate the eutrophication dynamics in Taihu Lake with a reasonable accuracy. From the simulation experiments, it was found that the meteorological forcing have significant influences on the temporal variations of the eutrophication dynamics. The wind-induced circulation and sediment distribution play an important role in the spatial distribution of the algae blooms.展开更多
Chaohu Lake, located in the central Anhui Province, is one of the five largest fresh lakes in China. Now it is one of the three most eutrophication lakes in China. The deterioration of its water quality has influenced...Chaohu Lake, located in the central Anhui Province, is one of the five largest fresh lakes in China. Now it is one of the three most eutrophication lakes in China. The deterioration of its water quality has influenced the sustainable development of society, economy and environment of Hefei City, the capital of Anhui Province. A series of measures have been carried out to control its eutrophication, but it is still serious. On the basis of the lake water quality data from 1984 to 2003, the causes of the eutrophication of Chaohu Lake are analyzed. Studies indicated that the suitable natural conditions and human activities played a crucial role in the process of the eutrophication of Chaohu Lake. A great amount of industrial, agricultural and domestic sewage discharged into the lake is the main cause of eutrophication in the lake. Land use, soil erosion and shoreline collapse destroyed the watershed eco-environment and the terrestrial ecosystem of Chaohu Lake. And the building of Yuxi Gate extends the sluggish of the nutritious substance and speeds up the process of the eutrophication. From the view of systematic engineering and watershed ecology, a series of the countermeasures have been put forward to control the eutrophication.展开更多
Water quality evaluation entails both randomness and fuzziness. Considering that water eutrophication evaluation involves many indices, different classifications and interval values, fuzzy variable sets theory was dev...Water quality evaluation entails both randomness and fuzziness. Considering that water eutrophication evaluation involves many indices, different classifications and interval values, fuzzy variable sets theory was developed to Lake Baiyangdian as a study case. Taking reference to eutrophication standard of Chinese lakes and local characteristic of Lake Baiyangdian, eutrophication degree of lake was divided into 8 levels. Total phosphorus, total nitrogen, and CODMn were selected as evaluation indices in this research. Based on the measured data, index feature value matrix of sample was built. Index weights were determined by means of pure threshold value method. Relative membership degree of each index to each classification was calculated with relative difference function model. Then the stability of feature value of classification corresponding was received by the comprehensive calculation with the relative membership degree and index weights. The results show that the proposed models are effective tools for generating a set of realistic and flexible optimal solutions for complicated water quality evaluation issues. It concluded that the model was reasonable and practical.展开更多
To assess the contamination trends and potential bio-availability of sediment-bound heavy metals,concentrations of heavy metals in acid-leaching fraction and in bulk sediments from the two typical bays(the Meiliang Ba...To assess the contamination trends and potential bio-availability of sediment-bound heavy metals,concentrations of heavy metals in acid-leaching fraction and in bulk sediments from the two typical bays(the Meiliang Bay and Xuhu Bay) of the Taihu Lake,East China,were studied.Pb and Zn showed elevated concentrations in the sediments from both areas,although sedimentation history and degree of pollution are different between the two bays.In the Meiliang Bay,both Pb and Zn pollutions started in the late 1970's,the same time as the beginning of eutrophication of the lake,while the in the Xuhu Bay the metal contamination started since recent 10 years.The concentrations of acid-leachable Pb in the sediments from the Meiliang Bay are correlated with the historical eutrophication process.Before the eutrophication and heavy metal pollution,the chemical properties of the lake sediments were the same as the source compositions of the Xiashu loess.Both Pb and Zn in the sediments mainly occur in leachable forms by nitric or hydrochloric acid,whilst most of Cu is in residual fraction.The results indicate that both Pb and Zn may have higher mobility and bioavailability in water and biology than Cu.展开更多
The Hydrobios in Dongping Lake, Shandong Province, mainly includes phytoplankton, zooplankton, benthic animals, fishes and hydrophytic vascular plants. Nitrogen and phosphorus are the restrictive factors for the growt...The Hydrobios in Dongping Lake, Shandong Province, mainly includes phytoplankton, zooplankton, benthic animals, fishes and hydrophytic vascular plants. Nitrogen and phosphorus are the restrictive factors for the growth and propagation of hydrophyta, therefore the key to the prevention and control of eutrophication in lakes lies in the control of the contents of the two elements in the water. Artificial fishing of algae can reduce the concentrations of trophic substances such as nitrogen and phosphorus in the water bodies, and biological measures may decrease the contents of these trophic substances in the bottom sediments and the water bodies, thereby playing an active role in modifying the eutrophication of the lake.展开更多
By analyzing the enhanced thematic mapper (ETM) images of September 1999, and quality observation data for many consecutive years in several parts of the Donghu Lake in Wuhan, China, the authors discovered a good line...By analyzing the enhanced thematic mapper (ETM) images of September 1999, and quality observation data for many consecutive years in several parts of the Donghu Lake in Wuhan, China, the authors discovered a good linear relation between grey scale (GS) abstracted from ETM b5, b7 images and eutrophication level of the lakes, and extended the study to eight other major lakes in the area of Wu- han by using lake eutrophication models. Based on the in situ monitoring data, we also evaluated the eu- trophication level of the lakes with modified trophic index method brought by M. Aizaki et al. The results of the two methods showed that the most of the lakes were eutrophicated, and even hyper-eutrophicated in some areas. Six of the 8 lakes had very similar trophic state index (TSI) values. Although two of them differed in TSI value, but within an order, while it was different largely from the one by traditional method. The difference of the results between the two methods might have been due to three causative reasons. First, remote sensing technology reflects the overall status of a certain area corresponding to the ETM images in a certain period, but the modified TSI reflects the annual average values of the monitoring spots. Second, the time the ETM images taken is later than that of in situ data. Third, ETM images are affected by clouds, water depth, and suspended matter. In short, remote sensing result agreed greatly with the in situ monitoring data, indicating that remote sensing technology is feasible and effective for moni- toring and evaluating the lake eutrophication in the Wuhan area and it also can be used to evaluate large-scope lake eutrophication.展开更多
Effect of the pollution on the Chaohu Lake ecosystem has been described based on the results obtained by analysis of water samples and field survey. The environmental behavior of pollutants and their toxicity is discu...Effect of the pollution on the Chaohu Lake ecosystem has been described based on the results obtained by analysis of water samples and field survey. The environmental behavior of pollutants and their toxicity is discussed in relation to biological effects. Most of the chemicals identified by GC/MS are biodegradable in the water environment except for some organochlorinated hydrocarbons and PAHs. The pollution of the water body particularly cutrophication has led not only to disruption of natural scenic beauty, but also to changes of biotic communities and extinction of certain species. Deterioration of water quality, eutrophication in particular have certainly had an impact on aquatic organisms and on the human health in this region.展开更多
[Objective] Current eutrophication of landscape lakes in Kaifeng City was evaluated to provide scientific support for the prevention and control of landscape water eutrophication.[Method] The comprehensive trophic lev...[Objective] Current eutrophication of landscape lakes in Kaifeng City was evaluated to provide scientific support for the prevention and control of landscape water eutrophication.[Method] The comprehensive trophic level index (TLI) and the modified Carlson's trophic state index (TSIM) were applied. [Result] TLI of water in Longting Lake and Baogong Lake was obtained as 73.84 and 70.23,TSIM was 66.51 and 65.23,respectively.[Conclusion] Water in both lakes was suffering from serious eutrophication,and urgent measures should be taken to control the eutrophication.展开更多
Growing trends in industrialization in Ethiopia have raised concerns about pollution of water bodies particularly of lakes. This study was therefore conducted to 1) characterize the chemical contents of major industri...Growing trends in industrialization in Ethiopia have raised concerns about pollution of water bodies particularly of lakes. This study was therefore conducted to 1) characterize the chemical contents of major industrial effluents (namely textile ceramic and soft drink factories) that reached Lake Hawassa and 2) investigate the effects of the above mentioned factory effluents on survival of larvae fish and growth of algae. Effluent samples were collected from the outlet lagoons of each factory in December, 2009. Then, effluent samples were analyzed for total N, NO3-N, NH4-N, S2-, , , COD, total dissolved solids (TDS) and heavy metals at the federal Environmental Protection Agency (EPA) Laboratory, Addis Ababa. The experiments on the impact of effluents on survival of fish larvae and growth of algae were conducted using six concrete paved ponds (with different concentration of effluent). The results of chemical analysis showed that textile effluent had high COD (nearly 3 times higher), TDS (19 times higher) as well as (39 times higher) than the maximum permissible limits (MPL) set by Environmental Protection Authority (EPA). Among heavy metals, Zn and Fe of textile effluent were much higher (41 and 1.5 times higher, respectively) than the MPL set by EPA. Ceramic effluent also contained high concentration of (24.5 times), S2-, (2 times) and Zn (14 times) exceeding the limit of EPA. Regarding soft drink factory, high values of COD, and Zn were found in the effluent than the limit specified by EPA. The biological treatment lagoons of the respective source were not effective since the effluents were taken from the last treatment lagoon (outlet lagoon) and some of the measured parameters were higher than MPL. Results of the pond experiment showed that 5%, 10% and 20% concentration levels of the HTF effluent killed significantly high proportion of the fry (65%, 86.8% and 88.7%, respectively). In contrast, fry mortality in ceramic and soft drink effluent treatments, even at 10 and 20% concentration levels, stayed nearly below 10%, which were not far off from the mortality of the control groups. Algal biomass in the treated ponds varied with the type of effluent treatment and concentration level. Compared with the first day, chlorophyll “a” concentration measured on the 7th day had increased by 51%, 48%, 74%, 27% and 31% at 0%, 1%, 5%, 10% and 20% concentrations, respectively of textile effluent. The 5% treatment level of textile effluent caused the highest rate of algal growth above the growth rate observed in the control pond, but further increased in concentration to 10% and 20% resulted in a lower growth of algae than in the control pond. Therefore, textile effluent may boost up algae growth at lower concentrations (~5%) but at higher concentration levels its toxic effect may become inhibitory. Regarding the effluent of soft drink factory, algal growth progressively diminished with increasing concentration of the effluent. The overall change (between initial and day 7) in chlorophyll “a” concentration was highest in the control pond (36.2%) and decreased with increasing effluent concentration (1% to 20%) from 21.7% to -9.4%. On the other hand, algal growth under ceramic effluent treatment was comparable with that observed in the control pond.展开更多
To study the influence of human activity on natural lake, chironomid fauna change in the 700–560cm lake sediment in Quidenham Mere of England associated with chironomid inferred TP presented that the lake experienced...To study the influence of human activity on natural lake, chironomid fauna change in the 700–560cm lake sediment in Quidenham Mere of England associated with chironomid inferred TP presented that the lake experienced a whole eutrophication process due to human hemp-retting in Post-Medieval based on the history record and pollen analysis, which was confirmed by mollusc and ostracod analysis. However, the response of chironomid and mollusc to retting was the strongest with ostracod a little behind. It proved that cultural eutrophication existed in history and could be recovered by itself despite of some long-term unachievable destroy. And it was most important for external nutrient to be cut off during lake restoration even in ancient times.展开更多
Greenhouse gases(GHGs)emitted or absorbed by lakes are an important component of the global carbon cycle.However,few studies have focused on the GHG dynamics of eutrophic saline lakes,thus preventing a comprehensive u...Greenhouse gases(GHGs)emitted or absorbed by lakes are an important component of the global carbon cycle.However,few studies have focused on the GHG dynamics of eutrophic saline lakes,thus preventing a comprehensive understanding of the carbon cycle.Here,we conducted four sampling analyses using a floating chamber in Daihai Lake,a eutrophication saline lake in Inner Mongolia Autonomous Region,China,to explore its carbon dioxide(CO_(2))and methane(CH_(4))emissions.The mean CO_(2)emission flux(FCO_(2))and CH_(4)emission flux(FCH_(4))were 17.54±14.54 mmol/m^(2)/day and 0.50±0.50 mmol/m^(2)/day,respectively.The results indicated that Daihai Lake was a source of CO_(2)and CH_(4),and GHG emissions exhibited temporal variability.The mean CO_(2)partial pressure(p CO_(2))and CH_(4)partial pressure(p CH_(4))were 561.35±109.59μatm and 17.02±13.45μatm,which were supersaturated relative to the atmosphere.The regression and correlation analysis showed that the main influencing factors of p CO_(2)were wind speed,dissolved oxygen(DO),total nitrogen(TN)and Chlorophyll a(Chl.a),whereas the main influencing factors of p CH_(4)were water temperature(WT),Chl.a,nitrate nitrogen(NO_(3)^(-)-N),TN,dissolved organic carbon(DOC)and water depth.Salinity regulated carbon mineralization and organic matter decomposition,and it was an important influencing factor of p CO_(2)and p CH_(4).Additionally,the trophic level index(TLI)significantly increased p CH_(4).Our study elucidated that salinity and eutrophication play an important role in the dynamic changes of GHG emissions.However,research on eutrophic saline lakes needs to be strengthened.展开更多
Many biodiversity indices were used to indicate the biological contamination degree in studies of lake water or seawater. Some were studied on biodiversity comparison for different areas at the same time, or initial s...Many biodiversity indices were used to indicate the biological contamination degree in studies of lake water or seawater. Some were studied on biodiversity comparison for different areas at the same time, or initial structure succession of some aerial lake water systems. The phytoplankton changed with the development of various dominant species. In this study, the dominant species at these stages were Chlorophyta in the beginning stage, Cyanophyta in the second stage, and Xanthophyta in the last stage. Seven of nine biodiversity indices (Margalef's, IE, Shannon-Wiener, Simpson's, McNaughton's, Species and Odds Measure of Diversity) showed their failure to represent the eutrophication trend, and the other two indices (Menhinick's and Monk) exhibited good efficiency to indicate the eutrophication trend for the static landscaping water body.展开更多
The eutrophication of lakes is a global environmental problem.Regulating nitrogen(N)and phosphorus(P)on phytoplankton is considered to be the most important basis of lake eutrophication management.Therefore,the effect...The eutrophication of lakes is a global environmental problem.Regulating nitrogen(N)and phosphorus(P)on phytoplankton is considered to be the most important basis of lake eutrophication management.Therefore,the effects of dissolved inorganic carbon(DIC)on phytoplankton and its role in mitigating lake eutrophication have often been overlooked.In this study,the relationships between phytoplankton and DIC concentrations,carbon isotopic composition,nutrients(N and P),and hydrochemistry in the Erhai Lake(a karst lake)were investigated.The results showed that when the dissolved carbon dioxide(CO_(2)(aq))concentrations in the water were higher than 15μmol/L,the productivity of phytoplankton was controlled by the concentrations of TP and TN,especially by that of TP.When the N and P were sufficient and the CO_(2)(aq)concentrations were lower than 15μmol/L,the phytoplankton productivity was controlled by the concentrations of TP and DIC,especially by that of DIC.Additionally,DIC significantly affected the composition of the phytoplankton community in the lake(p<0.05).When the CO_(2)(aq)concentrations were higher than 15μmol/L,the relative abundance of Bacillariophyta and Chlorophyta was much higher than those of harmful Cyanophyta.Thus,high concentrations of CO_(2)(aq)can inhibit harmful Cyanophyta blooms.展开更多
This paper has advanced a new method for determining historical earthquakes. Its object of study is lake sediments. The research method is environmental magnetism represented by susceptibility. The purpose is extracti...This paper has advanced a new method for determining historical earthquakes. Its object of study is lake sediments. The research method is environmental magnetism represented by susceptibility. The purpose is extracting historical earthquake informations from lake sediments to explore the correlation between the turbidity current sediments initiated by the earthquakes and historical earthquakes round Fuxian Lake.展开更多
Lakes play important roles in sustaining the ecosystem and economic development in Inner Mongolia Autonomous Region of China,but the spatial patterns and driving mechanisms of water quality in lakes so far remain uncl...Lakes play important roles in sustaining the ecosystem and economic development in Inner Mongolia Autonomous Region of China,but the spatial patterns and driving mechanisms of water quality in lakes so far remain unclear.This study aimed to identify the spatial changes in water quality and the driving factors of seven lakes(Juyanhai Lake,Ulansuhai Lake,Hongjiannao Lake,Daihai Lake,Chagannaoer Lake,Hulun Lake,and Wulannuoer Lake)across the longitudinal axis(from the west to the east)of Inner Mongolia.Large-scale research was conducted using the comprehensive trophic level index(TLI(Σ)),multivariate statistics,and spatial analysis methods.The results showed that most lakes in Inner Mongolia were weakly alkaline.Total dissolved solids and salinity of lake water showed obvious zonation characteristics.Nitrogen and phosphorus were identified as the main pollutants in lakes,with high average concentrations of total nitrogen and total phosphorus being of 4.05 and 0.21 mg/L,respectively.The values of TLI(Σ)ranged from 49.14 to 71.77,indicating varying degrees of lake eutrophication,and phosphorus was the main driver of lake eutrophication.The lakes of Inner Mongolia could be categorized into lakes to the west of Daihai Lake and lakes to the east of Daihai Lake in terms of salinity and TLI(Σ).The salinity levels of lakes to the west of Daihai Lake exceeded those of lakes to the east of Daihai Lake,whereas the opposite trend was observed for lake trophic level.The intensity and mode of anthropogenic activities were the driving factors of the spatial patterns of lake water quality.It is recommended to control the impact of anthropogenic activities on the water quality of lakes in Inner Mongolia to improve lake ecological environment.These findings provide a more thorough understanding of the driving mechanism of the spatial patterns of water quality in lakes of Inner Mongolia,which can be used to develop strategies for lake ecosystem protection and water resources management in this region.展开更多
Current trophic status and trend of Chinese freshwater lakes were investigated in this study. The results showed that all lakes studied were commonly undergoing the eutrophication process, water quality decreased and ...Current trophic status and trend of Chinese freshwater lakes were investigated in this study. The results showed that all lakes studied were commonly undergoing the eutrophication process, water quality decreased and lake's ecosystem is being declined. Most of the urban lakes are facing serious eutrophication. Many medium-sized lakes are in metrophic or eutrophic status, some local water are even approaching the hypertrophic level. The famous five freshwater lakes in China have entered into eutrophication in the condition of higher nutrient load. Lake Taihu, Hongze and Caohu are already in eutrophic state. Eutrophic lakes are mainly distributed in the middle and lower reaches of Yangtze River and Yungui plateau. Lake eutrophication developed rapidly. Among the 34 lakes studied in 1970's, most of lakes were in the mesotrophic status,mesotrophic water area accounted for 91.8%. With the nine year of 1978-1987 the area percentage of oligotrophic lakes decreased from 3.2% to 0.53%, and that of eutrophic lakes increased from 5.0% to 55.01%. Recent data showed 57.5% lakes were in eutrophic and hypertrophic status of the 40 surveyed lakes.Eutrophic trend of Lake Taihu, Chaohu and Xuanwu in the region of the middle and lower reaches of Yangtze River was predicated using the ecological stress model. The results showed that in 2008 Lake Taihu, Chaohu and Xuanwu might be of eutrophication, eutrophication and hypertrophication, respectively if no control measurement is taken. Provided the pollution water treatment rate is 60% in 2030, approximately 30 billion ton pollution water would still be discharged directly in the lakes. Therefore, in 2030 the urban lakes in China might be eutrophication or hypertrophication, and most of the medium-sized lakes at the urban-rural fringe might be in eutrophication or hypertrophication. The famous five biggest freshwater lakes in China might be eutrophication if control countermeasures are taken as now.Lake eutrophication has become a serious environmental problem in China. Based on the domestic and foreign experiences of the eutrophic control technologies, both nutrient pollution control and lake ecological restoration should be carried out and this may be the guidance for the eutrophic control of lakes in China.展开更多
基金Supported by Innovative Projects for University Students(2022XCX020).
文摘In this paper,the artificial lake on the campus of Tibet University was taken as the research object.By detecting the water quality of the lake,the standard index method and comprehensive pollution index method were used to understand the water quality characteristics,pollution status,and main pollutants of the Siyuan Lake.On this basis,the comprehensive nutritional status index method was used to evaluate the eutrophication status of the Siyuan Lake.The results showed that the overall water quality of the artificial lake was good,showing as still clean,with TN and TP being the main pollution factors of the artificial lake.The main nutritional indicators were TN,TP,and transparency,with a comprehensive nutritional level of middle eutropher.Based on the environmental characteristics of the artificial lake area on the campus of Tibet University,reasonable treatment measures have been proposed.It hoped to prevent and improve the water environment through these measures,and provide reference for the protection and restoration of campus landscape water body.
基金Supported by the National Natural Science Foundation of China(No.41601194)the Applied Basic Research Fund of Shanxi Province,China(No.201701D221214)。
文摘Lake eutrophication is recognised as a serious global challenge,and many regional legislative programmes are being made to attempt to relieve nutrient pollution and restore deteriorated lake ecological state.However,it is of primary importance to understand the degradation processes and reference conditions.The palaeolimnological approach allows us to use ecological evidences preserved in lake sediments to track the changes of lake trophic status under human impact.Diatoms,a proxy for ecological and limnological change,and pigments,a proxy for algal production and composition,were analysed on a short sediment sequence from Lake Dojran(Republic of North Macedonia and Greece),and their preservation qualities were evaluated before environmental interpretation.Good diatom preservation is inferred mainly from the consistent co-occurrence of robust,highly-silicified taxa and small taxa throughout the sequence.Pigment evaluation of the comparison between wet sediment samples in dark and cold storage and their corresponding dry sediment samples lyophilized immediately after the recovery reveals that sediment restoration conditions are critical for the accuracy of analysis.We show that the increased chlorophyll and xanthophyll pigment concentrations,particularly the siliceous-algae pigment fucoxanthin and diatoxanthin,together with the distinct increase in diatom concentration,indicate accelerated lake eutrophication and a major ecological shift linked to intensified water abstraction practice and agricultural expansion in the late 18th to early 19th century.Evidence of diatom assemblage composition is muted probably by the dominance of widely-tolerant small fragilaroid species in diatom composition and the better competitive ability of cyanobacteria and chlorophytes than diatoms for low light under eutrophic and turbid conditions.This study improves our understanding of recent human-induced environmental change and current ecological restoration target in this lake.
基金Supported by Key Project of Social Development Basic Research of Yunnan Provincial Science and Technology Department(2009cc025)
文摘[ Objective] The study aimed at discussing the purification effect of constructed wetlands for treating river water flowing from phosphate mine areas into Fuxian Lake. [Method] The running parameters of the constructed wetlands were investigated for one year, and the purification effect of the constructed wetlands for treating the sewage from phosphate mine areas was analyzed. [Result] With the aid of the constructed wet- land, the average removal rates of total nitrogen (TN), total phosphorus (TP) and CODcr were 52%, 32% and 54%, and the removal effects were best when the designed hydraulic load was 0.67 m3/( m2 · d). Running stably for six years, the constructed wetlands had advantages of no power, low resistance and high removal rate. [ Conclusion] The constructed wetlands reduced the load of pollutants from phosphate mine areas into Fuxian Lake effectivelv, which Dlaved important roles in the Drotection of water aualitv of Fuxian Lake.
基金supported by the Hi-Tech Research and Development Program(863)of China(No.2005AA6010100401)the National Natural Science Foundation of China(No.30200030).
文摘Taihu Lake, the largest freshwater shallow lake in eastern China, has suffered from severe eutrophication over the past two decades. This research developed a three-dimensional eutrophication model to investigate the eutrophication dynamics. The model fully coupled the biological processes and hydrodynamics, and also took into account the effects of sediment release and the external loads from the tributaries. After sensitivity analyses, the key parameters were defined and then calibrated by the field observation data. The calibrated model was applied to study the seasonal primary productions and its regional differences. The comparisons between model results and field data in year 2000 indicated that the model is able to simulate the eutrophication dynamics in Taihu Lake with a reasonable accuracy. From the simulation experiments, it was found that the meteorological forcing have significant influences on the temporal variations of the eutrophication dynamics. The wind-induced circulation and sediment distribution play an important role in the spatial distribution of the algae blooms.
基金U nderthe auspicesofthe cooperative projectbetw een G overnm entofChina and Japan (N o.JIC A G L:SCH EFY 98)
文摘Chaohu Lake, located in the central Anhui Province, is one of the five largest fresh lakes in China. Now it is one of the three most eutrophication lakes in China. The deterioration of its water quality has influenced the sustainable development of society, economy and environment of Hefei City, the capital of Anhui Province. A series of measures have been carried out to control its eutrophication, but it is still serious. On the basis of the lake water quality data from 1984 to 2003, the causes of the eutrophication of Chaohu Lake are analyzed. Studies indicated that the suitable natural conditions and human activities played a crucial role in the process of the eutrophication of Chaohu Lake. A great amount of industrial, agricultural and domestic sewage discharged into the lake is the main cause of eutrophication in the lake. Land use, soil erosion and shoreline collapse destroyed the watershed eco-environment and the terrestrial ecosystem of Chaohu Lake. And the building of Yuxi Gate extends the sluggish of the nutritious substance and speeds up the process of the eutrophication. From the view of systematic engineering and watershed ecology, a series of the countermeasures have been put forward to control the eutrophication.
文摘Water quality evaluation entails both randomness and fuzziness. Considering that water eutrophication evaluation involves many indices, different classifications and interval values, fuzzy variable sets theory was developed to Lake Baiyangdian as a study case. Taking reference to eutrophication standard of Chinese lakes and local characteristic of Lake Baiyangdian, eutrophication degree of lake was divided into 8 levels. Total phosphorus, total nitrogen, and CODMn were selected as evaluation indices in this research. Based on the measured data, index feature value matrix of sample was built. Index weights were determined by means of pure threshold value method. Relative membership degree of each index to each classification was calculated with relative difference function model. Then the stability of feature value of classification corresponding was received by the comprehensive calculation with the relative membership degree and index weights. The results show that the proposed models are effective tools for generating a set of realistic and flexible optimal solutions for complicated water quality evaluation issues. It concluded that the model was reasonable and practical.
基金supported by 973 Project on the Processes of Lake Eutrophication and the Mechanism of Cyanobacterial Blooming (2002CB412300)National Survey of Land and Source (200420130002)
文摘To assess the contamination trends and potential bio-availability of sediment-bound heavy metals,concentrations of heavy metals in acid-leaching fraction and in bulk sediments from the two typical bays(the Meiliang Bay and Xuhu Bay) of the Taihu Lake,East China,were studied.Pb and Zn showed elevated concentrations in the sediments from both areas,although sedimentation history and degree of pollution are different between the two bays.In the Meiliang Bay,both Pb and Zn pollutions started in the late 1970's,the same time as the beginning of eutrophication of the lake,while the in the Xuhu Bay the metal contamination started since recent 10 years.The concentrations of acid-leachable Pb in the sediments from the Meiliang Bay are correlated with the historical eutrophication process.Before the eutrophication and heavy metal pollution,the chemical properties of the lake sediments were the same as the source compositions of the Xiashu loess.Both Pb and Zn in the sediments mainly occur in leachable forms by nitric or hydrochloric acid,whilst most of Cu is in residual fraction.The results indicate that both Pb and Zn may have higher mobility and bioavailability in water and biology than Cu.
文摘The Hydrobios in Dongping Lake, Shandong Province, mainly includes phytoplankton, zooplankton, benthic animals, fishes and hydrophytic vascular plants. Nitrogen and phosphorus are the restrictive factors for the growth and propagation of hydrophyta, therefore the key to the prevention and control of eutrophication in lakes lies in the control of the contents of the two elements in the water. Artificial fishing of algae can reduce the concentrations of trophic substances such as nitrogen and phosphorus in the water bodies, and biological measures may decrease the contents of these trophic substances in the bottom sediments and the water bodies, thereby playing an active role in modifying the eutrophication of the lake.
基金Supported by Hubei Provincial Comprehensive Investigation of Land Resources Using Remote Sensing Technology Program (No. 0799210014).
文摘By analyzing the enhanced thematic mapper (ETM) images of September 1999, and quality observation data for many consecutive years in several parts of the Donghu Lake in Wuhan, China, the authors discovered a good linear relation between grey scale (GS) abstracted from ETM b5, b7 images and eutrophication level of the lakes, and extended the study to eight other major lakes in the area of Wu- han by using lake eutrophication models. Based on the in situ monitoring data, we also evaluated the eu- trophication level of the lakes with modified trophic index method brought by M. Aizaki et al. The results of the two methods showed that the most of the lakes were eutrophicated, and even hyper-eutrophicated in some areas. Six of the 8 lakes had very similar trophic state index (TSI) values. Although two of them differed in TSI value, but within an order, while it was different largely from the one by traditional method. The difference of the results between the two methods might have been due to three causative reasons. First, remote sensing technology reflects the overall status of a certain area corresponding to the ETM images in a certain period, but the modified TSI reflects the annual average values of the monitoring spots. Second, the time the ETM images taken is later than that of in situ data. Third, ETM images are affected by clouds, water depth, and suspended matter. In short, remote sensing result agreed greatly with the in situ monitoring data, indicating that remote sensing technology is feasible and effective for moni- toring and evaluating the lake eutrophication in the Wuhan area and it also can be used to evaluate large-scope lake eutrophication.
文摘Effect of the pollution on the Chaohu Lake ecosystem has been described based on the results obtained by analysis of water samples and field survey. The environmental behavior of pollutants and their toxicity is discussed in relation to biological effects. Most of the chemicals identified by GC/MS are biodegradable in the water environment except for some organochlorinated hydrocarbons and PAHs. The pollution of the water body particularly cutrophication has led not only to disruption of natural scenic beauty, but also to changes of biotic communities and extinction of certain species. Deterioration of water quality, eutrophication in particular have certainly had an impact on aquatic organisms and on the human health in this region.
基金Supported by Key Scientific and Technological Project of Henan Province(112102310442)Investigation Program ofHenan Federation of Social Science(SKL-2011-0338)
文摘[Objective] Current eutrophication of landscape lakes in Kaifeng City was evaluated to provide scientific support for the prevention and control of landscape water eutrophication.[Method] The comprehensive trophic level index (TLI) and the modified Carlson's trophic state index (TSIM) were applied. [Result] TLI of water in Longting Lake and Baogong Lake was obtained as 73.84 and 70.23,TSIM was 66.51 and 65.23,respectively.[Conclusion] Water in both lakes was suffering from serious eutrophication,and urgent measures should be taken to control the eutrophication.
文摘Growing trends in industrialization in Ethiopia have raised concerns about pollution of water bodies particularly of lakes. This study was therefore conducted to 1) characterize the chemical contents of major industrial effluents (namely textile ceramic and soft drink factories) that reached Lake Hawassa and 2) investigate the effects of the above mentioned factory effluents on survival of larvae fish and growth of algae. Effluent samples were collected from the outlet lagoons of each factory in December, 2009. Then, effluent samples were analyzed for total N, NO3-N, NH4-N, S2-, , , COD, total dissolved solids (TDS) and heavy metals at the federal Environmental Protection Agency (EPA) Laboratory, Addis Ababa. The experiments on the impact of effluents on survival of fish larvae and growth of algae were conducted using six concrete paved ponds (with different concentration of effluent). The results of chemical analysis showed that textile effluent had high COD (nearly 3 times higher), TDS (19 times higher) as well as (39 times higher) than the maximum permissible limits (MPL) set by Environmental Protection Authority (EPA). Among heavy metals, Zn and Fe of textile effluent were much higher (41 and 1.5 times higher, respectively) than the MPL set by EPA. Ceramic effluent also contained high concentration of (24.5 times), S2-, (2 times) and Zn (14 times) exceeding the limit of EPA. Regarding soft drink factory, high values of COD, and Zn were found in the effluent than the limit specified by EPA. The biological treatment lagoons of the respective source were not effective since the effluents were taken from the last treatment lagoon (outlet lagoon) and some of the measured parameters were higher than MPL. Results of the pond experiment showed that 5%, 10% and 20% concentration levels of the HTF effluent killed significantly high proportion of the fry (65%, 86.8% and 88.7%, respectively). In contrast, fry mortality in ceramic and soft drink effluent treatments, even at 10 and 20% concentration levels, stayed nearly below 10%, which were not far off from the mortality of the control groups. Algal biomass in the treated ponds varied with the type of effluent treatment and concentration level. Compared with the first day, chlorophyll “a” concentration measured on the 7th day had increased by 51%, 48%, 74%, 27% and 31% at 0%, 1%, 5%, 10% and 20% concentrations, respectively of textile effluent. The 5% treatment level of textile effluent caused the highest rate of algal growth above the growth rate observed in the control pond, but further increased in concentration to 10% and 20% resulted in a lower growth of algae than in the control pond. Therefore, textile effluent may boost up algae growth at lower concentrations (~5%) but at higher concentration levels its toxic effect may become inhibitory. Regarding the effluent of soft drink factory, algal growth progressively diminished with increasing concentration of the effluent. The overall change (between initial and day 7) in chlorophyll “a” concentration was highest in the control pond (36.2%) and decreased with increasing effluent concentration (1% to 20%) from 21.7% to -9.4%. On the other hand, algal growth under ceramic effluent treatment was comparable with that observed in the control pond.
基金Under the auspices of Knowledge Innovation Program of Chinese Academy of Sciences (No. KZCX1-SW-12-I)Pre-research Project of Major Basic Program of Ministry of Science and Technology (No. 2004CCA02900)
文摘To study the influence of human activity on natural lake, chironomid fauna change in the 700–560cm lake sediment in Quidenham Mere of England associated with chironomid inferred TP presented that the lake experienced a whole eutrophication process due to human hemp-retting in Post-Medieval based on the history record and pollen analysis, which was confirmed by mollusc and ostracod analysis. However, the response of chironomid and mollusc to retting was the strongest with ostracod a little behind. It proved that cultural eutrophication existed in history and could be recovered by itself despite of some long-term unachievable destroy. And it was most important for external nutrient to be cut off during lake restoration even in ancient times.
基金supported by the National Key Research and Development Program of China (No.2021YFC3201203)the National Natural Science Foundation of China (Nos.51869014 and 52279067)+2 种基金the Major Science and Technology Projects of Inner Mongolia Autonomous Region (Nos.2020ZD0009 and ZDZX2018054)the Key Scientific and Technological Project of Inner Mongolia (No.2019GG019)the Open Project Program of the Ministry of Education Key Laboratory of Ecology and Resources Use of the Mongolian Plateau (No.KF2020006)。
文摘Greenhouse gases(GHGs)emitted or absorbed by lakes are an important component of the global carbon cycle.However,few studies have focused on the GHG dynamics of eutrophic saline lakes,thus preventing a comprehensive understanding of the carbon cycle.Here,we conducted four sampling analyses using a floating chamber in Daihai Lake,a eutrophication saline lake in Inner Mongolia Autonomous Region,China,to explore its carbon dioxide(CO_(2))and methane(CH_(4))emissions.The mean CO_(2)emission flux(FCO_(2))and CH_(4)emission flux(FCH_(4))were 17.54±14.54 mmol/m^(2)/day and 0.50±0.50 mmol/m^(2)/day,respectively.The results indicated that Daihai Lake was a source of CO_(2)and CH_(4),and GHG emissions exhibited temporal variability.The mean CO_(2)partial pressure(p CO_(2))and CH_(4)partial pressure(p CH_(4))were 561.35±109.59μatm and 17.02±13.45μatm,which were supersaturated relative to the atmosphere.The regression and correlation analysis showed that the main influencing factors of p CO_(2)were wind speed,dissolved oxygen(DO),total nitrogen(TN)and Chlorophyll a(Chl.a),whereas the main influencing factors of p CH_(4)were water temperature(WT),Chl.a,nitrate nitrogen(NO_(3)^(-)-N),TN,dissolved organic carbon(DOC)and water depth.Salinity regulated carbon mineralization and organic matter decomposition,and it was an important influencing factor of p CO_(2)and p CH_(4).Additionally,the trophic level index(TLI)significantly increased p CH_(4).Our study elucidated that salinity and eutrophication play an important role in the dynamic changes of GHG emissions.However,research on eutrophic saline lakes needs to be strengthened.
基金Sponsored by the National Basic Research Program of China (Grant No.2004CB418505)
文摘Many biodiversity indices were used to indicate the biological contamination degree in studies of lake water or seawater. Some were studied on biodiversity comparison for different areas at the same time, or initial structure succession of some aerial lake water systems. The phytoplankton changed with the development of various dominant species. In this study, the dominant species at these stages were Chlorophyta in the beginning stage, Cyanophyta in the second stage, and Xanthophyta in the last stage. Seven of nine biodiversity indices (Margalef's, IE, Shannon-Wiener, Simpson's, McNaughton's, Species and Odds Measure of Diversity) showed their failure to represent the eutrophication trend, and the other two indices (Menhinick's and Monk) exhibited good efficiency to indicate the eutrophication trend for the static landscaping water body.
基金supported by the National Natural Science Foundation of China(Nos.42130501,42141008,and 41977298)the Strategic Priority Research Program of the Chinese Academy of Science(No.XDB40020000)Special thanks to the Dali Erhai Research Institute for supporting us in sampling Erhai Lake.
文摘The eutrophication of lakes is a global environmental problem.Regulating nitrogen(N)and phosphorus(P)on phytoplankton is considered to be the most important basis of lake eutrophication management.Therefore,the effects of dissolved inorganic carbon(DIC)on phytoplankton and its role in mitigating lake eutrophication have often been overlooked.In this study,the relationships between phytoplankton and DIC concentrations,carbon isotopic composition,nutrients(N and P),and hydrochemistry in the Erhai Lake(a karst lake)were investigated.The results showed that when the dissolved carbon dioxide(CO_(2)(aq))concentrations in the water were higher than 15μmol/L,the productivity of phytoplankton was controlled by the concentrations of TP and TN,especially by that of TP.When the N and P were sufficient and the CO_(2)(aq)concentrations were lower than 15μmol/L,the phytoplankton productivity was controlled by the concentrations of TP and DIC,especially by that of DIC.Additionally,DIC significantly affected the composition of the phytoplankton community in the lake(p<0.05).When the CO_(2)(aq)concentrations were higher than 15μmol/L,the relative abundance of Bacillariophyta and Chlorophyta was much higher than those of harmful Cyanophyta.Thus,high concentrations of CO_(2)(aq)can inhibit harmful Cyanophyta blooms.
文摘This paper has advanced a new method for determining historical earthquakes. Its object of study is lake sediments. The research method is environmental magnetism represented by susceptibility. The purpose is extracting historical earthquake informations from lake sediments to explore the correlation between the turbidity current sediments initiated by the earthquakes and historical earthquakes round Fuxian Lake.
基金funded by the National Key Research and Development Program of China(2021YFC3201203)the Major Science and Technology Projects of Inner Mongolia Autonomous Region(2020ZD0009)+2 种基金the National Natural Science Foundation of China(51869014)the Open Project Program of the Ministry of Education Key Laboratory of Ecology and Resources Use of the Mongolian Plateau(KF2020006)the Special Funds for Innovation and Entrepreneurship of Postgraduates in Inner Mongolia University(11200-121024).
文摘Lakes play important roles in sustaining the ecosystem and economic development in Inner Mongolia Autonomous Region of China,but the spatial patterns and driving mechanisms of water quality in lakes so far remain unclear.This study aimed to identify the spatial changes in water quality and the driving factors of seven lakes(Juyanhai Lake,Ulansuhai Lake,Hongjiannao Lake,Daihai Lake,Chagannaoer Lake,Hulun Lake,and Wulannuoer Lake)across the longitudinal axis(from the west to the east)of Inner Mongolia.Large-scale research was conducted using the comprehensive trophic level index(TLI(Σ)),multivariate statistics,and spatial analysis methods.The results showed that most lakes in Inner Mongolia were weakly alkaline.Total dissolved solids and salinity of lake water showed obvious zonation characteristics.Nitrogen and phosphorus were identified as the main pollutants in lakes,with high average concentrations of total nitrogen and total phosphorus being of 4.05 and 0.21 mg/L,respectively.The values of TLI(Σ)ranged from 49.14 to 71.77,indicating varying degrees of lake eutrophication,and phosphorus was the main driver of lake eutrophication.The lakes of Inner Mongolia could be categorized into lakes to the west of Daihai Lake and lakes to the east of Daihai Lake in terms of salinity and TLI(Σ).The salinity levels of lakes to the west of Daihai Lake exceeded those of lakes to the east of Daihai Lake,whereas the opposite trend was observed for lake trophic level.The intensity and mode of anthropogenic activities were the driving factors of the spatial patterns of lake water quality.It is recommended to control the impact of anthropogenic activities on the water quality of lakes in Inner Mongolia to improve lake ecological environment.These findings provide a more thorough understanding of the driving mechanism of the spatial patterns of water quality in lakes of Inner Mongolia,which can be used to develop strategies for lake ecosystem protection and water resources management in this region.
文摘Current trophic status and trend of Chinese freshwater lakes were investigated in this study. The results showed that all lakes studied were commonly undergoing the eutrophication process, water quality decreased and lake's ecosystem is being declined. Most of the urban lakes are facing serious eutrophication. Many medium-sized lakes are in metrophic or eutrophic status, some local water are even approaching the hypertrophic level. The famous five freshwater lakes in China have entered into eutrophication in the condition of higher nutrient load. Lake Taihu, Hongze and Caohu are already in eutrophic state. Eutrophic lakes are mainly distributed in the middle and lower reaches of Yangtze River and Yungui plateau. Lake eutrophication developed rapidly. Among the 34 lakes studied in 1970's, most of lakes were in the mesotrophic status,mesotrophic water area accounted for 91.8%. With the nine year of 1978-1987 the area percentage of oligotrophic lakes decreased from 3.2% to 0.53%, and that of eutrophic lakes increased from 5.0% to 55.01%. Recent data showed 57.5% lakes were in eutrophic and hypertrophic status of the 40 surveyed lakes.Eutrophic trend of Lake Taihu, Chaohu and Xuanwu in the region of the middle and lower reaches of Yangtze River was predicated using the ecological stress model. The results showed that in 2008 Lake Taihu, Chaohu and Xuanwu might be of eutrophication, eutrophication and hypertrophication, respectively if no control measurement is taken. Provided the pollution water treatment rate is 60% in 2030, approximately 30 billion ton pollution water would still be discharged directly in the lakes. Therefore, in 2030 the urban lakes in China might be eutrophication or hypertrophication, and most of the medium-sized lakes at the urban-rural fringe might be in eutrophication or hypertrophication. The famous five biggest freshwater lakes in China might be eutrophication if control countermeasures are taken as now.Lake eutrophication has become a serious environmental problem in China. Based on the domestic and foreign experiences of the eutrophic control technologies, both nutrient pollution control and lake ecological restoration should be carried out and this may be the guidance for the eutrophic control of lakes in China.