Composition and distribution of nitrogen in Chaohu Lake and Wabu Lake sediments were studied.The results showed that the mean total nitrogen content in Chaohu Lake and Wabu Lake was 0.533 g/kg and 0.265 g/kg respectiv...Composition and distribution of nitrogen in Chaohu Lake and Wabu Lake sediments were studied.The results showed that the mean total nitrogen content in Chaohu Lake and Wabu Lake was 0.533 g/kg and 0.265 g/kg respectively,and the primary composition of nitrogen was organic nitrogen(94%).The organic index indicated that the organic pollution degree of Wabu Lake was lower than that of Chaohu Lake.展开更多
[Objective] The aim of the research was to reveal the influence mechanism of sediment-water exchange of nutrients in Chaohu Lake. [Method] The effects of environmental factors (overlying water, temperature, pH and dis...[Objective] The aim of the research was to reveal the influence mechanism of sediment-water exchange of nutrients in Chaohu Lake. [Method] The effects of environmental factors (overlying water, temperature, pH and dissolved oxygen concentration) on NH_4^+ release in sediment from Chaohu Lake were studied under controlled laboratory conditions. [Results] With the rising of temperature and the decrease of NH_4^+ concentration in overlying water, NH_4^+ released from sediment increased significantly. pH had a great effect on NH_4^+ release with a complicated mechanism. The largest release amount of NH_4^+ under anaerobic condition was about 6 times as much as that under aerobic condition. [Conclusion] This research would provide theoretical support for environmental management of Chaohu Lake in the project of leading water from the Yangtze River to Chaohu Lake.展开更多
Temporal and spatial changes of total nitrogen （TN）, total phosphorus （TP） and chlorophyll-a （Chl-a） in a shallow lake, Lake Chaohu, China, were investigated using monthly monitoring data from 2001 through 2011....Temporal and spatial changes of total nitrogen （TN）, total phosphorus （TP） and chlorophyll-a （Chl-a） in a shallow lake, Lake Chaohu, China, were investigated using monthly monitoring data from 2001 through 2011. The results showed that the annual mean concentration ranges of TN, TP, and Chl-a were 0.08-14.60 mg/L, 0.02-1.08 mg/L, and 0.10-465.90 ~tg/L, respectively. Our data showed that Lake Chaohu was highly eutrophic and that water quality showed no substantial improvement during 2001 through 2011. The mean concentrations of TP, TN and Chl-a in the western lake were significantly higher than in the eastern lake, which indicates a spatial distribution of the three water parameters. The annual mean ratio of TN：TP by weight ranged from 10 to 20, indicating that phosphorus was the limiting nutrient in this lake. A similar seasonality variation for TP and Chl-a was observed. Riverine TP and NH4＋ loading from eight major tributaries were in the range of 1.56× 10^4-5.47 × 10^4 and 0.19 × 104-0.51 × 10^4 tons/yr over 2002-2011, respectively, and exceeded the water environmental capability of the two nutrients in the lake by a factor of 3-6. Thus reduction of nutrient loading in the sub-watershed and tributaries would be essential for the restoration of Lake Chaohu.展开更多
Based on the temporal-spatial distribution features of ancient settlement sites from the middle and late Neolithic Age to the Han dynasty in the Chaohu Lake Basin of Anhui Province, East China, using the methods of GI...Based on the temporal-spatial distribution features of ancient settlement sites from the middle and late Neolithic Age to the Han dynasty in the Chaohu Lake Basin of Anhui Province, East China, using the methods of GIS combined with the reconstructed paleoen- vironment by the records of lake sediment since Holocene, the transmutation of ancient set- tlements with response to environmental changes in this area has been discussed. Studies show that the main feature of transmutation of ancient settlements from the middle and late Neolithic Age to the Han Dynasty was that the distribution of settlements in this area changed from high altitudes to low ones and kept approaching the Chaohu Lake with the passage of time. These could be the response to the climate change from warm-moist to a relatively warm-dry condition during the middle Holocene, leading to the lake level fluctuations. The large area of exposed land provided enough space for human activities. These indicate that the above changes in geomorphologic evolution and hydrology influenced by climate condi- tions affected the transmutation of ancient settlements greatly. The distribution pattern of settlement sites was that the number of sites in the west was more than in the east. This pattern may be related to the geomorphologic conditions such as frequent channel shifting of the Yangtze River as well as flood disasters during the Holocene optimum. Therefore, climate change was the inducement of the transmutation of ancient settlements in the Chaohu Lake Basin, which exerted great influence on the distribution, expansion and development of the ancient settlements.展开更多
This paper reports a Lower Triassic inorganic carbon isotope profile from the North Pingdingshan Section in Chaohu, Anhui Province, China, which was situated in a deep part of the Lower Yangtze carbonate ramp. The ...This paper reports a Lower Triassic inorganic carbon isotope profile from the North Pingdingshan Section in Chaohu, Anhui Province, China, which was situated in a deep part of the Lower Yangtze carbonate ramp. The δ ( 13 C) excursion shows two periods from the Permian Triassic boundary to the lower Spathian substage, corresponding to the ecosystem undergoing evolution and recovery after the end Permian mass extinction and related events. The first period starts at the δ ( 13 C) depletion caused by the mass extinction and evolves with a gradual δ ( 13 C) increase resulting from the development of some disaster taxa during the Induan. The strong Smithian δ ( 13 C) depletion in the second period might be formed by the collapse of the disaster ecosystem and the biotic recovery occurred with the explosive increase of bioproductivity in the Spathian. Thus the δ ( 13 C) excursion in the Lower Triassic expresses patterns of biotic evolution and recovery during the erratic ecosystem that followed the great end Permian mass extinction.展开更多
The concentration and spatial distribution of persistent toxic substances （PTS） in the river sediment in Chaohu City, China were investigated. A total of nine surface sediments were collected and the selected PTS po...The concentration and spatial distribution of persistent toxic substances （PTS） in the river sediment in Chaohu City, China were investigated. A total of nine surface sediments were collected and the selected PTS pollutants including six heavy metals and nineteen polybrominated diphenyl ethers （PBDEs） were analyzed. The mean heavy metal concentrations （in mg/kg, dry weight） ranged within 0.18-1.53 （Fig）, 50.08-200.18 （Cu）, 118.70-313.65 （Zn）, 50,77-310,85 （Cr）, 37.12-92.72 （Pb） and 13.29-197.24 （As）, and Cu, Zn and As have been regarded as the main metal pollutants, The levels of PBDEs （1.2-12.1 ng/g） and BDE-209 （2.4--30.5 ng/g） were at the middle level of the global range. BDE-209 was the predominant congener （67.0%-85.7%）, which agrees with the fact that technical deca-BDE mixtures are the dominant PBDE formulation in China. The relative high level of PTS poUutants in the western part of the city is probably owing to the intensive agricultural activities and lack of sewerage system there. The ecological risk assessment with the sediment quality guidelines （$OGs） indicates that the urban river sediments in the city have been heavily contaminated by heavy metals with probable ecotoxicological impacts on freshwater organisms and the main toxic pollutants are Hg and As, The results of current study imply that the city, and perhaps many other small cities in China as well, requires immediate pollution control measures with emphasis on not only conventional organic pollutants but also on PTS such as heavy metals and PBDEs.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
Since the West Pingdingshan Section in Chaohu was proposed as the candidate of the Global Stratotype Section and Point of the Induan-Olenekian boundary in 2003, the Lower Triassic of Chaohu has been extensively studie...Since the West Pingdingshan Section in Chaohu was proposed as the candidate of the Global Stratotype Section and Point of the Induan-Olenekian boundary in 2003, the Lower Triassic of Chaohu has been extensively studied. Based on the studies on the Lower Triassic of Chaohu, （1） a continuous conodont zonation is established, which has become an important reference for Lower Triassic stratigraphic correlation over the world; （2） the First Appearance Datum of conodont Neospathodus waageni was suggested and has been basically accepted as the primary marker to define the InduanOienekian boundary; （3） a characteristic Lower Triassic excursion of carbon isotopes was brought to light and has been proven to be not only an excellent index for the stratigraphic correlation but also a unique indication for the perturbation of ecological environments in the aftermath of the end-Permian mass extinction; （4） a magnetostratigraphic sequence is constituted with a certain biostratigraphic control in the low-latitude region and it presents an important correlation to the Boreal sequence; （5） a cyclostratigraphic study provides an alternative method to constrain the age of the chronostratigraphic units; and （6） a scheme of the Olenekian subdivision is recently suggested to define the boundary between the Smithian and Spathian Substages. In addition, Chaohu is also the type locality of the Chaohuan Stage, the upper stage of the Lower Triassic in the China Chronostratigraphic System.Thus, the Lower Triassic of Chaohu is not only a classic sequence in South China, but also a key reference sequence to the investigation of the corresponding stratigraphy and geological events over the world. The recent achievements are viewed here for an overall understanding of the sequence. Then the current situation of the Induan-Olenekian and Smithian-Spathian boundaries is discussed to provide a reference for later works.展开更多
A total of 30 surface sediments samples from the estuary wetland of the Tangxi River, Chaohu Lake Basin were obtained and tested. Enrichment factor （EF） and geoaccumulation index （Igeo） as well as multivariate sta...A total of 30 surface sediments samples from the estuary wetland of the Tangxi River, Chaohu Lake Basin were obtained and tested. Enrichment factor （EF） and geoaccumulation index （Igeo） as well as multivariate statistical analysis methods including Factor Analysis （FA） and Hierarchical Cluster Analysis （HCA） were applied for the assessment of heavy metal pollution in surface sediments. The results of EF values show that the pollution of copper （Cu） and cadmium （Cd） occurs in the estuarine sediments, and that zinc （Zn）, lead （Pb） and chrome （Cr） may originate from crustal materials or natural weathering process. The mean EF values of the five heavy metals are in the decreasing order： Cu〉Cd）Zn〉Pb〉Cr. Based on the lgeo of target heavy metals, the surface sediments collected from the study area can be approximately categorized as unpolluted with Zn, Pb and Cr, and moderately polluted with Cu and Cd. The degree of heavy metal pollution decreases in the order of Cu〉Cd〉Zn〉Pb〉Cr. Three groups of pollution factors are presented from FA： Zn-TOC, Cu-Cd and Cr-Pb, which respectively accounte for 27.22%, 25.20% and 21.05% of variance. By means of HCA, a total number of seven groups are distinguished from 30 sampling sites. Results indicate that Cu and Cd are the prior controlled pollutants in the estuarine sediments of the Tangxi River.展开更多
Based on the remote sensing images of algae, the present work analyzes the horizontal distribution characteristics of algal blooms in Chaohu Lake, China, which also reveals the frequency of algal blooms under differen...Based on the remote sensing images of algae, the present work analyzes the horizontal distribution characteristics of algal blooms in Chaohu Lake, China, which also reveals the frequency of algal blooms under different wind directions. Further, an unstructured-grid, three-dimensional finite-volume coastal ocean model （FVCOM） is applied to investigate the wind-induced currents and the transport pro- cess to explain the reason why algal blooms occur at the detected places. We first deduce the primary distribution of biomass from overlaid satellite images, and explain the formation mechanism by analyzing the pollution sources, and simulating the flow field and transportation process under prevailing wind over Chaohu Lake. And then, we consider the adjustment action of the wind on the corresponding day and develop a two-time scale approach to describe the whole formation process of algae horizontal distribution in Chaohu Lake. That is, on the longer time scale, i.e., during bloom season, prevailing wind determines the primary distribution of biomass by inducing the characteristic flow field; on the shorter time scale, i.e., on the day when bloom occurs, the wind force adjusts the primary distribution of biomass to form the final distribution of algal bloom.展开更多
[Objective] To study the characteristics and effects of inorganic nitrogen in east water-source and inflow rivers of Chaohu Lake. [Method] The speciation and distribution characteristics of dissolvable inorganic nitro...[Objective] To study the characteristics and effects of inorganic nitrogen in east water-source and inflow rivers of Chaohu Lake. [Method] The speciation and distribution characteristics of dissolvable inorganic nitrogen （DIN） in east water-source and inflow rivers of Chaohu Lake were investigated, and their effects on water qual- ity were examined. [Result] The concentrations of NH3-N and NO2--N were the high in flood season, and low in non-flood season, while the concentration of NO3--N pre- sented the opposite trend; the concentration of NO3--N was the highest in Shuangqiao estuary, where the pollution was the worst. DIN in Zhegao estuary and Xiaozhegao estuary was mainly caused by domestic sewage and industrial wastewaters; surface runoff and pollution from ships contribute the most to the DIN content in Shuangqiao estuary. [Conclusion] This study provided basic data and theoretical basis for the control and management of eutrophication in Chaohu Lake.展开更多
This paper proposes a scheme for the definition of the Lower Triassic Induan Olenekian boundary (IOB) based on investigation of sections in Chaohu, Anhui Province, China as well as data accumulated from other studies...This paper proposes a scheme for the definition of the Lower Triassic Induan Olenekian boundary (IOB) based on investigation of sections in Chaohu, Anhui Province, China as well as data accumulated from other studies elsewhere. The conodont Neospathodus waageni is suggested as the index fossil of the boundary. According to the FAD of N. waageni , the IOB is at the base of bed 25 2 of the West Pingdingshan Section in Chaohu, 42.19 m above the Permian Triassic boundary, and it is slightly higher than the base of the Flemingites Euflemingites Ammonoid Zone at the section.展开更多
Flood is one kind of unexpected and the most common natural disasters, which is affected by many factors and has complex mechanism. At home and abroad, there is still no mature theory and method used for the long-term...Flood is one kind of unexpected and the most common natural disasters, which is affected by many factors and has complex mechanism. At home and abroad, there is still no mature theory and method used for the long-term forecast of natural precipitation at present. In the present paper the disadvantages of grey GM (1, 1) and Markov chain are ana- lyzed, and Grey-Markov forecast theory about flood is put forward and then the modifying model is developed by making prediction of Chaohu Lake basin. Hydrological law was conducted based on the theoretical forecasts by grey system GM (1, 1) forecast model with improved Markov chain. The above method contained Stat-analysis, embodying scientific approach, precise forecast and its reliable results.展开更多
An indicator system closely connected with eco-environment, in which indicator involves in such fields as society, economy, resources, environment and ecology, is first proposed for eco-environmental quality assessmen...An indicator system closely connected with eco-environment, in which indicator involves in such fields as society, economy, resources, environment and ecology, is first proposed for eco-environmental quality assessment. Then, a hierarchical model with four levels is established by virtue of these indicators and attributes. In the model, weights of indicators and attributes are determined by combining Delphi method with the Analytic Hierarchy Process (AHP) and a statistic method is used to eliminate the influences arising from the differences in dimension and magnitude of indicators. On these grounds, an AHP-statistics model is provided for regional eco-environmental quality assessment. As a case, such AHP-statistics model is utilized in the dynamic analysis of regional eco-environmental assessment in Chaohu Lake basin. Study results show that natural environmental quality in the watershed was in the declining state while social environmental quality was in a markedly improved situation from 1996, and the synthetic eco-environmental quality was gradually and slowly improved under the common influences of both natural and social environmental factors. Example of application testified the capacities of above methodology to evaluate the real and dynamic state of regional eco-environmental quality.展开更多
By interpreting the remote sensing data of aerial photos and satellite images in different time, combining with field investigation, landform and water level observation, collecting data of weather, hydrology in Chaoh...By interpreting the remote sensing data of aerial photos and satellite images in different time, combining with field investigation, landform and water level observation, collecting data of weather, hydrology in Chaohu Lake, Anhui Province from 1957 to 2003, the reasons for collapse of Chaohu lakeshore were analyzed. The results are as follows: 1) The collapse of the Chaohu lakeshore is controlled macroscopically by two sets of north-east and the north-west faults, and the degree of collapse is determined microcosmically by lithology. 2) The constant change of water level, resulting from precipitation, wind speed and its direction, is one of the main reasons for intermittence collapse. 3) The soil and water loss or mud and sand filling up, resulting from artificial factors, such as inconsequence control of Chaohu sluice or irrational agricultural and industrial activities, etc., can uplift the lake′s bed and drive water level up. The high water level also results in the collapse. Judging from the above mentioned reasons for the collapse, we have proposed some countermeasures: 1) Putting the lakeshore slope protection project such as stone and cement mortar into practice, and upstream slope should be 1∶2.5 or 1∶3, some parts of them should be 1∶4, if they were not stable. The back slope, which is from Gui Mountain to Zhongmiao Temple, should be 1∶1.5-1∶3. 2) Constructing a greenbelt for the lakeshore, planting some vegetation such as osier, bulrush and poplar, to resist waves between the high and the low water level. 3) Controlling Chaohu Lake water level scientifically. Corrosion of lakeshore that contains gravel clay and ferruginous-manganese concretionary structures, can decrease at low water level. 4) Renovating Chaohu Lake drainage area, strengthening the administration and supervision, breaking regionalism and establishing special administration organization.展开更多
The Lower Triassic in Chaohu （巢湖） area, Anhui （安徽） Province, China, is well developed and its sequence is typical in South China. After a brief introduction of the Induan-Olenekian boundary of Chaohu, this art...The Lower Triassic in Chaohu （巢湖） area, Anhui （安徽） Province, China, is well developed and its sequence is typical in South China. After a brief introduction of the Induan-Olenekian boundary of Chaohu, this article presents some new data on conodonts. More than ten times of conodont samplings and investigations have recovered thousands of conodont specimens, which are especially rich in the Induan-Olenekian boundary strata at the West Pingdingshan Section in Chaohu City, Anhui Province. The most distinctive forms are the conodonts of the Neospathodus dieneri group and N. waageni group. The first occurrence of N. waageni eowaageni, which is regarded as the indicator of the Induan-Olenekian boundary, is situated at 40.49 m above the base of Yinkeng （殷坑） Formation. Some key conodonts and seven new specimens are introduced.展开更多
This article reports a radiolarian fauna from the upper Dalong（大隆） Formation,Ping-dingshan（平顶山）,Chaohu（巢湖）,Anhui（安徽） Province,which includes 15 genera and 23 species.One new species,Copicyntra tongi G...This article reports a radiolarian fauna from the upper Dalong（大隆） Formation,Ping-dingshan（平顶山）,Chaohu（巢湖）,Anhui（安徽） Province,which includes 15 genera and 23 species.One new species,Copicyntra tongi Gui and Feng n.sp.,is described.Comparison of the fauna,lithology and biotic associations with those from Meishan（煤山） D and Dongpan（东攀） sections shows that the Dalong Formation in the Pingdingshan Section is deposited in a deep-water shelf basin,about 60-200 m in depth.On the basis of the biotic composition,diversity and morphology,the microfossil fauna from the Pingdingshan Section can be divided into three sedimentary assemblages and the extinction proc-esses of the assemblages are discussed.展开更多
Marine strata are widely exposed in the Hushan and Chaohu areas, Lower Yangtze region. As biomarker geochemistry of the strata has not been well documented, this paper deals with the biomarker composition of represent...Marine strata are widely exposed in the Hushan and Chaohu areas, Lower Yangtze region. As biomarker geochemistry of the strata has not been well documented, this paper deals with the biomarker composition of representative samples collected from the Silurian, Carboniferous and Triassic systems and their geological implications, thus providing clues to marine organic matter. On the basis of experimental results, it is shown that abundant biomarkers (e.g. n-alkanes, isoprenoids, terpanes and steranes) were detected. As organic matter in the strata is highly to over mature in general based on petrologic microobservation, some biomarkers (mainly n-alkanes) except terpanes and steranes cannot reflect the source, depositional environment and maturity of organic matter. Thus, primarily based on analyses of the terpanes and steranes, it is suggested that organic matter in the Silurian and Carboniferous strata is derived mainly from lower organisms, while higher plants are predominant in the Triassic organic matter. This further indicates that the depositional environment may have transformed from the marine to continental facies in the Late Triassic. These results provide new evidence for the study of regional depositional evolution, and have enriched the study of biological composition of organic matter. In addition, the biomarker geochemistry of organic matter at high to over maturation stage is addressed.展开更多
A preciously undescribed Lower Triassic sequence of a series of multiple cycles of mud-lime rocks, with the argillaceous content decreasing upward while limestone becomes the dominant lithology in the upper part, cont...A preciously undescribed Lower Triassic sequence of a series of multiple cycles of mud-lime rocks, with the argillaceous content decreasing upward while limestone becomes the dominant lithology in the upper part, contains abundant fossils such as conodonts, ammonoids and bivalves. The Yinkeng Formation is the oldest Triassic unit represented, and it conformably overlies dark-gray thin-bedded argillaceous silicalite and intercalated grayish illite clay interbeds of the Upper Permian of Dalong Formation. Conodont samples collected from west Pingdingshan Section, one of four measured sections in Chaohu, yielded abundant Lower Triassic conodonts from the middle part of the Yinkeng Formation. Most interesting and unusual is the abundant occurrence of Platyvillosus in seven samples from the Flemingites-Euflemingites bearing (Smithian) mudstone, rhyolitic clay and limestone part of the section. The associated conodonts are Neospathodus dieneri type 1, N. dieneri type 2, N. dieneri type 3, N. cristagalli, N. waageni eowaageni (nov. subsp.), N. waageni elongata (nov. subsp.), N. waageni waageni, N. sp. G (nov. sp.), N . sp. L (nov. sp.), N . sp. H (nov. sp.), N. alberti, N. novaehollandiae, N. peculiaris, N . aff. discretus, N. conservativus, Parachirognathodus sp. and ramiform elements. The species Platyvillosus , which is restricted to a 1.32 m interval, reveals great variety in shape and denticle ornamentation pattern on the platform. The morphological study of the samples indicates that all speciemens with denticles on the upper surface can be included in intraspecific variation in Platyvillosus costatus (Staesche). Platyvillosus hamadai (Koike), marked by smooth upper surface, also appears to be connected by transitional forms in some samples. The fauna corresponds closely with that of the Taho limestone in Japan, although the depositional environments differ. The associated lithologies of the Yinkeng Formation within Chaohu area reflect a deeper and low energy remaining basin of the northern edge of the Lower Yangtze block.展开更多
Cyanobacterial blooms occur frequently in lakes due to eutrophication. Although a number of models have been proposed to forecast algal blooms, a good and applicable method is still lacking. This study explored a simp...Cyanobacterial blooms occur frequently in lakes due to eutrophication. Although a number of models have been proposed to forecast algal blooms, a good and applicable method is still lacking. This study explored a simple and effective mathematical-ecological model to evaluate the growth status and predict the population dynamics of Microcystis blooms. In this study, phytoplankton were collected and identified from 8 sampling sites in Chaohu Lake every month from July to October, 2010. The niche breadth and niche overlap of common species were calculated using standard equations, and the potential relative growth rates of Microcystis were calculated as a weighted-value of niche overlap. In July, the potential relative growth rate was 2.79 (a.u., arbitrary units) but then rapidly declined in the following months to -3.99 a.u. in September. A significant correlation (R=0.998, P<0.01) was found in the model between the net-increase in biomass of Microcystis in the field and the predicted values calculated by the niche model, we concluded that the niche model is suitable for forecasting the dynamics of Microcystis blooms. Redundancy analysis indicated that decreases in water temperature, dissolved oxygen and total dissolved phosphorus might be major factors underlying bloom decline. Based on the theory of community succession being caused by resource competition, the growth and decline of blooms can be predicted from a community structure. This may provide a basis for early warning and control of algal blooms.展开更多
基金Supported by the National Natural science Foundation of China(50379003)the Natural Science Foundation of Anhui Province and Science(01045201)Science and Technological Fund of Anhui Province for Outstanding Youth~~
文摘Composition and distribution of nitrogen in Chaohu Lake and Wabu Lake sediments were studied.The results showed that the mean total nitrogen content in Chaohu Lake and Wabu Lake was 0.533 g/kg and 0.265 g/kg respectively,and the primary composition of nitrogen was organic nitrogen(94%).The organic index indicated that the organic pollution degree of Wabu Lake was lower than that of Chaohu Lake.
文摘[Objective] The aim of the research was to reveal the influence mechanism of sediment-water exchange of nutrients in Chaohu Lake. [Method] The effects of environmental factors (overlying water, temperature, pH and dissolved oxygen concentration) on NH_4^+ release in sediment from Chaohu Lake were studied under controlled laboratory conditions. [Results] With the rising of temperature and the decrease of NH_4^+ concentration in overlying water, NH_4^+ released from sediment increased significantly. pH had a great effect on NH_4^+ release with a complicated mechanism. The largest release amount of NH_4^+ under anaerobic condition was about 6 times as much as that under aerobic condition. [Conclusion] This research would provide theoretical support for environmental management of Chaohu Lake in the project of leading water from the Yangtze River to Chaohu Lake.
基金supported by the National Science-technology Support Project of China (No.2010BAC69B02)the National Natural Science Foundation of China (No. 41203080)
文摘Temporal and spatial changes of total nitrogen （TN）, total phosphorus （TP） and chlorophyll-a （Chl-a） in a shallow lake, Lake Chaohu, China, were investigated using monthly monitoring data from 2001 through 2011. The results showed that the annual mean concentration ranges of TN, TP, and Chl-a were 0.08-14.60 mg/L, 0.02-1.08 mg/L, and 0.10-465.90 ~tg/L, respectively. Our data showed that Lake Chaohu was highly eutrophic and that water quality showed no substantial improvement during 2001 through 2011. The mean concentrations of TP, TN and Chl-a in the western lake were significantly higher than in the eastern lake, which indicates a spatial distribution of the three water parameters. The annual mean ratio of TN：TP by weight ranged from 10 to 20, indicating that phosphorus was the limiting nutrient in this lake. A similar seasonality variation for TP and Chl-a was observed. Riverine TP and NH4＋ loading from eight major tributaries were in the range of 1.56× 10^4-5.47 × 10^4 and 0.19 × 104-0.51 × 10^4 tons/yr over 2002-2011, respectively, and exceeded the water environmental capability of the two nutrients in the lake by a factor of 3-6. Thus reduction of nutrient loading in the sub-watershed and tributaries would be essential for the restoration of Lake Chaohu.
基金Major Program of Natural Science Research at University of Anhui Province, No.ZD200908 National Sci ence and Technology Support Program, No.2010BAK67B02+1 种基金 National Natural Science Foundation of China, No.41010104005 No.40971115This work is supported by the Tracing Origin Project of Chinese Civilization. We thank Dr. An Ran and Dr. Heim. Jordan in Purdue University, USA, for their kind help and valuable discussions.
文摘Based on the temporal-spatial distribution features of ancient settlement sites from the middle and late Neolithic Age to the Han dynasty in the Chaohu Lake Basin of Anhui Province, East China, using the methods of GIS combined with the reconstructed paleoen- vironment by the records of lake sediment since Holocene, the transmutation of ancient set- tlements with response to environmental changes in this area has been discussed. Studies show that the main feature of transmutation of ancient settlements from the middle and late Neolithic Age to the Han Dynasty was that the distribution of settlements in this area changed from high altitudes to low ones and kept approaching the Chaohu Lake with the passage of time. These could be the response to the climate change from warm-moist to a relatively warm-dry condition during the middle Holocene, leading to the lake level fluctuations. The large area of exposed land provided enough space for human activities. These indicate that the above changes in geomorphologic evolution and hydrology influenced by climate condi- tions affected the transmutation of ancient settlements greatly. The distribution pattern of settlement sites was that the number of sites in the west was more than in the east. This pattern may be related to the geomorphologic conditions such as frequent channel shifting of the Yangtze River as well as flood disasters during the Holocene optimum. Therefore, climate change was the inducement of the transmutation of ancient settlements in the Chaohu Lake Basin, which exerted great influence on the distribution, expansion and development of the ancient settlements.
基金ThisresearchissupportedbytheChinese" 973Program" (No .G2 0 0 0 0 7770 5 ) theNationalNaturalScienceFoundationofChina (No .40 0 72 0 11) theChinaNationalCommissiononStratigraphyandtheYichangCenterofStratigraphyandPaleontology .
文摘This paper reports a Lower Triassic inorganic carbon isotope profile from the North Pingdingshan Section in Chaohu, Anhui Province, China, which was situated in a deep part of the Lower Yangtze carbonate ramp. The δ ( 13 C) excursion shows two periods from the Permian Triassic boundary to the lower Spathian substage, corresponding to the ecosystem undergoing evolution and recovery after the end Permian mass extinction and related events. The first period starts at the δ ( 13 C) depletion caused by the mass extinction and evolves with a gradual δ ( 13 C) increase resulting from the development of some disaster taxa during the Induan. The strong Smithian δ ( 13 C) depletion in the second period might be formed by the collapse of the disaster ecosystem and the biotic recovery occurred with the explosive increase of bioproductivity in the Spathian. Thus the δ ( 13 C) excursion in the Lower Triassic expresses patterns of biotic evolution and recovery during the erratic ecosystem that followed the great end Permian mass extinction.
基金supported by the National Key Technology R&D Program in the 12th Five-Year Plan of China:Research & Development on Suitable Key Technologies of the Village Environmental Monitoring of China (No.2012BAJ24B01)
文摘The concentration and spatial distribution of persistent toxic substances （PTS） in the river sediment in Chaohu City, China were investigated. A total of nine surface sediments were collected and the selected PTS pollutants including six heavy metals and nineteen polybrominated diphenyl ethers （PBDEs） were analyzed. The mean heavy metal concentrations （in mg/kg, dry weight） ranged within 0.18-1.53 （Fig）, 50.08-200.18 （Cu）, 118.70-313.65 （Zn）, 50,77-310,85 （Cr）, 37.12-92.72 （Pb） and 13.29-197.24 （As）, and Cu, Zn and As have been regarded as the main metal pollutants, The levels of PBDEs （1.2-12.1 ng/g） and BDE-209 （2.4--30.5 ng/g） were at the middle level of the global range. BDE-209 was the predominant congener （67.0%-85.7%）, which agrees with the fact that technical deca-BDE mixtures are the dominant PBDE formulation in China. The relative high level of PTS poUutants in the western part of the city is probably owing to the intensive agricultural activities and lack of sewerage system there. The ecological risk assessment with the sediment quality guidelines （$OGs） indicates that the urban river sediments in the city have been heavily contaminated by heavy metals with probable ecotoxicological impacts on freshwater organisms and the main toxic pollutants are Hg and As, The results of current study imply that the city, and perhaps many other small cities in China as well, requires immediate pollution control measures with emphasis on not only conventional organic pollutants but also on PTS such as heavy metals and PBDEs.
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.
基金supported by the Ministry of Science and Technology project (no. 2006FY120300-11)Ministry of Education project (no. 200804910503)National Natural Science Foundation of China (nos. 40830212, 40921062, 40972003)
文摘Since the West Pingdingshan Section in Chaohu was proposed as the candidate of the Global Stratotype Section and Point of the Induan-Olenekian boundary in 2003, the Lower Triassic of Chaohu has been extensively studied. Based on the studies on the Lower Triassic of Chaohu, （1） a continuous conodont zonation is established, which has become an important reference for Lower Triassic stratigraphic correlation over the world; （2） the First Appearance Datum of conodont Neospathodus waageni was suggested and has been basically accepted as the primary marker to define the InduanOienekian boundary; （3） a characteristic Lower Triassic excursion of carbon isotopes was brought to light and has been proven to be not only an excellent index for the stratigraphic correlation but also a unique indication for the perturbation of ecological environments in the aftermath of the end-Permian mass extinction; （4） a magnetostratigraphic sequence is constituted with a certain biostratigraphic control in the low-latitude region and it presents an important correlation to the Boreal sequence; （5） a cyclostratigraphic study provides an alternative method to constrain the age of the chronostratigraphic units; and （6） a scheme of the Olenekian subdivision is recently suggested to define the boundary between the Smithian and Spathian Substages. In addition, Chaohu is also the type locality of the Chaohuan Stage, the upper stage of the Lower Triassic in the China Chronostratigraphic System.Thus, the Lower Triassic of Chaohu is not only a classic sequence in South China, but also a key reference sequence to the investigation of the corresponding stratigraphy and geological events over the world. The recent achievements are viewed here for an overall understanding of the sequence. Then the current situation of the Induan-Olenekian and Smithian-Spathian boundaries is discussed to provide a reference for later works.
基金Under the auspices of the Key Technology R&D Program of Anhui Province,China (No. 07010302165)
文摘A total of 30 surface sediments samples from the estuary wetland of the Tangxi River, Chaohu Lake Basin were obtained and tested. Enrichment factor （EF） and geoaccumulation index （Igeo） as well as multivariate statistical analysis methods including Factor Analysis （FA） and Hierarchical Cluster Analysis （HCA） were applied for the assessment of heavy metal pollution in surface sediments. The results of EF values show that the pollution of copper （Cu） and cadmium （Cd） occurs in the estuarine sediments, and that zinc （Zn）, lead （Pb） and chrome （Cr） may originate from crustal materials or natural weathering process. The mean EF values of the five heavy metals are in the decreasing order： Cu〉Cd）Zn〉Pb〉Cr. Based on the lgeo of target heavy metals, the surface sediments collected from the study area can be approximately categorized as unpolluted with Zn, Pb and Cr, and moderately polluted with Cu and Cd. The degree of heavy metal pollution decreases in the order of Cu〉Cd〉Zn〉Pb〉Cr. Three groups of pollution factors are presented from FA： Zn-TOC, Cu-Cd and Cr-Pb, which respectively accounte for 27.22%, 25.20% and 21.05% of variance. By means of HCA, a total number of seven groups are distinguished from 30 sampling sites. Results indicate that Cu and Cd are the prior controlled pollutants in the estuarine sediments of the Tangxi River.
基金supported by the Hundred Talents Program of Chinese Academy of Sciencesthe National Natural Science Fundation of China for Distinguished Young Scholar(10825211)
文摘Based on the remote sensing images of algae, the present work analyzes the horizontal distribution characteristics of algal blooms in Chaohu Lake, China, which also reveals the frequency of algal blooms under different wind directions. Further, an unstructured-grid, three-dimensional finite-volume coastal ocean model （FVCOM） is applied to investigate the wind-induced currents and the transport pro- cess to explain the reason why algal blooms occur at the detected places. We first deduce the primary distribution of biomass from overlaid satellite images, and explain the formation mechanism by analyzing the pollution sources, and simulating the flow field and transportation process under prevailing wind over Chaohu Lake. And then, we consider the adjustment action of the wind on the corresponding day and develop a two-time scale approach to describe the whole formation process of algae horizontal distribution in Chaohu Lake. That is, on the longer time scale, i.e., during bloom season, prevailing wind determines the primary distribution of biomass by inducing the characteristic flow field; on the shorter time scale, i.e., on the day when bloom occurs, the wind force adjusts the primary distribution of biomass to form the final distribution of algal bloom.
基金Supported by the Special Fund for the Control and Management of Chaohu Lake of the National Key Technology R&D Program,China(2008ZX07103-005)the Special Fund for the Control and Management of Huaihe River of the National Key Technology R&D Program,China(2008ZX07010-004)+1 种基金National Natural Science Foundation of China(40073030,40972092,41172121)the Natural Science Foundation of Anhui Province,China(090413083)~~
文摘[Objective] To study the characteristics and effects of inorganic nitrogen in east water-source and inflow rivers of Chaohu Lake. [Method] The speciation and distribution characteristics of dissolvable inorganic nitrogen （DIN） in east water-source and inflow rivers of Chaohu Lake were investigated, and their effects on water qual- ity were examined. [Result] The concentrations of NH3-N and NO2--N were the high in flood season, and low in non-flood season, while the concentration of NO3--N pre- sented the opposite trend; the concentration of NO3--N was the highest in Shuangqiao estuary, where the pollution was the worst. DIN in Zhegao estuary and Xiaozhegao estuary was mainly caused by domestic sewage and industrial wastewaters; surface runoff and pollution from ships contribute the most to the DIN content in Shuangqiao estuary. [Conclusion] This study provided basic data and theoretical basis for the control and management of eutrophication in Chaohu Lake.
基金ThisresearchissupportedbytheNationalNaturalScienceFoundationofChina (No .40 0 72 0 11) theMinistryofScienceandTechnology (No .2 0 0 1DEA2 0 0 2 0 )andtheChinese"973Program" (No .G2 0 0 0 0 7770 5 ) .
文摘This paper proposes a scheme for the definition of the Lower Triassic Induan Olenekian boundary (IOB) based on investigation of sections in Chaohu, Anhui Province, China as well as data accumulated from other studies elsewhere. The conodont Neospathodus waageni is suggested as the index fossil of the boundary. According to the FAD of N. waageni , the IOB is at the base of bed 25 2 of the West Pingdingshan Section in Chaohu, 42.19 m above the Permian Triassic boundary, and it is slightly higher than the base of the Flemingites Euflemingites Ammonoid Zone at the section.
基金Under the auspices of the National Natural Science Foundation of China (No. 40571162)the Natural Science Foun-dation of Anhui Province (No. 050450401)
文摘Flood is one kind of unexpected and the most common natural disasters, which is affected by many factors and has complex mechanism. At home and abroad, there is still no mature theory and method used for the long-term forecast of natural precipitation at present. In the present paper the disadvantages of grey GM (1, 1) and Markov chain are ana- lyzed, and Grey-Markov forecast theory about flood is put forward and then the modifying model is developed by making prediction of Chaohu Lake basin. Hydrological law was conducted based on the theoretical forecasts by grey system GM (1, 1) forecast model with improved Markov chain. The above method contained Stat-analysis, embodying scientific approach, precise forecast and its reliable results.
基金Under the auspices of Tackling Key Program for Science and Technology of Anhui Province (No. 07010302165)Natural Science Foundation of Anhui Province (No. 050450303)
文摘An indicator system closely connected with eco-environment, in which indicator involves in such fields as society, economy, resources, environment and ecology, is first proposed for eco-environmental quality assessment. Then, a hierarchical model with four levels is established by virtue of these indicators and attributes. In the model, weights of indicators and attributes are determined by combining Delphi method with the Analytic Hierarchy Process (AHP) and a statistic method is used to eliminate the influences arising from the differences in dimension and magnitude of indicators. On these grounds, an AHP-statistics model is provided for regional eco-environmental quality assessment. As a case, such AHP-statistics model is utilized in the dynamic analysis of regional eco-environmental assessment in Chaohu Lake basin. Study results show that natural environmental quality in the watershed was in the declining state while social environmental quality was in a markedly improved situation from 1996, and the synthetic eco-environmental quality was gradually and slowly improved under the common influences of both natural and social environmental factors. Example of application testified the capacities of above methodology to evaluate the real and dynamic state of regional eco-environmental quality.
基金Under the auspices of Sciences Fund of Anhui Provincial Bureau of Education (No. 2004kj165 zd), High Edu-cation Teaching Research of Anhui Province (No. 2005021), the Natural Sciences Fund of Anhui Province, Key Subject of Physi-cal Geographyof Anhui Normal University
文摘By interpreting the remote sensing data of aerial photos and satellite images in different time, combining with field investigation, landform and water level observation, collecting data of weather, hydrology in Chaohu Lake, Anhui Province from 1957 to 2003, the reasons for collapse of Chaohu lakeshore were analyzed. The results are as follows: 1) The collapse of the Chaohu lakeshore is controlled macroscopically by two sets of north-east and the north-west faults, and the degree of collapse is determined microcosmically by lithology. 2) The constant change of water level, resulting from precipitation, wind speed and its direction, is one of the main reasons for intermittence collapse. 3) The soil and water loss or mud and sand filling up, resulting from artificial factors, such as inconsequence control of Chaohu sluice or irrational agricultural and industrial activities, etc., can uplift the lake′s bed and drive water level up. The high water level also results in the collapse. Judging from the above mentioned reasons for the collapse, we have proposed some countermeasures: 1) Putting the lakeshore slope protection project such as stone and cement mortar into practice, and upstream slope should be 1∶2.5 or 1∶3, some parts of them should be 1∶4, if they were not stable. The back slope, which is from Gui Mountain to Zhongmiao Temple, should be 1∶1.5-1∶3. 2) Constructing a greenbelt for the lakeshore, planting some vegetation such as osier, bulrush and poplar, to resist waves between the high and the low water level. 3) Controlling Chaohu Lake water level scientifically. Corrosion of lakeshore that contains gravel clay and ferruginous-manganese concretionary structures, can decrease at low water level. 4) Renovating Chaohu Lake drainage area, strengthening the administration and supervision, breaking regionalism and establishing special administration organization.
基金the National Natural Science Foundation of China (Nos. 40621002, 90714010, 40574028)the State Key Laboratory of Geological Processes and Mineral Resources (GPMR2007).
文摘The Lower Triassic in Chaohu （巢湖） area, Anhui （安徽） Province, China, is well developed and its sequence is typical in South China. After a brief introduction of the Induan-Olenekian boundary of Chaohu, this article presents some new data on conodonts. More than ten times of conodont samplings and investigations have recovered thousands of conodont specimens, which are especially rich in the Induan-Olenekian boundary strata at the West Pingdingshan Section in Chaohu City, Anhui Province. The most distinctive forms are the conodonts of the Neospathodus dieneri group and N. waageni group. The first occurrence of N. waageni eowaageni, which is regarded as the indicator of the Induan-Olenekian boundary, is situated at 40.49 m above the base of Yinkeng （殷坑） Formation. Some key conodonts and seven new specimens are introduced.
基金supported by the National Natural Science Foundation of China (Nos. 40839903 and 40621002)the 111 Project (No. B08030)
文摘This article reports a radiolarian fauna from the upper Dalong（大隆） Formation,Ping-dingshan（平顶山）,Chaohu（巢湖）,Anhui（安徽） Province,which includes 15 genera and 23 species.One new species,Copicyntra tongi Gui and Feng n.sp.,is described.Comparison of the fauna,lithology and biotic associations with those from Meishan（煤山） D and Dongpan（东攀） sections shows that the Dalong Formation in the Pingdingshan Section is deposited in a deep-water shelf basin,about 60-200 m in depth.On the basis of the biotic composition,diversity and morphology,the microfossil fauna from the Pingdingshan Section can be divided into three sedimentary assemblages and the extinction proc-esses of the assemblages are discussed.
基金funded by the National Natural Science Foundation of China (Grant Nos. 41072090 and 40872086)the Undergraduate Innovation Program of Nanjing Universitythe Open Project Program of Key Laboratory of Tectonics and Petroleum Resources (China University of Geosciences), Ministry of Education (Grant No. TPR-2010-26)
文摘Marine strata are widely exposed in the Hushan and Chaohu areas, Lower Yangtze region. As biomarker geochemistry of the strata has not been well documented, this paper deals with the biomarker composition of representative samples collected from the Silurian, Carboniferous and Triassic systems and their geological implications, thus providing clues to marine organic matter. On the basis of experimental results, it is shown that abundant biomarkers (e.g. n-alkanes, isoprenoids, terpanes and steranes) were detected. As organic matter in the strata is highly to over mature in general based on petrologic microobservation, some biomarkers (mainly n-alkanes) except terpanes and steranes cannot reflect the source, depositional environment and maturity of organic matter. Thus, primarily based on analyses of the terpanes and steranes, it is suggested that organic matter in the Silurian and Carboniferous strata is derived mainly from lower organisms, while higher plants are predominant in the Triassic organic matter. This further indicates that the depositional environment may have transformed from the marine to continental facies in the Late Triassic. These results provide new evidence for the study of regional depositional evolution, and have enriched the study of biological composition of organic matter. In addition, the biomarker geochemistry of organic matter at high to over maturation stage is addressed.
基金ThispaperissupportedbytheNationalNaturalScienceFoundationofChina (No .40 0 72 0 1 1 ) ,theMinistryofScienceandTechnology (No .2 0 0 1D2 0 0 2 0 ) ,theChinese"973Program" (No .G2 0 0 0 0 7770 5)andLaboratoryofEarthSurfaceSystem ,HubeiProvince
文摘A preciously undescribed Lower Triassic sequence of a series of multiple cycles of mud-lime rocks, with the argillaceous content decreasing upward while limestone becomes the dominant lithology in the upper part, contains abundant fossils such as conodonts, ammonoids and bivalves. The Yinkeng Formation is the oldest Triassic unit represented, and it conformably overlies dark-gray thin-bedded argillaceous silicalite and intercalated grayish illite clay interbeds of the Upper Permian of Dalong Formation. Conodont samples collected from west Pingdingshan Section, one of four measured sections in Chaohu, yielded abundant Lower Triassic conodonts from the middle part of the Yinkeng Formation. Most interesting and unusual is the abundant occurrence of Platyvillosus in seven samples from the Flemingites-Euflemingites bearing (Smithian) mudstone, rhyolitic clay and limestone part of the section. The associated conodonts are Neospathodus dieneri type 1, N. dieneri type 2, N. dieneri type 3, N. cristagalli, N. waageni eowaageni (nov. subsp.), N. waageni elongata (nov. subsp.), N. waageni waageni, N. sp. G (nov. sp.), N . sp. L (nov. sp.), N . sp. H (nov. sp.), N. alberti, N. novaehollandiae, N. peculiaris, N . aff. discretus, N. conservativus, Parachirognathodus sp. and ramiform elements. The species Platyvillosus , which is restricted to a 1.32 m interval, reveals great variety in shape and denticle ornamentation pattern on the platform. The morphological study of the samples indicates that all speciemens with denticles on the upper surface can be included in intraspecific variation in Platyvillosus costatus (Staesche). Platyvillosus hamadai (Koike), marked by smooth upper surface, also appears to be connected by transitional forms in some samples. The fauna corresponds closely with that of the Taho limestone in Japan, although the depositional environments differ. The associated lithologies of the Yinkeng Formation within Chaohu area reflect a deeper and low energy remaining basin of the northern edge of the Lower Yangtze block.
基金Supported by the National Basic Research Program of China (973 Program)(No. 2008CB418002)the National Major Programs of Water Body Pollution Control and Remediation (Nos. 2009ZX07106-001, 2009ZX07104-005)the National Natural Science Foundation of China (No. 30830025)
文摘Cyanobacterial blooms occur frequently in lakes due to eutrophication. Although a number of models have been proposed to forecast algal blooms, a good and applicable method is still lacking. This study explored a simple and effective mathematical-ecological model to evaluate the growth status and predict the population dynamics of Microcystis blooms. In this study, phytoplankton were collected and identified from 8 sampling sites in Chaohu Lake every month from July to October, 2010. The niche breadth and niche overlap of common species were calculated using standard equations, and the potential relative growth rates of Microcystis were calculated as a weighted-value of niche overlap. In July, the potential relative growth rate was 2.79 (a.u., arbitrary units) but then rapidly declined in the following months to -3.99 a.u. in September. A significant correlation (R=0.998, P<0.01) was found in the model between the net-increase in biomass of Microcystis in the field and the predicted values calculated by the niche model, we concluded that the niche model is suitable for forecasting the dynamics of Microcystis blooms. Redundancy analysis indicated that decreases in water temperature, dissolved oxygen and total dissolved phosphorus might be major factors underlying bloom decline. Based on the theory of community succession being caused by resource competition, the growth and decline of blooms can be predicted from a community structure. This may provide a basis for early warning and control of algal blooms.
