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Sample records for lake lake taihu

  1. Microplastics in Taihu Lake, China.

    Science.gov (United States)

    Su, Lei; Xue, Yingang; Li, Lingyun; Yang, Dongqi; Kolandhasamy, Prabhu; Li, Daoji; Shi, Huahong

    2016-09-01

    In comparison with marine environments, the occurrence of microplastics in freshwater environments is less understood. In the present study, we investigated microplastic pollution levels during 2015 in Taihu Lake, the third largest Chinese lake located in one of the most developed areas of China. The abundance of microplastics reached 0.01 × 10(6)-6.8 × 10(6) items/km(2) in plankton net samples, 3.4-25.8 items/L in surface water, 11.0-234.6 items/kg dw in sediments and 0.2-12.5 items/g ww in Asian clams (Corbicula fluminea). The average abundance of microplastics was the highest in plankton net samples from the southeast area of the lake and in the sediments from the northwest area of the lake. The northwest area of the lake was the most heavily contaminated area of the lake, as indicated by chlorophyll-α and total phosphorus. The microplastics were dominated by fiber, 100-1000 μm in size and cellophane in composition. To our best knowledge, the microplastic levels measured in plankton net samples collected from Taihu Lake were the highest found in freshwater lakes worldwide. The ratio of the microplastics in clams to each sediment sample ranged from 38 to 3810 and was negatively correlated to the microplastic level in sediments. In brief, our results strongly suggest that high levels of microplastics occurred not only in water but also in organisms in Taihu Lake.

  2. Eutrophication status and control strategy of Taihu Lake

    Institute of Scientific and Technical Information of China (English)

    Limin ZHANG; Minfang XIA; Lei ZHANG; Chun WANG; Jilai LU

    2008-01-01

    The water quality and eutrophication status of Taihu Lake in recent years are presented and the pollution trends are analyzed. It is shown that because of unreas-onable industrial structures, pollution discharge per GDP is high within the Taihu basin, and the pollution discharge from point and-non-point sources exceed the basin's environmental carrying capacity. Especially, excessive pollutants containing nitrgogen and phosphorus are being discharged. Moreover, eutrophication may also result from internal pollution sources such as the release of nutrient elements from sediment. All these factors have resulted in-the water quality deterioration of Taihu Lake. To solve this environmental problem, possible con-trol strategies are summarized, including the control of internal pollution sources and inflow-river pollution, eco-logical restoration and reconstruction of the degraded lakeside zone ecosystem, clean water diversion, dredging, and manual algae removal.

  3. Maintaining healthy rivers and lakes through water diversion from Yangtze River to Taihu lake in Taihu Basin

    Directory of Open Access Journals (Sweden)

    Hao-yun WU

    2008-09-01

    Full Text Available On the basis of the Taihu water resources assessment, an analysis of the importance and rationality of the water diversion from the Yangtze River to Taihu Lake in solving the water problem and establishing a harmonious eco-environment in the Taihu Basin is performed. The water quantity and water quality conjunctive dispatching decision-making support system, which ensures flood control, water supply and eco-aimed dispatching, is built by combining the water diversion with flood control dispatching and strengthening water resources monitoring and forecasting. With the practice and effect assessment, measures such as setting the integrated basin management format, further developing water diversion and improving the hydraulic engineering projects system and water monitoring system are proposed in order to maintain healthy rivers and guarantee the development of the economy and society in the Taihu Basin.

  4. Maintaining healthy rivers and lakes through water diversion from Yangtze River to Taihu Lake in Taihu Basin

    Institute of Scientific and Technical Information of China (English)

    Wu Haoyun; Hu Yan

    2008-01-01

    On the basis of the Taihu water resources assessment, an analysis of the importance and rationality of the water diversion from the Yangtze River to Taihu Lake in solving the water problem and establishing a harmonious eco-environment in the Taihu Basin is performed. The water quantity and watcr quality conjunctive dispatching decision-making support system, which ensures flood control, water supply and eco-aimed dispatching, is built by combining the water diversion with flood control dispatching and strengthening water resources monitoring and forecasting. With the practice and effect assessment, measures such as setting the integrated basin management format, further developing water diversion and improving the hydraulic engineering projects system and water monitoring system are proposed in order to maintain healthy rivers and guarantee the development of the economy and society in the Taihu Basin.

  5. Analysis of black water aggregation in Taihu Lake

    Directory of Open Access Journals (Sweden)

    Gui-hua LU

    2011-12-01

    Full Text Available Black water aggregation (BWA in Taihu Lake is a disaster for the lake environment. It is a phenomenon resulting from water environmental deterioration and eutrophication caused by accumulation of pollutants in the lake, according to research on the water quality, pollutants of BWA, and occurrence mechanisms of BWA. Dead algae are the material base of BWA, the polluted sediment is an important factor for the formation of BWA, and hydrological and meteorological conditions such as sun light, air temperature, wind speed, and water flow are the other factors that may lead to the formation of BWA. Thioether substances such as dimethyl trisulfide are the representative pollutants of BWA. Parameters such as chlorophyll-a, DO, pH, and water temperature are sensitive indicators of BWA. Measures such as algae collection, ecological dredging, pollution control, and water diversion from the Yangtze River to the lake, are effective, and strengthening aeration is an emergency measure to control BWA.

  6. Integrating three lake models into a Phytoplankton Prediction System for Lake Taihu (Taihu PPS) with Python

    NARCIS (Netherlands)

    Huang, J.C.; Gao, J.F.; Hormann, G.; Mooij, W.M.

    2012-01-01

    In the past decade, much work has been done on integrating different lake models using general frameworks to overcome model incompatibilities. However, a framework may not be flexible enough to support applications in different fields. To overcome this problem, we used Python to integrate three lake

  7. Integrating three lake models into a Phytoplankton Prediction System for Lake Taihu (Taihu PPS) with Python

    NARCIS (Netherlands)

    Huang, J.; Gao, J.; Hörmann, G.; Mooij, W.M.

    2012-01-01

    In the past decade, much work has been done on integrating different lake models using general frameworks to overcome model incompatibilities. However, a framework may not be flexible enough to support applications in different fields. To overcome this problem, we used Python to integrate three lake

  8. Bioaccumulation of heavy metals in fishes from Taihu Lake, China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The Cr, Zn, Cu, Cd, Pb contents were determined in Cyprinus carpio Linnaeus, Carassius auratus Linnaeus, Hypophthalmichthys molitrix and Aristichthys nobilis which were caught from Meiliang Bay, Lake Taihu, a large, shallow and eutrophic lake of China. The results showed that, (1) the Cr, Cu, Pb, Cd contents in the edible parts of four fish species were much lower than Chinese Food Health Criterion (1994), but the Zn contents were higher than the Criterion; (2) Cd contents were the highest in the liver of fish, Pb contents were almost the same in all organs of fish, the Cr contents mainly enriched in the skin and gonads, Zn contents were the highest in the gonad (♀), and Cu contents were the highest in the liver; (3) the total metal accumulation was the greatest in the liver and the lowest in the muscle. The total metal accumulation was the highest in C. auratus L. This investigation indicated that fish products in Taihu Lake were still safe for human consumption, but the amount consumed should be controlled under the Chinese Food Health Criterion to avoid excessive intake of Zn.

  9. SEDIMENT PROPERTIES AND DYNAMICS IN THE TAIHU LAKE, CHINA

    Institute of Scientific and Technical Information of China (English)

    Liancong LUO; Boqiang QIN; Guang GAO; Guangwei ZHU; Jinshan ZHANG

    2006-01-01

    Time-series measurements of wave, current and suspended sediment concentration (SSC) were made at three sites (Sites 1-3) and sediment samples were collected at different locations (Sites 4-7) in Lake Taihu. The significant wave height, length and period during the observation were 0.155m,3.45m and 1.9s and the mean current speed was 0.08m/s. The size distribution results show that the sediment is well sorted, coarse-skewed and very leptokurtic in the upper 10cm and clay and fine silt can account for more than 70% of the total within this depth. The median size remains constant vertically in the top 10cm in the eastern, southern, and northern areas of the lake, but changes significantly in the eastern area resulting from the short retention time of water in this area. The realistic settling velocity of suspended particles varies in the range of 0.01~0.05 cm s-1and they sink in a flocculated form rather than individually. Based on a simple mass flux model, the sediment erosion rate was estimated to range between 10-7 and 10-5kg/m2.s. The results in this study can be a great contribution to the development of a sediment transportation model in Lake Taihu.

  10. Characteristics of petroleum contaminants and their distribution in Lake Taihu, China

    Directory of Open Access Journals (Sweden)

    Guo Jixiang

    2012-08-01

    Full Text Available Abstract Background Taihu Lake is a typical plain eutrophic shallow lake. With rapidly economic development of the lake area, the petroleum products and oil wastewater produced in various processes have been inevitably discharged into Taihu Lake. As the major fresh water resource in the economically developed region of Yangtze River Delta, the water quality and environmental condition of Taihu Lake have the direct bearing on the natural environment and sustainable development of economy in this region. For this reason we carried out the study to explore the composition, distribution characteristics and sources of petroleum contaminants in Taihu Lake. The aim of this study was to provide the basis for standard management and pollution control of the Taihu Lake environment. Results The result showed that water samples from near industrial locations were of relatively higher petroleum contaminants concentrations. The oil pollutants concentrations in different areas of Lake Taihu ranged from 0.106 mg/L to 1.168 mg/L, and the sequence of total contents distribution characteristics of petroleum pollutants from high to low in different regions of Taihu Lake was: “Dapu”, “Xiaomeikou”, “Zhushan Bay”, “Lake center”, “Qidu”. The results showed that total concentrations of n-alkanes and PAHs ranged from 0.045 to 0.281 mg/L and from 0.011 to 0.034 mg/L respectively. In the same region, the concentrations of hydrocarbon pollutants in the surface and bottom of the lake were higher than that in the middle. Conclusion This paper reached a conclusion that the petroleum contaminants in Taihu Lake mainly derived from petroleum pollution caused by human activities as indicated by OEP, bimodal distribution, CPI, Pr/Ph ratio, the LMW/HMW ratio and other evaluation indices for sources of n-alkanes and polycyclic aromatic hydrocarbons (PAHs.

  11. Study on the simulation of transparency of Lake Taihu under different hydrodynamic conditions

    Institute of Scientific and Technical Information of China (English)

    PANG; Yong; LI; Yiping; LUO; Liancong

    2006-01-01

    It was indicated in this study that there were negative relations between the concentrations of suspended solid (SS) and transparency according to the analysis of measured data of Lake Taihu. Their relations in pervious studies were reviewed, which showed that the changes of transparency in Lake Taihu could be reflected by simulating suspended solid concentration (SSC). Measured data showed that the changes of SSC with wind speed were similar at different water depths.SSC increased with the increasing of wind speed. Both wave and lake current of Lake Taihu had positive relations with SSC. However, wave was the main factor affecting sediment suspension, while flow took the second place. In this study, a numerical model coupling lake current, wave and SSC of Lake Taihu was developed. In the SS model, the combined effects of wave and current were included.The amounts of suspended and deposited sediments near the lake bed surface layer were treated separately. The stochastic characteristics of turbulent flow pulsation near lake beds were also considered, and the start-up conditions of sediment suspension were introduced to the model. The model elucidated the mutual exchange processes between sediment particles in SS and active sediments within and on the bed surface layer. Simulated results showed that lake current had relatively significant effects on the SSC at littoral areas of Lake Taihu, while SSC at the central area of the lake was mainly influenced by wave. The changes of transparency with SSC were simulated for Lake Taihu using this model. Calculated results were validated by measured data with good fitness, which indicated that the model is basically suitable for the simulation and prediction of transparency of Lake Taihu.

  12. A critical review of the development, current hotspots, and future directions of Lake Taihu research from the bibliometrics perspective.

    Science.gov (United States)

    Zhang, Yunlin; Yao, Xiaolong; Qin, Boqiang

    2016-07-01

    Lake Taihu, as the important drinking water source of the Yangtze River Delta urban agglomeration and the third largest freshwater lake in China, has experienced serious lake eutrophication and water quality deterioration in the past three decades. Growing scientific, political, and public attention has been given to the water quality of Lake Taihu. This study aimed to conduct a comparative quantitative and qualitative analysis of the development, current hotspots, and future directions of Lake Taihu research using a bibliometric analysis of eight well-studied lakes (Lake Taihu, Lake Baikal, Lake Biwa, Lake Erie, Lake Michigan, Lake Ontario, Lake Superior and Lake Victoria) around the world based on the Science Citation Index (SCI) database. A total of 1582 papers discussing Lake Taihu research were published in 322 journals in the past three decades. However, the first paper about Lake Taihu research was not found in the SCI database until 1989, and there were only zero, one, or two papers each year from 1989 to 1995. There had been rapid development in Lake Taihu research since 1996 and a sharp increase in papers since 2005. A keyword analysis showed that "sediment," "eutrophication", "Microcystis aeruginosa", "cyanobacterial blooms", and "remote sensing" were the most frequently used keywords of the study subject. Owing to its significant impact on aquatic ecosystems, a crucial emphasis has been placed on climate change recently. In addition, the future focuses of research directions, including (1) environmental effects of physical processes; (2) nutrient cycles and control and ecosystem responses; (3) cyanobacteria bloom monitoring, causes, forecast and management; (4) eutrophication and climate change interactions; and (5) ecosystem degradation mechanism and ecological practice of lake restoration, are presented based on the keyword analysis. Through multidisciplinary fields (physics, chemistry, and biology) cross and synthesis study of Lake Taihu, the

  13. Modeling of sediment and heavy metal transport in Taihu Lake, China

    Institute of Scientific and Technical Information of China (English)

    WANG Chao; SHEN Chao; WANG Pei-fang; QIAN Jin; HOU Jun; LIU Jia-jia

    2013-01-01

    With the current rapid economic growth,heavy metal pollution has become one of the key issues in the Taihu Lake.Although heavy metal pollution levels and distributions of the Taihu Lake have previously been described,an effective model to describe the transport process of heavy metals between the water column and sediment bed for this lake is not available.It is known that heavy metals in the water column can be related to the resuspension of sediment in the lake bed.In this study,we set up a coupled model of relating hydrodynamics,sediment and heavy metals based on Environmental Fluid Dynamics Code (EFDC),and applied it to Taihu Lake,China.For calibration and validation of the model,we employed two series of field sampling data taken all over Taihu Lake during April and July of 2009.The results show that the hydrodynamics simulations of the coupled model agree with the observations reasonably well and the sediment and heavy metal model shows similar variation trends during the simulation.Our results indicate that the model can be used for simulating the sediment and heavy metal transport process in the Taihu Lake and here we provide an effective tool for water quality management at small time scales.

  14. Sediment resuspension under action of wind in Taihu Lake, China

    Institute of Scientific and Technical Information of China (English)

    Sha-sha ZHENG; Pei-fang WANG; Chao WANG; Jun HOU

    2015-01-01

    A field study was undertaken to investigate the changes of the current speed, wave parameters and sediment resuspension under different wind speeds in the Taihu Lake. The Acoustic Doppler Current Profiler (ADCP) and MIDAS DWR Wave Recorder were used to collect the data of currents and waves, respectively. The characteristics of sediment resuspension were investigated by a layered sampling technology. The measurement results showed that the current speed increased in direct proportion with the wind speed. Vertical distributions of the current speed represented significant inflection points at 0.4 of the relative water depth. Both the upper and lower layers followed logarithmic distributions. The mean wind speed and wave parameters (wave height and wave energy density) showed exponential distributions, meanwhile similar distribution was found between the mean wind speed and current speed. With rising surface wind, a corresponding increase in the concentration and particle size of the Suspended Particulate Matter (SPM) was observed in the water column. Different kinds of particles could influence the SPM concentration in the water column. The critical wind speed of sediment resuspension and the corresponding sediment incipient shear stress was found to be 3.7 – 4.0 m s-1 and 0.011 N m-2,respectively. The results of this study can be used to help understand and predict the changes of flow structure and water quality induced by different wind disturbances in shallow lakes.

  15. Estimation on dynamic release of phosphorus from wind-induced suspended particulate matter in Lake Taihu

    Institute of Scientific and Technical Information of China (English)

    FAN; Chengxin; ZHANG; Lu; QIN; Boqiang; WANG; Sumin; HU; We

    2004-01-01

    Through man-made disturbance experiments, the corresponding relationships between suspended particulate matter (SPM) and wind speed in different lake areas were simulated, the physicochemical formal transformation and biological mineralizing and decaying processes of phosphorus in SPM were studied, the contribution of phosphorus transformation to phosphorus loading of the water of Lake Taihu was quantitatively estimated. The results show SPM in physicochemical transformed to soluble reactive phosphorus (SRP), and the contribution of the total external loading of Lake Taihu, namely 4.7-7.5 times as much as SRP loading entering the lake by the rivers; thus it is the important source in dynamical internal loading of the lake. The determining factors for dynamical internal loading in lakes are organic phosphorus content in suspended solid and its biological transition availability.

  16. Aquatic vegetation in response to increased eutrophication and degraded light climate in Eastern Lake Taihu: Implications for lake ecological restoration

    Science.gov (United States)

    Zhang, Yunlin; Liu, Xiaohan; Qin, Boqiang; Shi, Kun; Deng, Jianming; Zhou, Yongqiang

    2016-04-01

    Terrestrial and aquatic ecosystem degradation is widely recognized as a major global environmental and development problem. Although great efforts have been made to prevent aquatic ecosystem degradation, the degree, extent and impacts of this phenomenon remain controversial and unclear, such as its driving mechanisms. Here, we present results from a 17-year field investigation (1998-2014) of water quality and a 12-year remote sensing mapping (2003-2014) of the aquatic vegetation presence frequency (VPF) in Eastern Lake Taihu, a macrophyte-dominated bay of Lake Taihu in China. In the past 17 years, nutrient concentrations and water level (WL) have significantly increased, but the Secchi disk depth (SDD) has significantly decreased. These changes were associated with increased lake eutrophication and a degraded underwater light climate that further inhibited the growth of aquatic vegetation. In Eastern Lake Taihu, increased nutrients, chlorophyll a and WL, and a decreased SDD were all significantly correlated with a decreased VPF. NH4+-N concentration and SDD/WL were the most important controlling factors for VPF. Therefore, increased anthropogenic nutrient inputs and a degraded underwater light climate surely result in a decreased VPF. These results elucidate the driving mechanism of aquatic vegetation degradation and will facilitate Lake Taihu ecological restoration.

  17. Dominant genera of cyanobacteria in Lake Taihu and their relationships with environmental factors.

    Science.gov (United States)

    Feng, Lijun; Liu, Shiyou; Wu, Wenxian; Ma, Jiawen; Li, Pei; Xu, Hailing; Li, Na; Feng, Yaoyu

    2016-07-01

    Cyanobacterial blooms in freshwaters have become one of the most widespread of environmental problems and threaten water resources worldwide. Previous studies on cyanobacteria in Lake Taihu often collected samples from one site (like Meiliang Bay or Zhushan Bay) and focused on the variation in patterns or abundance of Microcystis during the blooming season. However, the distribution of cyanobacteria in Lake Taihu shows differing pattern in various seasons. In this study, water samples were collected monthly for one year at five sites in Lake Taihu with different trophic status and a physicochemical analysis and denaturing gradient gel electrophoresis (DGGE) were conducted. DGGE fingerprint analysis showed that Microcystis (7/35 bands) and Synechococcus (12/35 bands) were the two most dominant genera present during the study period at all five sites. Cyanobium (3/35 bands) was the third most common genus which has seldom been previously reported in Lake Taihu. Redundancy analysis (RDA) indicated that the cyanobacterial community structure was significantly correlated with NO3 (-)-N, CODMn, and NH4 (+)-N in the winter and spring, whereas it was correlated with water temperature in the summer and autumn. Limiting the nutrient input (especially of N and C loading) in Lake Taihu would be a key factor in controlling the growth of different genera of cyanobacteria.

  18. [Spatial distribution pattern and stock estimation of nutrients during bloom season in Lake Taihu].

    Science.gov (United States)

    Jin, Ying-Wei; Zhu, Guang-Wei; Xu, Hai; Zhu, Meng-Yuan

    2015-03-01

    Based on the data of high density spatial sampling in July 2013, we analyzed the spatial distribution pattern of nutrients and estimated their amount during bloom season in Lake Taihu to discuss the correlation of algal bloom in different types of ecological water and nutrients in large shallow lake and the representative of its sampling sites. The research showed that nutrients and chlorophyll-a concentration (CHL) in Lake Taihu tended to reduce from northwest to southeast in general during bloom season. Nitrogen was mainly present in dissolved form, accounting for 76.28 percent of the total nitrogen (TN), and phosphorus was mainly present in particulate form, accounting for 66.38 percent of the total phosphorus (TP). The sampling points in the whole lake could be divided into four sections with significant difference between each other using principal component analysis and cluster analysis: The first section was located in the district of northwestern Lake Taihu, which represented the heavy eutrophic lake areas with serious blooms; the second section mainly included Meiliang Bay and area of river inflow into lake in South of Lake Taihu, which stood for moderate eutrophication of water quality; The third section included the central area and the southwest of lake, which represented the water area with medium water pollution, but blooms were frequent; And the fourth area was the remainder areas including Gonghu Bay, Xukou Bay, and Eastern Taihu, which stood for the region of weaker blooms and better water quality. Different factors also affected the growth of planktonic algae in different sections: From the point of the whole lake, CHL was significantly correlated with TP, TN, total dissolved nitrogen (TDN) and nitrate nitrogen (NO3(-) -N); while in the first section, CHL was significantly correlated to TP and TDN; CHL was correlated to TN and TDN in the second section; in the third section, the influencing factors were TP, reactive phosphate (PO4(3-) -P), TDN; PO

  19. Spatial distribution and pollution assessment of mercury in sediments of Lake Taihu, China

    Institute of Scientific and Technical Information of China (English)

    Chunxiao Chen; Binghui Zheng; Xia Jiang; Zheng Zhao; Yuzhu Zhan; Fengjiao Yi; Jiaying Ren

    2013-01-01

    Spatial distribution patterns of total mercury (THg) in 36 surficial sediment samples representing five regions of Lake Taihu were assessed using the ArcGis geostatistical analyst module.The pollution levels of THg were also evaluated from the same five lake regions.Concentrations of THg were in a ranged of 23-168 ng/g (mean 55 ng/g) in surfical sediments,which was significantly higher than those established baseline levels of the lake.Results of THg indicated that the northern region exhibited notably higher values,the bay regions showed elevated values relative to open areas,and the lakeside regions were higher than those observed in the central area.Lake Taihu suffered moderate to high Hg pollution,and expressed clear Hg enrichment status according to monomial pollution index Igeo and human activity factors.The concentrations of THg in the surticial sediments of Lake Taihu showed moderate-strong variation (coefficient of variation 52%).Geostatistical analysis indicated a weak spatial self-correlation,suggesting the contamination of Hg in Lake Taihu is primarily the result of anthropogenic activities.

  20. [Temporal and Spatial Characteristics of Lake Taihu Surface Albedo and Its Impact Factors].

    Science.gov (United States)

    Cao, Chang; Li, Xu-hui; Zhang, Mi; Liu, Shou-dong; Xiao, Wei; Xiao, Qi-tao; Xu, Jia-ping

    2015-10-01

    Lake surface albedo determines energy balance of water-atmospheric interface and water physical environment. Solar elevation angle, cloudiness, wind speed, water quality and other factors can affect lake surface albedo. Using solar radiation, wind speed, and water quality data (turbidity and chlorophyll-a concentration) which were observed in four eddy covariance sites (Meiliangwan, Dapukou, Bifenggang and Xiaoleishan i. e. MLW, DPK, BFG and XLS) in Lake Taihu and clearness index (k(t)), the influence of these factors on Lake Taihu surface albedo and the reasons that led to its spatial difference were investigated. The results showed that solar elevation angle played a leading role in the diurnal and seasonal change of lake surface albedo; lake surface albedo reached two peaks in 0 BFG > DPK > MLW. XLS and BFG belonged to the higher albedo group, while DPK and MLW belonged to the lower albedo group. The different biological environments caused by aquatic macrophytes and algae resulting in the spatial variation of Lake Taihu surface albedo. The relationship between albedo and chlorophyll-a concentration was not a very sensitive factor for indicating the outbreak of algae. This study can provide theoretical reference for lake albedo parameterization.

  1. Temporal-spatial variations of euphotic depth of typical lake regions in Lake Taihu and its ecological environmental significance

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Yunlin; QIN; Boqiang; HU; Weiping; WANG; Sumin; CHEN; Yuwei

    2006-01-01

    By using the data of underwater irradiance measured in the different lake regions of Lake Taihu during 1998-2004 and total suspended solids (TSS), wind speeds of the total 13 stations in typical lake regions during 1993-2003, this paper analyzes the factors of influencing on PAR (photosynthetically available radiation) attenuation, euphotic depth, and presents the temporal and spatial variations of euphotic depth of typical lake regions in Lake Taihu, and the spectral distributions of euphotic depth at station 2. The results show that the concentration of TSS is the most important factor impacting PAR attenuation, followed by chlorophyll a; chromophoric dissolved organic matter (CDOM) has little impact on the PAR euphotic depth. During 1993-2003, the mean yearly PAR euphotic depths of the typical lake regions ranged from 1.04 to 1.95 m with a mean value of 1.35±0.23 m. The PAR euphotic depth fell into 3 spatial zone types: Type I, the lowest, including the lake center and the inflows of rivers; Type II, intermediate, including Meiliang Bay, Wulihu Lake and Gonghu Bay; Type III, the greatest, including the East Lake Taihu; corresponding mean depths were approximately 1.1, 1.4, 2.0 m, respectively. The seasonal variations of euphotic depths were not quite the same in different lake regions. In the lake center, the mean values of PAR euphotic depth in summer and autumn were significantly greater than those in winter and spring; in the Meiliang Bay, winter means were significantly greater than in the other three seasons; in the East Lake Taihu, winter means were significantly less than in the other three seasons. However, no distinct seasonal change was recorded in the Wulihu Lake, Gonghu Bay and the inflows of rivers. The spectral distributions of euphotic depth present a minimal value at the blue light wave band of 400 nm, and a peak at the green light wave band of around 580 nm. In 1998 and 1999, based on the seasonal many-day continuous measurements, the PAR

  2. Application of MODIS data in monitoring suspended sediment of Taihu Lake, China

    Institute of Scientific and Technical Information of China (English)

    JIANG Xingwei; TANG Junwu; ZHANG Minwei; MA Ronghua; DING Jing

    2009-01-01

    Application of MODIS in ocean color is mainly based on bands 8-16 with the spatial resolution of 1 000 m. This spatial resolution, however, can not meet the application demand of inland waters where the areas are relatively small. With the assumption of the black water at shortwave infrared (SWIR) wavelengths (>1 000 nm), we first propose an atmospheric correction method for bands 1 and 2 with their spatial resolution of 250 m, and we then establish a quantitative retrieval model for suspended sediment concentration retrieval using the in-situ data collected in Taihu Lake. We also use MODIS data to retrieve the suspended sediment concentration of Taihu Lake with the retrieval model. The comparison between the retrieved and measured suspended sediment concentrations confirms that our algorithm can provide reliable data for monitoring the suspended sediment in Taihu Lake.

  3. Effects of internal loading on phosphorus distribution in the Taihu Lake driven by wind waves and lake currents.

    Science.gov (United States)

    Huang, Lei; Fang, Hongwei; He, Guojian; Jiang, Helong; Wang, Changhui

    2016-12-01

    Wind-driven sediment resuspension exerts significant effects on the P behavior in shallow lake ecosystems. In this study, a comprehensive dynamic phosphorus (P) model that integrates hydrodynamic, wind wave and sediment transport is proposed to assess the importance of internal P cycling due to sediment resuspension on water column P levels. The primary contribution of the model is detailed modeling and rigorous coupling of sediment and P dynamics. The proposed model is applied to predict the P behavior in the shallow Taihu Lake, which is the third largest lake in China, and quantitatively estimate the effects of wind waves and lake currents on P release and distribution. Both the prevailing southeast winds in summer and northwest winds in winter are applied for the simulation, and different wind speeds of 5 m/s and 10 m/s are also considered. Results show that sediment resuspension and the resulting P release have a dominant effect on P levels in Taihu Lake, and likely similar shallow lakes. Wind-driven waves at higher wind speeds significantly enhance sediment resuspension and suspended sediment concentration (SSC). Total P concentration in the water column is also increased but not in proportion to the SSC. The different lake circulations resulting from the different prevailing wind directions also affect the distribution of suspended sediment and P around the lake ultimately influencing where eutrophication is likely to occur. The proposed model demonstrates that internal cycling in the lake is a dominant factor in the lake P and must be considered when trying to manage water quality in this and similar lakes. The model is used to demonstrate the potential effectiveness of remediation of an area where historical releases have led to P accumulation on overall lake quality. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. 28. DIOXIN-LIKE AND ESTROGEN-LIKE POTENTIALS IN SURFACE WATER SAMPLES FROM TAIHU LAKE, YANGTZE DELTA

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@Taihu Lake is a major water source for Yangtze Delta, which is one of the most urbanized and economically prosperous areas in China. In last couple of decades, some parts of the lake were found to be heavily polluted due to eutrophication, In this study a batch of short-term biochemical assays were applied for the assessment of endocrine disruptive potentials and dioxin-like potentials in surface water samples from Taihu Lake.

  5. Spatial heterogeneity of cyanobacterial communities and genetic variation of Microcystis populations within large, shallow eutrophic lakes (Lake Taihu and Lake Chaohu, China)

    Institute of Scientific and Technical Information of China (English)

    Yuanfeng Cai; Fanxiang Kong; Limei Shi; Yang Yu

    2012-01-01

    Cyanobacteria,specifically Microcystis,usually form massive blooms in eutrophic freshwater lakes.Cyanobacterial samples were collected from eight sites of both Lake Taihu and Lake Chaohu in late summer to determine the diversity and distribution pattern of cyanobacteria and Microcystis in large,shallow,entropic lakes with significant spatial heterogeneity and long-term Microcystis bloom.Molecular methods based on denaturing gradient gel electrophoresis and clone library analysis were used.A similar heterogeneous distribution pattern of cyanobacteria in both lakes was observed.Most parts of these two lakes with high trophic level were dominated by Microcystis.However,in the regions with low trophic levels as well as low concentrations of chlorophyll a,Synechococcus occupied a considerable percentage.Different morphospecies and genotypes dominated the bloom-forming Microcystis populations in these two lakes.Microcystis viridis and Microcystis novacekii were dominant in Lake Chaohu,whereas Microcystis flos-aquae was dominant in Lake Taihu.Only 2 of thel3 Microcystis operational taxonomic units were shared between these two lakes.Analysis of molecular variance based on 16S to 23S internal transcribed spacer sequences indicated the significant genetic differentiation of Microcystis between these two lakes (Fst =0.19,p < 0.001).However,only 19.46% of the genetic variability was explained by the population variation between lakes,whereas most (80.54%) of the genetic variability occurred within the lakes.Phylogenetic analysis revealed no phylogeographic structure of Microcystis population in these two lakes,as illustrated by their cosmopolitan nature.Our results revealed that spatial heterogeneity within lakes has more impact on the cyanobacterial diversity than geographical isolation in a local scale.

  6. Genetic diversity of eukaryotic microorganisms in Lake Taihu, a large shallow subtropical lake in china.

    Science.gov (United States)

    Chen, Meijun; Chen, Feizhou; Yu, Yang; Ji, Jian; Kong, Fanxiang

    2008-10-01

    We investigated the genetic diversity of eukaryotic microorganisms (0.8-20 microm) by sequencing cloned 18S rRNA genes in six genetic libraries constructed from six locations in Lake Taihu, a large shallow subtropical lake in China. Genetic libraries of eukaryotic ribosomal RNA were screened by restriction fragment length polymorphism (RFLP) analysis, and one clone representative of each RFLP pattern was partially sequenced. A total of 528 clones were clustered into 165 RFLP patterns and finally into 131 operational taxonomic unit (OTUs). Phylogenetic analysis revealed that each library included many unique OTUs, as well as members of distantly related phylogenetic groups. A majority of the clones were from alveolates, stramenopiles, cercozoa, cryptophytes, chlorophytes, and fungi, with members of choanoflagellida, euglenida, centroheliozoa, ancyromonadidae, ichthyosporea, and kathablepharid representing a minor fraction of the library. Six OTUs (15 clones) were not related to any known eukaryotic group. Canonical correspondence analysis suggested that the differences in eukaryotic microorganism community composition of in the six regions were partially related to trophic status, sediment resuspension, and top-down regulation by metazooplankton.

  7. Microalga Euglena as a bioindicator for testing genotoxic potentials of organic pollutants in Taihu Lake, China.

    Science.gov (United States)

    Li, Mei; Gao, Xiangyu; Wu, Bing; Qian, Xin; Giesy, John P; Cui, Yibin

    2014-05-01

    The microalga Euglena was selected as a bioindicator for determining genotoxicity potencies of organic pollutants in Meiliang Bay of Taihu Lake, Jiangsu, China among seasons in 2008. Several methods, including the comet assay to determine breaks in DNA and quantification of antioxidant enzymes were applied to characterize genotoxic effects of organic extracts of water from Taihu Lake on the flagellated, microalga Euglena gracilis. Contents of photosynthetic pigments, including Chl a, Chl b and carotenoid pigments were inversely proportion to concentrations of organic extracts to which E. gracilis was exposed. Organic extracts of Taihu Lake water also affected activities of superoxide dismutase (SOD) and peroxidase (POD) of E. gracilis. There were no statistically significant differences in SOD activities among seasons except in June but significant differences in POD activities were observed among all seasons. The metrics of DNA fragmentation in the alkaline unwinding assay (Comet assay), olive tail moment (OTM) and tail moment (TM), used as measurement endpoints during the genotoxicity assay were both greater when E. gracilis was exposed to organic of water collected from Taihu Lake among four seasons. It is indicated that the comet assay was useful for determining effects of constituents of organic extracts of water on E. gracilis and this assay was effective as an early warning to organic pollutants.

  8. Cyanobacteria as a carbon source for zooplankton in eutrophic Lake Taihu, China, measured by

    NARCIS (Netherlands)

    de Kluijver, A.; Yu, J.L.; Houtekamer, M.; Middelburg, J.J.; Liu, Z.W.

    2012-01-01

    Using a combined stable-isotope and fatty-acid approach, we examined carbon-transfer routes from the cyanobacterium Microcystis to zooplankton in eutrophic Lake Taihu, China. Microcystis is generally considered poor food for zooplankton, and we hypothesized that most Microcystis carbon flows to zoop

  9. Variations in Optical Scattering and Backscattering by Organic and Inorganic Particulates in Chinese Lakes of Taihu, Chaohu and Dianchi

    Institute of Scientific and Technical Information of China (English)

    LYU Heng; WANG Qiao; WU Chuanqing; ZHU Li; LI Yunmei; HUANG Jiazhu

    2015-01-01

    This stu dy presents an investigation of the scattering and backscattering properties of the particulates in three Chinese inlandlakes (the Taihu Lake,the Chaohu Lake and the Dianchi Lake) based on in situ measurements taken at 119 sites.We modeled the particulate scattering spectra using a wavelength-dependent power-law function,finding that the power-law exponents in the Taihu Lake and the Chaohu Lake differ from those in the Dianchi Lake but are similar to the values in the U.S.coastal waters.In contrast to the open ocean,the backscattering properties in the three lakes can not be determined only from chlorophyll-a concentration.The backscattering ratio spectra exhibit a wavelength dependence feature in all three lakes,generally decreasing with the increasing wavelength.Analysis results of the correlations between the backscattering ratio and the individual water quality parameters clearly show that there are distinctive relations among the three lakes,attributed primarily to different compositions of optically active materials in the three lakes.Analysis of the mass-specific scattering and backscattering coefficients shows that the coefficients at wavelength 532 nm in the Taihu Lake and Chaohu Lake are similar,but they are apparently different from those in the Dianehi Lake.Lastly,Model I multiple linear regressions were adopted to partition the mass-specific cross-sections for scattering and backscattering into organic and inorganic cross-sections to further interpret the scattering and backscattering properties.The relative contribution of organic and inorganic particulates to scattering and backscattering is clearly different among the three lakes.The scattering and backscattering properties of the particulates in the three inland lakes vary significantly based on our collected data.The results indicated that the existing semi-analytical water quality retrieval models of the Taihu Lake can not be applied perfectly to the Chaohu Lake and the Dianchi Lake.

  10. The Impact of Land Use Changes on Runoff of Taihu Lake Basin of China

    Science.gov (United States)

    Li, Hengpeng; Yang, Guishan; Diao, Yaqin; Li, Pengcheng

    2017-04-01

    Land use/cover changes play a role of "interface" linking human activities and environmental systems. Land use changes alter the hydrological characteristics of the land surface, and have significant impacts on hydrological cycle and water balance, leading to increasing flood disaster. Taihu lake basin is fastest on urbanization among the regions in the east part of China. Impacted by cities' fast expansion, the problem of storm flood disaster is very serious. In this study, land use information was extracted from 5-year's TM/ETM images of 1985, 1995, 2000, 2005 and 2010. A grid-based distributed hydrological model was applied to estimate Runoff response to land use changes by simulating the monthly and annual runoff using long-term rainfall records from 1980 to 2010. Results showed that rapid changes in land use was noted in Taihu Lake catchment, which is characterized by conversion of agricultural land to construction land. The share of construction land increased from 9.7% to 13.4% in 15 years (1985-2000) with the increased area of 1388 km2; In the following 2000-2010, the share of construction land increased from 13.4% to 24.2% with the increased area of 4038 km2. The land use changes during 1985-2000 resulted in an average increase of runoff by 4.37% in the whole Taihu Lake basin, approximately 6.46×108m3. The land use changes during 1985-2010 led to an average increase of runoff by 12.82% in the whole basin, around 18.99×108m3. Based on the analysis of rainfall variation in recent years in Taihu Lake basin, it is concluded that the increasing urban storm floods in Taihu Lake basin are closely related to the fast urbanization process.

  11. Distribution, sources and composition of antibiotics in sediment, overlying water and pore water from Taihu Lake, China

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Jian [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Laboratory of Riverine Ecological Conservation and Technology, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Zhang, Yuan, E-mail: zhangyuan@craes.org.cn [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Laboratory of Riverine Ecological Conservation and Technology, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Zhou, Changbo [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Guo, Changsheng; Wang, Dingming [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Laboratory of Riverine Ecological Conservation and Technology, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Du, Ping [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Luo, Yi [College of Environmental Sciences and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Nankai University, Tianjin 300071 (China); Wan, Jun; Meng, Wei [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Laboratory of Riverine Ecological Conservation and Technology, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China)

    2014-11-01

    The occurrence of 15 antibiotics classified as sulphonamides, fluoroquinolones, macrolides, tetracyclines and trimethoprim in sediment, overlying water, and pore water matrices in Taihu Lake, China was studied. The total concentrations were from 4.1 μg/kg to 731 μg/kg, from 127 ng/L to 1210 ng/L, and from 1.5 ng/L to 216 ng/L in sediment, overlying water and pore water, respectively. Antibiotics in different locations originated from various sources, depending on human, agricultural and aquacultural activities. Composition analysis indicated that human-derived and animal-derived drugs significantly contributed to the total contamination of antibiotics in the lake, indicating the high complexity of contamination sources in Taihu Lake Basin. The in situ sediment–pore water partitioning coefficients were generally greater than sediment–overlying water partitioning coefficients, suggesting continuous inputs into the lake water. This study shows that antibiotics are ubiquitous in all compartments in Taihu Lake, and their potential hazards to the aquatic ecosystem need further investigation. - Highlights: • Antibiotics are ubiquitous in sediment, overlying water and pore water in Taihu Lake. • Antibiotics in Taihu Lake originated from human and nonhuman activities. • Ksp is higher than Ksw, indicating the continuous antibiotics input to lake water.

  12. Wind-induced flow velocity effects on nutrient concentrations at Eastern Bay of Lake Taihu, China.

    Science.gov (United States)

    Jalil, Abdul; Li, Yiping; Du, Wei; Wang, Jianwei; Gao, Xiaomeng; Wang, Wencai; Acharya, Kumud

    2017-07-01

    Shallow lakes are highly sensitive to respond internal nutrient loading due to wind-induced flow velocity effects. Wind-induced flow velocity effects on nutrient suspension were investigated at a long narrow bay of large shallow Lake Taihu, the third largest freshwater lake in China. Wind-induced reverse/compensation flow and consistent flow field probabilities at vertical column of the water were measured. The probabilities between the wind field and the flow velocities provided a strong correlation at the surface (80.6%) and the bottom (65.1%) layers of water profile. Vertical flow velocity profile analysis provided the evidence of delay response time to wind field at the bottom layer of lake water. Strong wind field generated by the west (W) and west-north-west (WNW) winds produced displaced water movements in opposite directions to the prevailing flow field. An exponential correlation was observed between the current velocities of the surface and the bottom layers while considering wind speed as a control factor. A linear model was developed to correlate the wind field-induced flow velocity impacts on nutrient concentration at the surface and bottom layers. Results showed that dominant wind directions (ENE, E, and ESE) had a maximum nutrient resuspension contribution (nutrient resuspension potential) of 34.7 and 43.6% at the surface and the bottom profile layers, respectively. Total suspended solids (TSS), total nitrogen (TN), and total phosphorus (TP) average concentrations were 6.38, 1.5, and 0.03 mg/L during our field experiment at Eastern Bay of Lake Taihu. Overall, wind-induced low-to-moderate hydrodynamic disturbances contributed more in nutrient resuspension at Eastern Bay of Lake Taihu. The present study can be used to understand the linkage between wind-induced flow velocities and nutrient concentrations for shallow lakes (with uniform morphology and deep margins) water quality management and to develop further models.

  13. The accumulation and potential ecological risk of heavy metals in microalgae from a eutrophic lake (Taihu Lake, China).

    Science.gov (United States)

    Yuan, Hezhong; Liu, Enfeng; Shen, Ji

    2015-11-01

    This study aimed to evaluate the bioaccumulation and enrichment of heavy metals in dominant microalgae and assess the potential ecological risk to the microalgae located at the northern region of Taihu Lake, China, a shallow freshwater lake. The concentrations of heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) in water and microalgae (predominant cyanophyta) collected from the north of Taihu Lake were analyzed. Subsequently, enrichment factors (EF) for heavy metals in microalgae relative to water were calculated. The concentrations and EF values of heavy metals were significantly higher in water and microalgae from the northern region compared with other regions for all the metals except As and Hg. Among the metals, Pb and Cd possessed higher enrichment levels, approx. 200 and 400 for Pb and Cd, respectively. This suggested that Pb and Cd had stronger chemisorption on microalgae, even though present at lower concentrations. Moreover, Ni and Zn in microalgae from the north of the lake also exhibited risk to the ecosystem owing to their high concentrations. In general, the microalgae tended to enrich Pb, Cd, Ni, and Zn by biosorption and bioaccumulation and thus exert a risk to the ecosystem and human populations.

  14. Integrative Indicator for Assessing the Alert Levels of Algal Bloom in Lakes: Lake Taihu as a Case Study

    Science.gov (United States)

    Li, Qinqin; Hu, Weiping; Zhai, Shuhua

    2016-01-01

    Algal blooms have recently become one of the most serious environmental problems in eutrophic freshwater ecosystems worldwide. Although many observation and simulation approaches have been applied to predict algal blooms, few studies have addressed the alert levels of algal blooms using integrative indicators in a large lake with multiple service function and significant horizontal heterogeneity. This study developed an integrative indicator assessment system (IIAS) to rank the alert level of algal blooms. In the IIAS, algal biomass, area percentage, distance from drinking water intake points, distance from scenic zones and duration of algal bloom were used as indicators to calculate a comprehensive alert level, which was classified into five grades (Vigilance, Low, Moderate, High, and Severe). Lake Taihu was taken as a case study to assess the comprehensive alert level of algal blooms in 2007 and 2010. The comprehensive alert level showed obvious spatial-temporal patterns, with an acceptable accuracy in Lake Taihu. The comprehensive alert levels were relatively higher in typical phytoplankton subzones than typical hydrophytes subzones and are more sensitive to weight factor in the northern and western subzones where high biomass usually occurs. Case study showed a very good application of the proposed comprehensive alert level assessment methodology, which can be adjusted to predict the degree of hazard of algal blooms in multi-service function large lakes to help the government and decision makers to act to prevent the disaster from algal bloom spreading.

  15. Spatial Evaluation of Heavy Metals Concentrations in the Surface Sediment of Taihu Lake.

    Science.gov (United States)

    Niu, Yong; Jiao, Wei; Yu, Hui; Niu, Yuan; Pang, Yong; Xu, Xiangyang; Guo, Xiaochun

    2015-11-27

    With regard to the size of China's freshwater lakes, Taihu Lake ranks third and it plays an important role in the supply of drinking water, flood prevention, farming and navigation, as well as in the travelling industry. The problem of environmental pollution has attracted widespread attention in recent years. In order to understand the levels, distribution and sources of heavy metals in sediments of Taihu Lake, random selection was carried out to obtain 59 samples of surface sediment from the entire lake and study the concentrations of Pb, Cd, Cu, Zn, Cr and Ni. Toxic units were also calculated to normalize the toxicities caused by various heavy metals. As a result, Cd and Cu in sediment were considered lower than the effect range low (ERL) at all regions where samples were gathered, while Pb and Ni were categorized into ERL-effect range median (ERM) at over 22% of the regions where samples were obtained. Nevertheless, all average concentrations of the samples were below the level of potential effect. According to the findings of this research, significant spatial heterogeneity existed in the above heavy metals. In conclusion, the distribution areas of heavy metals with higher concentrations were mainly the north bays, namely Zhushan Bay, Meiliang Bay as well as Gonghu Bay. The distribution areas of Cu, Zn, Cr and Ni with higher concentration also included the lake's central region, whereas the uniform distribution areas of those with lower concentrations were the lake's southeast region. In addition, it was most probable that the spatial distribution of heavy metals was determined by river inputs, whereas atmospheric precipitation caused by urban and traffic contamination also exerted considerable effects on the higher concentrations of Pb and Cd. Through evaluating the total amount of toxic units (ΣTU), it was found that higher toxicity existed primarily in the north bays and central region of the lake. If the heavy metals were sorted by the reduction of mean

  16. Lake

    Science.gov (United States)

    Wien, Carol Anne

    2008-01-01

    The lake is blue black and deep. It is a glaciated finger lake, clawed out of rock when ice retracted across Nova Scotia in a northerly direction during the last ice age. The lake is narrow, a little over a mile long, and deep, 90 to 190 feet in places according to local lore, off the charts in others. The author loves to swim there, with a sense…

  17. N pollution sources and denitrification in waterbodies in Taihu Lake region

    Institute of Scientific and Technical Information of China (English)

    邢光熹; 曹亚澄; 施书莲; 孙国庆; 杜丽娟; 朱建国

    2001-01-01

    Herein presented are the researches of the past few years related to characteristics of N pollution of waterbodies and N transport from croplands to the waterbodies in Suzhou and Wuxi regions, the center of the Taihu Lake valley. Based on the types of waterbodies, concentrations ofinorganic N of different forms, concentrations of PO43-, δ15NH4 values in river and lake waterbodies,the pollution sources of N in the river, lake and well waters are distinguished, and comparisons are made of trend of variation and amplitude of concentration between years, seasons and N pollutants in waterbodies. The increase in N2O concentration in different waterbodies and high δ15NO3-value in different waterbodies are deemed as an evidence of the existence of denitrification in the river, lake and well waters. Moreover, the role of denitrification in the waterbodies plays in stabilizing chronically concentration of N as pollutant in the waterbodies and mitigating N load in the waterbodies.

  18. N pollution sources and denitrification in waterbodies in-Taihu Lake region

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Herein presented are the researches of the past few years related to characteristics of N pollution of waterbodies and N transport from croplands to the waterbodies in Suzhou and Wuxi regions, the center of the Taihu Lake valley. Based on the types of waterbodies, concentrations of inorganic N of different forms, concentrations of , d15NH4 values in river and lake waterbodies, the pollution sources of N in the river, lake and well waters are distinguished, and comparisons are made of trend of variation and amplitude of concentration between years, seasons and N pollutants in waterbodies. The increase in N2O concentration in different waterbodies and high d 15 value in different waterbodies are deemed as an evidence of the existence of denitrification in the river, lake and well waters. Moreover, the role of denitrification in the waterbodies plays in stabilizing chronically concentration of N as pollutant in the waterbodies and mitigating N load in the water-bodies.

  19. Quantification of Climate Changes and Human Activities That Impact Runoff in the Taihu Lake Basin, China

    OpenAIRE

    Dingzhi Peng; Linghua Qiu; Jing Fang; Zhongyuan Zhang

    2016-01-01

    Although a fragile climate region, the Taihu Lake Basin is among the most developed regions in China and is subjected to intense anthropogenic interference. In this basin, water resources encounter major challenges (e.g., floods, typhoons, and water pollution). In this study, the impacts of climate changes and human activities on hydrological processes were estimated to aid water resource management in developed regions in China. The Mann-Kendall test and cumulative anomaly curve were applied...

  20. Underwater light field determined by water constituents in highly turbid water: the case of Taihu lake

    Directory of Open Access Journals (Sweden)

    Chang-Chun Huang

    2013-02-01

    Full Text Available The relationships between optical properties and water constituents in highly turbid productivewater were studied on the basis of the multiple bio-optical measurements and samplings of water constituents made during five cruises from 2006 to 2008 in Taihu lake. Taihu lake is a high dynamic ratio [(square root of area/depth] inland shallow lake. The spatial and temporal variation of water constituents and optical properties is significant. The inorganic suspended matter (ISMhas become the primary constituent in Taihu lake: its average percentage can reach 65.21%. The concentration of ISM is highly correlated to the optical properties in Taihu lake due to the sediment resuspension. Consequently, the ISM can be taken into account as an important optically-active constituent in Taihu lake. Resuspended sediments also lead to a poor correlation between scattering optical property and chlorophyll-a concentration (CChl-a. However, empirical relationship between the CChl-a and phytoplankton absorption coefficient at 675 nm is still valid when the package effect is removed. The parameters of linear equation in the present study have slight temporal variation, especially for the relationship between inherent optical properties (IOPs and concentration of total suspended matter (TSM. The relationship between apparent optical property (AOP (diffuse attenuation coefficient of particle, Kdbio and ISM has been examined as well. The Kdbio is strongly affected by ISM, and correlates to it with linear function. Thedifference between specific diffuse attenuation coefficients of organic [K*dOSM(λ] and inorganic [K*dISM(λ] particles is significant. K*dOSM(λ includes the absorption property of chlorophyll-a (chl-a at 675 nm, which is much higher than that of K*dISM(λ. This indicates that the attenuation ability of OSM is stronger than that of ISM although the Kdbio induced by large concentration of ISM is bigger than the Kdbio induced by small concentration of OSM

  1. Field application of a biofilm reactor based BOD prototype in Taihu Lake, China.

    Science.gov (United States)

    Liu, Changyu; Dong, Shaojun

    2013-05-15

    A tubular biofilm reactor (BFR) based online biochemical oxygen demand prototype was applied in Taihu Lake, China. Municipal tap water was used instead of conventional phosphate buffer as blank solution to avoid phosphate pollution. The background organic compounds in municipal tap water were taken into account and they were validated to result in negative deviation to accuracy. The microbial endogenous respiration was experimentally validated to be sensitive to salt ionic strength, and municipal tap water as blank was thought to generate positive deviation to accuracy. The system was continuously operated over 2 months without man intervention, and the automated monitoring data agreed well with that of the conventional BOD5 methods. The BFR resisted the frequent measurements with samples of high turbidity, and the BOD monitoring data indicated the index of biodegradable organic compounds of Taihu Lake was accorded with the second class described in the environmental quality standard of surface water. Analyzed together with permanganate index on site, Taihu Lake was revealed to be of good capacity of self cleaning. Importantly, field application study of new BOD method made it more objective in evaluating its applicability, and could provide practical information and useful improvements in the process of commercializing.

  2. Alkaline phosphatase activity and the phosphorus mineralization rate of Lake Taihu

    Institute of Scientific and Technical Information of China (English)

    GAO; Guang; ZHU; Guangwei; QIN; Boqiang; CHEN; Jun

    2006-01-01

    The phosphorus fractions, the alkaline phosphatase activity (APA) and other water chemical parameters were concomitantly monitored from April 2003 to October 2004 in different ecotype sites of Lake Taihu. During the stages of algae growth, the phosphorus fractions and their relationships with APA in different ecotype sites were discussed and the phosphorus mineralization rate was calculated. In the water of Lake Taihu, most of the phosphorus (70.2%) could be attributed to the suspended particulate phosphorus, while the dissolved reactive phosphorus (DRP) seems to contribute less than 7%. About 58% of the total phosphorus, however, can be hydrolyzed as inorganic phosphate to compensate for phosphorus deficiency of algae and bacteria growth. During the different algae growth stages, the APA and its Kinetic parameters were varied significantly between different ecotype sites of Lake Taihu. This trend is also visible by comparing the phosphorus mineralization rate,and the most rapidly phosphorus turnover time is only several minutes. The fast recycle of phosphorus can, to some extent, be explained that the phosphorus source of algal blooms. The phytoplankton seems to compensate for phosphorus deficiency by using the alkaline phosphatase to hydrolyze phosphomonoesters.

  3. Evidence from isotopic geochemistry as an indicator of eutrophication of Meiliang Bay in Lake Taihu, China

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In this paper, Lake Taihu, a large shallow freshwater lake in China, is chosen as an example of reconstruction of eutrophication through the comparison between stable isotopes from dissolved nutrients and plants and water column nutrient parameters and integration of multiple proxies in a sediment core from Meiliang Bay including TN, TP, TOC, C/N, δ15N, δ13C, etc. Differences in aquatic plant species and trophic status between East Taihu Bay and Meiliang Bay are indicated by their variations in δ13C and δ15N of aquatic plants and δ15N of NH4+. A significant influence ofexternal nutrient inputs on Meiliang Bay is reflected in temporal changes in δ 15N of NH4+ and hydro-environmental parameters. The synchronous change between δ13C and δ15N values of sedimented organic matter (OM) has been attributed to elevated primary production at the beginning of eutrophication between 1950 and 1990, then recent inverse correlation between them has been caused by the uptake of 15N-enriched inorganic nitrogen by phytoplankton grown under eutrophication and subsequent OM decomposition and denitrification in surface sediments, indicating that the lake has suffered from progressive eutrophication since 1990. Based on the use of a combination of stable isotopes and elemental geochemistry, the eutrophication of Meiliang Bay in Lake Taihu could be better traced. These transitions of the lake eutrophication respectively occurring in the 1950s and 1990s have been suggested as a reflection of growing impacts of human activities, which is coincident with the instrumental data.

  4. Impact assessment of climate change and human activities on annual highest water level of Taihu Lake

    Institute of Scientific and Technical Information of China (English)

    Qing-fang HU; Yin-tang WANG

    2009-01-01

    The annual highest water level of Taihu Lake (Zm) is very significant for flood management in the Taihu Basin. This paper first describes the inter-annual and intra-annual traits of Zm from 1956 to 2000. Then, using the Mann-Kenall (MK) and Spearman (SP) nonparametric tests, the long-term change trends of area precipitation and pan evaporation in the Taihu Basin are determined. Meanwhile, using the Morlet wavelet transformation, the fluctuation patterns and change points of precipitation and pan evaporation are analyzed. Also, human activities in the Taihu Basin are described, including land use change and hydraulic project construction. Finally, the relationship between Zm, the water level of Taihu Lake 30 days prior to the day of Zm (Z0), and the 30-day total precipitation and pan evaporation prior to the day of Zm (P and E0, respectively) is described based on multi-linear regression equations. The relative influence of climate change and human activities on the change of Zm is quantitatively ascertained. The results demonstrate that: (1) Zm was distinctly higher during the 1980-2000 period than during the 1956-1979 period, and the 30 days prior to the day of Zm are the key phase influencing Zm every year; (2) P increased significantly at a confidence level of 95% during the 1956-2000 period, while the reverse was true for E0; (3) The relationship between Zm, P and E0 distinctly changed after 1980; (4) Climate change and human activities together caused frequent occurrences of high Zm after 1980; (5) Climate change caused a substantially greater Zm difference between the 1956-1979 and 1980-2000 periods than human activities. Climate change, as represented by P and E0, was the dominant factor raising Zm, with a relative influence ratio of 83.6%, while human activities had a smaller influence ratio of 16.4%.

  5. Distribution and sources of n-alkanes in surface sediments of Taihu Lake, China

    Directory of Open Access Journals (Sweden)

    Yu Yunlong

    2016-03-01

    Full Text Available The last study on n-alkanes in surface sediments of Taihu Lake was in 2000, only 13 surface sediment samples were analysed, in order to have a comprehensive and up-to-date understanding of n-alkanes in the surface sediments of Taihu Lake, 41 surface sediment samples were analyzed by GC-MS. C10 to C37 were detected, the total concentrations of n-alkanes ranged from 2109 ng g−1 to 9096 ng g−1 (dry weight. There was strong odd carbon predominance in long chain n-alkanes and even carbon predominance in short chain n-alkanes. When this finding was combined with the analysis results of wax n-alkanes (WaxCn, carbon preference index (CPI, unresolved complex mixture (UCM, hopanes and steranes, it was considered that the long chain n-alkanes were mainly from terrigenous higher plants, and that the short chain n-alkanes mainly originated from bacteria and algae in the lake, compared with previous studies, there were no obvious anthropogenic petrogenic inputs. Terrestrial and aquatic hydrocarbons ratio (TAR and C21−/C25+ indicated that terrigenous input was higher than aquatic sources and the nearshore n-alkanes were mainly from land-derived sources. Moreover, the distribution of short chain n-alkanes presented a relatively uniform pattern, while the long chain n-alkanes presented a trend that concentrations dropped from nearshore places to the middle of lake.

  6. Heavy metal pollution status and ecological risks of sediments under the influence of water transfers in Taihu Lake, China.

    Science.gov (United States)

    Liu, Jiajia; Wang, Peifang; Wang, Chao; Qian, Jin; Hou, Jun

    2017-01-01

    The effects of water transfer projects on water channels and the receiving water involved need to be understood. In this research, the compositions and particle size distributions of surface sediment and the Cd, Cr, Cu, Ni, Pb, and Zn contents and distributions in the sediment along a water transfer route from the Wangyu River to Taihu Lake, China, were studied. The correlative relationship between the grain size trend and heavy metal content distribution suggested that heavy metals in Wangyu River sediment have affected the heavy metal contents of Taihu Lake sediment through silt and clay migrating in the transferred water. Enrichment factors and potential ecological risk values were calculated. Low levels of potential ecological risks are posed at 20 sampling sites in Taihu Lake, but higher-to-serious risks (potential ecological risk values >275) are posed at all Wangyu River sites. Toxicity of heavy metals (Cd, Cu, Zn, and Ni) in the Wangyu River sediments is more serious than those in the Taihu Lake, but is similar to the entrance of Gonghu Bay. Multivariate statistical analyses (Pearson correlation, cluster, and factor analyses) suggested heavy metals in the study area have many sources, and the relationships between particle migration and heavy metal contents indicated transferring water are likely to lead to adverse ecological risks being posed in Taihu Lake.

  7. [Suspension-sedimentation of sediment and release amount of internal load in Lake Taihu affected by wind].

    Science.gov (United States)

    Pang, Yong; Yan, Run-run; Yu, Zhong-bo; Li, Yi-ping; Li, Rui-ling

    2008-09-01

    The water quality in Meiliang Bay of the Taihu Lake was totally tested five times in the four seasons. The suspension samples were obtained by using a sediment trap. The sediment settling flux and resuspended flux were calculated according to the observation data by using Gansith formula, and the relationships between these fluxes and wind speeds were established. Seven experiments were conducted in Laboratory for hydrostatic settling behavior of suspended matter affected by different wind speeds in Lake Taihu. The hydrostatic settling fluxes of suspended matter were calculated and the relationships between the fluxes and suspended matter concentrations were established. Base on these works, the suspension-sedimentation process was decomposed and generalized according to the critical wind speed of 3.7 m/s. Daily sediment resuspended amount and settling amount of the year 2005 was calculated and annual average release amount of internal load in Lake Taihu was estimated using the wind data of nearly 10 years. The results indicate that daily release amount of internal load in Lake Taihu significantly influenced by wind and have the same trend of change with wind, while the release amount of different nutrients in the same condition are different. The Lake Taihu has an annual average release amount of internal load with COD 49,600 t, TN 7773.0 t and TP 275.5 t, of which summer has the markedly highest release amount than other seasons.

  8. Risk and toxicity assessments of heavy metals in sediments and fishes from the Yangtze River and Taihu Lake, China.

    Science.gov (United States)

    Fu, Jie; Hu, Xin; Tao, Xiancong; Yu, Hongxia; Zhang, Xiaowei

    2013-11-01

    Heavy metal pollution is one of the most serous environmental issues globally. To evaluate the metal pollution in Jiangsu Province of China, the total concentrations of heavy metals in sediments and fishes from the Yangtze River and Taihu Lake were analyzed. Ecological risk of sediments and human health risk of fish consumption were assessed respectively. Furthermore, toxicity of samples on expression of the stress responsive genes was evaluated using microbial live cell-array method. The results showed that the heavy metals concentrations in sediments from the Yangtze River were much higher than those in sediments from the Taihu Lake. However, the fishes from the Taihu Lake had higher concentrations of heavy metals than fishes from the Yangtze River. Ecological risk evaluation showed that the heavy metal contaminants in sediments from the Yangtze River posed higher risk of adverse ecological effects, while sediments from the study areas of Taihu Lake were relatively safe. Health risk assessment suggested that the heavy metals in fishes of both Yangtze River and Taihu Lake might have risk of adverse health effects to human. The toxicity assessment indicated that the heavy metals in these sediments and fishes showed transcriptional effects on the selected 21 stress responsive genes, which were involved in the pathways of DNA damage response, chemical stress, and perturbations of electron transport. Together, this field investigation combined with chemical analysis, risk assessment and toxicity bioassay would provide useful information on the heavy metal pollution in Jiangsu Province.

  9. [Space distribution characteristics and diversity analysis of phosphorus from overlying water and surface sediments in Taihu Lake].

    Science.gov (United States)

    Yuan, He-zhong; Shen, Ji; Liu, En-feng; Wang, Jian-jun; Meng, Xiang-hua

    2010-04-01

    The physi-chemical indexes in the overlying water and surface sediments of Taihu Lake, an eutrophic shallow lake, were determined. Then, the isopleth maps of spatial distribution of each parameter were illustrated. The results show that the concentrations of SRP, TP and TN in the overlying water and TOC, TN and TP as well as phosphorus fractions in surface sediments exhibit distinct diversity in spatially. The lowest values of TP and TN were 0.05, 0.88 mg x L(-1), respectively. The concentrations of Fe-P ranged from 29.13 to 258.31 mg x kg(-1). Besides, the northwest lake regions, high-load Ca-P was surveyed in the South Taihu Lake and East Taihu Lake with the highest value of 357.68 mg x kg(-1). The highest concentration of OP, 371.91 mg x kg(-1) was detected in the northwest region of the lake. IP takes up a greater proportion of TP than OP, and the highest value is approximately 50% higher than the lowest value. Fe-P has higher percentage in IP compared with Ca-P. Significant correlation between Fe-P, SRP and TP showed that Fe-P was the important phosphorus source of the overlying water (R: 0.49, 0.64). Furthermore, high correlation coefficients between TOC, TOC, C/N, TN, TP and phosphorus fractions suggest that higher concentration of organics was favor to the accumulation and burial of nutrients. The high-load contaminants exist principally in the Zhushan Bay, Wulihu Lake, Meiliang Bay and the northwest region of Taihu Lake. Significant heterogeneity of nutrients distribution in space of Taihu Lake connects with direct action of emission load of sewage. Simultaneously, different biogeochemical behaviors of each parameter play an important role.

  10. Artificial regulation of water level and its effect on aquatic macrophyte distribution in Taihu Lake.

    Directory of Open Access Journals (Sweden)

    Dehua Zhao

    Full Text Available Management of water levels for flood control, water quality, and water safety purposes has become a priority for many lakes worldwide. However, the effects of water level management on the distribution and composition of aquatic vegetation has received little attention. Relevant studies have used either limited short-term or discrete long-term data and thus are either narrowly applicable or easily confounded by the effects of other environmental factors. We developed classification tree models using ground surveys combined with 52 remotely sensed images (15-30 m resolution to map the distributions of two groups of aquatic vegetation in Taihu Lake, China from 1989-2010. Type 1 vegetation included emergent, floating, and floating-leaf plants, whereas Type 2 consisted of submerged vegetation. We sought to identify both inter- and intra-annual dynamics of water level and corresponding dynamics in the aquatic vegetation. Water levels in the ten-year period from 2000-2010 were 0.06-0.21 m lower from July to September (wet season and 0.22-0.27 m higher from December to March (dry season than in the 1989-1999 period. Average intra-annual variation (CV(a decreased from 10.21% in 1989-1999 to 5.41% in 2000-2010. The areas of both Type 1 and Type 2 vegetation increased substantially in 2000-2010 relative to 1989-1999. Neither annual average water level nor CV(a influenced aquatic vegetation area, but water level from January to March had significant positive and negative correlations, respectively, with areas of Type 1 and Type 2 vegetation. Our findings revealed problems with the current management of water levels in Taihu Lake. To restore Taihu Lake to its original state of submerged vegetation dominance, water levels in the dry season should be lowered to better approximate natural conditions and reinstate the high variability (i.e., greater extremes that was present historically.

  11. Identifying Watershed Regions Sensitive to Soil Erosion and Contributing to Lake Eutrophication--A Case Study in the Taihu Lake Basin (China).

    Science.gov (United States)

    Lin, Chen; Ma, Ronghua; He, Bin

    2015-12-24

    Taihu Lake in China is suffering from severe eutrophication partly due to non-point pollution from the watershed. There is an increasing need to identify the regions within the watershed that most contribute to lake water degradation. The selection of appropriate temporal scales and lake indicators is important to identify sensitive watershed regions. This study selected three eutrophic lake areas, including Meiliang Bay (ML), Zhushan Bay (ZS), and the Western Coastal region (WC), as well as multiple buffer zones next to the lake boundary as the study sites. Soil erosion intensity was designated as a watershed indicator, and the lake algae area was designated as a lake quality indicator. The sensitive watershed region was identified based on the relationship between these two indicators among different lake divisions for a temporal sequence from 2000 to 2012. The results show that the relationship between soil erosion modulus and lake quality varied among different lake areas. Soil erosion from the two bay areas was more closely correlated with water quality than soil erosion from the WC region. This was most apparent at distances of 5 km to 10 km from the lake, where the r² was as high as 0.764. Results indicate that soil erosion could be used as an indicator for identifying key watershed protection areas. Different lake areas need to be considered separately due to differences in geographical features, land use, and the corresponding effects on lake water quality.

  12. Assessment of Heavy Metal Pollution in Sediments of Inflow Rivers to Lake Taihu, China.

    Science.gov (United States)

    Niu, Yong; Niu, Yuan; Pang, Yong; Yu, Hui

    2015-11-01

    Lake Taihu, the third-largest freshwater body in China, has many functions, including drinking water supply, flood control, cultivation, navigation, and tourism. In this study, sediment samples were collected at 31 sites from 11 inflow rivers in 2012, to investigate the distribution and concentration of heavy metals copper (Cu), zinc (Zn), lead (Pb), nickel (Ni), and chromium (Cr), and to assess their potential ecological risk. The highest mean concentration was found for Zn, followed by Cu, Cr, Pb, and Ni. Generally, heavy metal pollution was more serious in Wu Jingang River and Caoqiao River, probably because they receive large amounts of wastewater from various local industrial enterprises. The potential ecological risk values of the heavy metals were larger than 120 in more than 25.8% of the sediment samples, indicating a very high risk. The largest ecological risk was due to copper. Furthermore, the results of a principal component analysis and subsequent analysis of variance showed that heavy metal concentrations in the sediment of inflow rivers were higher than those of the lake, which created a large hazard for the aquatic ecosystems of Lake Taihu.

  13. THREE-DIMENSIONAL NUMERICAL SIMULATION OF WIND-INDUCED CIRCULATION IN LAKE TAIHU

    Institute of Scientific and Technical Information of China (English)

    LUO Lian-cong; QIN Bo-qiang

    2004-01-01

    A three-dimensional (3-D) numerical circulation model for shallow-lake is presented and described in detail in this paper, which employs model-splitting technique in order to calculate water level, mean-depth velocities and horizontal and vertical velocities at different depth simultaneously. The results show the current circulation pattern features four eddies with two clockwise and two anticlockwise induced by prevailing wind. Opposite wind field will lead to opposite current pattern with phase shifted by 180°. The surface convergence zone is located in the upwind area and the surface divergence part in the downwind region, This results in drastic vertical movement in the two zones and the return currents at the bottom with phase shifted by 180°from the surface current vectors. Thus the water level decreases significantly at the leeward side and increases quickly at the windward part. Verification and calibration for the model were made based on the water-level and current data observed during the 9711 Storm in Lake Taihu. The predicted results are in satisfactory agreement with the observed data, which raises the possibility that this model can be used to decide the bottom current stress for sediment resuspension and also to simulate sediment transportation. It can provide a fundamental tool to study the nutrient release from bottom sediment in Lake Taihu.

  14. Off-flavor compounds from decaying cyanobacterial blooms of Lake Taihu

    Institute of Scientific and Technical Information of China (English)

    Zhimei Ma; Yuan Niu; Ping Xie; Jun Chen; Min Tao; Xuwei Deng

    2013-01-01

    The effect of cyanobacterial bloom decay on water quality and the complete degradation of cyanobacterial blooms in a short period were examined by an enclosure experiment in Gonghu Bay of Lake Taihu,China.Water quality parameters as well as taste and odor compounds during the breakdown of cyanobacterial blooms were measured.Results showed that the decay of cyanobacterial blooms caused anoxic water conditions,decreased pH,and increased nutrient loading to the lake water.The highest concentrations of dimethyl sulfide (DMS),dimethyl trisulfide (DMTS),and β-cyclocitral were observed in the anoxic water,at 62331.8,12413.3,and 1374.9 ng/L,respectively.2-Methylisoborneol was dominant during the live growth phase of cyanobacterial blooms,whereas DMS and DMTS were dominant during the decomposition phase.Dissolved oxygen,pH,and chlorophyll a were negatively correlated with DMS,DMTS,and β-cyclocitral,whereas total phosphorus,total nitrogen,and ammonium (NH4+-N) were positively correlated with DMS,DMTS,β-cyclocitral,and β-ionone.The experimental results suggested that preventing the anaerobic decomposition of cyanobactedal blooms is an important strategy against the recurrence of a malodor crisis in Lake Taihu.

  15. Response of freshwater algae to water quality in Qinshan Lake within Taihu Watershed, China

    Science.gov (United States)

    Zhang, Jianying; Ni, Wanmin; Luo, Yang; Jan Stevenson, R.; Qi, Jiaguo

    Although frequent algal blooms in Taihu Lake in China have become major environmental problems and have drawn national and international attention, little is understood about the relationship between algal blooms and water quality. The goal of this study was to assess the growth and species responses of freshwater algae to variation in water quality in Qinshan Lake, located in headwaters of the Taihu watershed. Water samples were collected monthly from ten study sites in the Qinshan Lake and were analyzed for species distribution of freshwater algae and physiochemical parameters such as total nitrogen (TN), NH4+-N, NO3--N, total phosphorus (TP), chemical oxygen demand (COD Mn) and Chl-a. The results showed that average TN was 4.47 mg/L, with 92.2% of values greater than the TN standard set by the Chinese Environmental Protection Agency; average TP was 0.051 mg/L, with 37.9% of values above the TP national standard; and average trophic level index (TLI) was 53, the lower end of eutrophic condition. Average Chl-a concentration was 12.83 mg/m 3. Green algae and diatom far outweighed other freshwater algae and were dominant most time of the year, with the highest relative abundances of 96% and 99%, respectively. Blue-green algae, composed mainly toxic strains like Microcystis sp ., Nostoc sp. and Oscillatoria sp., became most dominant in the summer with the maximum relative abundance of 69%. The blue-green algae sank to the lake bottom to overwinter, and then dinoflagellates became the dominant species in the winter, with highest relative abundance of 89%. Analysis indicated that nutrients, especially control of ammonia and co-varying nutrients were the major restrictive factor of population growth of blue-green algae, suggesting that control in nutrient enrichments is the major preventive measure of algal blooms in Qinshan Lake.

  16. Discovery and implication of shock metamorphic unloading microfractures in Devonian bedrock of Taihu Lake

    Institute of Scientific and Technical Information of China (English)

    WANG; Erkang(王尔康); WAN; Yuqiu(万玉秋); XU; Shijin(徐士进)

    2002-01-01

    Sphenoidal tensile microfractures with particular patterns have been discovered in the Late Devonian quartzose sandstone in islands and peninsula of the Taihu Lake area. Microfractures present a '人'-shape collective pattern, occurring in a single row or multiple rows. The quartz crystals in the inner acute angle area of some '人'-shape microfractures have severely been non-crystallized, showing the feature of diaplectic glass. The studies show that these special microfractures were formed during the unloading process after the compression was up to the peak of an impact event.

  17. Controlling cyanobacterial blooms by managing nutrient ratio and limitation in a large hyper-eutrophic lake: Lake Taihu, China.

    Science.gov (United States)

    Ma, Jianrong; Qin, Boqiang; Wu, Pan; Zhou, Jian; Niu, Cheng; Deng, Jianming; Niu, Hailin

    2015-01-01

    Excessive nitrogen (N) and phosphorus (P) loading of aquatic ecosystems is a leading cause of eutrophication and harmful algal blooms worldwide, and reducing nutrient levels in water has been a primary management objective. To provide a rational protection strategy and predict future trends of eutrophication in eutrophic lakes, we need to understand the relationships between nutrient ratios and nutrient limitations. We conducted a set of outdoor bioassays at the shore of Lake Taihu. It showed that N only additions induced phytoplankton growth but adding only P did not. Combined N plus P additions promoted higher phytoplankton biomass than N only additions, which suggested that both N and P were deficient for maximum phytoplankton growth in this lake (TN:TP=18.9). When nutrients are present at less than 7.75-13.95 mg/L TN and 0.41-0.74 mg/L TP, the deficiency of either N or P or both limits the growth of phytoplankton. N limitation then takes place when the TN:TP ratio is less than 21.5-24.7 (TDN:TDP was 34.2-44.3), and P limitation occurs above this. Therefore, according to this ratio, controlling N when N limitation exists and controlling P when P deficiency is present will prevent algal blooms effectively in the short term. But for the long term, a persistent dual nutrient (N and P) management strategy is necessary. Copyright © 2014. Published by Elsevier B.V.

  18. Spatial distribution of penetration depth in Taihu Lake (China) during spring and autumn

    Institute of Scientific and Technical Information of China (English)

    ZHAO Qiaohua; WEI Yingzhu; OUYANG Xiaoran

    2013-01-01

    In the context of remote sensing,sunlight penetration depth is the depth above which 90%of the diffusely reflected irradiance from a water body surface originates.Model algorithms to simulate water quality variables such as chlorophyll a,dissolved organic matter,suspended matter,and Secchi depth are sensitive to the variations of this variable.The penetration depth for Taihu Lake in China,a shallow and turbid lake,was calculated by using a multiple scattering model,and in situ optical measurements were carried out during May and October 2010.The results show that:1) the penetration depth generally increased from west to east during spring and from southeast to northwest during autumn,reflecting the prevailing wind direction and; 2) there was strong dependence of the penetration depth on the concentration of suspended matter.

  19. Spatial distribution of penetration depth in Taihu Lake (China) during spring and autumn

    Science.gov (United States)

    Zhao, Qiaohua; Wei, Yingzhu; Ouyang, Xiaoran

    2013-07-01

    In the context of remote sensing, sunlight penetration depth is the depth above which 90% of the diffusely reflected irradiance from a water body surface originates. Model algorithms to simulate water quality variables such as chlorophyll a, dissolved organic matter, suspended matter, and Secchi depth are sensitive to the variations of this variable. The penetration depth for Taihu Lake in China, a shallow and turbid lake, was calculated by using a multiple scattering model, and in situ optical measurements were carried out during May and October 2010. The results show that: 1) the penetration depth generally increased from west to east during spring and from southeast to northwest during autumn, reflecting the prevailing wind direction and; 2) there was strong dependence of the penetration depth on the concentration of suspended matter.

  20. Chemical composition and its origin in spring rainwater over Taihu Lake

    Institute of Scientific and Technical Information of China (English)

    WANG Xuemei; YANG Longyuan; QIN Boqiang; JI Lingling

    2006-01-01

    Chemical compositions of rainwater collected in three stations in Taihu Lake in Jiangsu Province, China between March and May 2003 were analyzed through numerical simulations and field observation data. In terms of average ion deposition rate in spring at the air/water interface, of all anions,that of so2-4 was the largest followed by NO-3, whereas among all cations, Ca2+ concentration and the rate was the largest, and then NH4+ was the next. The correlation of ion concentration indicated that the catchment of the lake has been artificially polluted considerably. Using backward trajectory analysis, the raining water in the stations in Taihu Lake was classified. In spring, marine-originated rain is the main contribution to this area, counting for 92.7% of the total precipitation, in which SO2-4, NO-3 and NH+4 contributed 89.2%, 88.1%, and 88.3% respectively to the total spring-rain chemicals, whereas land-originated rains contributed in a small amount. However, the ion concentration in the land-originated rain was higher and acidic, causing considerable harm to local ecosystem. The analysis of backward trajectory analysis shows that three types of air masses influenced the chemical composition of the lake water, namely, air mass from NE direction, air mass from SW direct ion, and local air mass. Although the local air masses often produced small rainfall amount, but the nature of high ion concentration and high acidity impacted the local ecosystem remarkably. The ion concentration and rainfall from long-distance boreal air mass are clearly greater than those in austral air.

  1. New evidence for an impact origin of Taihu lake, China: Possible trigger of the extinction of LiangChu Culture 4500 years ago

    Science.gov (United States)

    Xie, Z.; Wang, H.; Sharp, T.; Decarli, P.

    2008-12-01

    Here we report new evidence of an impact crater in south-east of China, Taihu Lake in Jiangsu Province. An impact origin was originally proposed on the basis of fractured quartz, wavy extinction quartz, and shatter cones in the sandstone of Devonian Wutong formation in the islands of Taihu lake (Wang, et al., 1992, 1993, 2000). In the absence of additional evidence, the impact origin hypothesis has fallen into disfavour. Here we report studies of sedimentary samples, which could be ejecta from Taihu, found in a small lake in the vicinity of Taihu lake. The samples consist of irregularly-shaped quartz-rich concretions found in lake sediments. Preliminary studies indicate that these samples contain angular fragments of shocked quartz. The stratigraphic age of the lake sediments is similar to that of the 65 km diameter Taihu lake. If the impact origin of Taihu lake can be conclusively established, it is of the correct age to explain the mysterious disappearance of the LiangChu culture about 4500 years ago.

  2. Encounter probability analysis of typhoon and plum rain in the Taihu Lake Basin

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    It is of great significance to study the encounter possibility of typhoon and plum rain in the Taihu Lake Basin in order to adjust the schemes of design storm and utilize flood resource and make the decision of real-time scheduling for flood control in the Basin. Based upon the existing research findings of description of encounter phenomena of typhoon and plum rain, the initial time of typhoon affecting the Taihu Lake Basin, the start time of plum rain season and the end time of plum rain season were selected as the characteristic indices of typhoon and plum rain, respectively. According to their synchronous data from 1954 to 2009, the distribution functions of the above-mentioned three random variables were identified and a formula expressing the encounter possibility of typhoon and plum rain was derived. In view of the complexity and solution of this formula, joint distribution functions of typhoon and plum rain were constructed by the use of Gumbel Copula function on the basis of the adaptability comparison among three functions (Gumbel Copula, Clayton Copula and Frank Copula) in Archimedean functions. For the characteristics of the formula with the joint distribution functions based on Gumbel Copula function, two methods, i.e., numerical integration and Monte Carlo simulation, were selected to solve the encounter probability, and the validity of the computed results was analyzed finally.

  3. [Genotoxicity effect of organic pollutants in Meiliang Bay of Taihu Lake on microalga Euglena gracilis].

    Science.gov (United States)

    Gao, Xiang-Yu; Cui, Yi-Bin; Hu, Chang-Wei; Qian, Xin; Kong, Zhi-Ming; Li, Mei

    2009-11-01

    Organic pollutant ingredients and content of water samples from Taihu Lake were analyzed by GC-MS. Results showed that Taihu Lake was already contaminated by the organic pollutant, and 15 kinds of targeted organic pollutants were detected. At lower concentrations (1 time), organic pollutants could not have notable effect on the growth of Euglena gracilis, but could increase the content of photosynthetic pigment. At higher concentrations (5, 10 times), organic pollutants restrained the growth of E. gracilis remarkably, and decreased the content of photosynthetic pigment. Activities of SOD and POD increased with the content of organic pollutants. It is indicated that organic pollution could induce activities of antioxidation enzymes in E. gracilis. TOM and TM for the genotoxicity assay increased and DNA damage was found. In higher concentration groups, DNA damage was serious and had an obvious dose-effect relationship. It is indicated that Meiliang bay water may have potential mutagenicity. Comet assay combined with SOD analysis was of value to genotoxic monitoring of polluted water and was a suitable biomarker for organic pollutants in water.

  4. Spatio-Temporal Patterns and Source Identification of Water Pollution in Lake Taihu (China

    Directory of Open Access Journals (Sweden)

    Yan Chen

    2016-03-01

    Full Text Available Various multivariate methods were used to analyze datasets of river water quality for 11 variables measured at 20 different sites surrounding Lake Taihu from 2006 to 2010 (13,200 observations, to determine temporal and spatial variations in river water quality and to identify potential pollution sources. Hierarchical cluster analysis (CA grouped the 12 months into two periods (May to November, December to the next April and the 20 sampling sites into two groups (A and B based on similarities in river water quality characteristics. Discriminant analysis (DA was important in data reduction because it used only three variables (water temperature, dissolved oxygen (DO and five-day biochemical oxygen demand (BOD5 to correctly assign about 94% of the cases and five variables (petroleum, volatile phenol, dissolved oxygen, ammonium nitrogen and total phosphorus to correctly assign >88.6% of the cases. In addition, principal component analysis (PCA identified four potential pollution sources for Clusters A and B: industrial source (chemical-related, petroleum-related or N-related, domestic source, combination of point and non-point sources and natural source. The Cluster A area received more industrial and domestic pollution-related agricultural runoff, whereas Cluster B was mainly influenced by the combination of point and non-point sources. The results imply that comprehensive analysis by using multiple methods could be more effective for facilitating effective management for the Lake Taihu Watershed in the future.

  5. Spatial and temporal variability in the nitrogen cyclers of hypereutrophic Lake Taihu.

    Science.gov (United States)

    Krausfeldt, Lauren E; Tang, Xiangming; Kamp, Jodie van de; Gao, Guang; Bodrossy, Levente; Boyer, Gregory L; Wilhelm, Steven W

    2017-02-23

    Harmful cyanobacterial blooms (cyanoHABs) are a major threat to freshwater ecosystems worldwide. Evidence suggests that both nitrogen and phosphorus are important nutrients in the development and proliferation of blooms, yet much less is known about nitrogen cycling dynamics in these systems. To assess the potential nitrogen cycling function of the cyanoHAB community, surface water samples were collected in Lake Tai (Taihu), China over a 5-month bloom event in 2014. The expression of six nitrogen cycling genes (nifH, hzsA, nxrB, nrfA, amoA, nosZ) was surveyed using a targeted microarray with probes designed to provide phylogenetic information. N-cycling gene expression varied spatially across Taihu, most notably near the mouth of the Dapu river. Expression of nifH was observed across the lake and attributable to both proteobacteria and cyanobacteria: proteobacteria were major contributors to nifH signal near shore. Other N transformations such as anaerobic ammonia oxidation and denitrification were evident in the surface waters as well. Observations in this study highlight the potential importance of heterotrophic bacteria in N-cycling associated with cyanoHABs.

  6. Cyanobacteria-/cyanotoxin-contaminations and eutrophication status before Wuxi Drinking Water Crisis in Lake Taihu, China

    Institute of Scientific and Technical Information of China (English)

    Yongmei Liu; Wei Chen; Dunhai Li; Zebo Huang; Yinwu Shen; Yongding Liu

    2011-01-01

    After the appalling “Wuxi Drinking Water Crisis”, increasing investigations concerning the contaminations of cyanobacterial blooms and their toxins in Lake Taihu have been performed and reported in the last two years.However, information regarding these issues before the crisis in 2007 remained insufficient.To provide some background data for further comparisons, the present study reported our investigations conducted in 2004, associated with the cyanotoxin contaminations as well as the eutrophication status in Lake Taihu.Results from the one-year-study near a drinking water resource for Wuxi City indicated that, unlike the status in recent two years, cyanobacteria and chlorophyta are the co-dominance species throughout the year.The highest toxin concentration (34.2 ng/mL)in water columns occurred in August.In bloom biomass, the peak value of intracellular toxin (0.59 μg/mg DW) was determined in October, which was lag behind that in water column.In addition, MC-RR was the major toxin variant throughout the year.During the study period, nutrients levels of total nitrogen and phosphorus were also recorded monthly.Results from the present study will lead to a better understanding of the eutrophication status and the potential risks before “Wuxi Drinking Water Crisis”.

  7. Denitrifying Bacteria in Paddy Soils of Taihu Lake Basin,China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hua-Yong; LI Zhen-Gao; PAN Ying-Hua; LI Liang-Mo

    2004-01-01

    This study attempted to determine the characteristics of the communities, the ecological factors, and the denitrifying enzyme activity for denitrifying bacteria found in the paddy soils of the Taihu Lake Basin, China. Samples of the six main soil types of the basin were taken from paddy fields with different fertilities. The total numbers of bacteria and denitrifying bacteria in the high fertility soils were much more than those in low fertility soils, and the number of denitrifying bacteria accounted for 49% to 80% of the total number of bacteria. The O2 content was an important ecological factor that affected denitrification. Of test the strains isolated from the paddy soils in the Taihu Lake Basin, some (e.g., Pseudomonas spp.)grew well under low oxygen partial pressure, while others (e.g., Bacillus spp.) had no strict predilection with O2 content.Another critical ecological factor was the nitrogen concentration. Three selected denitrifying bacteria grew better in a culture medium with 135 instead of 276 mg L-1 nitrogen. At the same time 67% of the test strains were able to reduce NO-3 to NO-2 and 56% had N2O reductase.

  8. Assessment of Nitrogen Pollutant Sources in Surface Waters of Taihu Lake Region

    Institute of Scientific and Technical Information of China (English)

    XIE Ying-Xin; XIONG Zheng-Qin; XING Guang-Xi; SUN Guo-Qing; ZHU Zhao-Liang

    2007-01-01

    The nitrogen(N)pollution status of the 12 most important rivers in Changshu,Taihu Lake region was investigated.Water samples were collected from depths of 0.5-1.0 m with the aid of the global positioning system (GPS).The seasonal variations in the concentrations of different N components in the rivers were measured.Using tension-free monolith lysimeters and 15 N-labeled fertilizer,field experiments were carried out in this region to determine variations of 15Nabundance of NO-3 in the leachate during the rice and wheat growing seasons,respectively.Results showed that the main source of N pollution of surface waters in the Taihu Lake region was not the N fertilizer applied in the farmland but the urban domestic sewage and rural human and animal excreta directly discharged into the water bodies without treatment.Atmospheric dry and wet N deposition was another evident source of N pollutant of the surface waters.In conclusion.it would not be correct to attribute the N applied to farmlands as the source of N pollution of the surface waters in this region.

  9. Losses of ecosystem service values in the Taihu Lake Basin from 1979 to 2010

    Science.gov (United States)

    Zhang, Hui; Wang, Qiao; Li, Guangyu; Zhang, Hanpei; Zhang, Jue

    2016-12-01

    The Taihu Lake Basin, an east-coastal developed area, is one of the fastest-growing metropolitan areas in China. Ecosystem services in the Taihu Lake Basin have been overexploited and jeopardized. Based on land-use and land-cover change (LUCC) data from 1979, 1984, 2000, and 2010, in conjunction with the adjusted ecosystem service values (ESV), changes in ESV were analyzed in detail. Results revealed that LUCC resulted in a substantial decrease in total ESV from 3.92 billion in 1979 to 2.98 billion in 2010. The ESV of cropland decreased from 1.64 billion in 1979 to 1.34 billion in 2010, which represented a 20.28% reduction. The ESV of water areas decreased from 1.08 billion in 1979 to 0.36 billion in 2010, which represented a 65.62% reduction mainly because of a decline in water quality. In terms of annual change rate, cropland and water areas showed a sustained downward trend. Spatially, ESV declines were mainly observed in Suzhou, Wuxi, Changzhou, and Shanghai, probably due to a combination of economic progress, population growth, and rapid urbanization. The research results can be a useful reference for policymakers in mitigating ESV decline.

  10. Novel acsF Gene Primers Revealed a Diverse Phototrophic Bacterial Population, Including Gemmatimonadetes, in Lake Taihu (China)

    DEFF Research Database (Denmark)

    Huang, Yili; Zeng, Yanhua; Lu, Hang

    2016-01-01

    Our results showed that most of the phototrophic species in Lake Taihu belong to Alpha- and Betaproteobacteria Sequences of green sulfur and green nonsulfur bacteria (phototrophic Chlorobi and Chloroflexi, respectively) were found in the sediment. Using the newly designed primers, we identified...

  11. Phosphorus export by runoff from agricultural field plots with different crop cover in Lake Taihu watershed

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Runoff and soil losses from agricultural fields are investigated as major nonpoint sources of phosphorus (P) entering lakes of Eastern China. There is relatively little information on P transport from ricefield and cropland of Lake Taihu watershed in Eastern China. Soil and P in surface runoff from a series of plots in the watershed were evaluated under simulated rainfall conditions. The objectives of this study were to evaluate theeffects of crop cover, slope, and fertilizer application on P concentrations in surface runoff and eroded soil. Accumulated sediment yields varied from 7.1 to 300 g/m2 for croplands, depending on management practices. For all experiment plots, weighted average concentrations of total-P (TP), dissolved P (DP) and particulate P (PP) are much higher than 0.02 mg/L, the limiting concentration in lake water. This result showed the potential contamination of lake water from agricultural surface runoff. Accumulated TP losses were 3.8 and 18.8 mg/m2 for ricefield and cropland, respectively. The estimated annual loss of TP was 0.74 kg/(hm2鷄) for cropland. Most of P loss is in PP form, which accounts for more than 90% of TP loss for cropland.

  12. Model AVSWAT apropos of simulating non-point source pollution in Taihu lake basin.

    Science.gov (United States)

    Zhang, Qiu-Ling; Chen, Ying-Xu; Jilani, Ghulam; Shamsi, Imran Haider; Yu, Qiao-Gang

    2010-02-15

    Accelerated eutrophication and nutrient loads in the lakes are of major concern for human health and environment. This study was undertaken for modeling the non-point source pollution of Taihu lake basin in eastern China. The SWAT model having an interface in ArcView GIS was employed. Model sensitive parameters related to hydrology and water quality were obtained by sensitivity analysis, and then calibrated and validated by comparing model predictions with field data. The GIS showed good potential for parameterization of hill-slopes, channels, and representative slope profiles for SWAT model simulations. In a monthly and daily time step, the model's Nash-Sutcliffe coefficient (E) and the coefficient of determination (R(2)) indicated that values of simulated runoff, NH(4)(+)-N and total phosphorus were acceptably closer to the measured data. Surface water parameters especially CN, Soil-AWC and ESCO were the most sensitive and had more recognition in the model. It is concluded that runoff carrying N and P nutrients from chemical fertilizer inputs in agricultural areas is the major contributor to NPSP in the lake basin. So, decrease in excessive use of N and P fertilizers and their synergism with organic manures is recommended that would significantly reduce nutrient pollution in the lake ecosystem.

  13. Variation characteristics of heavy metals and nutrients in the core sediments of Taihu Lake and their pollution history

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The sedimentary environment change, trophic evolution and heavy metals pollution history of the northern Taihu Lake in the last 100 years are studied according to the sedimentary geochemical proxies of the core sediments, such as grain size, nutrients, heavy metals, diatom, etc. The nutrients in the sediments depended mainly on the lake internal circulation and the heavy metals were from natural geogenic sources before the 1920s, which were not influenced by human activities generally, and grain size was one of the key factors influencing heavy metals content in the sediments.The alternation of manner and strength of human activities in Taihu Lake catchment before and after the 1920s made the lake sediments coarser, and hence heavy metals and TP content decreased contrasted with that before the 1920s. TP content in sediments and water increased from the 1950s to late 1970s due to anthropogenic pollutants discharge, and the lake belonging to mesotrophic state.TN and TOC content and C/N ratio increased due to the increasing external pollutants into Taihu Lake by human activities, TP content also increased obviously in water and sediments, and the diatom association was dominated by eutrophic species since the late 1970s, indicating the eutrophication state of Taihu Lake in this period. Meanwhile the increasing in heavy metals content, such as Cu, Mn,Ni, Pb and Zn, and their proportion of valid fractions in the sediments indicates that they all result from human pollutants since the late 1970s. The heavy metals in the surface sediments have certain potential biological toxicity due to the higher SEM/AVS ratio.

  14. Using integrated multivariate statistics to assess the hydrochemistry of surface water quality, Lake Taihu basin, China

    Directory of Open Access Journals (Sweden)

    Xiangyu Mu

    2014-09-01

    Full Text Available Natural factors and anthropogenic activities both contribute dissolved chemical loads to  lakes and streams.  Mineral solubility,  geomorphology of the drainage basin, source strengths and climate all contribute to concentrations and their variability. Urbanization and agriculture waste-water particularly lead to aquatic environmental degradation. Major contaminant sources and controls on water quality can be asssessed by analyzing the variability in proportions of major and minor solutes in water coupled to mutivariate statistical methods.   The demand for freshwater needed for increasing crop production puulation and industrialization occurs almost everywhere in in China and these conflicting needs have led to widespread water contamination. Because of heavy nutrient loadings from all of these sources, Lake Taihu (eastern China notably suffers periodic hyper-eutrophication and drinking water deterioration, which has led to shortages of freshwater for the City of Wuxi and other nearby cities. This lake, the third largest freshwater body in China, has historically beeen considered a cultural treasure of China, and has supported long-term fisheries. The is increasing pressure to remediate the present contamination which compromises both aquiculture and the prior economic base centered on tourism.  However, remediation cannot be effectively done without first characterizing the broad nature of the non-point source pollution. To this end, we investigated the hydrochemical setting of Lake Taihu to determine how different land use types influence the variability of surface water chemistry in different water sources to the lake. We found that waters broadly show wide variability ranging from  calcium-magnesium-bicarbonate hydrochemical facies type to mixed sodium-sulfate-chloride type. Principal components analysis produced three principal components that explained 78% of the variance in the water quality and reflect three major types of water

  15. Organochlorine pesticides in fish from Taihu Lake, China, and associated human health risk assessment.

    Science.gov (United States)

    Wang, Deqing; Yu, Yingxin; Zhang, Xinyu; Zhang, Dongping; Zhang, Shaohuan; Wu, Minghong

    2013-12-01

    Because contaminants and nutrients always coexist in fish, the risk from contaminants and the benefit from nutrients, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are also concomitant via fish consumption. To investigate the risk and benefit via fish consumption, concentrations of dichlorodiphenyltrichloroethane and its metabolites (DDTs), and hexachlorocyclohexanes (HCHs) in the whole- and portion-muscles of fish from Taihu Lake, China, were measured. Based on the contaminant data and nutrients from our previous study, and the associated risk and benefit via fish consumption were estimated. The concentrations of DDTs and HCHs in the whole-muscles ranged from 7.8 × 10² to 3.4×10³ pg g⁻¹ ww, and from 67.3 to 300 pg g⁻¹ ww, respectively. Of DDTs and HCHs measured, p,p'-DDE and β-HCH were respectively the most abundant pesticides. The composition profiles of DDTs and HCHs suggested that the pesticides were mainly historical residues. The benefit-risk quotient (BRQ) of EPA+DHA vs. POPs (persistent organic pollutants including data of DDTs, HCHs, and those of polychlorinated biphenyls and polybrominated diphenyl ethers cited from our previous study) via consumption of fish from Taihu Lake was calculated. As a result, to achieve the recommended EPA+DHA intake of 250 mg d⁻¹ for a healthy adult, the consumption of most fish species from the lake can cause cancer and non-cancer risks. However, the fish consumption at the rates of 44.9 g d⁻¹ by Chinese would not lead to the risks for most of the species. The results also suggested that the risk of consuming silver carp was generally lower than other fish species, and those of dorsal muscles were lower than ventral and tail muscles. Copyright © 2013 Elsevier Inc. All rights reserved.

  16. Tracing high time-resolution fluctuations in dissolved organic carbon using satellite and buoy observations: Case study in Lake Taihu, China

    Science.gov (United States)

    Huang, Changchun; Yunmei, Li; Liu, Ge; Guo, Yulong; Yang, Hao; Zhu, A.-xing; Song, Ting; Huang, Tao; Zhang, Mingli; Shi, Kun

    2017-10-01

    Field measurements of dissolved organic carbon (DOC) concentration and remote-sensing reflectance were conducted to develop a regional, empirical red-blue algorithm to retrieve surface DOC from Geostationary Ocean Color Imager (GOCI) data for Lake Taihu, China. The auxiliary data (in-situ observations of the optical properties and water quality, buoy measurements of hydrodynamic data and water chemical parameters) were used to investigate the spatial and temporal variations in DOC. GOCI was shown to be capable of successfully obtaining hourly variations in DOC, with a root mean square error percentage (RMSP) of 17.29% (RMSE = 0.69 mg/L) for the match-up data. The GOCI-derived DOC in Lake Taihu confirms that the highest DOC concentration is in northwest Lake Taihu, followed by Meiliang Bay, Gonghu Bay and northeast Lake Taihu. Hourly DOC variation is significant and presents a different trend for each lake segment due to the variety of influencing factors. Discharge of DOC from surrounding rivers is an important factor to the variation of DOC in northeast Lake Taihu. However, organic products of algae will be the primary contributor to DOC when algal bloom occurred. During the period of algal bloom, high DOC levels in Lake Taihu can lead to hypoxia when coupled with high temperatures and low disturbance.

  17. Sedimentary record of hydrophobic organic compounds in relation to regional economic development: A study of Taihu Lake, East China

    Energy Technology Data Exchange (ETDEWEB)

    Liu Guoqing, E-mail: liugq@szu.edu.c [Institute of Applied Nuclear Technology, Shenzhen University, Shenzhen 518060 (China); State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Zhang Gan [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Yantai Institute of Coastal Zone for Sustainable Development, Chinese Academy of Sciences, Yantai 264003 (China); Jin Zhangdong [State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi' an 710075 (China); Li Jun [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China)

    2009-11-15

    Sediment cores taken from Taihu Lake, East China were analyzed for polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and polybrominated biphenyl ethers (PBDEs). The results showed a general sharp increase of HCH, DDT, PAH and PBDE concentrations in the surface layers, corresponding to a sedimentation time of 1980 and 1990 onward in the Meiliang Bay and Xukou Bay, respectively. The source of PAHs has largely transferred from petrogenic to pyrogenic origin, and good relationships were observed between sediment PAH concentrations and the regional gross domestic product. The sharp increase of DDTs in recent years may be related to the mobilization and migration of these chemicals from surface soil to lake sediment, as a result of enhanced soil run-off due to large scale land transform, as well as the contribution of current usage of dicofol and DDT-containing anti-fouling paints. - PAHs, DDTs and PBDEs are still increasing in the Taihu Lake sediment.

  18. Spatiotemporal distribution of algal and nutrient, and their correlations based on long-term monitoring data in Lake Taihu, China

    Science.gov (United States)

    Acharya, K.; Li, Y.; Stone, M.; Yu, Z.; Young, M.; Shafer, D. S.; Zhu, J.; Warwick, J. J.

    2009-12-01

    Eutrophication in Lake Taihu - China’s third largest freshwater lake - has led to deterioration of water quality and caused more frequent cyanobacteria blooms at many lake locations in recent years. Eutrophication is thought to be fueled by increased nutrient loading, a consequence of rapid population and economic growth in the region. To understand the spatiotemporal distribution of algal blooms, a database was developed that includes long-term meteorological, hydrological, water quality, and socioeconomic data from the Lake Taihu watershed. The data were collected through various field observations, and augmented with information from local and provincial agencies, and universities. Based on the data, spatiotemporal distributions of, and correlations between, chlorophyll-a (Chl-a), total phosphorus (TP), total nitrogen (TN) and water temperature (WT) were analyzed. Results revealed a high degree of correlation between TP and Chl-a concentrations during warm seasons, with high concentrations of both substances present in the northern and northwest portions of the lake. During winter months, Chl-a concentrations were more strongly correlated with WT. Spatial trends in TP and TN concentrations corresponded to observed nutrient fluxes from adjoining rivers in densely populated areas, demonstrating the influence of watershed pollutant loads on lake water quality. Among important questions to be answered is whether wind-driven resuspension of existing nutrients in sediments in this shallow (cyanobacteria blooms to begin. This study identifies other questions, data gaps, and research needs, and provides a foundation for improving lake management strategies.

  19. Heavy-metal contents in suspended solids of Meiliang Bay, Taihu Lake and its environmental significances

    Institute of Scientific and Technical Information of China (English)

    ZHU Guang-wei; CHI Qiao-qiao; QIN Bo-qiang; WANG Wen-min

    2005-01-01

    Surface water was taken from river mouth to the central area of Meiliang Bay, Taihu Lake, a large shallow eutrophic lake in China. Suspended solids were condensed by centrifugation 25 L surface water samples from each selected site. Suspended solids and surface sediments were further freeze-dried and microwave digested before determining the metals by ICP-AES. Among the metals analyzed in suspended solids and sediments, contents of Cr, Cu, Mn, Ni, and Zn in suspended solids were significantly higher than those in sediments while contents of Al, Ba, Be, Ca, Co, Fe, K, Mg, Pb, and V in suspended solids were 10%-30% higher than those in sediments. Sr and Ti contents in suspended solids and sediments were very similar. Na content in suspended solids was lower than that in sediments. Heavy metals were significantly accumulated in suspended solids. From the river mouth to the center of Meiliang Bay,contents of Cr, Cu, Pb, and Zn in suspended solids showed a gradual decreasing trend indicating the river(Zhihugang River) still discharged large quantity of heavy metalsto Meiliang Bay. The study suggests that the geochemical behaviors and ecological effects of heavy metals in suspended solids may serve as a good indicator for the pollution of lake.

  20. Changes in phytoplankton communities along nutrient gradients in Lake Taihu: evidence for nutrient reduction strategies

    Science.gov (United States)

    Ai, Ying; Bi, Yonghong; Hu, Zhengyu

    2015-03-01

    An annual investigation on phytoplankton communities was conducted to reveal the effects of nutrients on phytoplankton assemblages in Lake Taihu, East China. A total of 78 phytoplankton taxa were identified. Phytoplankton biomass was higher in the northern part of the lake than in the southern part. Cyanobacteria and Bacillariophyta alternated dominance in the northern area, where algal blooms often appear, and co-dominated in the southern area. In the northern part, the proportions of cyanobacteria and Bacillariophyta varied significantly in total biovolume, both along the phosphorus (P) gradient, and between total nitrogen levels (≤3 mg/L and >3 mg/L TN). The proportions of cyanobacteria and Bacillariophyta had no significant variations in total biovolume along P and N (nitrogen) gradients in the southern part. Correlation analysis and CCA results revealed that P was the key factor regulating phytoplankton community structure. Nitrogen was also important for the phytoplankton distribution pattern. It was concluded that nutrient structure was heterogeneous in space and shaped the distribution pattern of phytoplankton in the lake. Both exogenous P and internally sourced P release needs to be considered. N reduction should be considered simultaneously with P control to efficiently reduce eutrophication and algal blooms.

  1. Three-dimensional eutrophication model and application to Taihu Lake,China

    Institute of Scientific and Technical Information of China (English)

    MAO Jingqiao; CHEN Qiuwen; CHEN Yongcan

    2008-01-01

    Talhu 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.

  2. [Integrated fuzzy evaluation of water eutrophication based on GIS in the Taihu Lake].

    Science.gov (United States)

    Gong, Shao-Qi; Huang, Jia-Zhu; Li, Yun-Mei; Wei, Yu-Chun; Gu, Zheng-Fan

    2005-09-01

    Supported by geographic information system and geostatistics, the application of fuzzy mathematics and analytic hierarchy process for water eutrophication evaluation was discussed. Taking Taihu Lake as an example, the research selected total phosphorus, total nitrogen, chlorophyll a, COD, BOD5, DO and transparence as evaluation index. After geostatistical analysis of the datum of monitoring site, the values of evaluation indices were estimated in the whole research area. Given that, the different dependence functions were developed for these indices and the function values were calculated. Furthermore, according to the principle of analytic hierarchy process, the weight of every index was calculated, then integrated evaluation value was obtained for the whole research area and the evaluation map for water eutrophication was drawn. The result shows that the level of nutrition is the highest in the north and north-west of lake, which is hypertrophic, that is meso-eutrophic in the middle and that is the lowest in the south-east of lake, which is mesotrophic.

  3. [Comparison of chlorophyll a concentration estimation in Taihu Lake using different methods].

    Science.gov (United States)

    Li, Yun-Liang; Zhang, Yun-Lin; Li, Jun-Sheng; Liu, Ming-Liang

    2009-03-15

    Based on the measured remote sensing reflectance and concurrent chlorophyll a (Chl-a) concentration in Taihu Lake from January 7 to 9 and July 29 to August 1, 2006, this study comparatively analyzed the estimation precision of three-band-model, two-band-model, reflectance peak position method and first derivative method, and further discussed the feasibility of the four methods to estimate Chl-a using remote sensing image. The data set of two samplings contained widely variable total suspended matter (12.24-285.20 mg x L(-1), Chl-a (4.83-155.11 microg x L(-1)) and chromophoric dissolved organic matte absorption coefficient at 440 nm (0.27-2.36 m(-1)). The former four methods all got high precisions on Chl-a concentration estimation in Taihu Lake with determination coefficients (r2) of 0.813, 0.838, 0.872 and 0.819, respectively. The root mean square error (RMSE) between measured and estimated Chi-a concentrations using the four models was 13.04, 12.12, 13.41 and 12.13 microg x L(-1), respectively, and the relatively error (RE) was 35.5%, 34.9%, 24.6% and 41.8%, respectively. Although the reflectance peak position method had the highest estimation precision, it was difficult to be applied on remote sensing image due to lacking spectral channel. The three-band-model and two-band-model had higher estimation precisions than the first order differential method and good application foreground in Chl-a retrieval using remote sensing image. The r2, RMSE, RE of [R(-1) (665)- R(-1) (709)] x R(754) in three-band-model and R(709)/R(681) in two-band-model based on simulation MERIS data were 0.788, 13.87 microg x L(-1), 37.3%, and 0.815, 12.96 microg x L(-1), 34.8%, respectively. The results in this study demonstrated MERIS data could be applied to retrieve Chl-a concentration in turbid Case-II waters as Taihu Lake.

  4. Effects of water diversion from Yangtze River to Taihu Lake on hydrodynamic regulation of Taihu Lake%引江济太调水工程对太湖水动力的调控效果

    Institute of Scientific and Technical Information of China (English)

    郝文彬; 唐春燕; 滑磊; ACHARYA Kumud

    2012-01-01

    为研究引江济太调水工程对太湖水动力调控所产生的效果,采用数学模型对其水动力进行模拟.利用环境流体动力学模型(EFDC模型),以湖体水龄(描述湖泊水体交换速率的参数)为研究 对象,系统地研究引江济太调水工程对太湖水动力的调控情况.结果表明:(a)引江济太调水工程对太湖湖体水动力过程的作用效果很大程度上取决于风速、风向以及出入湖的流量;(b)太湖湖体水龄的分布具有很强的时空异质性,夏天的平均水龄约为130 d,其他季节的平均水龄约为230 d;(c)太湖地区夏天的主导风向——东南风能够促进东部湖区(无锡、苏州水源地所在地)和梅梁湾湖区(太湖重污染区)的水交换,改善水体运动条件;(d)望虞河入湖的最经济调水流量为100m3/s.%To study the effects of a water diversion project from the Yangtze River to Taihu Lake on the hydrodynamic regulation of Taihu Lake, mathematical models were used to simulate the hydrodynamic process. With the water age of the lake being the research focus, the hydrodynamic regulation of Taihu Lake by the project was systematically studied using the environmental fluid dynamics code (EFDC) model. The results show the following: (a) The effects of water diversion from the Yangtze River to Taihu Lake on the hydrodynamic process in Taihu Lake were mainly determined by wind velocity, wind direction, and inflow of the lake, (b) The water age of Taihu Lake presented significant spatial and temporal heterogeneity, with a mean water age of approximately 130 days in the summer and 230 days in other seasons, ? The dominant southeastly wind of the summer greatly enhanced the transport of the transferred water into the eastern lake area (the drinking water source area of Wuxi and Suzhou cities) and Meiliang Bay (a seriously polluted area of Taihu Lake), and improved water movement conditions in these areas, (d) The most efficient discharge of the

  5. Accumulation of microcystins in a dominant Chironomid Larvae (Tanypus chinensis) of a large, shallow and eutrophic Chinese lake, Lake Taihu

    Science.gov (United States)

    Xue, Qingju; Su, Xiaomei; Steinman, Alan D.; Cai, Yongjiu; Zhao, Yanyan; Xie, Liqiang

    2016-08-01

    Although there have been numerous studies on microcystin (MC) accumulation in aquatic organisms recently, the bioaccumulation of MCs in relatively small sized organisms, as well as potential influencing factors, has been rarely studied. Thus, in this study, we investigated the bioaccumulation of three MC congeners (-LR, -RR and -YR) in the chironomid larvae of Tanypus chinensis (an excellent food source for certain fishes), the potential sources of these MCs, and potentially relevant environmental parameters over the course of one year in Lake Taihu, China. MC concentrations in T. chinensis varied temporally with highest concentrations during the warmest months (except August 2013) and very low concentrations during the remaining months. Among the three potential MC sources, only intracellular MCs were significantly and positively correlated with MCs in T. chinensis. Although MC concentrations in T. chinensis significantly correlated with a series of physicochemical parameters of water column, cyanobacteria species explained the most variability of MC accumulation, with the rest primarily explained by extraMC-LR. These results indicated that ingestion of MC-producing algae of cyanobacteria accounted for most of the MC that accumulated in T. chinensis. The high MC concentrations in T. chinensis may pose a potential health threat to humans through trophic transfer.

  6. EXPERIMENTAL STUDY ON SEDIMENT RESUSPENSION IN TAIHU LAKE UNDER DIFFERENT HYDRODYNAMIC DISTURBANCES

    Institute of Scientific and Technical Information of China (English)

    QIAN Jin; ZHENG Sha-sha; WANG Pei-fang; WANG Chao

    2011-01-01

    Contaminants resuspension in sediments rnduced by wind-wave could influence the water quality in shallow lakes.Resuspension of surface sediments from the Zhushan Bay,Taihu Lake was simulated under different wind forcing by using a pneumatic annular flume in this study.Acoustic Doppler Velocimeter (ADV) was used to measure flow velocity at each wind speed,and the characteristics of sediment resuspension were studied with the layered sampling technology.The experimental results show that the flow velocity increases with wind speed obviously and 6m/s is a critical wind speed which affected hydrodynamic conditions significantly.The distribution of flow velocity and water depth is different from that in ordinary open channel.With the enhanced hydrodynamic factors,the Suspended Solids Concentration (SSC) in water increases accordingly,and the incipient velocity of sediment resuspension is about 0.21 rm/s.Based on the analysis of wind speed and average SSC in water column,the quantitative relationship is obtained.The SSC of the bottom layer is higher than the content of surface layer under different hydrodynamic conditions,and there are similar distributions between SSC and flow velocity in different water layers.

  7. Inhibition of the growth of cyanobacteria during the recruitment stage in Lake Taihu.

    Science.gov (United States)

    Lu, Yaping; Wang, Jin; Zhang, Xiaoqian; Kong, Fanxiang

    2016-03-01

    Microcystis is the dominant algal bloom genus in Lake Taihu. Thus, controlling the recruitment and growth of Microcystis is the most crucial aspect of solving the problem of algal blooms. Different concentrations (0.025, 0.05, and 0.1 g L(-1)) of tea extract were used to treat barrels of lake water at the recruitment stage of cyanobacteria. There was an inhibitory effect on algal growth in all treatment groups. The inhibitory effect on cyanobacteria was stronger than on other algae. The metabolic activity of cells in the treatment groups was significantly enhanced compared to the control, as an adaptation to the stress caused by tea polyphenols. The photosynthetic activity diminished in the treatment groups and was barely detected in the 0.05 and 0.1 g L(-1) treatments. The levels of reactive oxygen species increased substantially in treated cells with the algal cells experiencing oxidative damage. The effect of tea on zooplankton was also studied. The number of Bosmina fatalis individuals did not change significantly in the 0.025 and 0.05 g L(-1) treatments. These results suggested that the application of tea extracts, during the recruitment stage of blue-green algae, suppressed the recruitment and growth of cyanobacteria, thus offering the potential to prevent cyanobacterial blooms.

  8. Estimation of internal nutrient release in large shallow Lake Taihu, China

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Based on field investigation of wave, sediment suspension and the changes in nutrient concentration of the water column in Lake Taihu, China, we proposed two release models to quantify nutrient release under static and dynamic conditions, respectively. Under static conditions, nutrient release from sediments to the overlying water mainly depends on chemical diffusion induced by concentration gradient, in which the nutrient release is controlled by the temperature, dissolved oxygen concentration in the sediment-water interface, oxidation-reduction potential and the concentration difference between porewater and overlying water. Under dynamic condition (or disturbed condition),both dissolved and particulate nutrients in sediments are released into the water column because of wind-induced sediment suspension. The amount of nutrient release under dynamic conditions is larger than that under the static condition. The release of dissolved nutrients, however, does not increase because the wind induced turbulence made oxidation of metallic elements such as Fe (ferric iron), Mn which are capable of precipitating soluble reactive phosphate (SRP). Under dynamic conditions, therefore, the release of total phosphorus (TP) increases dramatically but the release of SRP is close to those under static conditions. In sediments of Lake Taihu, high Fe content leads to a high ratio of Fe to P contents in sediments (Fe:P ratio). Under dynamic conditions, therefore, nutrient release is controlled by the intensity of disturbance, sediment consolidation and nutrient content in sediments.As for dissolved nutrients, especially SRP, the release is also controlled by the intensity of dynamic re-oxidation, Fe content in sediments and nutrient concentration gradient between porewater and overlying water. Based on these two release modes, the release flux in Lake Taihu has been estimated. In the static condition (i.e. laboratory experimental condition), total release of NH4+-N for whole lake is

  9. Physicochemical Process, Crustacean, and Microcystis Biomass Changes In Situ Enclosure after Introduction of Silver Carp at Meiliang Bay, Lake Taihu

    Directory of Open Access Journals (Sweden)

    Chengjie Yin

    2017-01-01

    Full Text Available In order to control cyanobacteria blooms with silver carp in Lake Taihu, an in situ experiment was carried out by stocking silver carp at a biomass of 35, 70, and 150 g m-3 and no carp control in waterproof enclosures. Physicochemical water parameters and biomass of plankton were measured in enclosures to evaluate the suitable stocking density of silver carp for relieving internal nutrients and constraining cyanobacteria growth in Lake Taihu. It is found that the 35 g m-3 silver carp group and 70 g m-3 silver carp group presented lower total phosphorus, lower chlorophyll-a, and higher water transparency. Increased nitrogen to phosphorus ratio, which indicated the result of algae decline in fish presence enclosures, was attributed to decline of phosphorus. Phosphorus decline also exerted limitation on reestablish of cyanobacteria bloom. Crustacean zooplankton biomass and Microcystis biomass decreased significantly in fish presence enclosures. Silver carp could be more effective to regulate algae bloom in enclosures with dense cyanobacteria. Therefore, nonclassic manipulation is supposed to be appropriate method to get rid of cyanobacteria blooms in Lake Taihu by stocking 35 to 70 g m-3 silver carp in application.

  10. Denitrification and Nitrate Reduction to Ammonium in Taihu Lake and Yellow sea Inter—Tidal Marine Sediments

    Institute of Scientific and Technical Information of China (English)

    YINSHIXUE; SHENQIRONG; 等

    1999-01-01

    Denitrification and nitrate reduction to ammonium in Taihu Lake and Yellow Sea inter-tidal marine sediments were studied.The sediment samples were made slurry containing 150g dry matter per liter.Various of glucose-C to nitrate-N.Acetylene inhibition technique was applied to measure denitrification in the slurres,All samples were incubated anaerobically under argon atmosphere,Data showed that Taihu Lake sediment produced more N2O than marine sediment,Denitrification potential was higher in Taihu Lake sediment than in marine one,Glucose added increase denitrification activity but not the denitrification potential of the sediments.Dissimilatory nitrate reduction to ammonium seemed to occur in marine sediment,but not in freshwater one.When the marine sediment was treated with 25mmol L-1 glucose,its denitrification potentail,as indicated by maximum N2O production by acetylene blockage,was lower than that treated with no or 2.5mmol L-1 glucose.Acetylene was suspected to have inhibitory effect on dissimilatory nitrate reduction to ammonium.

  11. Proteomic analysis of hepatic tissue of Cyprinus carpio L. exposed to cyanobacterial blooms in Lake Taihu, China.

    Directory of Open Access Journals (Sweden)

    Jinlin Jiang

    Full Text Available With the rapid development of industry and agriculture and associated pollution, the cyanobacterial blooms in Lake Taihu have become a major threat to aquatic wildlife and human health. In this study, the ecotoxicological effects of cyanobacterial blooms on cage-cultured carp (Cyprinus carpio L. in Meiliang Bay of Lake Taihu were investigated. Microcystins (MCs, major cyanobacterial toxins, have been detected in carp cultured at different experimental sites of Meiliang Bay. We observed that the accumulation of MCs in carp was closely associated with several environmental factors, including temperature, pH value, and density of cyanobacterial blooms. The proteomic profile of carp liver exposed to cyanobacterial blooms was analyzed using two-dimensional difference in-gel electrophoresis (2D-DIGE and mass spectrometry. The toxic effects of cyanobacterial blooms on carp liver were similar to changes caused by MCs. MCs were transported into liver cells and induced the excessive production of reactive oxygen species (ROS. MCs and ROS inhibited protein phosphatase and aldehyde dehydrogenase (ALDH, directly or indirectly resulting in oxidative stress and disruption of the cytoskeleton. These effects further interfered with metabolic pathways in the liver through the regulation of series of related proteins. The results of this study indicated that cyanobacterial blooms pose a major threat to aquatic wildlife in Meiliang Bay in Lake Taihu. These results provided evidence of the molecular mechanisms underlying liver damage in carp exposed to cyanobacterial blooms.

  12. Environmental factors regulating cyanobacteria dominance and microcystin production in a subtropical lake within the Taihu watershed, China

    Institute of Scientific and Technical Information of China (English)

    Wan-min NI; Jian-ying ZHANG; Teng-da DING; R. Jan STEVENSON; Yin-mei ZHU

    2012-01-01

    Understanding the pattern ofphytoplankton and their dependence on water quality variables,can help the management of eutrophic lakes.The aim of this study was to determine water quality and environmental factors associated with cyanobacteria dominance and microcystin production in Qingshan Lake,a subtropical lake located in the headwater of the Taihu watershed,China.Water samples collected monthly from 10 study sites in Qingshan Lake were analyzed for the species distributions of freshwater algae and physico-chemical parameters including total nitrogen (TN),ammonia (NH4+-N),nitrate (NO3 -N),total phosphorus (TP),and chlorophyll a (Chl-a) from June,2008 to May,2009.Qingshan Lake was found to be eutrophic,based on the calculated trophic state index (TSI).The average TN of 4.33 mg/L during the study period exceeded the Surface Water Quality Standards of China.TP was significantly correlated with relative abundance of cyanobacteria and Microcystis biovolume,indicating its important role in regulating cyanobacteria.Microcystis,Anabaena,and Oscillatoria were dominant cyanobacteria in Qingshan Lake from June to November,2008.Cyanobacteria dominance was regulated by water temperature and TP.Principal component analysis further indicated that microcystin production was most affected by water temperature,TP,and cyanobacteria biomass.Results suggest that the control of TP in summer can mitigate cyanobacteria dominance and microcystin production in Qingshan Lake,and close monitoring should be undertaken in summer.

  13. Effects of abiotic factors on ecosystem health of Taihu Lake, China based on eco-exergy theory

    Science.gov (United States)

    Wang, Ce; Bi, Jun; Fath, Brian D.

    2017-02-01

    A lake ecosystem is continuously exposed to environmental stressors with non-linear interrelationships between abiotic factors and aquatic organisms. Ecosystem health depicts the capacity of system to respond to external perturbations and still maintain structure and function. In this study, we explored the effects of abiotic factors on ecosystem health of Taihu Lake in 2013, China from a system-level perspective. Spatiotemporal heterogeneities of eco-exergy and specific eco-exergy served as thermodynamic indicators to represent ecosystem health in the lake. The results showed the plankton community appeared more energetic in May, and relatively healthy in Gonghu Bay with both higher eco-exergy and specific eco-exergy; a eutrophic state was likely discovered in Zhushan Bay with higher eco-exergy but lower specific eco-exergy. Gradient Boosting Machine (GBM) approach was used to explain the non-linear relationships between two indicators and abiotic factors. This analysis revealed water temperature, inorganic nutrients, and total suspended solids greatly contributed to the two indicators that increased. However, pH rise driven by inorganic carbon played an important role in undermining ecosystem health, particularly when pH was higher than 8.2. This implies that climate change with rising CO2 concentrations has the potential to aggravate eutrophication in Taihu Lake where high nutrient loads are maintained.

  14. Decomposition and phosphorus release from four different size fractions of Microcystis spp. taken from Lake Taihu, China

    Institute of Scientific and Technical Information of China (English)

    WANG Yuanyuan; CHEN Feizhou

    2008-01-01

    Decomposition of Microcystis is accompanied by the release of phosphorus, during which bacteria play an important role. A series of experiments were undertaken to evaluate the effect of bacteria on the decomposition of Microcystis taken from Lake Taihu, a Chinese lake that is suffering from dense Microcystis blooms. The 16 experiments involved four size fractions of colonial Microcystis from Lake Taihu, with and without the addition of lake sediment and Gram-negative bacterial inhibitor NaN3. The highest decomposition rates were recorded for the smallest size Microcystis fraction (< 25 μm) with the addition of the sediment. The lowest decomposition rates were recorded for the smallest Microcystis fraction without the sediment, but with the addition of Gram-negative bacterial inhibitor NaN3. The higher decomposition rates in the treatments with NaN3 and sediment suggest that Gram-positive bacteria in the sediment are important for the decomposition process. Additionally, higher concentrations of total dissolved phosphorus (TDP) in the treatments with NaN3 suggest that more phosphorus accumulates in the Gram-negative bacterial cells around the colony, which may be an important source of phosphorus for Microcystis cells. In the no-sediment treatments, the ratios of TDP concentration to initial TP concentration were 64%-82%. The results of this experiment suggest that both Gram-negative and Gram-positive bacteria play an important role in the decomposition of Microcystis cells and in the release of phosphorus from Microcystis colonies.

  15. Water quality, nutrient budget, and pollutant loads in Chinese mitten crab ( Eriocheir sinensis) farms around East Taihu Lake

    Science.gov (United States)

    Cai, Chunfang; Gu, Xiaohong; Huang, Hezhong; Dai, Xiuying; Ye, Yuantu; Shi, Chenjiang

    2012-01-01

    To understand the factors causing frequent outbreaks of harmful algae blooms in the Taihu Lake, China, we studied water quality and nutrient budget in Chinese mitten crab ( Eriocheir sinensis) farm ponds in the eastern part of the lake from November 2007 to December 2009. We estimated the nitrogen (N), phosphorus (P), and chemical oxygen demand (COD) loads. Materials input and output ponds, water exchange, and applied management practices of 838.5-hm2 crab ponds were surveyed using questionnaires. Water quality of 12 ponds, which were located no more than 2 km from East Taihu Lake, were monitored. The results show that water quality in the crab ponds was better than reference data. Feeds, including corn seed, commercial feed, trash fish, and gastropod, were the major sources of N and P input in the crab ponds, contributing 88.7% and 94.9%, respectively. In total, 60.5% of N and 37.3% of P were sequestered by macrophytes, and only 15.7% and 8.5% of them were discharged as effluent. The net loads of N and P in effluent were 16.43 kg/hm2/cycle and 2.16 kg/hm2/cycle, respectively, while the COD load was -17.88 kg/hm2/cycle. This indicated that crab farming caused minor negative impact on the trophic status of the lake area, which was attenuated by macrophytes. However, wastewater purification is still necessary in crab faming.

  16. Effects of abiotic factors on ecosystem health of Taihu Lake, China based on eco-exergy theory.

    Science.gov (United States)

    Wang, Ce; Bi, Jun; Fath, Brian D

    2017-02-21

    A lake ecosystem is continuously exposed to environmental stressors with non-linear interrelationships between abiotic factors and aquatic organisms. Ecosystem health depicts the capacity of system to respond to external perturbations and still maintain structure and function. In this study, we explored the effects of abiotic factors on ecosystem health of Taihu Lake in 2013, China from a system-level perspective. Spatiotemporal heterogeneities of eco-exergy and specific eco-exergy served as thermodynamic indicators to represent ecosystem health in the lake. The results showed the plankton community appeared more energetic in May, and relatively healthy in Gonghu Bay with both higher eco-exergy and specific eco-exergy; a eutrophic state was likely discovered in Zhushan Bay with higher eco-exergy but lower specific eco-exergy. Gradient Boosting Machine (GBM) approach was used to explain the non-linear relationships between two indicators and abiotic factors. This analysis revealed water temperature, inorganic nutrients, and total suspended solids greatly contributed to the two indicators that increased. However, pH rise driven by inorganic carbon played an important role in undermining ecosystem health, particularly when pH was higher than 8.2. This implies that climate change with rising CO2 concentrations has the potential to aggravate eutrophication in Taihu Lake where high nutrient loads are maintained.

  17. [Algae-removal effect of AS/PDM composite coagulants to winter Taihu Lake raw water].

    Science.gov (United States)

    Zhao, Xiao-Lei; Zhang, Yue-Jun; Li, Xiao-Xiao; Liu, Cheng; Zhu, Ling-Ling

    2009-04-15

    The series of stable AS/PDM composite coagulants prepared by polydimethyldiallylammonium chloride (PDM) and aluminium sulphate (AS) were used to research the algae-removal effect to winter Taihu Lake raw water. The effects of dosage of composite coagulants, composite mass ratios (20:1-5:1) of AS and PDM, intrinsic viscosity values (0.55-3.99 dL/g) of PDM on algae-removal rates were studied through coagulation and algae-removal experiments. The feasibility of using composite coagulants to substitute prechlorination process was analysed. The results show that when residual turbidity of 2 NTU to water after coagulation and sediment is required by water plant, the dosage (based on Al2O3) of AS, AS/PDM (0.55/20:1-3.99/5:1) composite coagulants are 4.24 mg/L, 3.96-1.87 mg/L, and the algae-removal rates are 83.00%, 87.52%-90.93% respectively. When dosage to raw water are 4.24 mg/L, the algae-removal rates of AS, AS/PDM (0.55/20:1-3.99/5:1) composite coagulants are 83.00%, 88.29%-97.66%, and the residual turbidities are 2.00 NTU, 1.76-0.43 NTU respectively. When dosage to chlorine-added water are 4.50 mg/L, the treatment effect of AS/PDM (1.53/10:1) composite coagulant to raw water is better than that of AS to chlorine-added water, and the treatment effect of AS/PDM (3.99/5:1) composite coagulant to raw water is better than that of AS, AS/PDM (0.55/20:1) and AS/PDM (1.53/10:1) composite coagulants to chlorine-added water. So using AS/PDM composite coagulants can enhance evidently the treatment effect of AS to winter Taihu Lake raw water. Compared with using AS solely, the dosage of AS in composite coagulants are saved when the residual turbidities are required in same level, and the treatment effect of AS is enhanced when the dosage of AS in composite coagulants are same as that of using AS solely. Moreover, using composite coagulants can replace the part chlorine-added function on increasing coagulation and algae-removal in prechlorination process and profitably increases

  18. Phragmites australis and Typha orientalis in removal of pollutant in Taihu Lake, China

    Institute of Scientific and Technical Information of China (English)

    TIAN Ziqiang; ZHENG Binghui; LIU Meizhen; ZHANG Zhenyu

    2009-01-01

    Two plant populations of Phragmites australis and Typha orientalis grown in gravel and sediment substrate were studied to assess their capabilities for purifying polluted water in Taihu Lake, China. The substrate displayed most significant effects on the suspended matter (P < 0.01), with the reduction of 76%-87% and 52%-63% for P. australis, and 83%-86% and 45%-62% for T. orientalis in gravel substrate and sediment substrate, respectively. Both species and substrates significantly decreased the N and P concentrations of water body (P < 0.01). P. australis showed higher total N and P concentrations in tissues than T. orientalis and had greater potential to remove nutrients from the lake. Phosphate was easily to concentrate in the belowground tissues, while nitrate concentration was higher in leaf and stalk. Therefore, harvesting the aboveground tissues could take most of nitrate out of the sediment. The saturate photosynthetic rate (Asat) of P. australis was higher than that of T. orientalis when grown in sediment substrate. But instance water use efficiency (WUEi) and intrinsic water use efficiency (A/gs) showed the maximum values of two species grown in river water. With significant difference in gs, however, intercellular CO2 concentration (Ci) had no obvious difference in two species which indicated that high Asat value of P. australis might result from the increased carboxylation capacity of the mesophyll, because of the central role of N in photosynthetic enzymes. Our findings suggest that the plants could absorb most of nitrogen in polluted water, while gravel displayed high capacity for absorbing the suspended matters and phosphate salts. Therefore, biological and physiological pathways for pollutant removal should be integrated.

  19. In Situ, High-Resolution Profiles of Labile Metals in Sediments of Lake Taihu

    Directory of Open Access Journals (Sweden)

    Dan Wang

    2016-09-01

    Full Text Available Characterizing labile metal distribution and biogeochemical behavior in sediments is crucial for understanding their contamination characteristics in lakes, for which in situ, high-resolution data is scare. The diffusive gradient in thin films (DGT technique was used in-situ at five sites across Lake Taihu in the Yangtze River delta in China to characterize the distribution and mobility of eight labile metals (Fe, Mn, Zn, Ni, Cu, Pb, Co and Cd in sediments at a 3 mm spatial resolution. The results showed a great spatial heterogeneity in the distributions of redox-sensitive labile Fe, Mn and Co in sediments, while other metals had much less marked structure, except for downward decreases of labile Pb, Ni, Zn and Cu in the surface sediment layers. Similar distributions were found between labile Mn and Co and among labile Ni, Cu and Zn, reflecting a close link between their geochemical behaviors. The relative mobility, defined as the ratio of metals accumulated by DGT to the total contents in a volume of sediments with a thickness of 10 mm close to the surface of DGT probe, was the greatest for Mn and Cd, followed by Zn, Ni, Cu and Co, while Pb and Fe had the lowest mobility; this order generally agreed with that defined by the modified BCR approach. Further analyses showed that the downward increases of pH values in surface sediment layer may decrease the lability of Pb, Ni, Zn and Cu as detected by DGT, while the remobilization of redox-insensitive metals in deep sediment layer may relate to Mn cycling through sulphide coprecipitation, reflected by several corresponding minima between these metals and Mn. These in situ data provided the possibility for a deep insight into the mechanisms involved in the remobilization of metals in freshwater sediments.

  20. Divergence of carbon dioxide fluxes in different trophic areas of Taihu Lake, China

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Carbon dioxide partial pressures(pCO2 ) and CO2 fluxes on air-water interface in different trophic-level areas of Taihu Lake werecalculated and corrected using alkalinity, pH, ionic strength, active coefficient, water temperature and wind speed on the basis of the data setsof monthly sampling in 1998. The mean values of pCO2 in the hypertrophic, eutrophic, and mesotrophic areas are 1807.8 + 1025.8(mean +standard deviation) μatm, 416.3 + 207.8 μatm, and 448.5 + 194.0 μatm,respectively. A maximum and minimum pCO2 values were found inthe hypertrophic(4053.7 μatm) and the eutrophic(3.2 μatm) areas. There was about one magnitude order of difference in mean CO2 fluxesbetween the hypertrophic area(27.3 + 17.4 mmol/( m2 @ d) ) and the eutrophic ( 1.99 + 4.50 mmol/( m2 @ d) ) and mesotrophic ( 2.22 + 4.31mmol/( m2 @ d)) areas. But there was no significant difference between eutrophic and mesotrophic areas in pCO2 and the flux of CO2. In respectto CO2 equilibrium, input of the rivers will obviously influence inorganic carbon distribution in the riverine estuary. An exponential relationshipbetween the pCO2 values and chlorophyll-a concentrations was obtained( r = 0.8356, n = 60) in eutrophic bay. Results suggested that lakeecosystems, also may be considered as unique aggregation, which can contain and be patient of different components that have their relativeindependence so long as its size enough to large. A productive lake, though it has positive fluxes of CO2 to atmosphere during the most of time,is a huge and permanent sink of carbon in terrestrial ecosystems through receiving a great quantity of carbon materials via rivers, precipitation,and biological production.

  1. Seasonal variation of Microcystis in Lake Taihu and its relationships with environmental factors

    Institute of Scientific and Technical Information of China (English)

    TAN Xiao; KONG Fanxiang; ZENG Qingfei; CAO Huansheng; QIAN Shanqin; ZHANG Min

    2009-01-01

    In order to monitor the changes of Microcystis along with temporal and spatial variations, seasonal variation of Microcystis in Lake Taihu was investigated by 16S-23S rRNA internal transcribed spacer denaturing gradient gel electrophoresis (16S-23S rRNA-ITS DGGE) and microscopic evaluation. Samples were collected quarterly at four sites (River Mouth, Meiliang Bay, Cross Area, and Lake Center) from August 2006 to April 2007. Results showed that Microcystis dominated total phytoplankton abundance at the four sites in all seasons except winter. The average annual abundance of Microcystis was relatively high at River Mouth and Meiliang Bay, reaching 81.22×106 and 61.32×106 cells/L, respectively. For temporal variations, Shannon-Wiener diversity index (H') according to DGGE profile revealed the richness of Microcystis in summer (H'=1.375±0.034) and winter (H'=1.650±0.032) was lower than that in spring (H'=2.078±0.031) and autumn (H'=2.365±0.032) (P0.05). Canonical correspondence analysis (CCA) was performed to elucidate the relationships between Microcystis operational taxonomic units (OTUs) composition and the environmental factors. Results of CCA revealed that temperature was strongly positively correlated with the first axis (r=0.963), while TSS was negative correlated with the second axis (r=-0.716). Phylogenetic tree based on the sequencing results of target bands on DGGE gel indicated that samples collected in summer and winter constituted two separated clusters.

  2. Differences in the Composition of Archaeal Communities in Sediments from Contrasting Zones of Lake Taihu

    Science.gov (United States)

    Fan, Xianfang; Xing, Peng

    2016-01-01

    In shallow lakes, different primary producers might impact the physiochemical characteristics of the sediment and the associated microbial communities. Until now, little was known about the features of sediment Archaea and their variation across different primary producer-dominated ecosystems. Lake Taihu provides a suitable study area with cyanobacteria- and macrophyte-dominated zones co-occurring in one ecosystem. The composition of the sediment archaeal community was assessed using 16S rRNA gene amplicon sequencing technology, based on which the potential variation with respect to the physiochemical characteristics of the sediment was analyzed. Euryarchaeota (30.19% of total archaeal sequences) and Bathyarchaeota (28.00%) were the two most abundant phyla, followed by Crenarchaeota (11.37%), Aigarchaeota (10.24%) and Thaumarchaeota (5.98%). The differences found in the composition of the archaeal communities between the two zones was significant (p = 0.005). Sediment from macrophyte-dominated zones had high TOC and TN content and an abundance of archaeal lineages potentially involved in the degradation of complex organic compounds, such as the order Thermoplasmatales. In the area dominated by Cyanobacteria, archaeal lineages related to sulfur metabolism, for example, Sulfolobales and Desulfurococcales, were significantly enriched. Among Bathyarchaeota, subgroups MCG-6 and MCG-15 were significantly accumulated in the sediment of areas dominated by macrophytes whereas MCG-4 was consistently dominant in both type of sediments. The present study contributes to the knowledge of sediment archaeal communities with different primary producers and their possible biogeochemical functions in sediment habitats. PMID:27708641

  3. Residual Levels and New Inputs of Chlorinated POPs in Agricultural Soils from Taihu Lake Region

    Institute of Scientific and Technical Information of China (English)

    GAO Hong-Jian; JIANG Xin; WANG Fang; BIAN Yong-Rong; WANG Dai-Zhang; DEND Jian-Cai; YAN Dong-Yun

    2005-01-01

    Selected persistent organochlorine pesticides (OCPs), including 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT)and its principal metabolites 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (DDD), hexachlorocyclohexane (HCH) and its isomers (α-, β-, γ-, and δ-HCH), hexachlorobenzene (HCB), endosulfan, dieldrin, and endrin were quantified to determine current levels of organochlorine pesticides, to assess the ecotoxicological potential, and to distinguish previous and current inputs in agricultural soils from the Taihu Lake region.Gas chromatography equipped with a 63Ni electron-capture detector (GC-ECD) system was employed. Thirteen OCPs were detectable in all soil samples, with DDTs being the main residues, and HCHs had the second highest level of OCP residues. Although OCP residual levels were lower than those in 1990s, the residual levels for most of the DDTs and some of HCHs were still higher than the national environmental standards for agricultural soils. The ratios of DDT/DDE and γ-/α-HCH in twelve soils indicated that new inputs could be present in the soils. Thus, efforts should be made to completely ban the production of OCPs and their use in agriculture so as to reduce the threat of OCPs to food quality and human health.

  4. Responses of soil nutrient to driving mechanism in Taihu Lake basin in last 20 years

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The objectives of this study is to understand the changing law of soil nutrient quality in Taihu Lake basin, Yangtze Delta in last 20 years, and reveal the relationship between soil nutrient changes and human driving forces in regional level over long period of time. Experiment on long-term collecting samples was conducted to study changes of soil organic matter, total N, available N, available P and available K in Dongting town, Wuxi city during the last 20 years. The paper analyses the co-relationship of the fluctuation of soil nutrient and state policy, cultivating practice, agricultural input, and per hectare agricultural net income. The results showed that at first the content of soil organic matter increased, then decreased, and increased again. The content of total N and available N steadily increased. The content of available K and available P steadily decreased. The authors found that the influence of state policy and cultivating practice on soil nutrient quality index (SNQI) is obvious, agricultural input and SNQI are positively correlated, and per hectare agricultural net income and SNQI are negatively correlated.

  5. Asticcacaulis taihuensis sp. nov., a novel stalked bacterium isolated from Taihu Lake, China.

    Science.gov (United States)

    Liu, Zhi-Pei; Wang, Bao-Jun; Liu, Shuang-Jiang; Liu, Ying-Hao

    2005-05-01

    A novel stalked bacterium, designated strain T3-B7(T), was isolated from sediment of Taihu Lake, Jiangsu Province, China, and its taxonomy was studied by using a polyphasic approach. Cell morphology, physiological and biochemical properties, and polar lipids indicated that strain T3-B7(T) represented a member of the genus Asticcacaulis. Based on 16S rRNA gene sequence similarity analysis, strain T3-B7(T) was found to be phylogenetically related to Asticcacaulis biprosthecium DSM 4723(T) (98.5 %) and Asticcacaulis excentricus DSM 4724(T) (95.0 %), but could be differentiated from these two species on the basis of the number and position of prosthecae, assimilation of sugars, nitrate reduction and tolerance to NaCl. Levels of DNA-DNA relatedness of strain T3-B7(T) to A. biprosthecium DSM 4723(T) and A. excentricus DSM 4724(T) were 37.1 and 18.0 %, respectively. The G + C content of strain T3-B7(T) was 59 mol% (T(m)). It is concluded that strain T3-B7(T) represents a novel species of the genus Asticcacaulis, for which the name of Asticcacaulis taihuensis sp. nov. is proposed. The type strain is T3-B7(T) (=AS 1.3431(T) = JCM 12463(T)).

  6. Quantification of Climate Changes and Human Activities That Impact Runoff in the Taihu Lake Basin, China

    Directory of Open Access Journals (Sweden)

    Dingzhi Peng

    2016-01-01

    Full Text Available Although a fragile climate region, the Taihu Lake Basin is among the most developed regions in China and is subjected to intense anthropogenic interference. In this basin, water resources encounter major challenges (e.g., floods, typhoons, and water pollution. In this study, the impacts of climate changes and human activities on hydrological processes were estimated to aid water resource management in developed regions in China. The Mann-Kendall test and cumulative anomaly curve were applied to detect the turning points in the runoff series. The year of 1982 divides the study period (1956~2008 into a baseline period (1956~1981 and a modified period (1982~2008. The double mass curve method and the hydrological sensitivity method based on the Budyko framework were applied to quantitatively attribute the runoff variation to climate changes and human activities. The results demonstrated that human activities are the dominant driving force of runoff variations in the basin, with a contribution of 83~89%; climate changes contributed to 11~17% of the variations. Moreover, the subregions of the basin indicated that humans severely disturbed the runoff variation, with contributions as high as 95~97%.

  7. Optimizing Nitrogen Fertilizer Application for Rice Production in the Taihu Lake Region, China

    Institute of Scientific and Technical Information of China (English)

    DENG Mei-Hua; SHI Xiao-Jun; TIAN Yu-Hua; YIN Bin; ZHANG Shao-Lin; ZHU Zhao-Liang; S. D. KIMURA

    2012-01-01

    To determine the optimal amount of nitrogen (N) fertilizer for achieving a sustainable rice production at the Taihu Lake region of China,two-year on-farm field experiments were performed at four sites using various N application rates.The results showed that 22%-30% of the applied N was recovered in crop and 7%-31% in soils at the rates of 100-350 kg N ha-1.Nitrogen losses increased with N application rates,from 44% of the applied fertilizer N at the rate of 100 kg N ha-1 to 69% of the N applied at 350 kg N ha-1.Ammonia volatilization and apparent denitrification were the main pathways of N losses.The N application rate of 300 kg N ha-1,which is commonly used by local farmers in the study region,was found to lead to a significant reduction in economic and environmental efficiency.Considering the cost for mitigating environmental pollution and the maximum net economic income,an application rate of 100-150 kg N ha-1 would be recommended.This recommended N application rate could greatly reduce N loss from 199 kg N ha-1 occurring at the N application rate of 300 kg N ha-1 to 80-110 kg N ha-1,with the rice grain yield still reaching 7300-8300 kg DW ha-1 in the meantime.

  8. Beta-Glucosidase Activity in Paddy Soils of the Taihu Lake Region, China

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-Chang; LU Qin

    2006-01-01

    The profile distribution ofβ-gulcosidase activity in twelve typical paddy soil profiles with high productivity in the Taihu Lake region of China were investigated. Activities ofβ-gulcosidase in the plow layers were in the range of 52.68-137.02μg PNP g-1 soil h-1 with a mean of 89.22μg PNP g-1 soil h-1. However, most plow layers ranged from 70 to 110μg PNP g-1 soil h-1. The profile distribution of β-gulcosidase activity in the 12 soil profiles decreased rapidly with soil depth, with activity at the 60 cm depth only about 10% of that in the surface layers (0-15 cm or 0-20 cm). In these soil profiles, β-gulcosidase activity was significantly positively correlated with soil organic carbon and arylsulphatase activity.Meanwhile, a significantly negative correlation was shown betweenβ-gulcosidase activity and soil pH.

  9. Epiphytic bacterial communities on two common submerged macrophytes in Taihu Lake: diversity and host-specificity

    Institute of Scientific and Technical Information of China (English)

    HE Dan; REN Lijuan; WU Qinglong

    2012-01-01

    Leaves of terrestrial and aquatic plants are home to a wide diversity of bacterial species.However,the diversity and variability of epiphytic bacteria on their submerged plant hosts remains poorly understood.We investigated the diversity and composition of epiphytic bacteria from two common submerged macrophytes:Vallisneria natans and Hydrilla verticillata in Taihu Lake,Jiangsu,China,using methods of terminal restriction fragment length polymorphisms (T-RFLP) and clone library analyses targeted at bacterial 16S rRNA genes.The results show that:(1) the libraries of the two waterweeds contain wide phylogenetic distribution of bacteria,and that the sequences of the two libraries can be separated into 93 OTUs (at 97% similar value); (2) Betaproteobacteria,including Burkholderiales,was the most abundant bacterial group on both plants.Cyanobacteria and Gammaproteobacteria were the second largest groups on V.natans and H.verticillata,respectively.Both clone libraries included some sequences related to those of methanotrophs and nitrogen-fixing bacteria; (3) Cluster analysis of the T-RFLP profiles showed two distinct clusters corresponding to the two plant populations.Both ANOSIM of the T-RFLPdata and Libshuff analysis of the two clone libraries indicated a significant difference in epiphytic bacterial communities between the two plants.Therefore,the epiphytic bacterial communities on submerged macrophytes appear to be diverse and host-specific,which may aid in understanding the ecological functions of submerged macrophytes in general.

  10. A Systematic Investigation into the Environmental Fate of Microcystins and The Potential Risk: Study in Lake Taihu

    Directory of Open Access Journals (Sweden)

    Junmei Jia

    2016-06-01

    Full Text Available A systematic investigation was conducted in Lake Taihu in autumn of 2013 and 2014, in order to understand the environmental fate of microcystins (MCs and evaluate the health risk from MCs. Samples of water, algal cells, macrophytes, shrimps and fish were taken to detect MCs by HPLC-MS/MS after solid phase extraction. Widespread MC contamination in water, algal cells, macrophytes, shrimps and fish was found in Lake Taihu. The ubiquitous presence of MCs in water, algal cells and biota was found in 100% of samples. MC accumulation was in the order of primary producer > tertiary consumer > secondary consumer > primary consumer. The highest levels of MCs in macrophytes, shrimps and fish tissue were found in Potamogeton maackianus, Exopalaemon modestus, and Hyporhamphus intermedius, respectively. The MCs level in shrimps and the tissues of three fish species, Neosalanx tangkahkeii taihuensis, Coilia ectenes and silver carp, was closely linked to their dietary exposure. Ceratophyllum demersum L. was an ideal plant for introduction into lakes to protect against Microcystis blooms and MCs, due to its ability to absorb nutrients, accumulate large amounts of MCs and tolerate these toxins compared to other macrophytes. The average daily intakes (ADIs of MCs for Exopalaemon modestus and three fish species, Coilia ectenes, Hyporhamphus intermedius and Carassius carassius, were all above the tolerable daily intakes (TDI set by the World Health Organization (WHO, implying there existed potential threats to human health.

  11. Long-term MODIS observations of cyanobacterial dynamics in Lake Taihu: Responses to nutrient enrichment and meteorological factors

    Science.gov (United States)

    Shi, Kun; Zhang, Yunlin; Zhou, Yongqiang; Liu, Xiaohan; Zhu, Guangwei; Qin, Boqiang; Gao, Guang

    2017-01-01

    We developed and validated an empirical model for estimating chlorophyll a concentrations (Chla) in Lake Taihu to generate a long-term Chla and algal bloom area time series from MODIS-Aqua observations for 2003 to 2013. Then, based on the long-term time series data, we quantified the responses of cyanobacterial dynamics to nutrient enrichment and climatic conditions. Chla showed substantial spatial and temporal variability. In addition, the annual mean cyanobacterial surface bloom area exhibited an increasing trend across the entire lake from 2003 to 2013, with the exception of 2006 and 2007. High air temperature and phosphorus levels in the spring can prompt cyanobacterial growth, and low wind speeds and low atmospheric pressure levels favor cyanobacterial surface bloom formation. The sensitivity of cyanobacterial dynamics to climatic conditions was found to vary by region. Our results indicate that temperature is the most important factor controlling Chla inter-annual variability followed by phosphorus and that air pressure is the most important factor controlling cyanobacterial surface bloom formation followed by wind speeds in Lake Taihu.

  12. Sediment distribution pattern mapped from the combination of objective analysis and geostatistics in the large shallow Taihu Lake, China.

    Science.gov (United States)

    Luo, Lian-Cong; Qin, Bo-Qiang; Zhu, Guang-Wei

    2004-01-01

    Investigation was made into sediment depth at 723 irregularly scattered measurement points which cover all the regions in Taihu Lake, China. The combination of successive correction scheme and geostatistical method was used to get all the values of recent sediment thickness at the 69 x 69 grids in the whole lake. The results showed that there is the significant difference in sediment depth between the eastern area and the western region, and most of the sediments are located in the western shore-line and northern regimes but just a little in the center and eastern parts. The notable exception is the patch between the center and Xishan Island where the maximum sediment depth is more than 4.0 m. This sediment distribution pattern is more than likely related to the current circulation pattern induced by the prevailing wind-forcing in Taihu Lake. The numerical simulation of hydrodynamics can strong support the conclusion. Sediment effects on water quality was also studied and the results showed that the concentrations of TP, TN and SS in the western part are obviously larger than those in the eastern regime, which suggested that more nutrients can be released from thicker sediment areas.

  13. Sediment distribution pattern mapped from the combination of objective analysis and geostatistics in the large shallow Taihu Lake, China

    Institute of Scientific and Technical Information of China (English)

    LUO Lian-cong; QIN Bo-qiang; ZHU Guang-wei

    2004-01-01

    Investigation was made into sediment depth at 723 irregularly scattered measurement points which cover all the regions in Taihu Lake, China. The combination of successive correction scheme and geostatistical method was used to get all the values of recent sediment thickness at the 69×69 grids in the whole lake. The results showed that there is the significant difference in sediment depth between the eastern area and the western region, and most of the sediments are located in the western shore-line and northern regimes but just a little in the center and eastern parts. The notable exception is the patch between the center and Xishan Island where the maximum sediment depth is more than 4.0 m. This sediment distribution pattern is more than likely related to the current circulation pattern induced by the prevailing wind-forcing in Taihu Lake. The numerical simulation of hydrodynamics can strong support the conclusion. Sediment effects on water quality was also studied and the results showed that the concentrations of TP, TN and SS in the western part are obviously larger than those in the eastern regime, which suggested that more nutrients can be released from thicker sediment areas.

  14. Long-term MODIS observations of cyanobacterial dynamics in Lake Taihu: Responses to nutrient enrichment and meteorological factors

    Science.gov (United States)

    Shi, Kun; Zhang, Yunlin; Zhou, Yongqiang; Liu, Xiaohan; Zhu, Guangwei; Qin, Boqiang; Gao, Guang

    2017-01-01

    We developed and validated an empirical model for estimating chlorophyll a concentrations (Chla) in Lake Taihu to generate a long-term Chla and algal bloom area time series from MODIS-Aqua observations for 2003 to 2013. Then, based on the long-term time series data, we quantified the responses of cyanobacterial dynamics to nutrient enrichment and climatic conditions. Chla showed substantial spatial and temporal variability. In addition, the annual mean cyanobacterial surface bloom area exhibited an increasing trend across the entire lake from 2003 to 2013, with the exception of 2006 and 2007. High air temperature and phosphorus levels in the spring can prompt cyanobacterial growth, and low wind speeds and low atmospheric pressure levels favor cyanobacterial surface bloom formation. The sensitivity of cyanobacterial dynamics to climatic conditions was found to vary by region. Our results indicate that temperature is the most important factor controlling Chla inter-annual variability followed by phosphorus and that air pressure is the most important factor controlling cyanobacterial surface bloom formation followed by wind speeds in Lake Taihu. PMID:28074871

  15. Lake topography and wind waves determining seasonal-spatial dynamics of total suspended matter in turbid Lake Taihu, China: assessment using long-term high-resolution MERIS data.

    Science.gov (United States)

    Zhang, Yunlin; Shi, Kun; Liu, Xiaohan; Zhou, Yongqiang; Qin, Boqiang

    2014-01-01

    Multiple comprehensive in situ bio-optical investigations were conducted from 2005 to 2010 and covered a large variability of total suspended matter (TSM) in Lake Taihu to calibrate and validate a TSM concentration estimation model based on Medium Resolution Imaging Spectrometer (MERIS) data. The estimation model of the TSM concentration in Lake Taihu was developed using top-of-atmosphere (TOA) radiance of MERIS image data at band 9 in combination with a regional empirical atmospheric correction model, which was strongly correlated with the in situ TSM concentration (r(2) = 0.720, pmean square error (RRMSE) and mean relative error (MRE) were 36.9% and 31.6%, respectively, based on an independent validation dataset that produced reliable estimations of the TSM concentration. The developed algorithm was applied to 50 MERIS images from 2003 to 2011 to obtain a high spatial and temporal heterogeneity of TSM concentrations in Lake Taihu. Seasonally, the highest and lowest TSM concentrations were found in spring and autumn, respectively. Spatially, TSM concentrations were high in the southern part and center of the lake and low in Xukou Bay, East Lake Taihu. The lake topography, including the water depth and distance from the shore, had a significant effect on the TSM spatial distribution. A significant correlation was found between the daily average wind speed and TSM concentration (r(2)= 0.685, p<0.001, and n = 50), suggesting a critical role of wind speed in the TSM variations in Lake Taihu. In addition, a low TSM concentration was linked to the appearance of submerged aquatic vegetation (SAV). Therefore, TSM dynamics were controlled by the lake topography, wind-driven sediment resuspension and SAV distribution.

  16. Microcystin-degrading activity of an indigenous bacterial strain Stenotrophomonas acidaminiphila MC-LTH2 isolated from Lake Taihu.

    Directory of Open Access Journals (Sweden)

    Fei Yang

    Full Text Available Microcystin-LR (MC-LR and microcystin-RR (MC-RR produced by harmful cyanobacterial blooms (HCBs pose substantial threats to the ecosystem and public health due to their potential hepatotoxicity. Degradation of microcystins (MCs by indigenous bacteria represents a promising method for removing MCs from fresh water without harming the aquatic environment, but only a few microcystin (MC-degrading bacteria have been isolated and had their mechanisms reported. This study aimed to isolate indigenous bacteria from Lake Taihu, and investigate the capability and mechanism of MC degradation by these bacteria. During a Microcystis bloom, an indigenous MC-degrading bacterium designated MC-LTH2 was successfully isolated from Lake Taihu, and identified as Stenotrophomonas acidaminiphila based on phylogenetic analysis. In the presence of MC-LR together with MC-RR, the strain MC-LTH2 was capable of totally degrading both simultaneously in 8 days, at rates of 3.0 mg/(L⋅d and 5.6 mg/(L⋅d, respectively. The degradation rates of MCs were dependent on temperature, pH, and initial MC concentration. Adda (3-amino-9-methoxy-2, 6, 8-trimethyl-10-phenyldeca-4, 6-dienoic acid was detected as an intermediate degradation product of MCs using high performance liquid chromatography coupled with time-of-flight mass spectrometry (HPLC-TOF-MS. To the best of our knowledge, this is the first report of Stenotrophomonas acidaminiphila capable of degrading two MC analogues and other compounds containing Adda residue completely under various conditions, although the mlrA gene in the strain was not detected. These results indicate the Stenotrophomonas acidaminiphila strain MC-LTH2 possesses a significant potential to be used in bioremediation of water bodies contaminated by MC-LR and MC-RR, and is potentially involved in the degradation of MCs during the disappearance of the HCBs in Lake Taihu.

  17. Organic carbon stratification and size distribution of three typical paddy soils from Taihu Lake region, China

    Institute of Scientific and Technical Information of China (English)

    PAN Genxing; WU Laosheng; LI Lianqing; ZHANG Xuhui; GONG Wei; WOOD Yvonne

    2008-01-01

    Developing realistic soil carbon (C) sequestration strategies for China's sustainable agriculture relies on accurate estimates of the amount, retention and turnover rates of C stored in paddy soils. Available C estimates to date are predominantly for the tilled and flood-irrigated surface topsoil (ca. 30 cm). Such estimates cannot be used to extrapolate to soil depths of 100 cm since soil organic carbon (SOC) generally shows a sharp decrease with depth. In this research, composite soil samples were collected at several depths to 100 cm from three representative paddy soils in the Taihu Lake region, China. Soil organic carbon distribution in the profiles and in aggregate-size fractions was determined. Results showed that while SOC decreased exponentially with depth to 100 cm, a substantial proportion of the total SOC (30%-40%) is stored below the 30 cm depth. In the carbon-enriched paddy topsoils, SOC was found to accumulate preferentially in the 2-0.25 and 0.25-0.02 mm aggregate size fractions. d13C analysis of the coarse micro-aggregate fraction showed that the high degree of C stratification in the paddy topsoil was in agreement with the occurrence of lighter d1313C in the upper 30 cm depth. These results suggest that SOC stratification within profiles varies with different pedogenetical types of paddy soils with regards to clay and iron oxyhydrates distributions. Sand-sized fractions of aggregates in paddy soil systems may play a very important role in carbon sequestration and turnover, dissimilar to other studied agricultural systems.

  18. Tracing the Nitrate Sources of the Yili River in the Taihu Lake Watershed: A Dual Isotope Approach

    Directory of Open Access Journals (Sweden)

    Haiao Zeng

    2014-12-01

    Full Text Available As the third largest freshwater lake in China, Taihu Lake has experienced severe cyanobacterial blooms and associated water quality degradation in recent decades, threatening the human health and sustainable development of cities in the watershed. The Yili River is a main river of Taihu Lake, contributing about 30% of the total nitrogen load entering the lake. Tracing the nitrate sources of Yili River can inform the origin of eutrophication in Taihu Lake and provide hints for effective control measures. This paper explored the nitrate sources and cycling of the Yili River based on dual nitrogen (δ15N and oxygen (δ18O isotopic compositions. Water samples collected during both the wet and dry seasons from different parts of the Yili River permitted the analysis of the seasonal and spatial variations of nitrate concentrations and sources. Results indicated that the wet season has higher nitrate concentrations than the dry season despite the stronger dilution effects, suggesting a greater potential of cyanobacterial blooms in summer. The δ15N-NO3− values were in the range of 4.0‰–14.0‰ in the wet season and 4.8‰–16.9‰ in dry, while the equivalent values of δ18O were 0.5‰–17.8‰ and 3.5‰–15.6‰, respectively. The distribution of δ15N-NO3− and δ18O-NO3− indicated that sewage and manure as well as fertilizer and soil organic matter were the major nitrate sources of the Yili River. Atmospheric deposition was an important nitrate source in the upper part of Yili River but less so in the middle and lower reaches due to increasing anthropogenic contamination. Moreover, there was a positive relationship between δ18O-NO3− and δ15N-NO3− in the wet season, indicating a certain extent of denitrification. In contrast, the δ18O-δ15N relationship in the dry season was significantly negative, suggesting that the δ15N and δ18O values were determined by a mixing of different nitrate sources.

  19. Water quality, nutrient budget, and pollutant loads in Chinese mitten crab (Eriocheir sinensis) farms around East Taihu Lake

    Institute of Scientific and Technical Information of China (English)

    CAI Chunfang; GU Xiaohong; HUANG Hezhong; DAI Xiuying; YE Yuantu; SHI Chenjiang

    2012-01-01

    To understand the factors causing frequent outbreaks of harmful algae blooms in the Taihu Lake,China,we studied water quality and nutrient budget in Chinese mitten crab (Eriocheir sinensis) farm ponds in the eastern part of the lake from November 2007 to December 2009.We estimated the nitrogen (N),phosphorus (P),and chemical oxygen demand (COD) loads.Materials input and output ponds,water exchange,and applied management practices of 838.5-hm2 crab ponds were surveyed using questionnaires.Water quality of 12 ponds,which were located no more than 2 km from East Taihu Lake,were monitored.The results show that water quality in the crab ponds was better than reference data.Feeds,including corn seed,commercial feed,trash fish,and gastropod,were the major sources of N and P input in the crab ponds,contributing 88.7% and 94.9%,respectively.In total,60.5% of N and 37.3% of P were sequestered by macrophytes,and only 15.7% and 8.5% of them were discharged as effluent.The net loads of N and P in effluent were 16.43 kg/hm2/cycle and 2.16 kg/hm2/cycle,respectively,while the COD load was -17.88 kg/hm2/cycle.This indicated that crab farming caused minor negative impact on the trophic status of the lake area,which was attenuated by macrophytes.However,wastewater purification is still necessary in crab faming.

  20. Effects of sludge dredging on the prevention and control of algae-caused black bloom in Taihu Lake, China

    Institute of Scientific and Technical Information of China (English)

    Wei He; Jingge Shang; Xin Lu; Chengxin Fan

    2013-01-01

    Algae-caused black bloom (also known as black water agglomerate) has recently become a critical problem in some Ctinese lakes.It has been suggested that the occurrence of algae-caused black bloom was caused by the cooperation of nutrient-rich sediment with dead algae,and sludge dredging was adopted to control black bloom in some lakes of China.In this article,based on the simulation of black bloom using a Y-shape apparatus for modeling natural conditions,both un-dredged and dredged sites in three areas of Taihu Lake,China were studied to estimate the effects of dredging on the prevention and control of black bloom.During the experiment,drained algae were added to all six sites as an additional organic load; subsequently,the dissolved oxygen decreased rapidly,dropping to 0 mg/L at the sediment-water interface.Black bloom did not occur in the dredged sites of Moon Bay and Nan Quan,whereas all three un-dredged sites at Fudu Port,Moon Bay and Nan Quan experienced black bloom.Black bloom also occurred at the dredged site of Fudu Port one day later than at the other sites,and the odor and color were lighter than at the other locations.The color and odor of the black water mainly result from the presence of sulfides such as metal sulfides and hydrogen sulfide,among other chemicals,under reductive conditions.The color and odor of the water,together with the high concentrations of nutrients,were mainly caused by the decomposition of the algae and the presence of nutrient-rich sediment.Overall,the removal of the nutrient-rich sediment by dredging can prevent the occurrence and control the degree of algae-caused black bloom in Taihu Lake.

  1. Algal sludge from Taihu Lake can be utilized to create novel PGPR-containing bio-organic fertilizers.

    Science.gov (United States)

    Zhang, Miao; Li, Rong; Cao, Liangliang; Shi, Juanjuan; Liu, Hongjun; Huang, Yan; Shen, Qirong

    2014-01-01

    Large amounts of refloated algal sludge from Taihu Lake result in secondary environmental pollution due to annual refloatation. This study investigated the possibility to produce bio-organic fertilizer (BIO) using algal sludge as a solid-state fermentation (SSF) medium. Results showed that addition of algal sludge contributed to efficient SFF by a plant growth-promoting rhizobacteria (PGPR) strain SQR9 and improved the nutrient contents in the novel BIO. The optimum water content and initial inoculation size were 45% and 5%, respectively. After 6 days of SSF, the biomass of strain SQR9 was increased to a cell density of more than 5 × 10(7) CFU g(-1). Microcystins were rapidly degraded, and a high germination index value was observed. Plant growth experiments showed that the produced BIO efficiently promoted plant growth. Additional testing showed that the novel SSF process was also suitable for other PGPR strains. This study provides a novel way of high-value utilization of algal sludge from Taihu Lake by producing low-cost but high-quality BIOs.

  2. Adsorption Behaviors of 17α-Ethinylestradiol in Sediment-Water System in Northern Taihu Lake, China

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    Yonghua Wang

    2014-01-01

    Full Text Available Adsorption behavior of 17α-ethinylestradiol (EE2 in northern Taihu Lake sediment was analyzed by using batch equilibrium experiment. Freundlich isotherm could describe the adsorption thermodynamic behavior of EE2 in sediment. Sediment organic matter (SOM contents had important impacts on the adsorption capacity for EE2. The pH values also influenced the adsorption capacity for EE2. Increase of pH value could decrease the EE2 adsorption, which might be due to the electrostatic repulsion between the anionic form of EE2 and sediments with negative charge under high pH values. Competitive effects of bisphenol A (BPA on EE2 adsorption were further analyzed. The results showed that low concentration BPA did not have significant influences on EE2 adsorption. However, high concentration BPA could reduce EE2 adsorption, which might be due to the similar molecular diameter of BPA with adsorption sites and one more benzene ring with a hydroxyl group in BPA. These results provide primary information of EE2 adsorption in sediment-water system in Taihu Lake, which is useful for the environmental risk assessment and management of EE2 in studied area.

  3. Identification and Determination of Microcystins in Source Water an Waterbloom Sample From Meiliang Bay, Taihu Lake, China

    Institute of Scientific and Technical Information of China (English)

    XIAO-GANG FENG; ZHEN DING; TAO WEI; CHUN-WEI YUAN; DE-GANG FU

    2006-01-01

    Objective To identify and determine the congener and level of microcystins in the source water of Taihu Lake. Methods Improved method of SPE combined with HPLC was employed to detect the concentration and varieties of microcystins in source water and bloom samples collected from Meiliang Bay, Taihu Lake. Results The contents of two predominant microcystin components, MC-RR, and MC-LR, were relatively high in samples during warm months and correlated with the phase of algae growth. The maximum concentrations of MC-RR and MC-LR in water sample reached 3.09 ±0.53 μg/L and 2.39±0.41 μg/L during the period of water bloom in September 2004, respectively. Even without waterbloom, the concentration of MC-LR in source water sample was still higher than the guideline value. Conclusion The status of microcystin pollution in this region is serious and measures to monitor and control the growth of cyanobacteria are urgently needed.

  4. The enrichment characteristics of mercury in the sediments of Dongjiu and Xijiu, Taihu Lake catchment, in the past century

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The concentration and the enrichment factors of mercury (Hg) in the sediment cores of Dongjiu and Xijiu, Taihu Lake catchment, were studied. The accumulation fluxes, anthropogenic input concentration and anthropogenic accumulation fluxes of Hg in recent 100 years were also analyzed based on the 210Pb dating. The results indicate that the increasing concentrations of Hg in the sediments are influ-enced by natural factors and anthropogenic input simultaneously. Generally, about 2/3 of the Hg in the sediment was from anthropogenic sources. In the early 20th century, the anthropogenic input was owing to the urban development and fossil fuel consumptions surrounding the Taihu Lake and the worldwide atmospheric deposition of Hg since the industrial revolution. The concentration and an-thropogenic fluxes of Hg increased with the industrial development in the catchment since the 1930s. It reached the maximum during the middle 1970s and middle 1990s, and decreased since the middle 1990s with constraints on high pollution industries.

  5. The enrichment characteristics of mercury in the sediments of Dongjiu and Xijiu, Taihu Lake catchment, in the past century

    Institute of Scientific and Technical Information of China (English)

    WU YanHong; JIANG XueZhong; LIU EnFeng; YAO ShuChun; ZHU YuXin; SUN ZhaoBin

    2008-01-01

    The concentration and the enrichment factors of mercury (Hg) in the sediment cores of Dongjiu and Xijiu, Taihu Lake catchment, were studied. The accumulation fluxes, anthropogenie input concentration and anthropogenie accumulation fluxes of Hg in recent 100 years were also analyzed based on the 210Pb dating. The results indicate that the increasing concentrations of Hg in the sediments are influ-enced by natural factors and anthropogenie input simultaneously. Generally, about 2/3 of the Hg in the sediment was from anthropogenie sources. In the early 20th century, the anthropogenie input was owing to the urban development and fossil fuel consumptions surrounding the Taihu Lake and the worldwide atmospheric deposition of Hg since the industrial revolution. The concentration and an-thropogenic fluxes of Hg increased with the industrial development in the catchment since the 1930s. It reached the maximum during the middle 1970s and middle 19908, and decreased since the middle 1990s with constraints on high pollution industries.

  6. Adsorption behaviors of 17α-ethinylestradiol in sediment-water system in northern Taihu Lake, China.

    Science.gov (United States)

    Wang, Yonghua; Hu, Liangfeng; Wang, Qiuying; Lu, Guanghua; Li, Yi

    2014-01-01

    Adsorption behavior of 17α-ethinylestradiol (EE2) in northern Taihu Lake sediment was analyzed by using batch equilibrium experiment. Freundlich isotherm could describe the adsorption thermodynamic behavior of EE2 in sediment. Sediment organic matter (SOM) contents had important impacts on the adsorption capacity for EE2. The pH values also influenced the adsorption capacity for EE2. Increase of pH value could decrease the EE2 adsorption, which might be due to the electrostatic repulsion between the anionic form of EE2 and sediments with negative charge under high pH values. Competitive effects of bisphenol A (BPA) on EE2 adsorption were further analyzed. The results showed that low concentration BPA did not have significant influences on EE2 adsorption. However, high concentration BPA could reduce EE2 adsorption, which might be due to the similar molecular diameter of BPA with adsorption sites and one more benzene ring with a hydroxyl group in BPA. These results provide primary information of EE2 adsorption in sediment-water system in Taihu Lake, which is useful for the environmental risk assessment and management of EE2 in studied area.

  7. Application of the environmental Gini coefficient in allocating water governance responsibilities: a case study in Taihu Lake Basin, China.

    Science.gov (United States)

    Zhou, Shenbei; Du, Amin; Bai, Minghao

    2015-01-01

    The equitable allocation of water governance responsibilities is very important yet difficult to achieve, particularly for a basin which involves many stakeholders and policymakers. In this study, the environmental Gini coefficient model was applied to evaluate the inequality of water governance responsibility allocation, and an environmental Gini coefficient optimisation model was built to achieve an optimal adjustment. To illustrate the application of the environmental Gini coefficient, the heavily polluted transboundary Taihu Lake Basin in China, was chosen as a case study. The results show that the original environmental Gini coefficient of the chemical oxygen demand (COD) was greater than 0.2, indicating that the allocation of water governance responsibilities in Taihu Lake Basin was unequal. Of seven decision-making units, three were found to be inequality factors and were adjusted to reduce the water pollutant emissions and to increase the water governance inputs. After the adjustment, the environmental Gini coefficient of the COD was less than 0.2 and the reduction rate was 27.63%. The adjustment process provides clear guidance for policymakers to develop appropriate policies and improve the equality of water governance responsibility allocation.

  8. Isolation, identification and characterization of an algicidal bacterium from Lake Taihu and preliminary studies on its algicidal compounds

    Institute of Scientific and Technical Information of China (English)

    Chuan Tian; Xianglong Liu; Jing Tan; Shengqin Lin; Daotang Li; Hong Yang

    2012-01-01

    In an effort to identify a bio-agent capable of controlling cyanobacterial blooms,we isolated a bacterial strain,A27,which exhibited strong algicidal activity against the dominant bloom-forming species of Microcystis aeruginosa in Lake Taihu.Based on 16S rRNA gene sequence analysis,this strain belongs to the genus Exiguobacterium.This is the first report of an algicidal bacterial strain belonging to the genus Exiguobacterium.Strain A27 exhibited algicidal activity against a broad range of cyanobacteria,but elicited little or no algicidal activity against the two green algal strains tested.The algicidal activity of strain A27 was shown to be dependent on the density of the bacteria and to have a threshold density of 1.5×106 CFU/mL.Our data also showed that the algicidal activity of strain A27 depended on different growth stages of Microcystis aeruginosa (exponential ≈ lag phase > early stationary) rather than that of the bacterium itself.Our results also suggested the algicidal activity of strain A27 occurred via the production of extracellular algicidal compounds.Investigation of the algicidal compounds revealed that there were at least two different algicidal compounds produced by strain A27.These results indicated that strain A27 has great potential for use in the control of outbreaks of cyanobacterial blooms in Lake Taihu.

  9. Simulation and Evaluation of Pollution Load Reduction Scenarios for Water Environmental Management: A Case Study of Inflow River of Taihu Lake, China

    Directory of Open Access Journals (Sweden)

    Ruibin Zhang

    2014-09-01

    Full Text Available In the beginning of the 21st century, the deterioration of water quality in Taihu Lake, China, has caused widespread concern. The primary source of pollution in Taihu Lake is river inflows. Effective pollution load reduction scenarios need to be implemented in these rivers in order to improve the water quality of Taihu Lake. It is important to select appropriate pollution load reduction scenarios for achieving particular goals. The aim of this study was to facilitate the selection of appropriate scenarios. The QUAL2K model for river water quality was used to simulate the effects of a range of pollution load reduction scenarios in the Wujin River, which is one of the major inflow rivers of Taihu Lake. The model was calibrated for the year 2010 and validated for the year 2011. Various pollution load reduction scenarios were assessed using an analytic hierarchy process, and increasing rates of evaluation indicators were predicted using the Delphi method. The results showed that control of pollution from the source is the optimal method for pollution prevention and control, and the method of “Treatment after Pollution” has bad environmental, social and ecological effects. The method applied in this study can assist for environmental managers to select suitable pollution load reduction scenarios for achieving various objectives.

  10. Calculation of permissible load capacity and establishment of total amount control in the Wujin River Catchment--a tributary of Taihu Lake, China.

    Science.gov (United States)

    Zhang, Ruibin; Gao, Hailong; Zhu, Wenting; Hu, Wei; Ye, Rui

    2015-08-01

    The deterioration of water quality in Taihu Lake, China, has caused widespread concern in recent years. The primary pollution sources of Taihu Lake are its inflow rivers. Effective environmental water management strategies need to be implemented in these rivers to improve the water quality of Taihu Lake and to promote sustainable development in the region. In this study, the QUAL2K model is used in conjunction with the trial and error approach to assess permissible load capacities for the Wujin River (a major tributary of Taihu Lake) in terms of COD, NH3-N, TN, and TP. Results show that permissible annual loads for these pollutants are 5216.31, 491.71, 948.53, and 104.38 t, respectively. This suggests that COD, NH3-N, TN, and TP loads in the Wujin River catchment need to be reduced by 13.35, 27.26, 47.75, and 37.08 %, respectively, to satisfy national water quality objectives. Total amount control measures are proposed to control and reduce pollution loads of the Wujin River catchment. The method applied in this study should provide a sound basis for water environmental management decision-making.

  11. [Estimation and remote sensing inversion of diffuse attenuation coefficient Kd(490) in Lake Taihu in spring based on semi-analytical model].

    Science.gov (United States)

    Liu, Zhong-Hua; Li, Yun-Mei; Li, Rui-Yun; Lü, Heng; Tan, Jing; Guo, Yu-Long

    2012-02-01

    Diffuse attenuation coefficient is not only an important optical parameter, but also an important factor of water ecological system. Two datasets measured in April 2009 and May 2010 were firstly used to calculate absorption coefficient [a (490)] and backscattering coefficient [b(b) (490)] at 490 nm, and then, the relationship between b(b) (490) and simulated remote sensing reflectance at different bands of HJ-1 was studied. The semi-analytical model of Kd (490) in Lake Taihu in spring was constructed based on this basis, and it was used to estimate Kd (490) of Lake Taihu via an image of HJ-1 finally. The results show that: 1) The values of a(490) and b(b)(490) can be calculated accurately based on optical closure principle, and the mean absolute percent error (MAPE) of a(490) between calculated and measured is 17.1%. In addition, the backscattering coefficient at 490 nm [b(b) (490)] exponentially relate with the simulated remote sensing reflectance at the fourth band of HJ-1; 2) The semi-analytical model constructed in this study has good accuracy and stability. The MAPE is 21.6% and RMSE is 1.68 m(-1) by comparing inversion result and quasi-synchronous measured data; 3) Kd (490) of Lake Taihu in spring differs a lot in space distribution. The values are relatively smaller in north and east part of Lake Taihu, but larger in west and south part.

  12. Simulation and evaluation of pollution load reduction scenarios for water environmental management: a case study of inflow river of Taihu Lake, China.

    Science.gov (United States)

    Zhang, Ruibin; Qian, Xin; Zhu, Wenting; Gao, Hailong; Hu, Wei; Wang, Jinhua

    2014-09-09

    In the beginning of the 21st century, the deterioration of water quality in Taihu Lake, China, has caused widespread concern. The primary source of pollution in Taihu Lake is river inflows. Effective pollution load reduction scenarios need to be implemented in these rivers in order to improve the water quality of Taihu Lake. It is important to select appropriate pollution load reduction scenarios for achieving particular goals. The aim of this study was to facilitate the selection of appropriate scenarios. The QUAL2K model for river water quality was used to simulate the effects of a range of pollution load reduction scenarios in the Wujin River, which is one of the major inflow rivers of Taihu Lake. The model was calibrated for the year 2010 and validated for the year 2011. Various pollution load reduction scenarios were assessed using an analytic hierarchy process, and increasing rates of evaluation indicators were predicted using the Delphi method. The results showed that control of pollution from the source is the optimal method for pollution prevention and control, and the method of "Treatment after Pollution" has bad environmental, social and ecological effects. The method applied in this study can assist for environmental managers to select suitable pollution load reduction scenarios for achieving various objectives.

  13. Amino Acids and Stable Carbon Isotope Distributions in Taihu Lake, China, Over the Last 15,000 Years, and Their Paleoecological Implications

    Science.gov (United States)

    Jinquan, Wang; Jinling, Liu

    2000-03-01

    Amino acid, organic nitrogen, and stable carbon isotope (13C/12C) profiles through a core from East Taihu Lake are interpreted in terms of paleoecology and paleoclimate over the last ca. 15,000 yr. Lower amino acid contents and higher δ13C values at the base of the core represent a cool and arid climate, and coincide with low organic productivity. A marked increase in total amino acids and organic nitrogen, with a decrease in δ13C values from 193 to 90 cm (ca. 6500-6000 yr B.P.), indicates a warmer and moist climate, and greater organic productivity. Amino acids then decrease in abundance, while δ13C values increase progressively, beginning at 73 cm (ca. 6000 yr B.P.), reflecting cooling and lower organic productivity. The average δ13C values from a core from West Taihu Lake are evidently higher than values from East Taihu Lake. The latter may reflect a stream environment, whereas the high δ13C values from West Taihu Lake likely reflect autotrophic carbon sources and a lacustrine environment since 11,000 yr B.P.

  14. 湖泊水质模型SALMO在太湖梅梁湾的应用%Application of lake model SALMO to the Meiliang Bay of Taihu Lake

    Institute of Scientific and Technical Information of China (English)

    郭静; 陈求稳; 李伟峰

    2012-01-01

    The lake model SALMO (Simulation by Means of an Analytical Lake Model) was applied to simulate the water quality of the Meiliang Bay in Taihu Lake.The model includes 8 state variables:nitrate nitrogen,phosphate phosphorus,detritus,dissolved oxygen,biomass of three algae (Cyanophyta,Chlorophyta and Bacillariophyta) and zooplankton.Because SALMO was originally developed for non-shallow lakes (maximum depth 5 m),some improvements were made to SALMO before simulating the shallow Meiliang Bay.The data from the year 2005 were used for model calibration and the data from the year 2006 were used for model verification.The results showed that the modeled biomass of the three algae followed the observed seasonal patterns:Bacillariophyta and Chlorophyta were dominant from the end of winter to the beginning of spring,while Cyanophyta was dominant in summer and autumn.The modeled nutrient concentrations also showed a good agreement with the observations.This indicates that after improvement SALMO is applicable for Taihu Lake and can be used to study the mechanisms of algae bloom.%改进了湖泊水质模型SALMO,针对太湖梅梁湾,利用2005年实测数据进行模型参数率定,并模拟了2006年水质.结果发现,绿藻、蓝藻、硅藻3种藻类的模拟结果与藻类的实测年变化格局一致,反应了3种藻类的季节性演替,其中,硅藻、绿藻在冬末春初占优势,蓝藻在夏秋季占优势;溶解氧模拟结果与实测数据非常一致,年平均相对误差为14.3%;NO-3-N和PO3-4-P的变化趋势与实测结果基本一致.研究结果表明,SALMO能很好地模拟藻类和营养盐的浓度动态,并在一定程度上揭示水华机制.

  15. Nutrient elements and heavy metals in the sediment of Baiyangdian and Taihu Lakes: A comparative analysis of pollution trends

    Institute of Scientific and Technical Information of China (English)

    YANG Zhuo; LI Bowen; LI Guibao; WANG Wei

    2007-01-01

    Based on the sample data on the concentrations of nutrient elements and heavy metals in the sediment collected from Baiyangdian Lake (BL) in June 2004,the pollution level and the distribution of N,P,organic matter (OM),and the heavy metals Cu,Zn,Cd and Pb in water body sediment were analyzed.The pollution trends and current loads between BL and Taihu Lake (TL) were compared using relevant data from BL obtained in 1982 and 1994 and from TL in 1988 and 2000.The findings showed an ever-increasing trend of pollution year by year both in the sediment of BL and TL,although N and P pollution was somehow controlled at the end of the 1990s.The pollution situation in the BL area indicated that the downriver regions were more seriously polluted than the upriver regions,and the most heavily polluted sites were the outlet of the Fuhe River,the original wastewater reservoir of Tanghe River,and the densely populated Chunshui and Wangjiazhai villages.For the TL,the northern lakeside regions were found to be more seriously polluted than the southern regions,although the center of the lake was still relatively pollution free.The most heavily polluted spots were Wuli Lake,Meiliang Bay near Changzhou,Wuxi and other neighboring cities.While the Cd pollution in BL was greater than that in TL,there were not many differences in the average loads of Cu,Zn and Pb.This paper discusses the alternative measures to deal with the different pollution levels in these two lakes.

  16. Monitoring cyanobacteria-dominant algal blooms in eutrophicated Taihu Lake in China with synthetic aperture radar images

    Science.gov (United States)

    Wang, Ganlin; Li, Junsheng; Zhang, Bing; Shen, Qian; Zhang, Fangfang

    2015-01-01

    Monitoring algal blooms by optical remote sensing is limited by cloud cover. In this study, synthetic aperture radar (SAR) was deployed with the aim of monitoring cyanobacteria-dominant algal blooms in Taihu Lake in cloudy weather. The study shows that dark regions in the SAR images caused by cyanobacterial blooms damped the microwave backscatter of the lake surface and were consistent with the regions of algal blooms in quasi-synchronous optical images, confirming the applicability of SAR for detection of surface blooms. Low backscatter may also be associated with other factors such as low wind speeds, resulting in interference when monitoring algal blooms using SAR data alone. After feature extraction and selection, the dark regions were classified by the support vector machine method with an overall accuracy of 67.74%. SAR can provide a reference point for monitoring cyanobacterial blooms in the lake, particularly when weather is not suitable for optical remote sensing. Multi-polarization and multi-band SAR can be considered for use in the future to obtain more accurate information regarding algal blooms from SAR data.

  17. Economic optimal nitrogen application rates for rice cropping in the Taihu Lake region of China: taking account of negative externalities

    Directory of Open Access Journals (Sweden)

    Y. Xia

    2011-07-01

    Full Text Available Nitrogen application rates (NARs is often overestimated over the rice (Oryza sativa L. growing season in the Taihu Lake region of China. This is largely because only individual nitrogen (N losses are taken into account, or the inventory flows of reactive N have been limited solely to the farming process when evaluating environmental and economic effects of N fertilizer. Since N can permeate the ecosystem in numerous forms commencing from the acquisition of raw material, through manufacturing and use, to final losses in the farming process (e.g., N2O, NH3, NO3 leaching, etc., the costs incurred also accumulate and should be taken into account if economically-optimal N rates (EONRs are to be established. This study integrates important material and energy flows resulting from N use into a rice agricultural inventory that constitutes the hub of the life-cycle assessment (LCA method. An economic evaluation is used to determine an environmental and economic NAR for the Taihu Lake region. The analysis reveals that production and exploitation processes consume the largest proportion of resources, accounting for 77.2 % and 22.3 % of total resources, respectively. Regarding environmental impact, global warming creates the highest cost with contributions stemming mostly from fertilizer production and raw material exploitation processes. Farming process incurs the biggest environmental impact of the three environmental impact categories considered, whereas transportation has a much smaller effect. When taking account of resource consumption and environmental cost, the marginal benefit of 1 kg rice would decrease from 2.4 to only 1.01 yuan. Accordingly, our current EONR has been evaluated at 185 kg N ha−1 for a single rice-growing season. This could enhance profitability, as well as reduce the N losses associated with rice growing.

  18. Soil phosphorus dynamic, balance and critical P values in long-term fertilization experiment in Taihu Lake region, China

    Institute of Scientific and Technical Information of China (English)

    SHI Lin-lin; SHEN Ming-xing; LU Chang-yin; WANG Hai-hou; ZHOU Xin-wei; JIN Mei-juan; WU Tong-dong

    2015-01-01

    Phosphorus (P) is an important macronutrient for plant but can also cause potential environmental risk. In this paper, we studied the long-term fertilizer experiment (started 1980) to assess the soil P dynamic, balance, critical P value and the crop yield response in Taihu Lake region, China. To avoid the effect of nitrogen (N) and potassium (K), only the folowing treatments were chosen for subsequent discussion, including: C0 (control treatment without any fertilizer or organic manure), CNK treatment (mineral N and K only), CNPK (balanced fertilization with mineral N, P and K), MNK (integrated organic ma-nure and mineral N and K), and MNPK (organic manure plus balanced fertilization). The results revealed that the response of wheat yield was more sensitive than rice, and no signiifcant differences of crop yield had been detected among MNK, CNPK and MNPK until 2013. Dynamic and balance of soil total P (TP) and Olsen-P showed soil TP pool was enlarged signiifcantly over consistent fertilization. However, the diminishing marginal utility of soil Olsen-P was also found, indicating that high-level P application in the present condition could not increase soil Olsen-P contents anymore. Linear-linear and Mitscherlich models were used to estimate the critical value of Olsen-P for crops. The average critical P value for rice and wheat was 3.40 and 4.08 mg kg–1, respectively. The smaler critical P value than in uplands indicated a stronger ability of P supply for crops in this paddy soil. We concluded that no more mineral P should be applied in rice-wheat system in Taihu Lake region if soil Olsen-P is higher than the critical P value. The agricultural technique and management referring to acti-vate the plant-available P pool are also considerable, such as integrated use of low-P organic manure with mineral N and K.

  19. Benefit Assessment of Forest Function in Reducing Soil Erosion and Nutrient Loss in Anji County of Taihu Lake Basin

    Institute of Scientific and Technical Information of China (English)

    Biao; ZHANG; Jixi; GAO; Gaodi; XIE; Changxin; ZOU; Bin; WANG

    2013-01-01

    The non-point source pollution arising from soil erosion is one of the main reasons for the deterioration of the water quality of the Taihu Lake Basin. Forest plays an important role in controlling soil erosion and reducing nutrient loss. Based on the survey data on forest resources in Anji County, we estimate the amount of soil erosion and nutrient loss of nitrogen and phosphorus reduced by forest, using soil erosion modulus method and soil nutrient content. In accordance with the degradation coefficient of pollutant and regional compensation standards of environmental resources, we assess the ecological benefits of forest function in reducing nutrient loss of nitrogen and phosphorus in Anji County. The results show that the forest in Anji County can reduce the soil erosion amount at 1.51 million t annually on the average, so as to control the nutrient loss of 1 409 t of total nitrogen and 577 t of total phosphorus in soil, equivalent to annually avoiding the flow of 824 t of total nitrogen and 410 t of total phosphorus into river water; this ecological service function can make forests in Anji County get 92.55 million yuan of ecological compensation funds (about 688 yuan/hm2·a), equivalent to 15 times of the current ecological compensation standard (47 yuan/hm2). The study reveals the importance of forest function in controlling soil erosion and nutrient loss in the upper reaches of Taihu Lake Basin to water environment protection in the basin, conducive to carrying out pollution control and protection work of the water environment in the basin.

  20. Wind-wave affected phosphate loading variations and their relationship to redox condition in Lake Taihu

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Variation of wind speed and the physico-chemical parameters, such as dissolved phosphate, ferrous and manganese in lake water were observed on site. Together with the chemistry analysis and simulated experiment in lab, the change of phosphate concentration in lake water was analyzed. The variation of ferrous/phosphate ratio explained that along with the enhancement of wind-wave effect and the oxidation ability of lake water, the effects of co-precipitation and removal of dissolved phosphate and iron in the lake water were reinforced. The ferrous/phosphate ratio in pore water was less than 2.0, demonstrating that the dissolved phosphate can be released into the overlying water. But, in the lake water, the stability of phosphate was controlled by the water dynamics.The phosphate release experiment showed that molecular release was only part of the whole and the direct discharge of phosphate in the pore water was also a part. The mineralization and biological process of suspended particulates in the water may be another important reason for the whole phosphate loadings.

  1. Dynamics of sediment resuspension and the conceptual schema of nutrient release in the large shallow Lake Taihu,China

    Institute of Scientific and Technical Information of China (English)

    QIN Boqiang; HU Weiping; GAO Guang; LUO Liancong; ZHANG Jinshan

    2004-01-01

    On the basis of investigations in situ, it was found that mass exchange on the water-sediment interface occurred chiefly on the superficial sediment within 5-10 cm. The spatial physicochemical character of sediment was distributed uniformly. The observation of lake currents and waves indicated that the dynamic sources, which act on the interface of water and sediment, came mainly from waves under strong wind forcing, while the critical shear stresses due to the waves and currents were of the same magnitude under weak wind forcing. The critical shear stress that leads to extensive sediment resuspension was about 0.03-0.04N/m2, equivalent to a wind speed in situ up to 4 m/s. If a dynamic intensity exceeded the critical shear stress, such as a wind velocity up to 6.5 m/s, massive sediment re-suspension would be observed in the lake. Furthermore, field investigations revealed that the nutrient concentration of pore water within the sediment was far greater than that of overlaying water, which provides objective conditions for the nutrient release from sediment. According to nutrient analyses in the pore water from the superficial 5-10 cm sediments, a severe dynamic process in the Taihu Lake would bring out a peak nutrient release, i.e. a 0.12 mg/L increase of TN, and 0.005 mg/L increase of TP in the lake. In the end, a general scheme of nutrient release from sediment in large shallow lakes was put forward: when the wind-driven forcing imposes on the lake, it will make the sediment resuspension. At the same time, the nutrition from the pore water will follow the sediment resuspension release to overlaying water. Because of oxidation of solid particulates when it resuspends from sediment, the disturbance of hydrodynamics will enhance the suspension particulates absorbing nutrition. After the withdrawal of wind forcing, the suspended mass would deposit and bring part of the released nutrients back into sediment. The degraded organic particulate would be separated to the

  2. Long-term joint effect of nutrients and temperature increase on algal growth in Lake Taihu, China

    Institute of Scientific and Technical Information of China (English)

    Chun Ye; Zhemin Shen; Tao Zhang; Maohong Fan; Yangming Lei; Jianda Zhang

    2011-01-01

    To study how global warming and eutrophication affect water ecosystems, a multiplicative growth Monod model, modified by incorporating the Arrhenius equation, was applied to Lake Taihu to quantitatively study the relationships between algal biomass and both nutrients and temperature using long-term data. To qualitatively assess which factor was a limitation of the improved model,temperature variables were calculated using annual mean air temperature (AT), water temperature (WT), and their average temperature (ST), while substrate variables were calculated using annual mean total nitrogen (TN), total phosphorus (TP), and their weighted aggregate (R), respectively. The nine fitted curves showed that TN and AT were two important factors influencing algal growth; AT limited growth as algal photosynthesis is mainly carried out near the water surface; N leakage of phytoplankton and internal phosphorus load from sediment explains why TN was the best predictor of peak biomass using the Monod model. The fitted results suggest that annual mean algal biomass increased by 0.145 times when annual mean AT increased by 1.0C. Results also showed that the more eutrophic the lake, the greater the effect AT had on algal growth. Subsequently, the long-term joint effect of annual temperature increase and eutrophication to water ecosys te.ms can be qu antitatively assessed and predicted.

  3. Impacts of algal blooms removal by chitosan-modified soils on zooplankton community in Taihu Lake,China

    Institute of Scientific and Technical Information of China (English)

    Jiajia Ni; Yuhe Yu; Weisong Feng; Qingyun Yan; Gang pan; Bo Yang; Xiang Zhang; Xuemei Li

    2010-01-01

    It is important to assess the effect on zooplankton when perform the environmental protection or restoration technology,especially removing algal blooms,because algae were the major primary producer in algal lakes.The influence on zooplankton community after half a year of algal blooms removed by chitosan-modified soils in Taihu Lake was assessed and the rationality of carrying out the process semiannually was evaluated in the present study.Morphological composition and genetic diversity of zooplankton community were investigated by microscope checkup and polymerase chain reaction-denatured gradient gel electrophoresis (PCR-DGGE).A total of 44 zooplankton taxa (23 protozoa,17 rotifers,3 copepoda and 1 cladocera) were detected by microscope checkup,and a total of 91 bands (28 bands amplified by primers F1427-GC and R1616,63 bands amplified by primers Fung-G-C and NS1) were detected by PCR-DGGE.The results of cluster analysis or detrended correspondence analysis indicated that there was no considerable difference in morphological composition of zooplankton and DGGE profiles between experimental and control sites,and DGGE profiles could represent the biologic diversity.The study showed that zooplankton community could recover original condition after half year of algal blooms removed by chitosan-modified soils and it was acceptable to apply this process semiannually.In addition,the results revealed that PCR-DGGE could be applied to investigate the impacts of the environmental protection or restoration engineering on zooplankton community diversity.

  4. Quantification of microcystin-producing and non-microcystin producing Microcystis populations during the 2009 and 2010 blooms in Lake Taihu using quantitative real-time PCR

    Institute of Scientific and Technical Information of China (English)

    Daming Li; Fanxiang Kong; Xiaoli Shi; Linlin Ye; Yang Yu; Zhen Yang

    2012-01-01

    Lake Taihu,a large,shallow hypertrophic freshwater lake in eastern China,has experienced lake-wide toxic cyanobacterial blooms annually during summer season in the past decades.Spatial changes in the abundance of hepatotoxin microcystin-producing and nonmicrocystin producing Microcystis populations were investigated in the lake in August of 2009 and 2010.To monitor the densities of the total Microcystis population and the potential microcystin-producing subpopulation,we used a quantitative real-time PCR assay targeting the phycocyanin intergenic spacer (PC-IGS) and the microcystin synthetase gene (mcyD),respectively.On the basis of quantification by real-time PCR analysis,the abundance of potential toxic Microcystis genotypes and the ratio of the mcyD subpopulation to the total Microcystis varied significantly,from 4.08×104 to 5.22×107 copies/mL,from 5.7% to 65.8%,respectively.Correlation analysis showed a strong positive relationship between chlorophyll-a,toxic Microcystis and total Microcystis; the abundance of toxic Microcystis correlated positively with total phosphorus and ortho-phosphate concentrations,but negatively with TN:TP ratio and nitrate concentrations.Meanwhile the proportion of potential toxic genotypes within Microcystis population showed positive correlation with total phosphorus and ortho-phosphate concentrations.Our data suggest that increased phosphorus loading may be a significant factor promoting the occurrence of toxic Microcystis bloom in Lake Taihu.

  5. Long-term moderate wind induced sediment resuspension meeting phosphorus demand of phytoplankton in the large shallow eutrophic Lake Taihu.

    Science.gov (United States)

    Chao, Jian-Ying; Zhang, Yi-Min; Kong, Ming; Zhuang, Wei; Wang, Long-Mian; Shao, Ke-Qiang; Gao, Guang

    2017-01-01

    The objective of this study was to investigate the impact of sediment resuspension and phosphorus (P) release on phytoplankton growth under different kinds of wind-wave disturbance conditions in the large and shallow eutrophic Lake Taihu in China. Short-term strong wind (STSW) conditions, long-term moderate wind (LTMW) conditions, and static/calm conditions were investigated. To address this objective, we (1) monitored changes in surface water P composition during field-based sediment resuspension caused by STSW conditions in Lake Taihu, and also conducted (2) a series of laboratory-based sediment resuspension experiments to simulate LTMW and calm conditions. The results showed that under both strong and moderate wind-wave conditions, suspended solids (SS) and total phosphorus (TP) in the water column increased significantly, but total dissolved phosphorus (TDP) and soluble reactive phosphorus (SRP) remained low throughout the experiments, indicating that the P released from sediments mainly existed in particulate forms. In STSW conditions, alkaline phosphatase activity (APA) and enzymatically hydrolysable phosphorus (EHP) increased rapidly, with the peak value occurring following the peak value of wind speed for 1-2 days, and then rapidly decreased after the wind stopped. Under LTMW conditions, APA and EHP increased steadily, and by the end of the laboratory experiments, APA increased by 11 times and EHP increased by 5 times. Chlorophyll a (Chl-a) in LTMW conditions increased significantly, but remained low under STSW conditions, demonstrating that the former type of sediment P release promoted phytoplankton growth more effectively, and the latter type did not. Despite the fact that STSW conditions resulted in the release of more TP, TP settled to the bottom rapidly with SS after the wind stopped, and did not promote algal growth. Under LTMW conditions, suspended particulate P was hydrolyzed to SRP by phosphatase and promoted algae growth. Algal growth in turn

  6. Delineation of level III aquatic ecological function regionalization in the Taihu Lake basin%太湖流域水生态功能三级分区

    Institute of Scientific and Technical Information of China (English)

    高永年; 高俊峰; 陈垌烽; 许妍; 赵家虎

    2012-01-01

    Aquatic ecoregions have been used as spatial units for aquatic ecosystem management at the watershed scale. According to the protection requirements and characteristics of aquatic ecosystems in the Taihu Lake basin, the main purpose and the principles of level III aquatic ecological function regionalization delineation in this basin were proposed. Then the indicators for delineating level III aquatic ecological function regionalization were established based on regionalization objective and principles. The indicators for delineating level Ili aquatic ecological function regionalization in the non-Taihu Lake area included benthic Shannon-Wiener diversity index, chlorophyll content, water habitat types and benthic indicator species types (including Ephemera, Bivalvia, snail, Chironomidae and Oligochaeta), and the regionalization indicators for delineating level III aquatic ecological function regionalization in the Taihu Lake area included benthic Shannon-Wiener diversity index, chlorophyll content, water flow velocity and benthic indicator species (including Oligochaeta, Chironomidae class, Bivalvia, snail and others) ratio. With the aid of GIS technology, the spatial distribution of the indicators for level III aquatic ecological function regionalization delineation was identified based on the raster data from 1106 aquatic ecoregion function units in the non-Taihu Lake area and 3568 aquatic ecoregion function units in the Taihu Lake area, respectively. Two-step spatial clustering analysis approach and manual-assisted method were used to delineate level III aquatic ecological function zones. Then the Taihu Lake basin was divided into 21 level III aquatic ecological function zones. Moreover, the characteristics of the 21 zones were summarized, showing that there were significant differences in the aspects such as topography, soil type, water quality and aquatic ecology. The results of quantitative comparison of aquatic life also indicated that the benthic dominant

  7. Geochemistry of iron,sulfur and related heavy metals in metal-polluted Taihu Lake sediments

    Institute of Scientific and Technical Information of China (English)

    YIN Hong-Bin; FAN Cheng-Xin; DING Shi-Ming; ZHANG Lu; ZHONG Ji-Cheng

    2008-01-01

    To understand the geochemical characteristics of iron and sulfur and the extent of iron-sulfide minerals influencing heavy metal behaviour in metal-polluted sediments of Talhu Lake,two sites,in Meiliang Bay (ML) and Wuli Lake (WL),were selected to study the fractionation of iron,sulfur and related heavy metals.There were relatively high concentrations of Fe2+ and low concentrations of total S2- in porewaters,indicating that conditions in these sediments favored iron reduction.The concentrations of acid volatile sulfides in sediments were 1.9-9.6μmol g-1 at ML and 1.0-11.7 μmol g-1 at WL,both in the range of values detected in unpolluted lakes.Pyrite-S was 10.2-49.4 μmol g-1 at ML and 10.333.0 μmol g-1 at WL,accounting for more than 69% of the reduced inorganic sulfur at both sites.The low degree of sulphidization (<14%) and pyritization (<10%) indicate that sulfate may be the limiting factor for pyrite formation.The extractability of Mn,Cu,Pb,Zn,Ni,and Cr in sediments all suggest that sulfides are not the major binding phase for these metals during early diagenesis.Sulfur may play a modest role in the geochemistry of iron and traced metals in the sediments.

  8. Maintaining yields and reducing nitrogen loss in rice-wheat rotation system in Taihu Lake region with proper fertilizer management

    Science.gov (United States)

    Xue, Lihong; Yu, Yingliang; Yang, Linzhang

    2014-11-01

    In the Tailake region of China, heavy nitrogen (N) loss of rice-wheat rotation systems, due to high fertilizer-N input with low N use efficiency (NUE), was widely reported. To alleviate the detrimental impacts caused by N loss, it is necessary to improve the fertilizer management practices. Therefore, a 3 yr field experiments with different N managements including organic combined chemical N treatment (OCN, 390 kg N ha-1 yr-1, 20% organic fertilizer), control-released urea treatment (CRU, 390 kg N ha-1 yr-1, 70% resin-coated urea), reduced chemical N treatment (RCN, 390 kg N ha-1 yr-1, all common chemical fertilizer), and site-specific N management (SSNM, 333 kg N ha-1 yr-1, all common chemical fertilizer) were conducted in the Taihu Lake region with the ‘farmer’s N’ treatment (FN, 510 kg N ha-1 yr-1, all common chemical fertilizer) as a control. Grain yield, plant N uptake (PNU), NUE, and N losses via runoff, leaching, and ammonia volatilization were assessed. In the rice season, the FN treatment had the highest N loss and lowest NUE, which can be attributed to an excessive rate of N application. Treatments of OCN and RCN with a 22% reduced N rate from FN had no significant effect on PNU nor the yield of rice in the 3 yr; however, the NUE was improved and N loss was reduced 20-32%. OCN treatment achieved the highest yield, while SSNM has the lowest N loss and highest NUE due to the lowest N rate. In wheat season, N loss decreased about 28-48% with the continuous reduction of N input, but the yield also declined, with the exception of OCN treatment. N loss through runoff, leaching and ammonia volatilization was positively correlated with the N input rate. When compared with the pure chemical fertilizer treatment of RCN under the same N input, OCN treatment has better NUE, better yield, and lower N loss. 70% of the urea replaced with resin-coated urea had no significant effect on yield and NUE improvement, but decreased the ammonia volatilization loss. Soil

  9. Controlling cyanobacterial blooms in hypertrophic Lake Taihu, China: will nitrogen reductions cause replacement of non-N2 fixing by N2 fixing taxa?

    Directory of Open Access Journals (Sweden)

    Hans W Paerl

    Full Text Available Excessive anthropogenic nitrogen (N and phosphorus (P inputs have caused an alarming increase in harmful cyanobacterial blooms, threatening sustainability of lakes and reservoirs worldwide. Hypertrophic Lake Taihu, China's third largest freshwater lake, typifies this predicament, with toxic blooms of the non-N2 fixing cyanobacteria Microcystis spp. dominating from spring through fall. Previous studies indicate N and P reductions are needed to reduce bloom magnitude and duration. However, N reductions may encourage replacement of non-N2 fixing with N2 fixing cyanobacteria. This potentially counterproductive scenario was evaluated using replicate, large (1000 L, in-lake mesocosms during summer bloom periods. N+P additions led to maximum phytoplankton production. Phosphorus enrichment, which promoted N limitation, resulted in increases in N2 fixing taxa (Anabaena spp., but it did not lead to significant replacement of non-N2 fixing with N2 fixing cyanobacteria, and N2 fixation rates remained ecologically insignificant. Furthermore, P enrichment failed to increase phytoplankton production relative to controls, indicating that N was the most limiting nutrient throughout this period. We propose that Microcystis spp. and other non-N2 fixing genera can maintain dominance in this shallow, highly turbid, nutrient-enriched lake by outcompeting N2 fixing taxa for existing sources of N and P stored and cycled in the lake. To bring Taihu and other hypertrophic systems below the bloom threshold, both N and P reductions will be needed until the legacy of high N and P loading and sediment nutrient storage in these systems is depleted. At that point, a more exclusive focus on P reductions may be feasible.

  10. [Sources of dissolved organic carbon and the bioavailability of dissolved carbohydrates in the tributaries of Lake Taihu].

    Science.gov (United States)

    Ye, Lin-Lin; Wu, Xiao-Dong; Kong, Fan-Xiang; Liu, Bo; Yan, De-Zhi

    2015-03-01

    Surface water samples of Yincungang and Chendonggang Rivers were collected from September 2012 to August 2013 in Lake Taihu. Water temperature, Chlorophyll a and bacterial abundance were analyzed, as well as dissolved organic carbon (DOC) concentrations, stable carbon isotope of DOC (Δ13C(DOC)), specific UV absorbance (SUVA254 ) and dissolved carbohydrates concentrations. Δ13C(DOC) ranged from -27.03% per thousand ± 0.30% per thousand to -23.38%per thousand ± 0.20% per thousand, indicating a terrestrial source. Both the autochthonous and allochthonous sources contributed to the carbohydrates pool in the tributaries. Significant differences in PCHO (polysaccharides) and MCHO (monosaccharides) concentrations were observed between spring-summer and autumn-winter (P carbohydrates. PCHO contributed a major fraction to TCHO (total dissolved carbohydrates) in autumn and winter, which could be explained by the accumulation of undegradable PCHO limited by the low water temperature; MCHO contributed a major fraction to TCHO in spring and summer, which might be caused by the transformation from PCHO by microbes at high water temperature.

  11. Identification and Characterization of Quantitative Trait Loci for Shattering in Rice Landrace Jiucaiqing from Taihu Lake Valley, China.

    Science.gov (United States)

    Cheng, Jinping; He, Yongqi; Zhan, Chengfang; Yang, Bin; Xu, Enshun; Zhang, Hongsheng; Wang, Zhoufei

    2016-11-01

    Easy shattering reduces yield from grain loss during rice ( L.) harvest. We characterized a nonshattering rice landrace Jiucaiqing from Taihu Lake valley in China. The breaking tensile strength (BTS; grams force, gf) of the grain pedicel was measured using a digital force gauge to evaluate the degree of shattering at 0, 7, 14, 21, 28, and 35 d after heading (DAH). The BTS of Jiucaiqing did not significantly decrease with increasing DAH, maintaining a level of 152.2 to 195.9 gf, while that of IR26 decreased greatly during 0 to 14 DAH and finally stabilized at ∼100 gf. Then the chromosome segment substitution lines (CSSLs) and near isogenic lines (NILs) of Jiucaiqing in IR26 background were developed for quantitative trait loci (QTL) mapping. Four putative QTL (, , , and ) for shattering were detected, and the was confirmed on chromosome 1. We further mapped to a 98.4-kb region, which contains 14 genes. Os01g62920 was considered to be a strong candidate for , which colocated with . Further quantitative real-time polymerase chain reaction (PCR) analyses confirmed that the QTL can significantly decrease the expression of shattering related genes (, , , , and ) especially at the middle development stage at 10 and 15 cm panicle length, which causes rice shattering decrease. The elite allele and the NIL with desirable agronomic traits identified in this study could be useful for rice breeding.

  12. Ammonia Volatilization and Nitrogen Utilization Efficiency in Response to Urea Application in Rice Fields of the Taihu Lake Region, China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Ammonia volatilization losses, nitrogen utilization efficiency, and rice yields in response to urea application to a rice field were investigated in Wangzhuang Town, Changshu City, Jiangsu Province, China. The N fertilizer treatments, applied in triplicate, were 0 (control), 100, 200, 300, or 350 kg N ha-1. After urea was applied to the surface water, a continuous airflow enclosure method was used to measure ammonia volatilization in the paddy field. Total N losses through ammonia volatilization generally increased with the N application rate, and the two higher N application rates (300 and 350 kg N ha-1) showed a higher ratio of N lost through ammonia volatilization to applied N. Total ammonia loss by ammonia volatilization during the entire rice growth stage ranged from 9.0% to 16.7% of the applied N. Increasing the application rate generally decreased the ratio of N in the seed to N in the plant. For all N treatments, the nitrogen fertilizer utilization efficiency ranged from 30.9% to 45.9%. Surplus N with the highest N rate resulted in lodging of rice plants, a decreased rate of nitrogen fertilizer utilization, and reduced rice yields. Calculated from this experiment, the most economical N fertilizer application rate was 227 kg ha-1 for the type of paddy soil in the Taihu Lake region. However, recommending an appropriate N fertilizer application rate such that the plant growth is enhanced and ammonia loss is reduced could improve the N utilization efficiency of rice.

  13. [Effects of large bio-manipulation fish pen on community structure of crustacean zooplankton in Meiliang Bay of Taihu Lake].

    Science.gov (United States)

    Ke, Zhi-Xin; Xie, Ping; Guo, Long-Gen; Xu, Jun; Zhou, Qiong

    2012-08-01

    In 2005, a large bio-manipulation pen with the stock of silver carp and bighead carp was built to control the cyanobacterial bloom in Meiliang Bay of Taihu Lake. This paper investigated the seasonal variation of the community structure of crustacean zooplankton and the water quality within and outside the pen. There were no significant differences in the environmental parameters and phytoplankton biomass within and outside the pen. The species composition and seasonal dynamics of crustacean zooplankton within and outside the pen were similar, but the biomass of crustacean zooplankton was greatly suppressed by silver carp and bighead carp. The total crustacean zooplankton biomass and cladocerans biomass were significantly lower in the pen (P crustacean zooplankton was observed in the Bay. Many crustacean species were only dominated in given seasons. Large-sized crustacean (mainly Daphnia sp. and Cyclops vicnus) dominated in winter and spring, while small-sized species (mainly Bosmina sp., Ceriodaphnia cornuta, and Limnoithona sinensis) dominated in summer and autumn. Canonical correspondence analysis showed that water transparency, temperature, and phytoplankton biomass were the most important factors affecting the seasonal succession of the crustacean.

  14. Identification and Characterization of Quantitative Trait Loci for Shattering in Japonica Rice Landrace Jiucaiqing from Taihu Lake Valley, China

    Directory of Open Access Journals (Sweden)

    Jinping Cheng

    2016-11-01

    Full Text Available Easy shattering reduces yield from grain loss during rice ( L. harvest. We characterized a nonshattering rice landrace Jiucaiqing from Taihu Lake valley in China. The breaking tensile strength (BTS; grams force, gf of the grain pedicel was measured using a digital force gauge to evaluate the degree of shattering at 0, 7, 14, 21, 28, and 35 d after heading (DAH. The BTS of Jiucaiqing did not significantly decrease with increasing DAH, maintaining a level of 152.2 to 195.9 gf, while that of IR26 decreased greatly during 0 to 14 DAH and finally stabilized at ∼100 gf. Then the chromosome segment substitution lines (CSSLs and near isogenic lines (NILs of Jiucaiqing in IR26 background were developed for quantitative trait loci (QTL mapping. Four putative QTL (, , , and for shattering were detected, and the was confirmed on chromosome 1. We further mapped to a 98.4-kb region, which contains 14 genes. Os01g62920 was considered to be a strong candidate for , which colocated with . Further quantitative real-time polymerase chain reaction (PCR analyses confirmed that the QTL can significantly decrease the expression of shattering related genes (, , , , and especially at the middle development stage at 10 and 15 cm panicle length, which causes rice shattering decrease. The elite allele and the NIL with desirable agronomic traits identified in this study could be useful for rice breeding.

  15. Spatial correlations between urbanization and river water pollution in the heavily polluted area of Taihu Lake Basin, China

    Institute of Scientific and Technical Information of China (English)

    ZHAO Haixia; DUAN Xuejun; Becky STEWART; YOU Bensheng; JIANG Xiaowei

    2013-01-01

    Water pollution in the Taihu Lake Basin has been the focus of attention in China and abroad for a long time,due to its position in the forefront of urban development in China.Based on data gathering and processing from 84 monitoring sections in this heavily polluted area,this study first analyzes spatial patterns of urbanization and the distribution of river water pollution,and then uses the GeoDa bivariate spatial autocorrelation model to investigate the spatial correlation between urbanization and river water pollution at the scale of township units.The results show that urbanization has adverse impacts on water pollution,and the influence varies in different levels of development areas.The urban township units have the highest level of urbanization and highest pollution,but the best water quality; the suburban units have lower level of urbanization,but higher pollution and worse water quality;however the rural units have the lowest level of urbanization and lowest pollution,mainly affected by upstream pollution,but worst water quality.Lastly,urban and rural planning committees,while actively promoting the process of development in the region,should gradually resolve the issue of pollution control lagging behind urban life and urban development,giving priority to construction of centralized sewage treatment facilities and associated pipeline network coverage in the rural areas and suburban areas.

  16. Use of fluorescent europium chelates as labels for detection of microcystin-LR in Taihu Lake, China

    Institute of Scientific and Technical Information of China (English)

    NIU Weimin; HE Enqi; WU Qinggang; ZHOU Weijie; ZHANG Yi; HUANG Biao; ZHAO Xiaolian

    2012-01-01

    A method using the time-resolved fluorescence technology to establish a highly sensitive microcystin-LR (MC-LR) indirect competitive immunoassay was proposed in this work.This method was used to monitor the MC-LR level in source water and treated drinking water from Taihu Lake.Algae in the water samples were removed by centrifugation,and the MC-LR level was quantified using this method.Testing results showed that the sensitivity of this method was 0.01 μg/L,and the dynamic measuring range was from 0.05 to 2 μg/L.The average recovery was 115%,and the variation (CV) within and between different batches were 7.3% and 9.7%,respectively.Testing results also indicated that this time-resolved fluoroimmunoassay was sensitive and accurate in measuring MC-LR level,especially for quantitative analysis MC-LR level in bulk water.

  17. Analyzing the spatial patterns and drivers of ecosystem services in rapidly urbanizing Taihu Lake Basin of China

    Science.gov (United States)

    Ai, Junyong; Sun, Xiang; Feng, Lan; Li, Yangfan; Zhu, Xiaodong

    2015-09-01

    Quantifying and mapping the distribution patterns of ecosystem services can help to ascertain which services should be protected and where investments should be directed to improve synergies and reduce tradeoffs. Moreover, the indicators of urbanization that affect the provision of ecosystem services must be identified to determine which approach to adopt in formulating policies related to these services. This paper presents a case study that maps the distribution of multiple ecosystem services and analyzes the ways in which they interact. The relationship between the supply of ecosystem services and the socio-economic development in the Taihu Lake Basin of eastern China is also revealed. Results show a significant negative relationship between crop production and tourism income ( p<0.005) and a positive relationship between crop production, nutrient retention, and carbon sequestration ( p<0.005). The negative effects of the urbanization process on providing and regulating services are also identified through a comparison of the ecosystem services in large and small cities. Regression analysis was used to compare and elucidate the relative significance of the selected urbanization factors to ecosystem services. The results indicate that urbanization level is the most substantial factor inversely correlated with crop production ( R 2 = 0.414) and nutrient retention services ( R 2 = 0.572). Population density is the most important factor that negatively affects carbon sequestration ( R 2 = 0.447). The findings of this study suggest the potential relevance of ecosystem service dynamics to urbanization management and decision making.

  18. Occurrence and partitioning of bisphenol analogues in water and sediment from Liaohe River Basin and Taihu Lake, China.

    Science.gov (United States)

    Jin, Hangbiao; Zhu, Lingyan

    2016-10-15

    Bisphenol analogues are widely used in the manufacture of polycarbonate plastics and epoxy resins, and the demand and production capacity of these compounds are growing rapidly in China. The occurrence and distribution of bisphenol analogues other than bisphenol A (BPA) in the aquatic environment is still poorly understood. In this study, nine bisphenol analogues were measured in water and sediment samples from Taihu Lake (TL), Liaohe River basin, including Liaohe River (LR) and Hunhe River (HR), China. Water samples from LR and HR contained much higher total bisphenols (∑BPs) concentrations. BPA and bisphenol S (BPS) were predominant with a summed contribution of 55, 75, and 75% to the ∑BPs in TL, LR, and HR waters, respectively. This suggests that BPA and BPS were the most widely used and manufactured bisphenols in these regions. In sediment, BPA was always predominant, with the next abundant compound bisphenol F (BPF) in TL and HR sediment, but BPS in LR sediment. The average field sediment-water partitioning coefficients (log Koc) were calculated for the first time for certain bisphenols and were determined to be 4.7, 4.6, 3.8, 3.7, and 3.5 mL/g for BPF, BPAP, BPA, BPAF, and BPS, respectively.

  19. [Rainfall intensity effects on nutrients transport in surface runoff from farmlands in gentle slope hilly area of Taihu Lake Basin].

    Science.gov (United States)

    Li, Rui-ling; Zhang, Yong-chun; Liu, Zhuang; Zeng, Yuan; Li, Wei-xin; Zhang, Hong-ling

    2010-05-01

    To investigate the effect of rainfall on agricultural nonpoint source pollution, watershed scale experiments were conducted to study the characteristics of nutrients in surface runoff under different rainfall intensities from farmlands in gentle slope hilly areas around Taihu Lake. Rainfall intensity significantly affected N and P concentrations in runoff. Rainfall intensity was positively related to TP, PO4(3-) -P and NH4+ -N event mean concentrations(EMC). However, this study have found the EMC of TN and NO3- -N to be positively related to rainfall intensity under light rain and negatively related to rainfall intensity under heavy rain. TN and TP site mean amounts (SMA) in runoff were positively related to rainfall intensity and were 1.91, 311.83, 127.65, 731.69 g/hm2 and 0.04, 7.77, 2.99, 32.02 g/hm2 with rainfall applied under light rain, moderate rain, heavy rain and rainstorm respectively. N in runoff was mainly NO3- -N and NH4+ -N and was primarily in dissolved form from Meilin soils. Dissolved P (DP) was the dominant form of TP under light rain, but particulate P (PP) mass loss increased with the increase of rainfall intensity and to be the dominant form when the rainfall intensity reaches rainstorm. Single relationships were used to describe the dependence of TN and TP mass losses in runoff on rainfall, maximum rainfall intensity, average rainfall intensity and rainfall duration respectively. The results showed a significant positive correlation between TN mass loss and rainfall, maximum rainfall intensity respectively (p rainfall, maximum rainfall intensity respectively (p < 0.01).

  20. Nitrogen Cycling and Losses Under Rice-Wheat Rotations with Coated Urea and Urea in the Taihu Lake Region

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-Zhi; ZHU Jian-Guo; GAO Ren; H. YASUKAZU; FENG Ke

    2007-01-01

    A lysimeter experiment with undisturbed soil profiles was carried out to study nitrogen cycling and losses in a paddy soil with applications of coated urea and urea under a rice-wheat rotation system in the Taihu Lake region from 2001 to 2003. Treatments for rice and wheat included urea at conventional, 300 (rice) and 250 (wheat) kg N ha-1, and reduced levels, 150 (rice) and 125 (wheat) kg N ha-1, coated urea at two levels, 100 (rice) and 75 (wheat) kg N ha-1, and 150(rice) and 125 (wheat) kg N ha-1, and a control with no nitrogen arranged in a completely randomized design. The results under two rice-wheat rotations showed that N losses through both NH3 volatilization and runoff in the coated urea treatments were much lower than those in the urea treatments. In the urea treatments N runoff losses were significantly (P < 0.001) positively correlated (r = 0.851) with applied N. N concentration in surface water increased rapidly to maximum two days after urea application and then decreased quickly. However, if there was no heavy rain within five days of fertilizer application, the likelihood of N loss by runoff was not high. As the treatments showed little difference in N loss via percolation, nitrate N in the groundwater of the paddy fields was not directly related to N leaching. The total yieldof the two rice-wheat rotations in the treatment of coated urea at 50% conventional level was higher than that in the treatment of urea at the conventional level. Thus, coated urea was more favorable to rice production and environmental protection than urea.

  1. Isolation and growth kinetics of a novel phenol-degrading bacterium Microbacterium oxydans from the sediment of Taihu Lake (China).

    Science.gov (United States)

    Wang, Linqiong; Li, Yi; Niu, Lihua; Dai, Yu; Wu, Yue; Wang, Qing

    2016-01-01

    Seven phylogenetically diverse phenol-degrading bacterial strains designated as P1 to P7 were isolated from the industry-effluent dump sites of an industrial area near Taihu Lake, China. Through the 16S rDNA sequence analysis, these strains were widely distributed among five different genera: Rhodococcus (P1), Pseudomonas (P2-P4), Acinetobacter (P5), Alcaligenes (P6), and Microbacterium (P7). All seven isolates were capable of growing with phenol as the sole carbon source. Strain P7 was found to be a novel phenol-degrading strain by detailed morphological, physiological and biochemical characteristic analysis as well as the 16S rDNA sequence analyses, and was named Microbacterium oxydans LY1 (M. oxydans LY1 in its short form). Degradation experiments of phenol at various initial concentrations (20-1,000 mg/L) revealed that phenol is an inhibitory substrate to M. oxydans LY1. In a batch culture experiment, more than 95% of the phenol (500 mg/L) was degraded by M. oxydans LY1 at 30°C, pH 7.0 and 120 rpm within 88 h. Phenol concentration higher than 200 mg/L was found to inhibit the bacterial growth. The growth kinetics correlated well with the Haldane model with μmax (maximum specific cell growth rate) = 0.243 h(-1), Ks (saturation constant) = 25.7 mg/L, and Ki (self-inhibition constant) = 156.3 mg/L. This is the first report of the ability of M. oxydans to degrade phenol, and the results could provide important information for bioremediation of phenol-contaminated environments.

  2. A Method for Retrieving Water-leaving Radiance from Landsat TM Image in Taihu Lake, East China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The visible and infrared bands of Landsat Thematic Mapper (TM) can be used for inland water studies. A method of retrieving water-leaving radiance from TM image over Taihu Lake in Jiangsu Province of China was investigated in this article. To estimate water-leaving radiance, atmospheric correction was performed in three visible bands of 485nm, 560nm and 660nm. Rayleigh scattering was computed precisely, and the aerosol contribution was estimated by adopting the clear-water-pixels approach. The clear waters were identified by using the Landsat TM middle-infrared band (2.1 μm), and the water-leaving radiance of clear water pixels in the green band was estimated by using field data.Aerosol scattering at green band was derived for six points, and interpolated to match the TM image. Assuming the atmospheric correction coefficient was 1.0, the aerosol scattering image at blue and red bands were derived. Based on a simplified atmospheric radiation transfer model, the water-leaving radiance for three visible bands was retrieved. The water-leaving radiance was normalized to make it comparable with that estimated from other remotely sensed data acquired at different times, and under different atmospheric conditions. Additionally, remotely sensed reflectance of water was computed. To evaluate the atmospheric correction method presented in this article, the correlation was analyzed between the corrected remotely sensed data and the measured water parameters based on the retrieval model. The results show that the atmospheric correction method based on the image itself is more effective for the retrieval of water parameters from Landsat TM data than 6S (Second Simulation of the Satellite Signal in the Solar Spectrum) code based on standard atmospheric and aerosol models.

  3. Polysaccharide biosynthesis-related genes explain phenotype-genotype correlation of Microcystis colonies in Meiliang Bay of Lake Taihu, China

    Science.gov (United States)

    Xu, Shutu; Sun, Qianqian; Zhou, Xiaohua; Tan, Xiao; Xiao, Man; Zhu, Wei; Li, Ming

    2016-01-01

    The 16S rDNA, 16S-23S rDNA-ITS, cpcBA-IGS, mcy gene and several polysaccharide biosynthesis-related genes (epsL and TagH) were analyzed along with the identification of the morphology of Microcystis colonies collected in Lake Taihu in 2014. M. wesenbergii colonies could be distinguished directly from other colonies using espL. TagH divided all of the samples into two clusters but failed to distinguish different phenotypes. Our results indicated that neither morphology nor molecular tools including 16S rDNA, 16S-23S ITS and cpcBA-IGS could distinguish toxic and non-toxic species among the identified Microcystis species. No obvious relationship was detected between the phenotypes of Microcystis and their genotypes using 16S, 16S-23S and cpcBA-IGS, but polysaccharide biosynthesis-related genes may distinguish the Microcystis phenotypes. Furthermore, the sequences of the polysaccharide biosynthesis-related genes (espL and TagH) extracted from Microcystis scums collected throughout 2015 was analyzed. Samples dominated by M. ichthyoblabe (60–100%) and M. wesenbergii (60–100%) were divided into different clade by both espL and TagH, respectively. Therefore, it was confirmed that M. wesenbergii and M. ichthyoblabe could be distinguished by the polysaccharide biosynthesis-related genes (espL and TagH). This study is of great significance in filling the gap between classification of molecular biology and the morphological taxonomy of Microcystis. PMID:27752091

  4. Influence of Land Use/Cover Change on Storm Runoff——A Case Study of Xitiaoxi River Basin in Upstream of Taihu Lake Watershed

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Land use/cover change (LUCC) is one of the main boundary conditions which influence many hydrologic processes. In view of the importance of Taihu Lake Watershed in China and the urgency of discovering the impacts of LUCC on storm runoff, two flood events under five land cover scenarios in the Xitiaoxi River Basin of the upstream of Taihu Lake watershed were simulated by distributed hydrologic modeling system HEC-HMS. The influences of each land cover on storm runoffwere discussed. It was concluded that under the same rainstorm the ascending order of runoff coefficient and peak flow produced by the 5 different land covers were woodland, shrub, grassland, arable land,and built-up land; the descending order of swelling time were woodland, shrub, grassland, arable land, and built-up land. Scenario of built-up land was the first to reach peak flow, then arable land, grassland, shrub, and woodland.There were close relationships between the runoff coefficients produced by the 5 different land covers. The degrees of impacts on runoff coefficient of land cover change modes were sorted by descending: woodland to built-up land, shrub to built-up land, grassland to built-up land, arable land to built-up land, woodland to arable land, shrub to arable land,arable land to grassland, shrub to grassland, grassland to arable land, and woodland to shrub. Urbanization will contribute to flood disaster, while forestation will mitigate flood disaster.

  5. Development of the Greening of Industrial Firms in the Cities along Taihu Lake: A Case Study in Wuxi City, Jiangsu Province

    Institute of Scientific and Technical Information of China (English)

    Wang Yihu; Chen Wen; Chen Jianglong; Zuo Wenfang

    2007-01-01

    Under the globalization, the coastal China becomes a hot area of the international manufacturing investment due to its priority location, excellent environment, lower labor and land costs, etc. However, the fast industrialization has aroused the great demolishment to the local ecological environment. For example,the heavy water eutrophication in Taihu Lake has affected the source of drinking water for the cities around the lake. Anyway, in order to keep the economic increase and reduce the resource expense and pollution at the same time, it is necessary to encourage the greening of industrial enterprises actively for sustainable development. On the basis of the investigation of industrial enterprises in Wuxi city within Taihu Basin, the relatively developed region in coastal China, this paper analyzed the development process of green industry. This article concluded that governmental principal is the main pressure for enterprises to protect environment while the market factor plays a part role. Moreover, enterprises in the high technology development zone work better in environmental protection than those in the villages and towns, while the large enterprises work better than those small enterprises.

  6. Quantifying methane emissions from rice fields in the Taihu Lake region, China by coupling a detailed soil database with biogeochemical model

    Directory of Open Access Journals (Sweden)

    L. Zhang

    2009-05-01

    Full Text Available As China has approximately 22% of the world's rice paddies, the regional quantification of CH4 emissions from these paddies is important in determining their contribution to the global greenhouse gas effect. This paper reports the use of a biogeochemical model (DeNitrification and DeComposition or DNDC for quantifying CH4 emissions from rice fields in the Taihu Lake region of China. For this application, the DNDC model was linked to a 1:50 000 soil database derived from 1107 paddy soil profiles compiled during the Second National Soil Survey of China in the 1980s–1990s. The simulated results showed that the 2.3 Mha of paddy rice fields in the Taihu Lake region emitted the equivalent of 5.7 Tg C from 1982–2000, with the average CH4 flux ranging from 114 to 138 kg C ha−1 y−1. As for soil subgroups, the highest emission rate (660 kg C ha−1 y−1 was linked to gleyed paddy soils accounting for about 4.4% of the total area of paddy soils. The lowest emission rate (91 kg C ha−1 y−1 was associated with degleyed paddy soils accounting for about 18% of the total area of paddy soils. The most common soil in the area was hydromorphic paddy soils, which accounted for about 53% of the total area of paddy soils with a CH4 flux of 106 kg C ha−1 y−1. On a regional basis, the annual averaged CH4 flux in the Taihu Lake plain soil region and alluvial plain soil region were higher than that in the low mountainous and hilly soil region and the polder soil region. The model simulation was conducted with two databases using polygons or counties as the basic units. The county-based database contained soil information coarser than the polygon system built based on the 1:50 000 soil database. The modeled results with the two databases found similar spatial patterns of CH4 emissions in the Taihu

  7. First flush characteristics of rainfall runoff from a paddy field in the Taihu Lake watershed, China.

    Science.gov (United States)

    Li, Songmin; Wang, Xiaoling; Qiao, Bin; Li, Jiansheng; Tu, Jiamin

    2017-02-06

    Nonpoint storm runoff remains a major threat to surface water quality in China. As a paddy matures, numerous fertilizers are needed, especially in the rainy seasons; the concentration of nitrogen and phosphorus in rainfall runoff from farmland is much higher than at other times, and this poses a great threat to water bodies and is the main reason for water eutrophication, especially in high concentration drainages. To date, most studies regarding the characteristics of pollutants in rainfall runoff have mainly been concentrated on urban runoff and watershed runoff; therefore, it is particularly important to investigate the characteristics of nitrogen and phosphorus loss in rainfall runoff from paddy fields. To study the characteristics of nitrogen and phosphorus loss and whether the first flush effect exists, continuous monitoring of the rainfall runoff process of six rainfall events was conducted in 2013, of which four rainfall events during storm, high, middle, and low intensity rainfalls were analyzed, and runoff and quality parameters, such as suspended solids (SS), total nitrogen (TN), ammonium nitrogen (NH4(+)-N), nitrate nitrogen (NO3(-)-N), total phosphorus (TP), and phosphate (PO4(3-)-P), were analyzed to determine the relationship between runoff and water quality. The paddy field is located north of Wuxi Lake Basin along the Hejia River upstream in Zhoutie town, Yixing city. An analysis of the load distribution during rainfall runoff was conducted. Event mean concentration (EMC) was used to evaluate the pollution situation of the paddy field's rainfall runoff. A curve of the dimensionless normalized cumulative load (L) vs. normalized cumulative flow (F) (L-F curve), the probability of the mass first flush (MFFn), and the pollutants carried by the initial 25% of runoff (FF25) were used to analyze the first flush effect of the paddy field runoff, and different contaminants show different results: the concentration of nitrogen and phosphorus fluctuate and

  8. Growth Responses of Trees to Micronutrients and Their Feedback Effect in Various Soil-Forest Ecosystems of Taihu Lake Region

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Vector analysis technique and ecological sequential comparison methods were adopted to study tree growth response to the micronutrients, B, Mo, Cu, Zn, Fe, and Mn, in soils derived from various parent materials in the forest area of Taihu Lake region in southeast China. The results showed that the dry weight of individual current-year needle of Chinese fir (Cunninghamia lanceolata) grown on the soil derived from granite parent rock was increased by 8% and 13% in comparison with that grown on the soils derived from sandstone and ash-tuff parent rock, respectively. And such dry weight of loblolly pine (Pinus taeda) grown on the soil derived from sandstone parent rock was increased by 21% in comparison with that on the soil derived from ash-tuff parent rock. One of the reasons for those results was that micronutrients content in the soil derived from ash-tuff parent rock were not sufficient to meet the requirement of the growth of Chinese fir and loblolly pine, i.e., micronutrients in soil were deficient and/or induced deficient. The amounts of Cu, Zn, Fe, and Mn uptake by Chinese fir and loblolly pine were in agreement with the contents of available micronutrients in soil respectively, except for B and Mo. Meanwhile, there might exist an "antagonism" between the uptake of B versus Mo by trees, although more studies are needed to confirm it. Regression analysis indicated that amount of a soil available micronutrient was correlated to the type of parent material and its total amount in the forest floor, except for B. The F test identified that the correlation of each equation reached the significant level to different extents, respectively. The t test confirmed that amount of available forms was mainly depended on the type of parent material for Mo, Cu, Zn and Mn but on the forest floor for Fe. There was a feedback effect of forest stand on the amount of soil available micronutrients. The ability of accumulating available micronutrients in soil was better by the

  9. Remote sensing of aquatic vegetation distribution in Taihu Lake using an improved classification tree with modified thresholds.

    Science.gov (United States)

    Zhao, Dehua; Jiang, Hao; Yang, Tangwu; Cai, Ying; Xu, Delin; An, Shuqing

    2012-03-01

    Classification trees (CT) have been used successfully in the past to classify aquatic vegetation from spectral indices (SI) obtained from remotely-sensed images. However, applying CT models developed for certain image dates to other time periods within the same year or among different years can reduce the classification accuracy. In this study, we developed CT models with modified thresholds using extreme SI values (CT(m)) to improve the stability of the models when applying them to different time periods. A total of 903 ground-truth samples were obtained in September of 2009 and 2010 and classified as emergent, floating-leaf, or submerged vegetation or other cover types. Classification trees were developed for 2009 (Model-09) and 2010 (Model-10) using field samples and a combination of two images from winter and summer. Overall accuracies of these models were 92.8% and 94.9%, respectively, which confirmed the ability of CT analysis to map aquatic vegetation in Taihu Lake. However, Model-10 had only 58.9-71.6% classification accuracy and 31.1-58.3% agreement (i.e., pixels classified the same in the two maps) for aquatic vegetation when it was applied to image pairs from both a different time period in 2010 and a similar time period in 2009. We developed a method to estimate the effects of extrinsic (EF) and intrinsic (IF) factors on model uncertainty using Modis images. Results indicated that 71.1% of the instability in classification between time periods was due to EF, which might include changes in atmospheric conditions, sun-view angle and water quality. The remainder was due to IF, such as phenological and growth status differences between time periods. The modified version of Model-10 (i.e. CT(m)) performed better than traditional CT with different image dates. When applied to 2009 images, the CT(m) version of Model-10 had very similar thresholds and performance as Model-09, with overall accuracies of 92.8% and 90.5% for Model-09 and the CT(m) version of Model

  10. Study on Movement of Cyanobacteria Bloom with Special Wind-field Condition in Taihu Lake%特殊风场条件对太湖蓝藻水华迁移的影响研究

    Institute of Scientific and Technical Information of China (English)

    陈黎明; 王成林; 李褆来

    2012-01-01

    High temperature and gentle breeze would create special weather condition of cyanobacteria bloom. A divergence wind field was frequently found above the surface of the Taihu Lake under the weather condition. Driven by divergence wind field or single wind field, the movement of cyanobacteria bloom formed a different transfer path. After water flow field and water quality of the Taihu Lake were simulated under the divergence wind field, results showed that cyanobacteria would easily gather in western area of the Taihu Lake under the divergence wind field, particularly in shore of Zhushan lake and Meiliang bay. The research would help know space distribution and understand moving mechanism of pollutants and cyanobacteria bloom in the Taihu Lake.%在高温、微风气象条件下,适宜蓝藻水华形成.在特殊非均一风场的驱动下,太湖蓝藻水华迁移过程与被均匀风场驱动有所不同.选取太湖典型风向进行分析,并采用三维水动力水质模型对表面非均一风场条件下的风生流流场及水质进行模拟,结果表明,在特殊非均一风场的驱动下,当太湖蓝藻浓度较高时,容易在西部湖区特别在竺山湖、梅梁湾湾内、岸边及湾口聚集,形成水华暴发,这有助于研究太湖污染物及蓝藻水华的输移及空间分布和机理.

  11. Multi-angle Indicators System of Non-point Pollution Source Assessment in Rural Areas: A Case Study Near Taihu Lake

    Science.gov (United States)

    Huang, Lei; Ban, Jie; Han, Yu Ting; Yang, Jie; Bi, Jun

    2013-04-01

    This study aims to identify key environmental risk sources contributing to water eutrophication and to suggest certain risk management strategies for rural areas. The multi-angle indicators included in the risk source assessment system were non-point source pollution, deficient waste treatment, and public awareness of environmental risk, which combined psychometric paradigm methods, the contingent valuation method, and personal interviews to describe the environmental sensitivity of local residents. Total risk values of different villages near Taihu Lake were calculated in the case study, which resulted in a geographic risk map showing which village was the critical risk source of Taihu eutrophication. The increased application of phosphorus (P) and nitrogen (N), loss vulnerability of pollutant, and a lack of environmental risk awareness led to more serious non-point pollution, especially in rural China. Interesting results revealed by the quotient between the scores of objective risk sources and subjective risk sources showed what should be improved for each study village. More environmental investments, control of agricultural activities, and promotion of environmental education are critical considerations for rural environmental management. These findings are helpful for developing targeted and effective risk management strategies in rural areas.

  12. Technical Process in Advanced Treatment of Taihu Lake Source Water%太湖水源水深度处理直饮的技术工艺

    Institute of Scientific and Technical Information of China (English)

    胡孟春; 张永春; 唐晓燕; 沈海风; 王文林

    2013-01-01

    To address the problem of organic compound pollution in the Taihu Lake drinking water source, a combined process composed mainly of bio-filter and reverse osmosis membrane was developed. The process included pretreatment with BAF, the combined treatment system with ultrafiltration (UF) , micro-filtration (MF) and reverse osmosis (RO) membrane, and the product water system with ultraviolet sterilization. The design focused on key parts such as the pretreatment system with BAF, combined membranes treatment optimization, washing and backwashing system. The operation results showed that the combined process was suitable for advanced treatment of the organically polluted and eutrophicated source water of Taihu Lake. The product water met the standard for direct drinking quality.%针对太湖有机复合污染饮用水源的主要问题,设计了以生物过滤、反渗透膜为主的组合技术工艺,包括:曝气生物滤池前处理系统;超滤、微滤、反渗透膜组合处理系统;紫外消毒产品水出水系统.在设计中着重解决了关键部分的设计:生物滤池前处理系统;膜组合处理系统优化;清洗系统.设备运行结果表明,该工艺适合太湖有机污染富营养化水源水的深度净化处理,产品水可达到高品质直饮水水质标准.试验研究为太湖水源水的深度净化找到了一条可行的技术途径.

  13. A new tool for spatiotemporal pattern decomposition based on empirical mode decomposition: A case study of monthly mean precipitation in Taihu Lake Basin, China

    Science.gov (United States)

    Chenhua, Shen; Yani, Yan

    2017-02-01

    We present a new tool for spatiotemporal pattern decomposition and utilize this new tool to decompose spatiotemporal patterns of monthly mean precipitation from January 1957 to May 2015 in Taihu Lake Basin, China. Our goal is to show that this new tool can mine more hidden information than empirical orthogonal function (EOF). First, based on EOF and empirical mode decomposition (EMD), the time series which is an average over the study region is decomposed into a variety of intrinsic mode functions (IMFs) and a residue by means of EMD. Then, these IMFs are supposed to be explanatory variables and a time series of precipitation in every station is considered as a dependent variable. Next, a linear multivariate regression equation is derived and corresponding coefficients are estimated. These estimated coefficients are physically interpreted as spatial coefficients and their physical meaning is an orthogonal projection between IMF and a precipitation time series in every station. Spatial patterns are presented depending on spatial coefficients. The spatiotemporal patterns include temporal patterns and spatial patterns at various timescales. Temporal pattern is obtained by means of EMD. Based on this temporal pattern, spatial patterns at various timescales will be gotten. The proposed tool has been applied in decomposition of spatiotemporal pattern of monthly mean precipitation in Taihu Lake Basin, China. Since spatial patterns are associated with intrinsic frequency, the new and individual spatial patterns are detected and explained physically. Our analysis shows that this new tool is reliable and applicable for geophysical data in the presence of nonstationarity and long-range correlation and can handle nonstationary spatiotemporal series and has the capacity to extract more hidden time-frequency information on spatiotemporal patterns.

  14. Microbial profiles of a drinking water resource based on different 16S rRNA V regions during a heavy cyanobacterial bloom in Lake Taihu, China.

    Science.gov (United States)

    Zhang, Junyi; Zhu, Congming; Guan, Rui; Xiong, Zhipeng; Zhang, Wen; Shi, Junzhe; Sheng, Yi; Zhu, Bingchuan; Tu, Jing; Ge, Qinyu; Chen, Ting; Lu, Zuhong

    2017-05-01

    Understanding of the bacterial community structure in drinking water resources helps to enhance the security of municipal water supplies. In this study, bacterial communities were surveyed in water and sediment during a heavy cyanobacterial bloom in a drinking water resource of Lake Taihu, China. A total of 325,317 high-quality sequences were obtained from different 16S ribosomal RNA (rRNA) regions (V3, V4, and V6) using the Miseq sequencing platform. A notable difference was shown between the water and sediment samples, as predominated by Cyanobacteria, Proteobacteria, and Actinobacteria in the water and Proteobacteria, Chloroflexi, and Verrucomicrobia in the sediment, respectively. The LD12 family dominated the water surface and was tightly associated with related indicators of cyanobacterial propagation, indicating involvement in the massive proliferation of cyanobacterial blooms. Alternatively, the genus Nitrospira dominated the sediment samples, which indicates that nitrite oxidation was very active in the sediment. Although pathogenic bacteria were not detected in a large amount, some genera such as Mycobacterium, Acinetobacter, and Legionella were still identified but in very low abundance. In addition, the effects of different V regions on bacterial diversity survey were evaluated. Overall, V4 and V3 were proven to be more promising V regions for bacterial diversity survey in water and sediment samples during heavy water blooms in Lake Taihu, respectively. As longer, cheaper, and faster DNA sequencing technologies become more accessible, we expect that bacterial community structures based on 16S rRNA amplicons as an indicator could be used alongside with physical and chemical indicators, to conduct comprehensive assessments for drinking water resource management.

  15. Stocks and dynamics of particulate and dissolved organic matter in a large, shallow eutrophic lake (Taihu, China) with dense cyanobacterial blooms

    Science.gov (United States)

    Shi, Limei; Huang, Yaxin; Lu, Yaping; Chen, Feizhou; Zhang, Min; Yu, Yang; Kong, Fanxiang

    2017-08-01

    Cyanobacterial blooms occur in eutrophic lakes worldwide, and greatly impair these ecosystems. To explore influences of cyanobacterial blooms on dynamics of both particulate organic matter (POM) and dissolved organic matter (DOM), which are at the base of the food chain, an investigation was conducted from December 2014 to November 2015 that included various stages of the seasonal cyanobacterial blooms (dominated by Microcystis) in a large-shallow eutrophic Chinese lake (Taihu Lake). Data from eight sites of the lake are compiled into a representative seasonal cycle to assess general patterns of POM and DOM dynamics. Compared to December, 5-fold and 3.5-fold increases were observed in July for particulate organic carbon (POC, 3.05-15.37 mg/L) and dissolved organic carbon (DOC, 5.48-19.25 mg/L), respectively, with chlorophyll a (Chl a) concentrations varying from 8.2 to 97.7 μg/L. Approximately 40% to 76% of total organic carbon was partitioned into DOC. All C, N, and P in POM and DOC were significantly correlated with Chl a. POC:Chl a ratios were low, whereas proportions of the estimated phytoplankton-derived organic matter in total POM were high during bloom seasons. These results suggested that contributions of cyanobacterial blooms to POM and DOC varied seasonally. Seasonal average C:P ratios in POM and DOM varied from 79 to 187 and 299 to 2 175, respectively. Both peaked in July and then sharply decreased. Redundancy analysis revealed that Chl a explained most of the variations of C:N:P ratios in POM, whereas temperature was the most explanatory factor for DOM. These findings suggest that dense cyanobacterial blooms caused both C-rich POM and DOM, thereby providing clues for understanding their influence on ecosystems.

  16. Risk evaluation method of cyanobacteria bloom hazard in Taihu Lake%太湖蓝藻水华灾害风险分区评估方法研究

    Institute of Scientific and Technical Information of China (English)

    刘聚涛; 杨永生; 姜加虎; 高俊峰

    2011-01-01

    Based on the risk analysis of cynaobacteria bloom hazard in Taihu Lake, the index system for the cynaobacteria bloom risk evaluation was constructed. Combined with the concept of risk evaluation, the risk evaluation method was established. On the basis, the hazard risk, exposure risk, vulnerability risk, and comprehensive risk of the nine lake regions in Taihu Lake were evaluated taking 2008 as the base year. The largest risk regions were in northern part of Taihu Lake,especially the Gonghu Lake was the most serious as the water source area. The risk in Zhushan Lake, Meiliang Bay and western coastal was middle for the large hazard risk. In the other regions, the risk in Xuhu Lake, southern coastal and big Talhu Lake was light risk, and there were almost no cyanobacteria bloom outbreak risk for the light eutrophication and large vegetation cover in the southwest regions of Taihu Lake.%通过对太湖蓝藻水华灾害风险分析,构建太湖蓝藻水华风险评估指标体系,结台风险评估概念,建立太湖蓝藻水华灾害风险评估方法.在此基础上,以2008年为基准年,结合太湖9个分区,评估各湖区蓝藻水华灾害危险性、易损性、脆弱性和综合风险.结果表明,综合风险最大的区域集中在太湖的北部,尤其作为水源地的贡湖风险最大,为重度风险;竺山湖、梅粱湾和西部沿岸由于其危险性较大,而总体风险较大,为中度风险;其他湖区风险较小,胥湖、南部沿岸和大太湖为轻度风险;太湖的东南部湖区箭湖东茭咀和东太湖由于水体富营养化程度较低,植物覆盖率较高,蓝藻水华发生危险性较小,综合风险指数较小,为轻微风险.

  17. Factors Affecting Temporal and Spatial Variations of Microcystins in Gonghu Bay of Lake Taihu, with Potential Risk of Microcystin Contamination to Human Health

    Directory of Open Access Journals (Sweden)

    Qing Wang

    2010-01-01

    Full Text Available A field survey of the seasonal variation of microcystin (MC concentration was performed in Gonghu Bay (a total of 15 sampling sites of Lake Taihu from January to December 2008. Microcystis spp. biomass and intra-/extracellular MCs were significantly correlated with water temperature, suggesting the importance of temperature in cyanobacterial blooming in the lake. Higher MC concentration was found in summer and autumn, and peaks of Microcystis biomass and intra-/extracellular MC concentrations were all present in October. Spatially, risk of MCs was higher in littoral zones than in the pelagic area. There were significant correlations between N or P concentrations, and Microcystis biomass or MC content, suggesting that N and P levels affected MC production through influencing Microcystis biomass. Intra-/extracellular MCs and Microcystis biomass had negative exponential relationships with TN:TP, and the maximum values all occurred when TN:TP was <25. Multivariate analyses by pcca indicated that intra- and extracellular MC concentrations had better correlations with biological factors (such as Microcystis biomass and chl-a than physicochemical factors. The maximum concentration reached up to 17 µg/L MC-Lreq, considerably higher drinking water safety standard (1 µg/L recommended who. So it is necessary take measures reduce exposure risk of cyanobacterial toxins human beings.

  18. Seasonal, Spatial Distribution and Ecological Risk Assessment of Heavy Metals in Surface Sediments from a Watershed Area in Gonghu Bay in Taihu Lake, China

    Directory of Open Access Journals (Sweden)

    Peifang Wang

    2014-01-01

    Full Text Available Surface sediments from five stations within Gonghu Bay in Taihu Lake, China, were sampled for seasonal and spatial metal contamination analysis variations and ecological risks assessment from April 2009 to January 2010. The Contamination Factor (CF and geo-accumulation index (Igeo indicated that the sediments in Gonghu Bay ranged from unpolluted to moderately polluted, except for Cd. The one-way ANOVA analysis results showed that the Pb, Zn, Cr, and Cu concentrations were higher at station 3 (lake inlet and the Cr, Pb, and Zn concentrations were significantly higher in the spring. Additionally, using BCR¡¦s sequential extraction, the results showed that the fractionated metals Zn and Cd were observed as bioavailable fractions in the sediments, which could have potential moderate mobility in the water system. There was a significant increase in the bioavailable form during winter. The ratio of secondary and primary phrase (RSP decreased according to the order Zn > Cu > Ni > Pb > Cd > Cr. Finally, these results indicated that the sediments of Gonghu Bay were polluted by Cd, Zn, and Cu, which provides a scientific basis for effectively protecting sediments in watershed areas from long-term heavy metal accumulation.

  19. Water Environmental Capacity Analysis of Taihu Lake and Parameter Estimation Based on the Integration of the Inverse Method and Bayesian Modeling

    Directory of Open Access Journals (Sweden)

    Ranran Li

    2015-09-01

    Full Text Available An integrated approach using the inverse method and Bayesian approach, combined with a lake eutrophication water quality model, was developed for parameter estimation and water environmental capacity (WEC analysis. The model was used to support load reduction and effective water quality management in the Taihu Lake system in eastern China. Water quality was surveyed yearly from 1987 to 2010. Total nitrogen (TN and total phosphorus (TP were selected as water quality model variables. Decay rates of TN and TP were estimated using the proposed approach. WECs of TN and TP in 2011 were determined based on the estimated decay rates. Results showed that the historical loading was beyond the WEC, thus, reduction of nitrogen and phosphorus input is necessary to meet water quality goals. Then WEC and allowable discharge capacity (ADC in 2015 and 2020 were predicted. The reduction ratios of ADC during these years were also provided. All of these enable decision makers to assess the influence of each loading and visualize potential load reductions under different water quality goals, and then to formulate a reasonable water quality management strategy.

  20. Analysis of the influence of Taihu Lake and the urban heat islands on the local circulation in the Yangtze Delta

    Institute of Scientific and Technical Information of China (English)

    李维亮; 刘洪利; 周秀骥; 秦瑜

    2003-01-01

    A fine-mesh regional meteorological model that suits the Yangtze Delta region was developed. This model was used to simulate some micro weathers, such as the land and sea breezes, land and lake breezes and urban heat island effect, in the Yangtze Delta successfully. The model was also used to study the characteristics and the formation mechanism of surface shear line in the region. It is indicated that the interaction between the sea breeze and the lake breeze is the main factor for the formation and maintenance of the surface shear line.

  1. Heavy Metal Pollution History Inferred from East Taihu Lake Cores Sediment%东太湖钻孔揭示的重金属污染历史

    Institute of Scientific and Technical Information of China (English)

    姚书春; 薛滨

    2012-01-01

    Taihu Lake is the third largest freshwater lake in China.East Taihu Lake with an area of 131 km2 and water depth of 0.9 m,dominated by macrophyte,is important drinking water source of Suzhou and Shanghai City.Sedimentary cores named DJZ and DQG were collected from East Taihu Lake in 2009 using gravity corer.The length of DJZ and DQG is 59 and 33 cm,respectively.Radio nuclides including 210Pb and 137Cs were also analyzed for dating the sediments at both cores.Sediment accumulation rate(SAR) of DQG was averaged to be 0.15 g/cm2/a based on 1963 dating marker of 137Cs.At DJZ core,SAR was higher relative to DQG core showing variation between 1.0~2.0 g/cm2/a.Elements including copper,lead,zinc,chromium,nickel,ferrum and others were analyzed for the purpose of understanding metal accumulation and human impact at East Taihu Lake combined with dating results.Between bottom to 30 cm,Cu,Pb,Zn,Cr and Ni in DJZ core showed increase trend.In the upper 30 cm sediments of DJZ core,the profiles of Pb,Cr and Ni showed relatively constant value while Cu and Zn demonstated upward increase in these sections.The average contents of Cu,Pb,Zn,Cr and Ni in DQG core were 22.34,50.83,98.35,66.19,26.74 mg/kg respectively for sediments between 0 and 9 cm,while 13.18,26.25,46.33,58.95,20.45 mg/kg for 9~33 cm sediments.In this paper Fe element as a proxy of grain size was selected for normalization and calculation of metal enrichment factor(EF) and anthropogenic heavy metal fluxes.The results showed that,except the cores surface sediment,Pb,Zn,Cu,Cr and Ni enrichment factors did not exceed 2,and EF of Cr and Ni was nearly 1.It was revealed that the heavy metals including lead,copper,zinc were continuously enriched in recent decades,especially since the 1970s at East Taihu Lake.From 1970s to 1990s anthropogenic fluxes of Pb,Zn,Cu changed slightly,and then increased corresponding to development of industry in catchment.Since early 2000s,the total and anthropogenic Pb fluxes declined

  2. 太湖地区水稻地方品种品质性状多样性研究进展%Research Progresses on Diversity of Quality Traits of Landrace Rice in Taihu Lake Region

    Institute of Scientific and Technical Information of China (English)

    敖雁; 吴启; 薛萍; 朱志强; 陆豪杰

    2016-01-01

    太湖地区种稻历史悠久,积累了丰富的水稻地方品种资源,水稻地方品种的遗传多样性研究可为优质资源的保护利用以及选育新品种提供一些参考。本文从遗传多样性的概念、研究方法、太湖地区水稻地方品种品质性状多样性研究进展等方面进行了综述,总结了太湖流域水稻地方品种资源的相关利用价值。%It has a long history of rice cultivating in Taihu lake region, with abounds landrace rice resources. The research on genetic di-versity of landrace rice resources can provide some reference for the protection and utilization of high-quality germplasm resources and breeding of new variety. In this study, the author reviewed the concepts of genetic diversity, research methods, genetic diversity of quality traits of landrace rice in Taihu lake region and summarized the relevant utilization value of the landrace rice from Taihu lake region.

  3. Climatic and human impacts on quasi-periodic and abrupt changes of sedimentation rate at multiple time scales in Lake Taihu, China

    Science.gov (United States)

    Liu, Huiyu; Xu, Xiaojuan; Lin, Zhenshan; Zhang, Mingyang; Mi, Ying; Huang, Changchun; Yang, Hao

    2016-12-01

    With the ensemble Empirical Mode Decomposition Method (EEMD) and the non-parametric Mann-Kendall Test, the quasi-periodic and abrupt changes of sedimentation rate at multiple time scales, and their relations to climate changes and human activities from 1951 to 2010 in Meiliang Bay of Lake Taihu (China) were studied. The results showed the following. (1) The change in sedimentation rate can be completely decomposed into three quasi-periodic changes on 3.7, 6.4, and 24-yr time scales, and a long-term trend. (2) The quasi-periodic changes in sedimentation rate are significantly and positively related to changes in annual average temperature at 6.4 and 24-yr time scales and human activities at 3.7-yr time scales, and not significantly related to precipitation at these time scales. The trend of sedimentation rate has a negative relation with temperature, but positive relations with precipitation and human activities. As a whole, the total variance contribution of climate changes to the quasi-periodic changes of sedimentation rate is close to that of human activities; (3) Temperature and precipitation are possibly related to the abrupt change of sedimentation rate as a whole. Floods have significant impacts on abrupt changes in the sedimentation rate at 3.7, 6.4 and 24-yr time scales. Moreover, some abrupt changes of sedimentation rate at 3.7- and 6.4-yr time scales are partly related to the changes of precipitation at 3.1-yr time scale and temperature at 5-yr time scale. The results of this study will help identify the impacts of climate change and human activities on lake sedimentation at different time scales, and will be available for use as a guide for reasonable development and effective protection of lake resources.

  4. Evaluation of the AnnAGNPS Model for Predicting Runoff and Nutrient Export in a Typical Small Watershed in the Hilly Region of Taihu Lake

    Directory of Open Access Journals (Sweden)

    Chuan Luo

    2015-09-01

    Full Text Available The application of hydrological and water quality models is an efficient approach to better understand the processes of environmental deterioration. This study evaluated the ability of the Annualized Agricultural Non-Point Source (AnnAGNPS model to predict runoff, total nitrogen (TN and total phosphorus (TP loading in a typical small watershed of a hilly region near Taihu Lake, China. Runoff was calibrated and validated at both an annual and monthly scale, and parameter sensitivity analysis was performed for TN and TP before the two water quality components were calibrated. The results showed that the model satisfactorily simulated runoff at annual and monthly scales, both during calibration and validation processes. Additionally, results of parameter sensitivity analysis showed that the parameters Fertilizer rate, Fertilizer organic, Canopy cover and Fertilizer inorganic were more sensitive to TN output. In terms of TP, the parameters Residue mass ratio, Fertilizer rate, Fertilizer inorganic and Canopy cover were the most sensitive. Based on these sensitive parameters, calibration was performed. TN loading produced satisfactory results for both the calibration and validation processes, whereas the performance of TP loading was slightly poor. The simulation results showed that AnnAGNPS has the potential to be used as a valuable tool for the planning and management of watersheds.

  5. Remote estimation of chlorophyll-a concentration in turbid water using a spectral index: a case study in Taihu Lake, China

    Science.gov (United States)

    Cheng, Chunmei; Wei, Yuchun; Lv, Guonian; Yuan, Zhaojie

    2013-01-01

    Chlorophyll-a concentration (Chla) is a key indicator of water quality, and accurate estimates of Chla using remote sensing data remain challenging in turbid waters. Previous research has demonstrated the feasibility of retrieving Chla in vegetation using spectral index, which may be the potential reference for Chla inversion in turbid waters. In this study, 106 hyperspectral indices, including vegetation, fluorescence, and trilateral indices, as well as combinations thereof, are calculated based on the in situ spectra data of 2004 to 2011 in Taihu Lake, China, to explore their potential use in turbid waters. The results show that the normal chlorophyll index (NCI) (R690/R550-R675/R700)/(R690/R550+R675/R700) is optimal for Chla estimation, with a determination coefficient (R) of 0.92 and a root mean square error (RMSE) of 14.36 mg/m3 for the data from July to August 2004, when Chla ranged from 7 to 192 mg/m3. Validation using the datasets of 2005, 2010, and 2011 shows that after reparameterization, the NCI model yields low RMSEs and is more robust than the three- and four-band algorithms. The results indicate that the NCI model can satisfactorily estimate Chla in multiple datasets without the need of additional band tuning.

  6. Investigation and Analysis on Technical Modes of Rural Domestic Sewage Treatment in Taihu Lake Basin:Taking Jiangsu Province as an Example

    Directory of Open Access Journals (Sweden)

    ZHANG Ya-ping

    2017-08-01

    Full Text Available According to the wide investigation on the current rural domestic wastewater treatment in the Taihu Lake basin, four typical treatment technologies, including DSP-SH(Anaerobic-Anoxic-Oxic,A2/O, HyWat compound bio-filter, membrane bio-reactor(MBR and sequencing batch reactor activated sludge(SBR, were selected and had been monitored for eight months. The results showed that the wastewater treatment effect of HyWat compound bio-filter could meet the emission standard while DSP-SH(A2/O, SBR and MBR had poor removal efficiency of nitrogen and phosphorus, which needed to add medicine to improve the removal rate. The operation and management of DSP-SH(A2/O and HyWat compound bio-filter were more convenient. MBR process was suitable for the economically developed areas or the areas with high water-quality demand, because it had a good treatment effect with high running cost. SBR process was easy to operate flexibly and affordably, which was suitable for the densely populated areas with topography or land area restrictions. Our research concluded that choosing sewage technology should consider the local conditions combined with stable and effective capital investment and management and maintenance mechanisms to guarantee the rural sewage treatment effect.

  7. Dynamics of soil available phosphorus and its impact factors under simulated climate change in typical farmland of Taihu Lake region, China.

    Science.gov (United States)

    Yu, Kaihao; Chen, Xiaomin; Pan, Genxing; Zhang, Xuhui; Chen, Can

    2016-02-01

    Global climate change affects the availability of soil nutrients, thereby influencing crop productivity. This research was conducted to investigate the effects of elevated CO2, elevated temperature, and the interaction of the elevated CO2 and temperature on the soil available phosphorus (P) of a paddy-wheat rotation in the Taihu Lake region, China. Winter wheat (Triticum aestivum L.) was cultivated during the study period from 2011 to 2014 at two CO2 levels (350 μL•L(-1) ambient and 500 μL•L(-1) elevated by 150 μL•L(-1)) and two temperatures (ambient and 2 °C above the ambient). Soil available P content increased at the first season and decreased at the last season during the three wheat growing seasons. Soil available P content showed seasonal variation, whereas dynamic changes were not significant within each growing season. Soil available P content had no obvious trends under different treatments. But for the elevated temperature, CO2, and their combination treatments, soil available P content decreased in a long time period. During the period of wheat ripening stage, significant positive correlations were found between soil available P content and saturated hydraulic conductivity (Ks) and organic matter, but significant negative correlations with soil clay content and pH value; the correlation coefficients were 0.9400 (p climate change scenario.

  8. Atmospheric Wet Deposition Characteristics of Nitrogen and Phosphorus Nutrients in Taihu Lake and Contributions to the Lake%太湖氮磷营养盐大气湿沉降特征及入湖贡献率

    Institute of Scientific and Technical Information of China (English)

    余辉; 张璐璐; 燕姝雯; 李焕利; 徐军

    2011-01-01

    To understand seasonal and spatial wet deposition characteristics of nutrients in Taihu Lake during precipitation, more than 230 precipitation samples were collected at ten monitoring sites from August 2009 to July 2010 in different regions around the Taihu Lake basin. Mass concentrations of total nitrogen (TN), dissolved total nitrogen (DTN), nitrate nitrogen (NO3--N), ammonia nitrogen (NH4+-N), total phosphorus (TP), dissolved total phosphorus (DTP) and dissolved inorganic phosphorus (DIP) in the precipitation samples were measured. The precipitation characteristics of nitrogen and phosphorus nutrients in atmospheric wet deposition, the deposition rates and their contributions compared with their counterparts from external loading of rivers to the lake were studied. The results indicated that the annual average mass concentration of TN in the wet deposition was 3. 16 mg/L, in which that of DTN accounted for more than 70% of TN, with a major form of NH4+ -N. The maximum values of TN appeared in the southern lake district, and the minimum in the north. The TP deposition mass concentrations were relatively lower,with an annual average value of 0.08 mg/L. Seasonally, mass concentrations of different forms of nitrogen in wet deposition in the five regions were high in winter and low in summer, although the wet deposition of different forms of nitrogen and phosphorus were all highest in summer. Spatially, the deposition rates of TN were relatively higher in the southern and eastern lake regions. The deposition rates of NH4 + -N and NO3- -N accounted for approximately 30.4% -52. 0% and 31.6%of DTN, respectively, while the deposition rate proportion of DTP to TP varied greatly among these monitoring sites. The annualsettlements of TN and TP in the precipitation were 10,868 and 247 t, respectively, accounting for 18.6% and 11.9% of theannual loading of rivers into Taihu Lake. These settlements could promote eutrophication and have strong impacts on the lakeecosystem.%2009

  9. Lake Cadagno

    DEFF Research Database (Denmark)

    Tonolla, Mauro; Storelli, Nicola; Danza, Francesco

    2017-01-01

    Lake Cadagno (26 ha) is a crenogenic meromictic lake located in the Swiss Alps at 1921 m asl with a maximum depth of 21 m. The presence of crystalline rocks and a dolomite vein rich in gypsum in the catchment area makes the lake a typical “sulphuretum ” dominated by coupled carbon and sulphur cyc...

  10. 太湖鱼类群落结构及多样性%Community structure and diversity of fish in Lake Taihu

    Institute of Scientific and Technical Information of China (English)

    毛志刚; 谷孝鸿; 曾庆飞; 周露洪; 王小林; 吴林坤; 曹萍; 孙明波

    2011-01-01

    In 2009-2010, bottom trawl surveys were conducted on the fish resources in Lake Taihu, aimed to understand the characteristics of fish community structure and diversity in the Lake. A total of 50 fish species were collected, belonging to 40 genera, 15 families, and 10 orders, among which, Cypriniformes had the largest species number, accounting for 68% of the total. The fish community was composed of three ecological guilds, and limnology species were most abundant (78% of the total abundance). The dominant species were of mini-type fish such as Coilia ectenes taihuensis, Hyporhamphus intermedius, and Salangichthys jordani. As compared with historical data, the fish species number in the Lake decreased, the composition of dominant species changed greater, and the mini-type fishes with body mass <30 g were absolutely dominant , with an obvious tendency of fish resources becoming smaller-scale. Due to overfishing and water pollution, the Margalef richness index D, Shannon diversity indices H'N and H'N, and Pielou evenness indices J'N and J'w in the Lake all decreased, being 1.54, 0.21, 0.46, 0.07, and 0. 14, respectively. To some extent, the differences in the fish species composition and biodiversity reflected the adaption characteristics of the fishes to the environmental variables such as nutrients and transparency in the Lake.%为了解太湖鱼类群落结构和多样性的分布特征,于2009-2010年利用拖网等网具对该水域的鱼类资源进行了调查.结果表明:本次调查共采获鱼类50种,隶属10目15科40属,其中鲤形目种类最多,占总数的68%;鱼类生态类型以湖泊定居性种类为主,群落优势种为湖鲚(Coilia ectenes taihuensis)、间下鱵(Hyporhamphus intermedius)和陈氏短吻银鱼(Salangichthys jordani)等小型鱼类;与历史资料相比,太湖鱼类的物种数量下降,优势种组成发生较大变化,鱼类群落中体质量<30 g的小型鱼类占绝对优势,渔业资源小型化趋势明显.由

  11. LIMNOLOGY, LAKE BASINS, LAKE WATERS

    Directory of Open Access Journals (Sweden)

    Petre GÂŞTESCU

    2009-06-01

    Full Text Available Limnology is a border discipline between geography, hydrology and biology, and is also closely connected with other sciences, from it borrows research methods. Physical limnology (the geography of lakes, studies lake biotopes, and biological limnology (the biology of lakes, studies lake biocoenoses. The father of limnology is the Swiss scientist F.A. Forel, the author of a three-volume entitled Le Leman: monographie limnologique (1892-1904, which focuses on the geology physics, chemistry and biology of lakes. He was also author of the first textbook of limnology, Handbuch der Seenkunde: allgemeine Limnologie,(1901. Since both the lake biotope and its biohydrocoenosis make up a single whole, the lake and lakes, respectively, represent the most typical systems in nature. They could be called limnosystems (lacustrine ecosystems, a microcosm in itself, as the American biologist St.A. Forbes put it (1887.

  12. 预氧化去除太湖水中有机物和臭味物质的研究%Study on the pre-oxidation of organics and odor in Taihu Lake

    Institute of Scientific and Technical Information of China (English)

    董秉直; 姚迎迎; 杜嘉丹

    2016-01-01

    研究臭氧、高锰酸钾和次氯酸钠去除太湖水有机物和臭味物质的去除效果。试验结果表明,臭氧易于降解大分子有机物,而高锰酸钾和次氯酸钠易于降解小分子有机物。氧化降解β-环柠檬醛(β-Cyclocitral)的效果最佳,其次为β-紫罗兰酮(β-Ionone),土臭素(geosmin,GSM)和二甲基异冰片(2-methylisoborneol,2-MIB)的降解效果最差。太湖水的臭味降解规律与其相似。研究还表明,太湖水的有机物会促进次氯酸钠降解臭味物质。%The effect of ozone potassium permanganate and sodium hypochlorite on removing or-ganics and taste and odor compounds in Taihu Lake was investigated.The experimental results showed that ozone would tend to remove organics with higher molecular weight.However,potassi-um permanganate and sodium hypochlorite would tend to remove organics with lower molecular weight.It was found that the effect of oxidation of β-Cyclocitral was best,followed by β-Ionone and GSM and 2-MIB was least.Oxidation of taste and odor compounds in Taihu Lake showed the same trendency.It was also found that organics in Taihu Lake could promote destruction of taste and odor compounds by sodium hypochlorite.

  13. Analysis of wind field features causing cyanobacteria bloom in Taihu Lake combined with remote sensing methods%结合卫星遥感技术的太湖蓝藻水华形成风场特征

    Institute of Scientific and Technical Information of China (English)

    李亚春; 谢小萍; 杭鑫; 朱小莉; 黄珊; 景元书

    2016-01-01

    On the basis of the meteorological observation data and remote sensing data over the Taihu Lake and its surrounding areas during 2003 to 2013, combined with the WRF3.5.1 simulations, the relationships between the cyanobacteria blooms in Taihu Lake and surface wind speeds were analyzed. The results show that cyanobacteria blooms mainly occurred in the period of the weak wind speed about 0.5~3.4m/s, about six hours earlier than the MODIS satellite overpass time in Taihu Lake, which accounts for 94.7% of all cyanobacteria blooms events. As the area of cyanobacteria blooms decreasing with the wind speed strengthening, a large bloom of cyanobacteria bloom mainly occurred 6 hours ahead with the average wind speed less than 2m/s, accounting for 89%. In addition, the wind direction mainly affects the spatial patterns of cyanobacteria blooms in Taihu Lake. All these results suggest that the wind patterns play an important role on the formation, drifting and distribution of cyanobacteria blooms.%为进一步了解太湖蓝藻水华形成和分布与近地面风场的关系,利用太湖湖面及周边地区2003~2013年气象与卫星观测数据分析、并应用WRF3.5.1数值模型模拟,发现太湖蓝藻水华主要出现在卫星观测时刻前6h平均风速为0.5~3.4m/s的区间,占比达94.7%;蓝藻水华面积总体上随风速增大而减小,大范围蓝藻水华主要出现在前6h平均风速≤2m/s的情形下,占比达89%;风向则主要影响蓝藻水华在太湖的空间分布格局.结果表明局地风场对于太湖蓝藻水华的形成、输移和分布具有重要作用.

  14. Vertical and temporal distribution of nitrogen and phosphorus and relationship with their influencing factors in aquatic-terrestrial ecotone: a case study in Taihu Lake, China

    Institute of Scientific and Technical Information of China (English)

    YANG Hong-jun; SHEN Zhe-min; ZHU Song-he; WANG Wen-hua

    2007-01-01

    Vertical and temporal distributions of N and P in soil solution in aquatic-terrestrial ecotone (ATE) of Taihu Lake were investigated, and the relations among N, P, ORP, TOC, root system biomass and microorganism were studied. As a whole, significant declines in TN, NO3-N, DON and TP concentration in soil solution have occurred with increase of the depth, and reached their minima at 60 cm depth, except for NH4+-N, which increased with depth. the concentration of TP increased gradually from spring to winter in the topsoil, the maximum 0.08 mg/L presented in the winter while the minimum 0.03 mg/L in spring. In the deeper layer, the concentration value of TP fluctuated little. As for the NO3-N, its seasonal variation is significant at 20 cm depth, its concentration increased gradually from spring to autumn, and decreased markedly in winter. Vertical and temporal distribution of DON is contrary to that of NO3-N. The results also show that the variation of N and P in the percolate between adjacent layers is obviously different. The vertical variation of TN, TP, NO3-N, NH4+-N and DON is significant, of which the variation coefficient of NO3-N along the depth reaches 100.23%, the highest; while the variation coefficient of DON is 41.14%, the smallest. The results of correlation analysis show that the concentration of nitrogen and phosphorus correlate significantly with TOC, ORP, root biomass and counts of nitrifying bacteria. Most nutrients altered much from 20 to 40 cm along the depth. However, DON changed the more between 60 and 80 cm. Results show that soil of 0-60 cm depth is active rhizoplane, with strong capability to remove the nitrogen and phosphorus in ATE. It may suggest that there exists the optimum ecological efficiency in the depth of above 60cm in reed wetland. This will be very significant for ecological restoration and reestablishment.

  15. Measuring the past 20 years of urban-rural land growth in flood-prone areas in the developed Taihu Lake watershed, China

    Science.gov (United States)

    Su, Weizhong

    2017-03-01

    There is growing interest in using the urban landscape for stormwater management studies, where land patterns and processes can be important controls for the sustainability of urban development and planning. This paper proposes an original index of Major Hazard Oriented Level (MHOL) and investigates the structure distribution, driving factors, and controlling suggestions of urban-rural land growth in flood-prone areas in the Taihu Lake watershed, China. The MHOL of incremental urban-rural land increased from M 31.51 during the years 1985-1995 to M 38.37 during the years 1995-2010 (M for medium structure distribution, and the number for high-hazard value). The index shows that urban-rural land was distributed uniformly in flood hazard levels and tended to move rapidly to high-hazard areas, where 72.68% of incremental urban-rural land was aggregated maximally in new urban districts along the Huning traffic line and the Yangtze River. Thus, the current accelerating growth of new urban districts could account for the ampliative exposure to high-hazard areas. New districts are driven by the powerful link between land financial benefits and political achievements for local governments and the past unsustainable process of "single objective" oriented planning. The correlation categorical analysis of the current development intensity and carrying capacity of hydrological ecosystems for sub-basins was used to determine four types of development areas and provide decision makers with indications on the future watershed-scale subdivision of Major Function Oriented Zoning implemented by the Chinese government.

  16. Retrieval of chlorophyll a and suspended solid concentrations by hyperspectral remote sensing in Taihu Lake,China

    Institute of Scientific and Technical Information of China (English)

    YANG Dingtian; PAN Delu; ZHANG Xiaoyu; ZHANG Xiaofeng; HE Xianqiang; LI Shujing

    2006-01-01

    Chlorophyll a (chl-a) and suspended solid concentrations are two frequently used water quality parameters for monitoring a lake. Traditional measurement of chl-a and suspended solids, requiring laborious laboratory work, which is often expensive and time consuming. Hyperspectral remote-sensing measurement provides a fast and easy tool for estimating water trophic status. In situ hyperspectral data on March 7-8, July 6-7, September 20 and December 7-8, 2004 and the corresponding water chemical data were used to regress the algorithm of water quality parameters. Results showed that the peak of water leaving radiance around 700 nm (R700) varied proportionally with chl-a concentration,and moved to infrared when algal bloom occurred. The reflectance ratio of R702/R685 was well correlated with chl-a when water surface in no algal bloom case and the correlation coefficient was better if absorption of phycocyanin was considered. The reflectance ratio R620/R531 was highly correlated to the concentration of suspended solids. The relationship between suspended solids and other band groups were also compared. Secchi disk depth could be calculated by non-linear correlation with suspended solids concentration.

  17. Nitrate removal under different ecological remediation measures in Taihu Lake: a 15N mass-balance approach.

    Science.gov (United States)

    Liu, Dandan; Li, Zhengkui; Zhang, Wanguang

    2014-12-01

    Ecological remediation is an important measure for the protection of lake water quality in removing nutrients, such as nitrate (NO3 (-)). In this study, four bioremediation processes (bare sediment, immobilized nitrogen cycling bacteria (INCB) added, Elodea nuttallii added, E. nuttallii-INCB assemblage) were operated at a lab to elucidate the effect of macrophyte appearance and INCB addition on NO3 (-) removal and achieve the optimal processes for biomediation. (15) N-NO3 solution was added to microcosms to identify the key nitrogen transformation processes responsible for NO3 (-) removal. Results showed that nitrate removal was significantly enhanced after the addition of INCB and E. nuttallii. In the treatments with INCB added, E. nuttallii added, and INCB and E. nuttallii-INCB assemblage, nitrate removal ratio achieved 94.74, 98.76, and 99.15 %, respectively. In contrast, only 23.47 % added nitrate was removed in the control. Plant uptake and denitrification played an important role in nitrogen removal. The water quality was substantially improved by the addition of INCB and macrophyte that can accelerate denitrification and promote nitrogen assimilation of plants. The results indicated that plant uptake and microbial denitrification were key processes for nitrate removal.

  18. NCAR湖泊子模型对东太湖湖-气交换的离线模拟及评估%Evaluation and Offline Simulation for Lake-air Exchange of the East Taihu Lake Based on the NCAR Lake Sub-model

    Institute of Scientific and Technical Information of China (English)

    刘寿东; 梁宇飞; 朴美花; 王咏薇; 齐德莉

    2015-01-01

    Accurate lake-air land surface process is important for simulation and prediction of weather and cli-mate. Seasonal changes of water plant characteristics in the east Taihu Lake were analyzed to adjust the extinction coefficient, eddy diffusion coefficient and roughness length in the NCAR lake sub-model;the observed data of east Lake Taihu BFG No. 1 platform on January, April, July, October of 2012 was used to drive offline lake model and evaluate the NCAR lake sub-model on sensible heat flux, latent heat flux, lake surface temperature and friction ve-locity in different seasons. The results show that, the simulation results using turned parameters have been im-proved in four seasons, especially, the root mean square error ( RMSE) of simulated and observed sensible heat flux reduces from 12. 37 W·m-2 to 9. 7 W·m-2 , the RMSE of latent heat flux reduces from 50. 19 W·m-2 to 31. 48 W·m-2 , the RMSE of lake surface temperature decreases from 1. 03 ℃ to 0. 62 ℃, and the RMSE of fric-tion velocity decreases from 0. 23 m·s-1 to 0. 10 m·s-1.%准确的湖泊-大气陆面过程方案对天气气候的模拟和预测十分重要。通过对内陆浅水湖泊太湖东部不同季节水生植物特征进行分析,调整了NCAR湖泊子模型的消光系数、湍流扩散系数及粗糙度等参数;利用东太湖避风港1号观测平台2012年1、4、7、10月的观测数据驱动离线湖模式,评估了NCAR湖泊子模型对不同季节感热通量、潜热通量、湖表温度及摩擦速度的模拟性能。结果表明,参数调整后的NCAR湖泊子模型的模拟结果在4个季节都有了不同程度的改善,其中感热通量模拟值与观测值的均方根误差由12.37 W·m-2减小到9.7 W·m-2,潜热通量由50.19 W·m-2减小到31.48 W·m-2,湖表温度由1.03℃减小到0.62℃,摩擦速度由0.23 m·s-1到0.10 m·s-1。

  19. 中华鳖太湖种群淋巴细胞培养及染色体核型分析%The Lymphocytic Cell Culture and Chromosome Karyotype of Trionyx sinensis in Taihu Lake Population

    Institute of Scientific and Technical Information of China (English)

    熊良伟; 王建国; 封琦; 黄爱军

    2013-01-01

    In order to provide the logical proofs for germplasm research and chromosomal manipulation of Trionyx sinensis. The karyotypes of the chromosomes of Trionyx sinensis in Taihu Lake were examined by lymphocytic cell cultivation-air drying-Giemsa staining method. The results showed that the chromosome karyotype of T. Sinensis in Taihu Lake population could be obtained through the lymphocytic cell cultivation method. There were 33 pairs chromosome including 6 pairs of large chromosome and 27 pairs of smaller chromosome.%为给中华鳖种质研究和染色体操作提供理论依据.以中华鳖太湖种群为材料,采用淋巴细胞培养、空气干燥法制片、Giemsa染色,对中华鳖染色体核型进行了分析.结果表明:通过淋巴细胞培养法可以得到良好的染色体制片;中华鳖太湖种群具有33对染色体,其中6对是大型染色体,27对是小型染色体.

  20. The Application of Ann to Prediction of Winter Wheat Scab in Area of Taihu Lake%人工神经网络方法在赤霉病预报中的应用研究

    Institute of Scientific and Technical Information of China (English)

    高苹; 居为民; 陈宁; 金龙

    2001-01-01

    通过统计分析,选取与江苏省太湖地区小麦赤霉病发生程度显著相关的前期海温作为预报因子,并结合对小麦赤霉病病穗率序列进行拓展,采用人工神经网络的BP网络模型进行预报赤霉病的初步试验,取得了满意的效果。%Based on the data of SST and winter wheat scab in Taihu-lake of Jiangsu Province from 1951 to 1998, the statistical analyses about the influence of abnormality of SST in pacific round equator on occurrence of winter wheat scab in Taihu-lake area were carried out. It was found that situation of wheat scab would often be heavier in the next year when ENSO begin or last. Finally, a mixed long-term prediction model of wheat scab was developed with the method of ANN (artificial neural network).

  1. Water pollution control technology and strategy for river-lake systems: a case study in Gehu Lake and Taige Canal.

    Science.gov (United States)

    Zhang, Yimin; Zhang, Yongchun; Gao, Yuexiang; Zhang, Houhu; Cao, Jianying; Cai, Jinbang; Kong, Xiangji

    2011-07-01

    The Taoge water system is located in the upstream of Taihu Lake basin and is characterized by its multi-connected rivers and lakes. In this paper, current analyses of hydrology, hydrodynamics and water pollution of Gehu Lake and Taige Canal are presented. Several technologies are proposed for pollution prevention and control, and water environmental protection in the Taihu Lake basin. These included water pollution control integration technology for the water systems of Gehu Lake, Taige Canal and Caoqiao River. Additionally, river-lake water quality and quantity regulation technology, ecological restoration technology for polluted and degraded water bodies, and water environmental integration management and optimization strategies were also examined. The main objectives of these strategies are to: (a) improve environmental quality of relative water bodies, prevent pollutants from entering Gehu Lake and Taige Canal, and ensure that the clean water after the pre-treatment through Gehu Lake is not polluted before entering the Taihu Lake through Taige Canal; (b) stably and efficiently intercept and decrease the pollution load entering the lake through enhancing the river outlet ecological system structure function and water self-purifying capacity, and (c) designate Gehu Lake as a regulation system for water quality and water quantity in the Taoge water system and thus guarantee the improvement of the water quality of the inflow into Taihu Lake.

  2. 江苏省太湖应急防控形势及对策体系研究%Situation and Solution System for Prevention and Control of Emergency in Taihu Lake

    Institute of Scientific and Technical Information of China (English)

    张利民; 钱江; 汪琦

    2011-01-01

    Situation of recent 3 years were studied including water quality in Taihu Lake, cyanophyta outbreak, generating process of lake-flooding, influencing factors of cyanophyta outbreak, causes of lake-flooding,cyanophyta growth on Lake water quality, cyanophyta and lake-flooding on safety of drinking water. Deferent departments from environment protection, construction, water conservancy as well as nanjing institute of geography and limnology, Chinese Academy of Sciences gave full play to cooperation, rapid response, consultation and response procedures in monitoring and warning, water supply safeguard, water transfer and conduction, catching eyanophyta, ecological desilting, polluting source control and stop pollution, artificial increasing precipitation. It made suggestion for improving management system of algae catch and processing, long term planning of ecological desilting and measurement, normalization of cyanophyta outbreak prevention and control, establishing Lake Taihu emergency command system to achieve target of rapidly transmitting information, accurate analysis, scientific decision and precise deployment.%对2008年-2010年来太湖水质状况、蓝藻暴发状况及影响因素、湖泛发生状况及成因、蓝藻生长对湖体水质的影响、蓝藻与湖泛对饮用水安全影响进行了研究.简述了环保、建设、水利、气象、中科院南京地理与湖泊研究所等部门和单位,在监测预警、供水保障、调水引流、打捞蓝藻、生态清淤、控源截污、人工增雨、统筹协调等方面团结协作、多措并举、快速应对,建立了会商机制和响应程序,充分发挥整体效能.提出,应创新蓝藻打捞与处理的管理体制;完善生态清淤长期计划与管理措施;应急防控工作常态化;建立太湖应急指挥系统,实现快速传递、准确分析、科学决策、精确部署的目标.

  3. Long-Term Effects of Inorganic and Organic Amendments on Organic Carbon in a Paddy Soil of the Taihu Lake Region, China

    Institute of Scientific and Technical Information of China (English)

    MA Li; YANG Lin-Zhang; XIA Li-Zhong; SHEN Ming-Xing; YIN Shi-Xue; LI Yun-Dong

    2011-01-01

    A long-term experiment set up in 1980 compared the effects of applying manures and chemical fertilizers on a paddy soil in the Taihu Lake region, China. Of the fourteen randomly distributed treatments consisting of different combinations of organic manure, inorganic nitrogen (N), phosphorus (P), and potassium (K), and rice straw, eight were selected for the present study in 2007. Application of organic manure plus straw significantly increased soil organic carbon (SOC) content of the topsoil (0-10 cm) compared to that of chemical fertilizers alone. The content of SOC was relatively stable in the 10-30 cm layer in the chemical fertilizer treatments and in the 20-40 cm layer in the manure treatments. The stable carbon isotope ratio (δ13C) ranged from -24‰ to -28‰ and increased gradually with depth. The content of SOC was significantly (P < 0.05) negatively correlated with δ13C. In the 0-20 cm layer, the δ13C value significantly decreased in the treatments of manure alone (M), manure and chemical N and P fertilizers (MNP), manure and chemical N, P, and K fertilizers (MNPK), manure, rice straw, and chemical N fertilizer (MRN), and chemical N fertilizer and rice straw (CNR), as compared with the no-fertilizer control. In the 30-50 cm layer, however, the ratio significantly increased in all the treatments except Treatment CNR. Mineralization of organic C peaked in the first 2-4 d of incubation and gradually leveled off thereafter over the first 3 weeks, being faster in the manure treatments than the chemical fertilizer treatments. The average rate of mineralization varied from 55.36 to 75.46 mL CO2 kg-1 d-1 and that of stable mineralization from 10 to 20 mL CO2 kg-1 d-1. In eight weeks of incubation, cumulative mineralization was always higher in the manure treatments than the chemical fertilizer treatments, being the highest in Treatment MRN. Combined humus in the soil was mainly (over 50%) composed of tightly combined fraction. The loosely combined humus and

  4. 太湖鱼类放流增殖的有效数量和合理结构%Fish stocking quantities and structures of the fishery resources enhancement in Lake Taihu

    Institute of Scientific and Technical Information of China (English)

    何俊; 谷孝鸿; 王小林; 吴林坤; 陈非洲; 曹萍; 刘家驹; 张宪中

    2012-01-01

    根据2006-2007年太湖生物资源调查,估算出太湖浮游植物、浮游动物、底栖动物和水生植物总渔产潜力约为78494 t.太湖实施以渔改水的生物调控措施,应加大鲢、鳙放流数量和放流规格,在提高鱼产量的同时对抑制太湖蓝藻水华能起到积极作用;推算每年放流鳙约1000×104尾,鲢约300×104尾,规格为20尾/kg为宜.草鱼、团头鲂、青鱼、鲤等要在保护太湖水草和底栖动物资源和生物多样性前提下适当放流,每年宜放流草鱼150×104尾,团头鲂165×104尾,青鱼8×104 ~ 10×104尾,鲤夏花2500×104尾.而对调控鱼类结构小型化、单一化具有重要作用的肉食性鱼类翘嘴铂建议加大放流量,年放流量可扩大至500×104尾左右,在调控的同时提高湖泊渔业附加值.%According to the investigations of biological resources in Lake Taihu during 2006 -2007, we calculated that total fishery yield potential of phytoplankton, zooplankton, zoobenthos and aquatic macrophytes in Lake Taihu was about 78494 t. In order to increase fish yields and inhibit cyanobacteria bloom in Lake Taihu, stocking number of silver carp (Hypohthalmichlhys molitrix Richardson) and bighead carpi Aristichthys nobilis Cuvier) should be increased to 10 million and 3 million tails, respectively, and the specification should be 20 tails per kilogram. To protect resources of aquatic macrophytes and zoobenthos, the reasonable stocking number of grass carp (Ctenopharyngodon idellus Cuvier), blunt snout bream ( Megalobrama amblycephala Yih) , black carp (Mylopharyngodan piceus Richardson) and common carp( Cyprinidae carpio Linnaeus) should be 1. 5 million, 1.65 million, 80 -100 thousand and 25 million tails,respectively. As topmouth cutler such as cutler albumus could play important roles in controlling miniaturization and singleness of fishery structure and increase added-value of fishery economy, its stocking quantity should be increased to S million tails.

  5. 太湖流域水产品中羟基多溴联苯醚污染情况调查%Situation of hydroxy polybrominated diphenylethers contamination in aquatic of Taihu Lake basin

    Institute of Scientific and Technical Information of China (English)

    姚永青; 刘欣; 丁洪流; 纪丽君; 姚卫蓉; 陈英

    2014-01-01

    目的:调查太湖水域水产品中羟基多溴联苯醚(OH-PBDEs)的污染情况。方法首先建立测定水产品中OH-PBDEs的方法,之后分别测定了太湖流域中17种水产品和3种水生蔬菜中的OH-PBDEs。结果生活在中下层和泥层的水产品体内的OH-PBDEs含量(ND~3.3839 ng/g(干重))高于中上层的(ND~1.6169 ng/g(干重));动物水产体内的OH-PBDEs含量高于植物水产的;常见的鱼中草鱼、鳊鱼、花鲢和桂鱼体内的OH-PBDEs含量高于其他种类的鱼,且 OH-PBDEs 多数集中在内脏的内膜脏层。结论较系统地调查了太湖流域水产品中OH-PBDEs的污染情况。%Objective To investigate the contamination of OH-PBDEs in aquatic products of Taihu Lake. Methods A method for the determination of OH-PBDEs in aquatic products was established firstly, and then the concentration of OH-PBDEs in 17 kinds of aquatic products and 3 species of aquatic vegetables in the Taihu lake basin was measured. Results Fish living in the middle and lower layers and mud had higher levels of OH-PBDEs(ND~3.3839 ng/g(dw))than the upper’s(ND~1.6169 ng/g(dw)); there was higher level of OH-PBDEs in fish than plant. The concentration of OH-PBDEs in the grass carp, bream, bighead carp and siniperca chuatsi was higher than the other types of fish, and most OH-PBDEs was contained in the intima of the visceral. Conclusion The contamination of OH-PBDEs in aquatic products of Taihu Lake was surveyed systematically.

  6. Spatial Distribution Pattern and StocK Estimation of Nutrients During Bl oom Season in LaKe Taihu%太湖水华期营养盐空间分异特征与赋存量估算

    Institute of Scientific and Technical Information of China (English)

    金颖薇; 朱广伟; 许海; 朱梦圆

    2015-01-01

    基于2013年7月的空间高密度采样数据,对太湖水华期水体营养盐进行了空间分异特征分析及赋存量估算,探讨了大型浅水湖泊不同生态类型湖区水华与营养盐的相关关系及样点设置的代表性.结果发现,水华期太湖水体营养盐及叶绿素 a浓度( CHL)总体上均呈现由西北向东南降低的趋势;氮主要以溶解态存在,占总氮( TN)的76.28%,磷主要以颗粒态赋存,占总磷( TP)的66.38%.采用主成分分析和聚类分析,可以将采样点分为相互之间具有显著性差异的4个区域:第一区位于西北湖区,代表水华严重的重富营养湖区;第二区主要包括梅梁湾及南太湖的入湖河口一带湖区,代表水华和富营养化程度都相对中等的湖区;第三区包括湖心区和西南湖区,代表中等污染但水华频现湖区;第四区包括贡湖湾、胥口湾和东太湖等其他区域,代表水华影响较弱、水质较好湖区.分区统计分析表明,不同湖区影响浮游藻类生长的因子也不同:从全湖来看,与CHL显著相关的营养盐指标为TP、TN、溶解性总氮( TDN)和硝态氮( NO3--N),而在第一区则为TP和TDN,第二区为TN和TDN,第三区为TP、磷酸盐( PO3-4-P)和TDN,第四区为PO3-4-P、溶解性总磷( TDP)和亚硝酸盐( NO2--N).基于空间插值获得调查期间太湖水体TN、TDN、TP和TDP的赋存量分别为12800、9800、445和150 t.研究表明,作为一个大型浅水湖泊,因蓝藻水华空间迁移积聚特征和生态类型异化等特征,太湖水华期的营养盐具有高度空间异质性,对于此类大型浅水湖泊的监测与评价,应当考虑点位的合理布设及结果的恰当解读,避免因监测布点和统计方法不当而以偏概全.%Based on the data of high density spatial sampling in July 2013, we analyzed the spatial distribution pattern of nutrients and estimated their amount during bloom season in Lake Taihu to discuss the correlation of algal

  7. Playa Lakes

    Data.gov (United States)

    Kansas Data Access and Support Center — This digital dataset provides information about the spatial distribution of soil units associated with playa lakes. Specific soil types have been designated by the...

  8. Water-to-Sediment Exchange of Organochlorine Pesticides in Taihu Lake%有机氯农药在太湖水体-沉积物中的交换特征

    Institute of Scientific and Technical Information of China (English)

    亓学奎; 马召辉; 王英; 姜霞; 金军; 汪雨

    2014-01-01

    migrate between the different environmental media, proceed to long-range transport in the air, and lead to global environmental problems. High level of OCPs in the Taihu Lake Region was reported by the latest research. In order to understand the sources and the environmental behaviors of these OCPs in the Taihu Lake, the contents of OCPs in both water and sediment samples from Zhushan Bay of Taihu Lake were determined by GC-MS. The potential sources and water-sediment exchange flux of OCPs was discussed. The results indicated that HCB were the most dominant compounds in the sediment, and the content was 2.33 ng·g-1 (DW). Relative higher contents of OCPs werep,p’-DDT,p,p’-DDE andβ-HCH, the contents were 0.67 ng·g-1, 0.64 ng·g-1 and 0.37 ng·g-1, respectively. It can be seen from the OCPs in Taihu Lake water samples, the highest content ofp,p’-DDT was 426.26 pg·L-1, followed byα-HCH and endosulfan which contents were 289.99 pg·L-1 and 215.20 pg·L-1. According to ratio ofα-HCH/γ-HCH and HCHs source analysis, it can be found that HCHs pollution in Taihu Lake came from the use of industrial HCHs and lindane. The net exchange flux of HCHs were release fluxes, indicating the tendency to transfer these contaminants from sediment to water. This implies that the residue of HCHs in the lake sediment might have been an important source of HCHs to the water. The ratio ofp,p’-DDT/p,p’-DDE in water bodies is much larger than 1, and the net exchange flux of p,p’-DDT were deposition fluxes, indicating the new sources of input. It is notable that the fluxes for endosulfan I also followed the same pattern asp,p’-DDT, reflecting there were probably new sources to the Taihu Lake.

  9. New Ideas on Water Transfer and Pollution Treatment Based on Artificial Diversion in Taihu Lake%基于人工导流的太湖调水清污新思路

    Institute of Scientific and Technical Information of China (English)

    陈凯麒; 祁昌军; 李巍; 陶洁

    2014-01-01

    The ecological treatment measures and methods in the Taihu Lake were analyzed and summarized, andthe numerical simulation method adopted to establish a two-dimensional plane hydrodynamic and water qualitymodel.According the simulated results of different dominant wind direction combinations of southeast, northwestand northeast, the flow field variation regularities and streamline variation forms of the Taihu Lake were analyzed.Under the new idea of reducing invalid closed circulation system and improving the contaminant exchange ratethrough artificial diversion, the construction of diversion dike with the combination of sludge dredging, waterwaydredging and landscaping engineering in the Taihu Lake was proposed, which could barrier the invalid endless loopsystem forced by wind, organize and guide the water flow, promote water cycle, and then improve the clean-upeffective significantly.The results show that it plays an obvious role in promoting contaminant exchange rate of theTaihu Lake.Among the five diversion dike schemes, Scheme 5 is the optimal one with most obvious improvement ofthe contaminant exchange rate.%分析总结了太湖生态治理措施和方法,利用数值模拟方法建立太湖平面二维水动力、水质模型,根据东南风、西北风和东北风不同主导风组合下的计算结果,分析太湖流场变化规律和太湖湖区流线变化形态。基于人工导流,减少太湖无效闭合环流,提高太湖污染物置换率的考虑,提出一种新思路,在太湖内结合清淤、航道疏浚及景观美化工程建设导流堤,阻隔太湖在风力作用下形成无效的“死”循环系统,有组织地引导、控制水体流动,从而促进湖体的有序水循环,大幅度、高效地改善太湖调水清污效果。结果表明,在太湖配合引水工程修建导流堤,对促进太湖污染物置换有明显的改善作用,与原始工况相比,导流堤方案五对太湖污染物置换率的改

  10. 苏州地产水生蔬菜和太湖水产品总汞含量分析%Analysis of Total Mercury in Aquatic Vegetables Cultivated in Suzhou and Aquatic Products in Taihu Lake

    Institute of Scientific and Technical Information of China (English)

    范丽丽; 傅春玲; 丁薇薇

    2012-01-01

    Total mercury content in aquatic vegetables cultivated in Suzhou and aquatic products in Taihu Lake was determined by microwave digestion and cold atomic fluorescent spectrometry (AFS). The highest total mercury content was found in crab among six species of aquatic production from Taihu Lake, which was as high as 0.470 mg/kg in male crab paste. Total mercury content was relatively lower in other aquatic products such as white fish, white shrimp, Margarya, and so on. Except Zizania caduciflora, all other aquatic vegetables from Suzhou under investigation were polluted by mercury to different extent with a content exceeding the national standard limit. Total mercury content was higher in floating leaf vegetable than emerged vegetable, in naked vegetable than wrapped vegetable.%通过微波消解-冷原子荧光光谱法检测苏州地产水生蔬菜与太湖水产品的总汞含量,并研究其分布规律。测定结果显示:螃蟹总汞含量最高,其中雄蟹蟹膏部位高达0.470mg/kg,其他水产品包括白鱼、白虾及螺蛳等总汞含量均较低;水生蔬菜除茭白外,均受到不同程度的汞污染,汞含量已超过我国限量标准,其变化呈现浮叶植物高于挺水植物、裸露植物高于有包裹植物的趋势。

  11. Comprehensive evaluation method of cyanobacteria bloom hazard in Lake Taihu%太湖蓝藻水华灾害灾情评估方法初探

    Institute of Scientific and Technical Information of China (English)

    刘聚涛; 杨永生; 高俊峰; 姜加虎

    2011-01-01

    通过对太湖蓝藻水华灾害影响分析,探讨了太湖蓝藻水华灾害灾情评估指标的选取和评价标准的划分,并采用模糊评价模型构建太湖蓝藻水华灾害灾情综合评估方法.评价指标分为影响人口、影响范围、生态环境影响和经济损失四个方面,其中影响人口指标为受灾人口,影响范围指标包括蓝藻水华面积发生百分比和影响时间,生态环境影响指标包括藻细胞浓度、TN浓度和TP浓度,经济损失指标包括直接经济损失和间接经济损失,分别将太湖蓝藻水华灾害分为轻灾、中灾、重灾、极重灾和巨灾五个级别.根据灾害综合评估方法,以2007年5月29日太湖蓝藻水华灾害事件为实例进行评估,该次蓝藻水华灾害为巨灾,与该次事件引起的社会经济影响基本相一致,表明该方法具有一定的科学性和适用性.%According to the analysis of the cyanobacteria bloom disaster effect, this paper discussed the evaluation indices and criteria of the hazard, constructed hazard evaluation method applying fuzzy comprehensive evaluation model. In the indicator layer, the affected population was the population affected by the hazard. The affected area included the percentage of the cyanobacteria bloom area and affected days. The eco-environmental indices included cyanobacteria cell concentration, total nitrogen concentration and total phosphorus concentration. The economic losses included direct loss and indirect loss, and it took the drinking water loss and tourism loss as direct losses and the hazard relief loss as indirect loss. Through the analysis of indicator system, according to the experts' determination, the cyanobacteria bloom hazard classification in Lake Taihu was divided into five classes which were light damage, mid-damage, heavy damage, heavier damage and catastrophic damage. Based on the fuzzy comprehensive evaluation method, this paper evaluated the cyanobacteria bloom hazard events from

  12. Microbial diversity in lake sediments detected by PCR-DGGE

    Institute of Scientific and Technical Information of China (English)

    Xinqing ZHAO; Liuyan YANG; Can CHEN; Lin XIAO; Lijuan JIANG; Zhe MA; Haowei ZHU; Zhenyang YU; Daqiang YIN

    2008-01-01

    In this study,PCR-denaturing gradient gel electrophoresis (DGGE) was applied to analyze the microbial communities in lake sediments from Lake Xuanwu,Lake Mochou in Nanjing and Lake Taihu in Wuxi.Sediment samples from seven locations in three lakes were collected and their genomic DNAs were extracted.The DNA yields of the sediments of Lake Xuanwu and Lake Mochou were high (10 μg/g),while that of sediments in Lake Taihu was relatively low.After DNA purification,the 16S rDNA genes (V3 to V5 region) were amplified and the amplified DNA fragments were separated by parallel DGGE.The DGGE profiles showed that there were five common bands in all the lake sediment samples indicating that there were similarities among the populations of microorganisms in all the lake sediments.The DGGE profiles of Lake Xuanwu and Lake Mochou were similar and about 20 types of micro-organisms were identified in the sediment samples of both lakes.These results suggest that the sediment samples of these two city lakes (Xuanwu,Mochou) have similar microbial communities.However,the DGGE profiles of sediment samples in Lake Taihu were significantly differ-ent from these two lakes.Furthermore,the DGGE pro-files of sediment samples in different locations in Lake Taihu were also different,suggesting that the microbial communities in Lake Taihu are more diversified than those in Lake Xuanwu and Lake Mochou.The differences in microbial diversity may be caused by the different environmental conditions,such as redox potential,pH,and the concentrations of organic matters.Seven major bands of 16S rDNA genes fragments from the DGGE profiles of sediment samples were further re-amplified and sequenced.The results of sequencing analysis indicate that five sequences shared 99%-100% homology with known sequences (Bacillus and Brevibacillus,uncultured bacteria),while the other two sequences shared 93%-96% homology with known sequences (Acinetobacter,and Bacillus).The study shows that the PCR-DGGE tech

  13. CHARACTERISTICS OF LAND USE AND ITS MECHANISM IN TAIHU LAKE BASIN%太湖流域土地利用变化特征与机制分析

    Institute of Scientific and Technical Information of China (English)

    张落成; 刘存丽

    2011-01-01

    太湖流域土地总面积36895km2,包括了上海、江苏、浙江两省一市的部分区域,其中,江苏占53%,浙江占33%,上海占14%。太湖流域土地利用按下垫面可以分为耕地、建设用地、水域和其他用地4种类型。采用2005年土地详查数据与上次防洪规划数据进行比较。研究发现:耕地是太湖流域最重要的下垫面,占土地总面积的36.6%,建设用地占土地占面积的23%,与耕地的矛盾十分尖锐,水域面积较大,占土地总面积的14.5%。1996~2005年,土地利用变化的总体趋势是,耕地面积减少,减少幅度最大的地区在太湖流域江苏部分,两省一市建设用地均有30%左右的增长幅度,土地围垦得到有效控制,水域面积略有下降。人口增长和城市化快速发展、经济发展、效益驱动与土地管制差异是造成土地利用变化的主要原因。%With an area of 36 895 square kilometers, Taihu Lake basin extends across East China's regions including Jiangsu and Zhejiang Provinces and Shanghai Municipality. Of all the land, Jiangsu accounts for 53 percent, while zhejiang accounts for 33 percent and Shanghai 14 percent. It can be divided into four kinds of underlying surfaces, such as cultivated land, construction land, water area and other land. In 1999, the flood protection planning in Taihu Lake basin was announced and the data of land area was wild- ly used. To discover the real change of land use, we used the investigation data from the bureau of land management in 2005. It showed that the cultivated land was the most important underlying surface in Taihu basin, the contradiction between agricultural land and construction land was much serious, and wa ter area was large, accounting for 14.5 percent of the total area. From 1996 to 2005, the cultivated land had decreased a lot, especially in Jiangsu province; the construction land had increased for about 30 percent in Taihu

  14. An analysis on the evolvement processes of lake eutrophication and their characteristics of the typical lakes in the middle and lower reaches of Yangtze River

    Institute of Scientific and Technical Information of China (English)

    CHENG Xiaoying; LI Shijie

    2006-01-01

    According to the study on the aquatic environment of the typical lakes in the middle and lower reaches of Yangtze River, lake eutrophication is a process in which the lake ecosystem degenerates,resulting in the deterioration of the water quality due to the enrichment of the nutrients. Moreover, the succession of lake ecosystem and change of water quality both couple well with the evolvement of trophic state. Then the conceptual model is mentioned and ten lake states are classified. Based on these,the authors analyzed the eutrophication processes of the typical lakes in the middle and lower reaches of Yangtze River. The large lakes with taking in - sending out water typical of Poyang Lake evolve from State 1 before the 1980s into State 2 after the 1980s,the large and medium lakes typical of Taihu Lake evolve from State 1 -2 in the 1960s into State 8 in the 1980s then into State 9 in the 1990s, the medium and small shallow lakes typical of Honghu Lake evolve from State 1 in the 1960s into State 2 after the 1980s and the small city (suburban) lakes typical of Donghu Lake evolve from State 2 in the 1960s into State 9after the 1970s. Further, the 1980s is the key conversion period of the lakes of various types typical of Poyang Lake, Honghu Lake and Taihu Lake converting into mesotrophic state, the 1990s is that of Taihu Lake into eutrophic state and the 1970s is that of the small city (suburban) lakes typical of Donghu Lake into eutrophic state. The series of nutrient evolvement of different typical lakes are similar, but the processes are not synchronous, which is related to the various human and natural driving mechanisms in lake basins.

  15. Great Lakes

    Science.gov (United States)

    Edsall, Thomas A.; Mac, Michael J.; Opler, Paul A.; Puckett Haecker, Catherine E.; Doran, Peter D.

    1998-01-01

    The Great Lakes region, as defined here, includes the Great Lakes and their drainage basins in Minnesota, Wisconsin, Illinois, Indiana, Ohio, Pennsylvania, and New York. The region also includes the portions of Minnesota, Wisconsin, and the 21 northernmost counties of Illinois that lie in the Mississippi River drainage basin, outside the floodplain of the river. The region spans about 9º of latitude and 20º of longitude and lies roughly halfway between the equator and the North Pole in a lowland corridor that extends from the Gulf of Mexico to the Arctic Ocean.The Great Lakes are the most prominent natural feature of the region (Fig. 1). They have a combined surface area of about 245,000 square kilometers and are among the largest, deepest lakes in the world. They are the largest single aggregation of fresh water on the planet (excluding the polar ice caps) and are the only glacial feature on Earth visible from the surface of the moon (The Nature Conservancy 1994a).The Great Lakes moderate the region’s climate, which presently ranges from subarctic in the north to humid continental warm in the south (Fig. 2), reflecting the movement of major weather masses from the north and south (U.S. Department of the Interior 1970; Eichenlaub 1979). The lakes act as heat sinks in summer and heat sources in winter and are major reservoirs that help humidify much of the region. They also create local precipitation belts in areas where air masses are pushed across the lakes by prevailing winds, pick up moisture from the lake surface, and then drop that moisture over land on the other side of the lake. The mean annual frost-free period—a general measure of the growing-season length for plants and some cold-blooded animals—varies from 60 days at higher elevations in the north to 160 days in lakeshore areas in the south. The climate influences the general distribution of wild plants and animals in the region and also influences the activities and distribution of the human

  16. 太湖冬季军团菌(Legionella spp.)的分布和多样性%Distribution and Diversity of Legionella spp. in Lake Taihu in the Winter

    Institute of Scientific and Technical Information of China (English)

    王娜; 邢鹏; 吴庆龙; 余多慰

    2011-01-01

    The Legionella spp. are ubiquitous in aquatic environment and could cause certain risks on human health. In order to investigate the distribution and diversity of Legionella spp. in Lake Taihu during winter time, water samples were collected from 32 sites of the whole lake in February 2010. The presence of Legionella spp. was screened by nested-PCR and their phylogenetic diversity was determined by denaturing gradient gel electrophorese(DGGE) and sequencing analysis of excised DGGE bands. The Legionella spp. was detected from 21 out of 32 sites in particle-associated bacterial samples and 11 out of 32 sites in free-living bacterial samples, which accounted for 65.63% and 34.38% of each type of bacteria, respectively. In total, 40 and 36 unique bands were identified among those particle-associated and free-living bacterial DGGE profiles, respectively. Community characteristic indices of different euthrophic areas showed that the diversity of LegioneUa spp. in mild eutrophic areas was higher than that in the moderate eutrophic areas. In total, thirty-four DGGE bands were excised and sequenced, which could be classified into 12 OTUs by 97% similarity. Among all the sequences, three showed a high similarity with two pathogenic Legionella species Legionella feeleii and Legionella longbeachae. This revealed potential healthy risks to the people lived around the Lake Taihu.%军团菌(Legionellas pp.)广泛存在于各种水体中,对人类的健康造成了一定的安全隐患.为了解太湖在冬季是否存在军团菌,以及它的分布和多样性,本研究于2010年2月,在全太湖32个点位采样,使用巢式PCR对样品中军团菌进行检测,并用变性梯度凝胶电泳(denaturing gradient gel eletrophoresis,DGGE)及对典型条带切胶测序来分析军团菌的基因多样性.结果表明,太湖32个位点中,附着细菌和浮游细菌分别有21个点和11个点检出军团菌,检出率分别为65.63%和34.38

  17. Phosphorus forms and bioavailability of lake sediments in the middle and lower reaches of Yangtze River

    Institute of Scientific and Technical Information of China (English)

    ZHU; Guangwei; QIN; Boqiang; ZHANG; Lu

    2006-01-01

    Forms of phosphorus in sediments from 25 lakes in the middle and lower reaches of Yangtze River were analyzed by the sequential extraction procedure. Contents and spatial distrubution of algal available phosphorus (AAP) in sediments of Lake Taihu, the third largest freshwater lake of China, were also studied. Relationships between phosphorus forms in sediment and macrophytes coverage in sample sites, as well as phosphorus forms in sediments and chlorophyal contents in lake water were discussed. Exchangeable form of phosphorus (Ex-P) in surface sediments was significantly positive correlative to total phosphorus (TP), dissolved total phosphorus (DTP) and soluble reactive phosphorus (SRP) contents in the lake water. Bioavailable phosphorus (Bio-P) contents in sediments from macrophytes dominant sites were significantly lower than that in no macrophyte sites. In Lake Taihu, Ex-P content in top 3 cm sediment was highest.However, content of ferric fraction phosphorus (Fe-P) was highest in 4-10 cm. Bioavalilble phosphorus (Bio-P) contents in surface sediments positively correlated to Chlorophyll a contents in water of Lake Taihu with significant difference. Therefore, contents of Bio-P and AAP could be acted as the indicators of risks of internal release of phosphorus in the shallow lakes. It was estimated that there were 268.6 ton AAP in top 1 cm sediments in Lake Taihu. Sediment suspension caused by strong wind-induced wave disturbance could carry plenty of AAP into water in large shallow lakes like Lake Taihu.

  18. Ammonium, microcystins, and hypoxia of blooms in eutrophic water cause oxidative stress and C-N imbalance in submersed and floating-leaved aquatic plants in Lake Taihu, China.

    Science.gov (United States)

    Zhang, Meng; Wang, Zhengqi; Xu, Jun; Liu, Yaqin; Ni, Leyi; Cao, Te; Xie, Ping

    2011-01-01

    The heavy bloom of cyanobacteria is a disastrous consequence of freshwater eutrophication, and the bloom is highly toxic due to its secondary metabolites called microcystins (MCs). The release of organic substances from dense blooms causes an increase in NH4+ and decrease in oxygen in lake water. In the present study, the dynamics of physio-biochemical responses of five aquatic macrophytes to MCs and NH4+ stresses in Meiliang Bay were evaluated. The bay is one of the most seriously eutrophized areas dominated by the toxic cyanobacteria of Lake Taihu, China. The results demonstrate that aquatic macrophytes in Meiliang Bay are subjected to successive external stresses. From January to May, they are subjected to high NH4+ stress (>0.56 mg L(-1)), whereas from June to September or during dense blooms, the macrophytes experience both MC proliferation and moderate NH4+ toxicity (>0.3 mg L(-1)). In August, high NH4+ stress occurs along with hypoxia stress, whereas from September to December, the macrophytes experience moderate NH4+ stress, causing a serious imbalance in C-N metabolism and oxidative stress. Between the two aquatic plant life forms, floating-leaved plants are more resistant to the stresses of eutrophication than are submersed plants. Elevated MCs in the water column can aggravate oxidative stress and suppress the soluble protein contents of aquatic plants. High NH4+ in the water causes severe C and N imbalance in submersed macrophytes because of considerable carbon consumption for free amino acid synthesis. The superoxide dismutase activities of submersed macrophytes are suppressed by low light penetrating the eutrophic water, which might impair the antioxidative function of the plants. The findings of this study provide mainly field evidence that reveals the physical, chemical, and biological stresses on aquatic plants in bloom-prevailed eutrophic lakes.

  19. 太湖浮游植物群落结构及其与水质指标间的关系%Structure of Phytoplankton Community and Relationship between Phytoplankton Community and Water Quality in Taihu Lake

    Institute of Scientific and Technical Information of China (English)

    李娣; 李旭文; 牛志春; 王霞; 师伟; 于红霞

    2014-01-01

    To research the structure of phytoplankton community and relationship between phytoplankton community and water quality in Taihu Lake, phytoplankton community structure and water quality indicators (temperature, transparency, pH value, dissolved oxygen, conductivity, total nitrogen, total phosphorus, ammonia, high manganese on permanganate index, chemical oxygen demand, fluoride, biological oxygen demand, nitrate, nitrite, phosphate solubility and chlorophyll a) were monthly investigated at seven sites in Taihu Lake between January and December of 2013 in our study. Meanwhile, Pearson’s correlations between phytoplankton communities and environmental variables were used to find the factors that influenced the distribution of phytoplankton community. The results found that there were 124 species of phytoplankton, including 30 taxa Cyanophyta, 47 kinds of Bacillariophyta, 34 species Chlorophyta, 3 Cryptophyta, 6 Euglenophyta, 4 Dinoflagellate; as an absolute dominant species, dominance of Microcystis spp. was 80.8 %. From space, phytoplankton density in Gonghu was highest among the seven sites. Diversity of phytoplankton community was lower than other sites. Meanwhile, density percentage of Microcystis spp. in Gonghu was 90.1%, far higher than other sites. From the time point of view, December was when the density of phytoplankton community in Taihu Lake was highest, followed by June. The principal pollutant was total nitrogen, secondly total phosphorus, thirdly chemical oxygen demand. Concentration of pollutants in West Taihu was highest in our study. Through correlation analysis of phytoplankton community and water quality, it showed that water temperature, transparency, total nitrogen, chemical oxygen demand and chlorophyll a were main factors that influenced phytoplankton community structure in Taihu Lake. Controlling water pollutant emissions and restoring ecological function should be an effective method to manage cyanobacteria bloom in Taihu Lake. Meanwhile

  20. 竺山湖及太湖西沿岸北段的重金属分布特征及其生态风险评价%Distribution of heavy metals in sediments of Zhushan Lake and northern segment of western shore of Taihu Lake and its ecological risk assessment

    Institute of Scientific and Technical Information of China (English)

    任小龙; 朱玲; 姚华; 王苓

    2012-01-01

    对竺山湖及太湖西沿岸北段底泥沉积物中6种重金属Cd、As、Cr、Hg、Pb和Cu的质量比进行分析,结果表明,底泥沉积物中Cd、As、Cr、Hg、Pb和Cu的平均质量比分别为1.23 mg/kg、10.28 mg/kg、82.98 mg/kg、0.074 mg/kg、35.27 mg/kg和33.9 mg/kg,分别是各自背景值的4.6倍、1.1倍、1.0倍、0.7倍、2.2倍和1.8倍;底泥沉积物中重金属的垂向分布特点是:随底泥沉积物深度的增加,重金属质量比逐渐降低,并在底泥沉积物50 cm深处表现出明显的重金属质量比降低拐点.利用潜在生态风险指数法对竺山湖及太湖西沿岸北段的重金属生态风险进行评价,结果表明,该区域重金属生态风险值范围为34 ~444,平均值为117,太湖西沿岸大浦口区域的生态风险较大,Cd是生态风险的主要贡献元素.建议对竺山湖以及太湖西沿岸区大浦口区域Cd的污染进行必要的疏浚控制,疏浚深度在底泥50 cm深处,以有效去除该区域的Cd污染.%The concentrations of six heavy metals, Cd, As, Cr, Hg, Pb, and Cu, in sediments of Zhushan Lake and the northern segment of the western shore of Taihu Lake were analyzed. The results show that the average concentrations of Cd, As, Cr, Hg, Pb, and Cu were 1. 23 mg/kg, 10. 28 mg/kg, 82. 98 mg/kg, 0. 074 mg/kg, 35. 27 mg/kg, and 33. 9 mg/kg, which were 4. 6 times, 1. 1 times, 1. 0 times, 0. 7 times, 2. 2 times, and 1. 8 times their background values, respectively. The concentrations of heavy metals in the sediments decreased with the increase of the sediment depth and had a significant decreasing tendency at a depth of 50 cm. The potential ecological risk index method was used to evaluate the ecological risk of heavy metals in sediments of Zhushan Lake and the northern segment of the western shore of Taihu Lake. The results show that the RI index of the study area ranged from 34 to 444, with an average value of 117, the ecological risk in the Dapukou area on the western shore of

  1. STUDY ON HISTORICAL EXTREME FLOODS IN OCCURRENCE YEAR AND FLOODY HEIGHT,TAIHU LAKE%探讨太湖历史极端洪水发生年份和水位高程

    Institute of Scientific and Technical Information of China (English)

    于革; 胡守云; 李春海

    2013-01-01

    较之气候水文平均态的缓慢变化,特大洪水引发的灾害对人类社会影响更加显著,而关注极端洪水、认识小概率事件需要更长时间序列.本文通过对太湖钻孔的沉积和磁学参数特征研究,对比太湖文物发掘的历史洪水资料,试图多指标定量重建太湖长序列极端洪水.太湖水则碑对1600~1954A.D.特大洪水记录了15次,通过与现代洪水仪器记录对比和论证,其最低4.03m水位相当于1921~2004A.D.观测太湖的年最高水位80%百分位.太湖钻孔中的沉积粒度和磁化率特征捕捉了水则碑洪水序列中的85%的洪水年,同时补充了水则碑洪水漏失的信号.3次能够被历史文献佐证的洪水沉积信号发生在1766A.D.、1875A.D.和1882A.D.,其洪水水位估计在4.0~4.1m,4.1~4.2m和4.13 ~4.23m.频谱分析显示了沉积洪水指标与水则碑洪水指标具有3个同步的重现期,分别约在90~102年、60~ 62年和42~44年.分析历史洪水与PDO一致性的统计关系,获得估计概率为0.17 ~0.20,肯定了太湖洪水年与PDO存在关联,反映出历史洪水的发生与现代过程相同,受到了太平洋季风环流和夏季降水控制.这些结论为延长洪水时间系列、分析小概率事件、认识极端洪水特征和重现期等提供了重要水文依据.%Extreme large floods have caused disaster much severity for human society, when compared with the equilibrium changes of the climate-hydology. Taihu Lake catchment is influenced by the subtropical monsoon climate with dominant summer-precipitation type, leading that the extreme lake levels during flood years has a close relationship with changes in summer monsoon precipitation not only in modern time but also in the historical periods. In the 20th century, several extreme large floods in 1954A. D. , 1991A. D. and 1999A. D. have been diagnosed to be caused by abnormal summer precipitations that were controlled by the Pacific tropical hurricanes

  2. Current status and future tendency of lake eutrophication in China

    Institute of Scientific and Technical Information of China (English)

    JIN Xiangcan; XU Qiujin; HUANG Changzhu

    2005-01-01

    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

  3. Research on Water Pollution Risk Assessment of Typical Transferring Water Experiment in Taihu Lake Basin%太湖流域典型调水试验水质污染风险研究

    Institute of Scientific and Technical Information of China (English)

    宋兰兰; 麻林; 刘凌

    2013-01-01

    Inter-basin water transfer is an important component of optimal deployment of water resources.Slow velocity of plain river networks leads to little water environmental capacity in Taihu drainage basin.Diverting water to flush out pollutants becomes a solution to improving water environment.Combining failure probability with calamity consequence of inter-basin water transfer projects,the risk assessment system of water transfer project has been proposed.Then,ammonia nitrogen as triangular fuzzy numbers is utilized to assess the recontamination risk of water diversion experiment in Taihu Lake.A case study shows that the models provided here are quite suitable for pollutants recontamination risk assessment of typical transferring water experiment.%跨区域跨流域调水是我国水资源优化配置的重要组成部分之一.太湖流域内水流缓慢,环境容量低,引水清污成为太湖流域改善水环境质量的手段之一.在污染源难以得到有效治理的条件下,引水使得江河原水中污染物发生二次迁移,对流域水环境质量产生污染风险.基于三角模糊数原理以及a-截集技术,选取氨氮关键水质参数,评估太湖流域典型调水试验受水区水质污染风险程度,从而为太湖流域水利工程的科学调度提供理论依据.

  4. Growth and mortality of topmouth gudgeon Pseudorasbora parva and evaluation on resource utilization in Taihu Lake%太湖麦穗鱼生长、死亡和利用状况评估

    Institute of Scientific and Technical Information of China (English)

    刘凯; 景丽; 陈永进; 徐东坡

    2016-01-01

    为研究太湖麦穗鱼Pseudorasbora parva 的种群结构、生长特征、死亡特征和资源利用状况,于2014年1—12月使用虾笼网在太湖水域逐月进行了采样调查,并对采集的1207尾样本进行了分析。结果表明:麦穗鱼样本标准体长为27.03~107.36 mm,平均为(60.03±13.29) mm,体质量为0.4~21.2 g,平均为(4.51±3.16) g;其体长与体质量呈幂函数相关,拟合关系式为W=2.1606×10-5 L2.9537( R2=0.9323, n=1207); Von Bertalanffy生长方程各参数为L∞=112.88 mm、 K=0.46、 t0=-0.51 a,体质量生长拐点为1.84 a;应用变换体长渔获曲线法估算总死亡系数(Z)为1.87,利用Pauly经验公式估算自然死亡系数(M)为1.07,捕捞死亡系数(F)为0.80,开发率(E)为0.43。研究表明,太湖水域麦穗鱼面临的捕捞压力较轻,处于适度利用状态,这与太湖水域无针对性捕捞且设有禁渔期有关,同时开捕期内肉食性鱼类面临的捕捞压力也有利于小型鱼类种群增殖。%Based on a total of 1207 samples of topmouth gudgeon Pseudorasbora parva collected by shrimp pot from January to December in 2014, an investigation was conducted monthly in Taihu Lake to study the composition, growth and mortality of capture as well as the resources utilization. The standard body length of samples ranged from 27 . 03 mm to 107 . 36 mm with mean value of ( 60 . 03 ± 13 . 29 ) mm while the body weight ranged from 0 . 4 g to 21. 2 g with the mean value of (4. 51±3. 16) g. A power function was presented between the body length and body weight while the relationship exhibited as follows:W=2. 1606í10-5L2.9537(R2=0. 9323, n=1207). The parameters of Von Bertalanffy growth equation were displayed as below:L∞=112. 88 mm, K=0. 46, t0=-0. 51 a. The inflec-tion point of body weight was about 1. 84 years. Total mortality coefficient (Z) was 1. 87 estimated by transformed body length catch curve method and natural mortality coefficient ( M) was estimated about 1. 07 with

  5. 太湖流域排污权交易的实践与立法问题探析%Analysis of Practical and Legislative Issues on Emission Trading in the Taihu Lake Basin

    Institute of Scientific and Technical Information of China (English)

    戴忱; 闵庆文; 杨素娟

    2011-01-01

    Emission trading, as a means of economic stimulus, is a hot spot in current studies associated with environmental laws. In areas of China' s Taihu Lake Basin, a pilot project of emission trading was conducted and successful. There are 890 companies joining in the pilot project and the amount of emission trading is about 1.49 billion Yuan during the period between 2007 (when the Emission Trading Center was found in Jiaxing, Zhejiang Province) and 2009 in Jiaxing, Zhejiang Province. Meanwhile, pollution discharge rights amounting to 1.41 billion Yuan have been sold to 915 companies during the last two years in Jiangsu Province. In despite of the overall success, the project is being faced with some problems to be urgently addressed.Construction of the relations and standards of the emission trading system, and the coordination between the emission trading system and the other relation systems are particularly important. In the practice of emission trading, there are still a lot of problems, e.g., the convergence of existing systems and laws, establishing a unified market of pollution discharge rights over the basin, and the activation of the secondary market, need to be resolved. As far as legislation is concerned, the absence of national legislation, the lack of coordination between local legislation, and the lag of systematic regulations are the major problems. As an economic stimulus of water pollution prevention and control, the emission trading system requires an emergent legal regulation. A complete legal regulation system of emission trading include not only laws formulated by the National People' s Congress and the standing committee, but also the administrative rules and regulations, the department rules and regulations, as well as the matching specifications. The legal regulation system of emission trading in Taihu Lake basin has not yet completely established. The emission trading in the basin can be operated stably only within a complete and reasonable

  6. Bathymetry of Lake Michigan

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lake Michigan has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and geophysical data and make it more...

  7. Bathymetry of Lake Ontario

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lake Ontario has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and geophysical data and make it more...

  8. Designated Wildlife Lakes - points

    Data.gov (United States)

    Minnesota Department of Natural Resources — This is a point shapefile of Designated Wildlife Lakes in Minnesota. This shapefile was created by converting lake polygons from the Designated Wildlife Lakes...

  9. Great Lakes Bathymetry

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lakes Michigan, Erie, Saint Clair, Ontario and Huron has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and...

  10. Bathymetry of Lake Superior

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lake Superior has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and geophysical data and make it more...

  11. Hydrography - Lakes Assessments - Attaining

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This layer shows only attaining lakes of the Integrated List. The Lakes Integrated List represents lake assessments in an integrated format for the Clean Water Act...

  12. Bathymetry of Lake Huron

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lake Huron has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and geophysical data and make it more...

  13. 太湖流域低污染水处理技术研究%Applied Research on Treatment Technique for Low-polluted Water in the Taihu Lake Basin

    Institute of Scientific and Technical Information of China (English)

    周灵君; 范亚民

    2016-01-01

    针对太湖流域某流域低污染水存在的主要问题,通过好氧-缺氧-生化强化及人工湿地组合工艺处理农村生活污水、生态沟渠拦截面源排水和低污染水的复合型强化净化系统,其应用表明:各单项处理单元平均削减主要污染物40%以上,复合型强化净化系统毒死蜱去除率超过了90%,特别是引入潜流湿地及强化净化区明显提高了污染物的去除效果,提高了复合型强化净化系统的净化效率及面积利用率,为低污染水的处理提供技术支撑。%It was important to treat low-polluted water pollution in the Taihu Lake basin at present. In the paper, the main problems of low-polluted water were diagnosed.The aerobic-anoxic-biochemical and artificial wetland combined process, process removal of ecological ditches purification technology and a complex pre-dam systems, have realized that the removal of the total pollutant could reach up to more than 40%, respectively.The total removal rates of chlorpyrifos were more than 90%using a complex pre-dam. Moreover, increased areas (surface flow wetland (E) and biological membrane purification area ) could significantly improve the major pollutants removal, particularly optimized the system to improve the purification efficiency and high area utilization. The results of this study indicated that pre-dams may be successfully applied to reduce low-polluted water pollution in the Taihu Lake basin which provide a technical support for the treatment of low-polluted water.

  14. 太湖蓝藻的时空变化规律及治理方法%The temporal and spatial distribution pattern of cyanobacteria and its control method in Taihu Lake

    Institute of Scientific and Technical Information of China (English)

    周笑白; 张宁红; 张咏; 牛志春; 彭露露; 刘雷; 于红霞

    2013-01-01

    the analysis of the relationship between the cyanobacteria distribution and the physical, chemical and biological parameters, such as water temperature, pH value, the concentration of organic pollutants and nutrients, and the density of the phytoplankton and zooplankton. Results showed that the water quality of Taihu Lake exceeded the V class of National Standard for Groundwater Environmental Quality, and the main element exceeding the standard was nitrogen. The concentrations of the total nitrogen in Taihu Lake in wet season and normal season were 3.05 mg·L-1 and 1.65 mg·L-1, and the main reason of the lower nitrogen concentration in wet season was probably that cyanobacteria grew fast and absorbed a great quantity of nutrients in this period of time. The cyanobacteria were still the dominated species of the phytoplankton in the sampling sites. There was no significant annual change of the density of cyanobacteria during the year of 2009─2012, while the density of cyanobacteria in different seasons and different sites were varied:the average density of cyanobacteria in the wet seasons (4.87×107 cell·L-1) was significantly higher than in the normal seasons (1.51×106 cell·L-1), and the density of cyanobacteria in the sampling sites of the Eastern Taihu Lake was significantly lower than the other parts. Abiotic factors including temperature, pH value and the concentration of nutrients could influence the density of cyanobacteria. Higher temperature, pH value and higher concentration of nutrients could increase the density of cyanobacteria. Competition between the growth of cyanobacteria and other primary producers (phytoplanktons and macrophytes) had been observed, and the increase of cyanobacteria density stimulated the growth of the cladocera. The mechanical removal technique and phytoremediation were recommended in this research, for they could reduce the risk of the cyanobacterial bloom in Taihu Lake by reducing the density of cyanobacteria and the

  15. Great Lakes Science Center

    Data.gov (United States)

    Federal Laboratory Consortium — Since 1927, Great Lakes Science Center (GLSC) research has provided critical information for the sound management of Great Lakes fish populations and other important...

  16. Distribution and Speciation of Mercury in Different Eutrophic Regions of Taihu Lake%太湖不同营养水平湖区汞的形态和分布特征

    Institute of Scientific and Technical Information of China (English)

    陈春霄; 郑丙辉; 王金枝; 王坤; 姜霞; 赵铮

    2015-01-01

    To investigate the impacts of eutrophication on the biogeochemical cycling of mercury in Taihu Lake,the contents and distribution of the total mercury (THg),dissolved mercury (DHg),total methylmercury (TMeHg) and dissolved methylmercury (DMeHg) were investigated in different eutrophicated lake regions (Zhushan Bay,Gonghu Bay and the southern part of Taihu Lake) during a heavy algal bloom in 2011.The results indicated that there was no significant difference in the ρ(THg) (4.67-12.15 ng/L) or ρ(DHg) (2.27-10.36 ng/L) among the three regions.ρ(RHg) (0.79 ng/L) was affected by algal activities;the higher the trophic level was,the lower the ρ (RHg) level was.In the lake water,ρ (TMeHg) and ρ (DMeHg) were 0.10-0.27 and 0.09-0.23 ng/L,respectively.The relatively low methylmercury contents might be the result of the uptake by algae,and the fact that high Eh and pH inhibited the mercury methylation.However,the relatively high ρ(TMeHg) (0.22 ng/L) in hyper-eutrophication sites of Zhushan Bay may have been influenced by the high primary productivity and algal blooms.%为研究富营养化对太湖汞形态分布特征的影响,于2011年水华暴发期,在太湖不同营养水平湖区(竺山湾、贡湖湾及南太湖)采集水样,测定了水体中THg(总汞)、DHg(溶解态总汞)、RHg(活性汞)、TMeHg(总甲基汞)、DMeHg(溶解态甲基汞)的质量浓度及其分布特征.结果表明,太湖不同营养水平湖区水体中ρ(THg)和ρ(DHg)无显著差异,ρ(THg)为4.67 ~ 12.15 ng/L,ρ(DHg)为2.27 ~ 10.36 ng/L.太湖水体中ρ(RHg)平均值为0.79 ng/L,藻类的生长对水体中ρ(RHg)的分布有显著影响,水体营养水平越高,ρ(RHg)越低.水体中ρ(TMeHg)和ρ(DMeHg)分别为0.10~0.27和0.09 ~0.23 ng/L,藻类的吸附及水体中较高的Eh(氧化还原电位)和pH抑制了汞的甲基化,但在富营养化较严重的竺山湾,受藻类生长及水华的影响,水体中ρ(TMeHg) (0.22ng/L)仍相对较高.

  17. 太湖地区小麦赤霉病与ENSO事件之关系及其预报%Relationship of ENSO to Winter Wheat Gibberellin in the Area of Taihu Lake and Its Prediction

    Institute of Scientific and Technical Information of China (English)

    居为民; 高苹; 武金岗

    2001-01-01

    统计分析了江苏省太湖地区小麦赤霉病发生规律及其对ENSO事件的响应特征,发现在ENSO事件开始或维持的下一年,太湖地区小麦赤霉病常偏重发生。在此基础上,建立了太湖地区小麦赤霉病的海温长期预报模型。%Based on the data of SST(Sea Surface Temperature)and winter wheat gibberellin in the area of Taihu Lake of Jiangsu Province from 1952 to 1998,the statistical analyses of regularity on occurrence of the gibberellin and its response to ENSO were carried out . It was found out that situation of the gibberellin would be heavier in the next year when ENSO begins or lasts. Finally, long-range prediction model of the gibberellin was developed according to the result from the analyses.

  18. Detection of climate change and projection of future climate change scenarios in Taihu Lake Basin%太湖流域气候变化检测与未来气候变化情景预估

    Institute of Scientific and Technical Information of China (English)

    徐宗学; 刘浏

    2012-01-01

    基于1954-2006年太湖流域6个气象站点的降水、气温资料,探讨了1954年以来太湖流域的气候变化问题,并同时应用统计降尺度模型SDSM和动力降尺度模型PRECIS,对太湖流域的日降水量和日最高、最低气温进行降尺度处理,建立未来2021-2050年的气候变化情景.结果表明:20世纪90年代以来,太湖流域发生了突变式增温,冬、春季节尤为显著;太湖流域降水变化相对较复杂,Mann-Kendall法检测到太湖流域年降水量呈振荡性周期变化,并在1980年和2003年发生突变,而Pettitt方法没有检测出太湖流域年降水量的突变.两种降尺度方法模拟的未来时期日最高、最低气温季节和年的变化情景增幅总体上基本一致,均呈显著增加趋势,与Mann-Kendall趋势分析结果一致,高排放情景A2下模拟生成的情景增温幅度较低排放情景B2大,最高气温增加幅度比最低气温明显.降水变化情景差异较大,SDSM模拟的未来时期降水并无明显变化趋势,而PRECIS模拟结果与趋势检验结果较为一致,即未来降水增加趋势明显,增幅较大,总体上全流域年降水量呈增加趋势,并且在未来一段时间内仍将持续增加.%Based on the data of precipitation and temperature at 6 meteorological stations in Taihu Lake Basin from 1954 to 2006, the problems of climate change in the basin during the past 53 years are investigated. The scenarios of climate change during the period from 2021 to 2050 are generated through the downscaling treatment of daily precipitation and the maximum and minimum daily air temperatures in the basin by means of the statistical downscaling model (SDSM) and the providing regional climates for impacts studies (PRECIS). The results show that since the 1990s, the abrupt increase of temperatures has been occurred in Taihu Lake basin, especially in winter and spring. The change of precipitation in the basin has been relatively complex. The annual

  19. Determining Long-Term Trends of Four Fast-Eutrophicated Lakes in China and Finland

    DEFF Research Database (Denmark)

    Liao, Mengna; Yu, Ge; Ventelä, Anne-Mari

    2016-01-01

    in different trophic stages, which represent three developing stages from forest- to agriculture-, and then to urban-lake, typically in Lakes Lugu, Taibai, and Taihu. To determine long-term water quality trends, the three lakes were chosen for statistic analysis on dominant effects on the diatom...... by increases in tourism, farming and urbanization respectively. Water quality changes in Lakes Lugu, Taibai and Taihu captured 68.4%, 54.9%, and 86.0% of the temperature variations before the turning points. The anthropogenic impacts explained 84.0%, 96.4% and 96.0% of the water quality variations after...

  20. 太湖东部地区利用太湖规划建设备用水库的关键问题探讨%Discussion on Some Key Issues of Using Taihu Lake to Plan and Construct Spare Reservoir in Eastern Region of Taihu Basin

    Institute of Scientific and Technical Information of China (English)

    胡伟

    2011-01-01

    围绕太湖备用水库的选址、建设、运行及维护全过程中需要关注并亟待解决的问题出发,从技术、经济及生态保护等多角度阐述了备用水库规模确定、水库水体流动、水质的维护及联合调度等关键问题的工程设计思路,以尽量降低或减免建设对太湖水质的影响.%Several key issues on spare reservoir location, construction, operation and maintenance were expounded in this paper, which should be paid great attention and must be solved. Meanwhile, from the technical, economic, and ecological protection angles, some design ideas on the critical problems of project design were put forward such as spare reservoir scale determination, water flowing, water quality maintenance and combined scheduling, so as to decrease or avoid the influence of construction to Taihu Lake.

  1. Bathymetry of Lake Erie and Lake Saint Clair

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lake Erie and Lake Saint Clair has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and geophysical data and...

  2. Remote sensing monitoring and analysis of dominant species of submerged vegetation in Taihu Lake over last 30 years%近30年太湖沉水植物优势种遥感监测及变化分析

    Institute of Scientific and Technical Information of China (English)

    王琪; 周兴东; 罗菊花; 陈冲

    2016-01-01

    Multi-temporal remote sensing image data over the periods from 1985 to 1986 , from 1995 to 1996 , from 2004 to 2006 , and from 2014 to 2015 were used to construct a classification tree ( CT ) model for aquatic vegetation. With consideration of the differences in phenological information of submerged vegetation in Taihu Lake, the succession of the dominant species of submerged vegetation in the lake over the last 30 years was studied. The overall accuracies and Kappa coefficients of the remote sensing classification results for the four periods were 64. 86% and 0. 59, 70. 83% and 0. 65, 63. 93% and 0. 50, and 64. 94% and 0. 60, respectively. The results show that Potamogeton malaianus has expanded from Dongshan Bay to Xishan Island, and from East Taihu Lake to South Taihu Lake from 1985 to 2015 . There was a declining trend in the growth of Vallisneria spiralis in the Zhushan and Meiliang bays. There was only one kind of submerged vegetation ( i. e. , Potamogeton orispus) in Meiliang Bay in recent years. No submerged vegetation was found in the central part of the lake. The submerged vegetation was widely distributed in East Taihu Lake, with the most species. The submerged vegetation has experienced the following four stages of succession in the last 30 years: Vallisneria spiralis-Potamogetonaceae, Potamogeton pusillus, Ceratophyllum Demersum-Elodea nuttalli, and Potamogetonaceae-Elodea nuttalli. Eutrophication and aquatic breeding are the main factors leading to the succession of submerged vegetations in Taihu Lake.%利用1985—1986年、1995—1996年、2004—2006年和2014—2015年多时相遥感影像数据,构建了水生植物分类决策树模型,结合沉水植物的生活史差异,研究太湖近30年沉水植物优势种的演替模式。4个时期的沉水植物遥感分类总体精度与 Kappa 系数依次为64.86%和0.59,70.83%和0.65,63.93%和0.50,64.94%和0.60。研究表明:1985—2015年马来眼子菜由东山湾向西山岛、东太湖向南

  3. Lake metabolism scales with lake morphometry and catchment conditions

    DEFF Research Database (Denmark)

    Stæhr, Peter A.; Baastrup-Spohr, Lars; Jensen, Kaj Sand

    2012-01-01

    We used a comparative data set for 25 lakes in Denmark sampled during summer to explore the influence of lake morphometry, catchment conditions, light availability and nutrient input on lake metabolism. We found that (1) gross primary production (GPP) and community respiration (R) decline with lake...... in lake morphometry and catchment conditions when comparing metabolic responses of lakes to human impacts....

  4. Characteristics of Periphytic Algae Communities in Wuli Lake,Lake Taihu%太湖五里湖着生藻类群落结构特征分析

    Institute of Scientific and Technical Information of China (English)

    丁娜; 徐东坡; 刘凯; 周彦锋

    2015-01-01

    A monthly monitoring program of periphytic algae was conducted on Wuli Lake in Wuxi City from May 2009 to June 2010.Based on the investigations,periphytic algae species composition,biomass,tempo⁃ral distribution and community structure were analyzed with Pielou uniformity index,Mcnaughton predominance index and Shannon⁃Wiener diversity index.The results showed that there were 5 classes including 43 species of periphytic algae in Wuli Lake.Among them, Bacillariophyta was the predominant phylum,which had 24 spe⁃cies,accounting for 55. 81% of the total species. Chlorophyta was recorded 16 species, which accounted for 37.21% of the total species.1,3 species of Cyanophyta and Cryptophyta were recorded respectively,1 species of Euglenophyta was recorded,which accounted for 2. 33%. There were 20 species of periphytic algae being the dominant species in Wuli Lake;Bacillariophyta was the dominant class in Wuli Lake.The biomass of periphytic algae in Wuli Lake ranged from 0.88×104 ind./cm2 to 2.73×104 ind./cm2,its annual mean was 1.95×104 ind./cm2.The community structure and amounts of the periphytic algae varied seasonally.The species and amounts of periphytic algae were the largest in summer and the smallest in winter.Periphytic algae varied spatially both in terms of taxonomic composition and abundance. The taxonomic amounts of periphytic algae in sludge areas of algae were more than in other bottom sediment areas.The Shannon⁃Wiener diversity index ranged from 2.12 to 2.94,the mean value was 2.50,the Pielou uniformity index ranged from 0.76 to 0.88,the mean value was 0.85. In conclusion,the periphytic algae community structure was in a complex,integrated state in Wuli Lake.%通过对2009年5月—2010年6月五里湖人工基质上着生藻类群落的全年连续监测,研究了五里湖着生藻类群落的种类组成、数量及其时空差异。结果表明,五里湖共检出着生藻类5门34属43种,其中硅藻门为全年优势门类,共12属24

  5. 太湖流域生态系统健康的空间分异及其动态转移%Spatial Variation and Dynamics of Ecosystem Health in the Taihu Lake Watershed

    Institute of Scientific and Technical Information of China (English)

    许妍; 高俊峰; 高永年; 刘聚涛

    2011-01-01

    根据研究地域的生态特征,综合考虑流域内生态系统相互影响机制,结合遥感解译、野外调查及社会统计等多源数据,运用PSR模型从胁迫因子、状态因子以及效应因子三方面构建了流域生态系统健康评价指标体系,对太湖流域综合生态健康进行评价,并对其空间分异及动态转移特征进行深入分析.结果表明:2000年-2008年间,研究区域生态系统健康状况整体处于亚健康水平,区域综合生态健康指数由2000年的0.584下降至2008年的0.512,有92%的区域综合生态健康指数呈下降态势.生态健康存在明显区域性差异,整体呈现由东北至西南逐渐下降的趋势.生态健康状态较好的区域主要集中在西南部苕溪流域的安吉县、德清县及长兴县一带,而生态健康较差的区域主要分布于东北部的无锡市区和常州市区.%Based on ecological characteristics of the Taihu Lake watershed, the authors synthetically considered mechanisms of the interactions among ecosystems in the watershed. Using multiple scenes of Landsat Thematic Mapper (TM) imageries, land use/cover data, field investigation data, and social statistic data within the framework of the Pressure-State-Response (P-S-R) model, we constructed a comprehensive assessment index system about ecosystem health,evaluated the ecological health of the Taihu Lake watershed, as well as analyzed the spatial variation and dynamics of ecosystem health. Results showed that during the period 2000-2008, the ecosystem health maintained a subhealthy level as a whole. The comprehensive ecological health index decreased from 0.584 to 0.512, with showing a decreasing comprehensive ecological health index across almost 92% of the study area. Areas with better, moderate, and worse health conditions accounted for 14.29%, 71.43%, and 14.29% of the total area, respectively. There were no areas with the best health conditions. Ecological health for about 28.57

  6. 基于ELCOM-CAEDYM模型的太湖蓝藻水华早期预测探讨%The discussion of the early forecasting of cyanobacteria bloom in the Lake Taihu based on ELCOM-CAEDYM model

    Institute of Scientific and Technical Information of China (English)

    王长友; 于洋; 孙运坤; 李洪利; 孔繁翔; 张民; 史小丽; 阳振

    2013-01-01

    结合太湖蓝藻水华形成的“四阶段理论”,基于澳大利亚西澳大学水研究中心开发的ELCOM-CAEDYM耦合模型框架构建了太湖水华蓝藻生态动力学模型,对蓝藻水华的形成进行模拟,分析了太湖蓝藻水华早期预测的可行性.结果表明:该模型在较长时间尺度上对春季复苏阶段及生长上浮阶段蓝藻水华的形成模拟效果较好,蓝藻生物量模拟值与站点调查值的误差变化范围在1.0%~70.4%,平均误差为28.0%,与MODIS卫星反演值的误差变化范围在3.8%~83.9%,平均误差40.5%;但越冬阶段蓝藻生物量模拟输出值与站点调查值的误差变化范围在3.0%~143.6%,平均误差为40.1%,与MODIS卫星反演值的误差变化范围在9.7%~118.4%,平均误差为48.8%,表明模型对蓝藻越冬过程模拟能力还不强,应在蓝藻越冬机制模拟计算方面进一步改进,以满足蓝藻水华早期预测的需要.%An ecological dynamic model for cyanobacteria bloom in Taihu Lake was structwed based on the theory of "four phases of cyanobacteria bloom development" and the coupling model of ELCOM - CAEDYM developed by Centre for Water Research, University of Western Australia. The cyanobacteria bloom development was modeled and the possibility for early forecast of cyanobacteria bloom in Taihu Lake was discussed. The model outputs met well with the cyanobacteria biomass in a large temporal scale covering the phases of anabiosis, growth and upfloat. The differences between modeled data and field-determined (or surveyed) ones varied in the range 1.0%~70.4% with a mean of 28.0%. The differences between modeled data and the inferred ones from MODIS satellite imagery varied in the range 3.8%~83.9% with a mean of 40.5%. However, the model outputs weakly reflected the cyanobacteria biomass in the phase of overwintering, the differences ranged from 3.0% to 143.6% with a mean of 40.1% between modeling data and the field

  7. Analysis on Pollution Characteristics of the Textile Industry in Typical Region of Taihu Lake Basin%太湖流域典型区域纺织行业污染特征分析

    Institute of Scientific and Technical Information of China (English)

    王水; 屈健; 李冰; 刘伟; 柏立森

    2012-01-01

    Based on municipal pollutant sources data of Taihu Lake Basin in 2009, the spatial distribution and pollution characteristics in recent years of the textile industry in the typical region of the Taihu Lake Basin was analyzed. Identified heavy polluting industries by two indicators like economic contribution rate and pollution contribution rate, evaluated the coordination of economic development with pollution emissions and resource consumption of different enterprises by emission unfair coefficient, resource consumption unfair coefficient. The results showed that 66.1% of the region's textile enterprises located in Wujin, Huishan and Yixing. Cotton, chemical fiber dyeing finishing industry is the leading industries in the region, accounting for 56% enterprises, 72.8% economic contribution rate. The contribution rate of industrial wastewater, COD and ammonia nitrogen as high as 88.7%, 81.5% and 89.1%. the 81.6% of textile companies which Industrial output value is less than 5 million, accounted 0.73% economic contribution rate, and the match between economic and pollution, resource consumption is poor, the imbalance of pollution emissions and resource consumption is particularly prominent.%基于2009年太湖流域各市污染源统计及调查数据,分析了近年太湖流域典型区域的纺织行业空间分布特征和污染特征,利用经济贡献率、污染贡献率2项指标识别了重污染行业,利用污染物排放不公平系数、资源消耗不公平系数指标评价了不同规模企业的经济发展与污染排放及资源消耗的协调关系.结果表明,研究区内66.1%的纺织企业分布于武进区、惠山区和宜兴市.棉、化纤印染精加工业是该区域纺织行业的主导产业,企业数量占56%,经济贡献率为72.8%,工业废水、COD及氨氮等污染物贡献率分别高达88.7%,81.5%和89.1%.棉、化纤印染工业总产值小于5千万的纺织企业数量占81.6%,经济贡献率仅为0.73%,且

  8. Muti-model Collaborative Retrieval of Chlorophyll a in Taihu Lake Based on Data Assimilation%基于数据同化的太湖叶绿素多模型协同反演

    Institute of Scientific and Technical Information of China (English)

    李渊; 李云梅; 吕恒; 朱利; 吴传庆; 杜成功; 王帅

    2014-01-01

    Under the efforts of many scholars, large amount of remote retrieval models of water quality parameters have been developed. However, each model could only reflect the“true value” from one level because of the natural limitation of remote sensing. To get the relatively true value by combining various retrieval models, in this work, we developed a multi-model collaborative retrieval algorithm for retrieving the concentration of Chlorophyll a based on data assimilation. We measured water quality parameters and water reflectance spectra in Taihu Lake during 2006 to 2009. There were seven retrieve models established and six models were selected to participate in the multi-model collaborative retrieval algorithm. Then these selected models were combined to establish a multi-model for retrieving the concentration of Chlorophyll a. The results indicated:① the accuracy of multi-model retrieval algorithm was better than that of single-model retrieval method, with an optimal MAPE of only 22. 4℅; ② with more models participating in the multi-model collaborative retrieval algorithm, the accuracy became better, the average MAPE was decreased from 25. 6℅ to 23. 4℅, the average RMSE was decreased from 15. 082 μg•L-1 to 14. 575 μg•L-1 , and the average correlation coefficient was improved from 0. 91 to 0. 92;③ the accuracy and errors of retrieval products could be effective evaluated through calculating the confidence interval, which makes possible the acquirement of spatial and temporal error distribution of Chlorophyll a concentration retrieval in Taihu Lake.%在国内外众多学者的不懈努力下,开发了大量的水质参数遥感估算反演模型,但不同的模型都具有其“局限性”,只能从某个层面反映“真值”.基于上述考虑,本研究发展了基于数据同化方法的太湖叶绿素a浓度多模型协同反演算法.利用2006~2009年太湖野外实测水体高光谱遥感反射率数据,构建了7个叶绿素a浓度反

  9. 太湖流域水资源保护天地一体化监测体系构想%An Idea of An Integrated Sky-earth Monitoring System for Water Resources Protection in Taihu Lake Valley

    Institute of Scientific and Technical Information of China (English)

    左一鸣; 李健; 林荷娟

    2013-01-01

    According to current status and existing problems of monitoring for water resources protection in the Taihu lake valley, the essay provides an idea of an integrated sky-earth monitoring system for water resources protection in the Taihu lake valley based on the application of remote sensing at water environment monitoring. The system consists of network guarantee system, standard system, satellite-earth monitoring system, analysis and evaluation system, and early-warning system. The satellite-earth monitoring system offers monitoring measures of satellite remote-sensing imagery monitoring, automatic water quantity and quality station monitoring, conventional tour gauging and additional mobile gauging. Through a comparison between tour gauging data, automatic monitoring station data and analytic data from satellite remote-sensing images, water environment status distribution of the valley can be analogized. By using standard system to ensure data consistency, network guarantee system to ensure data integration, analysis and evaluation system to describe data utility, and early-warning system to predict and prevent future events based on monitoring data, an overall integrated monitoring is realized.%  针对太湖流域原有水资源保护监测的现状和存在问题,结合遥感技术在水环境监测中的应用,提出太湖流域水资源保护天地一体化监测体系的构想。一体化监测体系包括网络保障、标准、星地监测、分析评价和预警等系统,其中星地监测体系包括遥感卫片监测、水量水质自动站监测、常规巡测和移动加测,这4种监测手段各有优缺点,具体监测时以常规巡测和自动站监测数据为基础,通过与遥感卫片解析数据进行比对,建立相关关系,类推出全流域水环境现状分布情况;标准体系建设保障监测数据的一致性;网络保障体系建设保障数据的完整性;分析评价系统是对监测数据的实用性

  10. Temporal and spatial patterns of Limnodrilus hoffmeisteri Claparède in Lake Taihu%太湖霍甫水丝蚓(Limnodrilus hoffmeisteri Claparède)的时空格局

    Institute of Scientific and Technical Information of China (English)

    李艳; 蔡永久; 秦伯强; 龚志军

    2012-01-01

    The population of Limnodrilus haffmeisteri Claparede in Lake Taihu ( Eastern China) wag investigated in 2005 by monthly sampling. The annual average density and biomass of this worm were 3273. 75 ind. /m2 and 4. 697 g/m2, respectively. Both population density and biomass peaked in February. According to the annual dynamics of the frequency distributions of body length, the species had three generations and reproduced in considerable time throughout the year. The results showed a strong clumped distribution pattern of L hqffineisteri but it changed hole among seasons. The highest population density and biomass of L. hoffineisteri were found in Meiliang Bay, Zhushan Bay and the river-mouths areas in the west, while other plar.es of the lake had very low worm density. The key factors regulating this spatial distribution pattern may be nutrient state, types of substrate, food availability and habitat stability.%2005年1-12月对太湖霍甫水丝蚓进行了逐月调查.太湖霍甫水丝蚓年均密度和生物量分别为3273.75 ind./m2和4.697 g/m2,均在2月份达到最大值.根据体长频数分布的周年变化,推测太湖霍甫水丝蚓一年有三代.太湖霍甫水丝蚓密度和生物量在空间上表现出明显的差异性,且随季节变化较小,其高值区域均出现在太湖北部梅梁湾和竺山湾及西部河口湖区,而在其它区域的现存量均较低.分析表明太湖霍甫水丝蚓空间差异可能与营养水平、底质类型、可摄食的食物及生境的稳定性等因素有关.

  11. Comparison of RT-qPCR approaches for quantification of cyanobacteria in Lake Taihu%应用RT-qPCR技术定量检测湖泊水体中蓝藻方法的比较

    Institute of Scientific and Technical Information of China (English)

    彭宇科; 岳冬梅; 武俊; 肖琳; 杨柳燕

    2011-01-01

    In the study, four methods used for quantification of cyanobacteria and Microcystis by SYBR Green Ⅰ real-time quantitative PCR (RT-qPCR) were established based on the target genes, including the 16S rRNA gene of cyanobacteria, the phycocyanin and the 16S rRNA gene of Microcystis.Then the cultured M.aeruginosa and the environmental samples of Lake Taihu were evaluated by the established methods.Comparison between the new approaches and microscope counting indicated that RT-qPCR analysis could meet the requirement of algae bloom quantification and it was convenient, rapid and specific.%利用RT-qPCR技术建立了对湖泊水体中的微囊藻和蓝藻的SYBR Green Ⅰ荧光定量PCR检测方法,在所建立的方法中,对以微囊藻藻蓝蛋白基因、蓝藻16S rRNA基因、微囊藻16S rRNA基因分别作为RT-qPCR检测的目的基因所得结果进行了比较,并对实验室培养的微囊藻和太湖的环境样品进行了检测.结果表明,用藻蓝蛋白基因作为检测目的基因,以M.aeruginosa PCC 7806基因组DNA作为标准品的测定方法与显微镜计数的结果有较好的相关性和一致性,并具有简便、快速、特异性高的特点,可以满足检测的要求.

  12. DNR 24K Lakes

    Data.gov (United States)

    Minnesota Department of Natural Resources — Medium scale lake polygons derived from the National Wetlands Inventory (NWI) polygons and MnDOT Basemap lake delineations. Integrated with the DNR 24K Streams...

  13. Lake trout rehabilitation in Lake Ontario

    Science.gov (United States)

    Elrod, Joseph H.; O'Gorman, Robert; Schneider, Clifford P.; Eckert, Thomas H.; Schaner, Ted; Bowlby, James N.; Schleen, Larry P.

    1995-01-01

    Attempts to maintain the native lake trout (Salvelinus namaycush) population in Lake Ontario by stocking fry failed and the species was extirpated by the 1950s. Hatchery fish stocked in the 1960s did not live to maturity because of sea lamprey (Petromyzon marinus) predation and incidental commercial harvest. Suppression of sea lampreys began with larvicide treatments of Lake Ontario tributaries in 1971 and was enhanced when the tributaries of Oneida Lake and Lake Erie were treated in the 1980s. Annual stocking of hatchery fish was resumed with the 1972 year class and peaked at about 1.8 million yearlings and 0.3 million fingerlings from the 1985–1990 year classes. Survival of stocked yearlings declined over 50% in the 1980 s and was negatively correlated with the abundance of lake trout > 550 mm long (r = −0.91, P < 0.01, n = 12). A slot length limit imposed by the State of New York for the 1988 fishing season reduced angler harvest. Angler harvest in Canadian waters was 3 times higher in eastern Lake Ontario than in western Lake Ontario. For the 1977–1984 year classes, mean annual survival rate of lake trout age 6 and older was 0.45 (range: 0.35–0.56). In U.S. waters during 1985–1992, the total number of lake trout harvested by anglers was about 2.4 times greater than that killed by sea lampreys. The number of unmarked lake trout < 250 mm long in trawl catches in 1978–1992 was not different from that expected due to loss of marks and failure to apply marks at the hatchery, and suggested that recruitment of naturally-produced fish was nil. However, many of the obstacles which may have impeded lake trout rehabilitation in Lake Ontario during the 1980s are slowly being removed, and there are signs of a general ecosystem recovery. Significant recruitment of naturally produced lake trout by the year 2000, one interim objective of the rehabilitation plan for the Lake, may be achieved.

  14. LAKE VICTORIA BASIN

    African Journals Online (AJOL)

    selected satellite lakes and Mara River in Lake Victoria basin, during wet and dry seasons in. 2002. Samples ... The wet season recorded higher biomass in all satellite lakes than during the dry season (t = 2.476, DF ..... communication. Urbana ...

  15. ISOTOPIC TRACING OF TERRESTRIAL CONTRIBUTION TO ORGANIC MATTER OF SEDIMENTS IN THE ESTUARY OF TAIHU LAKE BASIN%外源对太湖河口沉积物有机质贡献的同位素示踪

    Institute of Scientific and Technical Information of China (English)

    曾海鳌; 吴敬禄

    2009-01-01

    分析了太湖流域不同土地利用类型土壤、河口表层沉积物及主要生物的有机碳含量和同位素分布特征,并利用端元混合法求取了陆源输入对湖泊沉积物有机质的贡献及分布.研究结果表明,流域表层土壤有机质δ~(13)C受植物群落的δ~(13)C值影响,不同植被类型的土壤有机质δ~(13)C值存在差异.茶园、菜地、林地和农田δ~(13)C_(org)平均值分别为-25.4‰、-25.8‰、-27.1‰和-28.1‰,其中茶园有机碳同位素值最高.河口表层沉积物有机碳同位素变化范围为-27.5‰~-25.1‰,平均值为-25.7‰.河口近岸区域表层沉积物δ~(13)C_(org)偏低,且以河口为轴心向湖心逐渐增大,呈扇形条状分布,其分布主要受低δ~(13)C值的陆源有机质输入影响.利用端元混合法求得近河口表层沉积物中陆源有机质贡献高达70%~80%,随着离岸距离的增加,陆源有机质贡献量逐渐减少.%The authors analyzed characteristics of organic carbon content and isotope distribution of top soil in different Land use types within the Taihu Lake basin, as well as surface sediments and organisms within the estuary. The sources of organic matter of lake sediments were obtained by using two-member mixing model. The results showed that there were differences of organic δ~(13)C in different plant types, which affected organic δ~(13)C of top soil within the catchment. The average δ~(13)C_(org) values of tea plantations, vegetable lands, forest lands and paddy fields were - 25. 4‰, - 25. 8‰,-27.1‰ and -28. 1‰ respectively,and the highest δ~(13)C_(org) value existed in tea plantations. The range of δ~(13)C_(org) values of surface sediments within the estuary were -27. 5‰~-25. 1‰ with the average value of -25. 7‰. The δ~(13)C_(org) of surface sediments near the shore was low, and gradually decreased from the estuary to center. The reason was the effect of import of terrestrial source with lower δ~(13)C

  16. Determining Long-Term Trends of Four Fast-Eutrophicated Lakes in China and Finland

    DEFF Research Database (Denmark)

    Liao, Mengna; Yu, Ge; Ventelä, Anne-Mari;

    2016-01-01

    the turning points, where the sharp change of water quality by human activity has played an accelerated effect on the gentle change of temperature. Compared with the 4 phases of water quality development in Pyhäjärvi Lake (SW Finland), Lakes Lugu and Taibai have experienced the 1st and 2nd phases, and Taihu...

  17. 经济快速增长区土地利用信息图谱构建——以江苏省环太湖地区为例%Construction of Land Use Information Tupu in the Rapidly Developing Regions: A Case Study of the Surrounding Regions of Taihu Lake In Jiangsu Province

    Institute of Scientific and Technical Information of China (English)

    陆汝成; 黄贤金; 左天惠; 肖思思; 张兴榆; 赵小风

    2009-01-01

    Based on four remote sensing data of land use in the regions surrounding Taihu Lake in Jiangsu Province from 1980 to 2005, the theory of Geo-information Tupu and GIS technology, land use pattern information Tupu, classification information Tupu and transfer information Tupu are constructed in 4 units of the timing sequence. The result from Tupu construction indicates that the land use change has the obvious characteristics of spatial and temporal variation, and that transfer information Tupu of the surrounding regions of Taihu Lake is similar in the past 25 years. The characteristics of spatial and temporal variation are mainly reflected in the adjustment of the internal structure of agriculture from 1980 to 1990. However, it manifests that construction land has occupied a large area of cultivated land after 1990. The similar transfer information Tupu suggests that cultivated land has been converted to various types of land from 1980 to 2005. According to the integrated application of CLUE-S and Markov model, the land use change is simulated to complement the shortcomings of previous study of land use information Tupu which lacks simulation of the future. According to the simulation result, it can be concluded that both the increase rate of construction land and the decrease rate of cultivated land will reduce because of the planning target control and of the enhanced land intensive utilization of the surrounding regions of Taihu Lake in 2015. Big cities such as Suzhou, Wuxi and Changzhou are the typical regions of land use changes around Taihu Lake Regions. In these areas, land use changes are fast in response to the rapid economic growth around Taihu Lake Regions. The rate at which cultivated land is converted to construction land is large in the periphery of cities and towns, along the traffic routes, around the lake areas, and other regions. The research can enrich the research methods of land use information Tupu, summarize the spatial and temporal changes of

  18. 大型浅水湖泊与大气之间的动量和水热交换系数——以太湖为例%Transfer coefficients of momentum, heat and water vapour in the atmospheric surface layer of a large shallow freshwater lake: A case study of Lake Taihu

    Institute of Scientific and Technical Information of China (English)

    肖薇; 刘寿东; 李旭辉; 王伟; 胡凝; 江晓东; 李永秀; 徐向华; 张雪松

    2012-01-01

    and mieromeieorology measurements made over a large shallow freshwater lake (Lake Taihu) shows that the. Transfer coefficients of momentum ( CDION ) , water ( CEION ) and heat ( CHION ) were CDION = 1.52 ×10 -3, CEION = 0. 82 × 10-3 and CHION = 1. 02 × 10 ~ , respectively. These values are in good agreement with the values derived from the eddy covarianec measurement in other inland lakes. Comparison with oeeanographic parameterizations suggests that lake surfaces were aerodynamic-ally rougher than open oceans under similar wind conditions, which may due to the shallow depth of the lake, and that these parameterizations can bias the annual lake evaporation estimate by as much as 40% higher. Our results also suggest that these coefficients ran be regarded as constants independent of stability and wind speed. Sensitivity analysis indicated that the mean error between calculation and observation of latent heat flux ( LE) decreased 0. 5 W/m2 , that of sensible heat flux (H) decreased 0. 4 W/m2 , and no difference between friction velocity (u ) calculation and observation if stability correction was considered since around 83% of data were in neutral condition. If the effect of wind was considered, the mean error between calculation and observation decreased 0.004 m/s for u, , increased 1. 3 W/m2 for IE, and negligible for H. This study can provide reference for the research on lake-atmosphere interaction.

  19. 太湖沉积物中多溴联苯醚和类二(噁)英多氯联苯的水平垂直分布%Vertical Distribution of PBDEs and DL-PCBs in Sediments of Taihu Lake

    Institute of Scientific and Technical Information of China (English)

    马召辉; 金军; 亓学奎; 王英; 姜霞; 何松洁; 李明圆

    2013-01-01

    Sediment core samples collected from the Zhushan Bay, Meiliang Bay, South Taihu of Taihu Lake were analyzed for 8 polybrominated diphenylethers (PBDEs) and 12 dioxin-like PCBs (DL-PCBs). The results revealed that the PBDEs levels were highest in the Zhushan Bay, followed by Meiliang Bay and South Taihu; and the DL-PCB levels were highest in the Meiliang Bay, followed Zhushan Bay and South Taihu. The vertical distribution of PBDEs level showed an exponential growth trend in Taihu Lake sediments, BDE-209 was the most abundant PBDEs congeners; and the vertical distribution of the DL-PCBs level in the sediments revealed that the contamination caused by DL-PCBs continued to increase in recent years, indicating that there were PCBs sources in the Taihu Lake region. There was significant difference in the composition of PBDEs congeners at different depths in the sediments of Meiliang Bay, however, the detailed causes remain to be investigated in further studies. The vertical distribution pattern of PCBs congeners revealed that PCB-77 ,-118 ,-105 levels significantly decreased with increasing depth in 0-15 cm upper sediments and there were no significant change in the lower sediments.%分析了太湖竺山湾、梅梁湾、南太湖的3个柱状沉积物样品中8种溴代阻燃剂(PBDEs)和12种类二(噁)英多氯联苯(DL-PCBs).结果表明太湖PBDEs污染水平为竺山湾最高,其余依次为梅梁湾、南太湖;DL-PCB污染水平梅梁湾最高,其次则为竺山湾、南太湖.沉积物中PBDEs的水平垂直分布显示:近年来在太湖PBDEs污染呈现指数式增长趋势,BDE-209为最主要的PBDEs同族体;沉积物中DL-PCBs的水平垂直分布显示:DL-PCBs污染近年仍有增加,说明在太湖地区存在PCBs的释放源.太湖梅梁湾不同深度的沉积物中PBDEs同族体组成差异明显,具体原因需要进一步研究证实.PCBs在垂直分布模式显示:在0 ~ 15 cm的上层沉积物中PCB-77、-118、-105水平随深度增加而

  20. Lake retention of manufactured nanoparticles

    NARCIS (Netherlands)

    Koelmans, A.A.; Quik, J.T.K.; Velzeboer, I.

    2015-01-01

    For twenty-five world lakes and three engineered nanoparticles (ENP), lake retention was calculated using a uniformly mixed lake mass balance model. This follows similar approaches traditionally used in water quality management. Lakes were selected such that lake residence times, depths and areal hy

  1. Lake retention of manufactured nanoparticles

    NARCIS (Netherlands)

    Koelmans, A.A.; Quik, J.T.K.; Velzeboer, I.

    2015-01-01

    For twenty-five world lakes and three engineered nanoparticles (ENP), lake retention was calculated using a uniformly mixed lake mass balance model. This follows similar approaches traditionally used in water quality management. Lakes were selected such that lake residence times, depths and areal hy

  2. 太湖水华危机应急预案在线风险补偿启动策略%Online Risk-reward Starting Strategy of Emergency Preplan Against Water Bloom Crisis in Taihu Lake

    Institute of Scientific and Technical Information of China (English)

    余昇; 徐寅峰; 郑斐峰

    2011-01-01

    In coping with crises, when to start an emergency preplan is a problem that calls for solution.Water bloom crisis in Taihu Lake represents a kind of public health emergency whose growth rate or diffusion speed is unexpected.Based on online theory and taking this crisis as the background, the authors present preplan starting strategy and prove it to be optimal competitive strategy.At the same time, taking into account the expectation of further information, we design an online risk-reward starting strategy.At last a practical example is given, which points out the relationship between the competitive ratio of strategy and response intensity of the preplan, and the relationship between the risk-reward and the tolerance of the decision maker.The results of the study have guiding significance and reference value to decision makers facing these crucial emergencies.%应急预案启动时机的选择是应急管理领域中应对危机时需要解决的关键问题.太湖水华危机代表一类具有生长速度或传播速度不确定性的突发公共卫生事件,以此为背景基于在线方法,设计了应急预案启动策略,并证明是最优竞争比策略.同时,考虑到对未知信息的预期,设计了在线风险补偿启动策略.最后对危机进行实际数值计算,并指出策略的竞争性与预案应对强度之间的关系,还有在线风险补偿策略的补偿收益与决策者风险容忍度之间的关系,研究结果具有一定的实际指导意义和参考价值.

  3. Preliminary Study on Freshwater Algae Monitoring by Flow Cytometer: A Case Study in Taihu Lake%应用流式细胞仪监测太湖藻类初探

    Institute of Scientific and Technical Information of China (English)

    徐兆安; 高怡; 吴东浩; 张会勇

    2012-01-01

    Flow cytometer was widely used in marine microbial plankton research, but seldomly used in freshwater algae quantitative study biological monitoring and early warning of algae blooms. In this paper, we discussed the possibility of algae monitoring by CytoSense flow cytometer. The results indicated that field operation is the best way to get good results. The lower detection limit was 1 million cells/L and above which the results of flow cytometer agrees well with manual microscopy results. Besides, flow cytometer acquired reliable reaulta in waters where suspended sediment concentration less than 108 mg/L. Cyt^Sense is portable, easy to operate, and with fast analysis ability and non-pollution to environments. It shows extensive application prospects in Taihu Lake algae monitoring.%流式细胞仪在海水微型浮游生物监测领域应用较为广泛,但在淡水藻类定量研究以及生物监测中应用仍较少.探讨了应用便携式浮游植物流式细胞仪CytoSense监测太湖藻类的可行性和时效性.结果表明,为了提高检测结果的准确性,流式细胞仪的应用过程中最好是现场采样、现场分析.流式细胞仪对藻细胞密度的检测下限为100万个/L,大于100万个/L时检测结果与人工镜检结果相吻合;在悬浮物含量小于108 mg/L的水体中,流式细胞仪检测结果具备较高的准确性.另外,流式细胞仪操作简单、分析速度快、便携性好、无污染,在太湖藻类监测中具有一定应用前景.

  4. O3-BAC工艺处理太湖原水的技术研究和生产实践%Technical study and production practice of the O3-BAC to treat the raw water from Taihu lake

    Institute of Scientific and Technical Information of China (English)

    蒋福春; 张雪; 李琴; 陈玲瑚; 周洵

    2011-01-01

    以苏州相城水厂臭氧—生物活性炭(O3-BAC)工艺的应用情况为基础,分析和探讨该工艺实际应用效果和运行管理要求.结果表明:在常规工艺基础上,有机物去除率可提高20%~40%,氯消毒副产物降低近40%,出厂水水质稳定;O3-BAC工艺能有效应对藻类暴发和原水水质短暂突变等事件;水温对生物活性炭的处理效果影响较大,夏季较冬季理想;运行管理中应重点关注和解决活性炭寿命、溴酸盐、水质生物安全性及冬季高氨氮的处理等问题;针对太湖原水而言,O3-BAC工艺具有一定技术优势.%Based on the application of Ozone-Bilological Activated Carbon (O3 - BAC) in the Xiangcheng Water Treatment Plant of Suzhou, this paper analyzed and studied the practical application effects and operation requirements of this process. The results showed: based on conventional treatment, the organic removal efficiency would be improved by 20%~40%, chlorine disinfection byproducts would be reduced by 40%, and the effluent water quality was stable; O3 -BAC could handle the unexpected accidents, such as algae outbreak, and raw water quality temporal sudden deterio-ration; water temperature had a significant effects on BAC treatment, and the winter treatment was better than summer; during the operation, attention should be paid on the problems such as BAC lifetime, bromated, aqua-organism safety, and high ammonian nitrogen concentration in winter; according to the Taihu lake raw water, the O3 - BAC process had some technical advantages.

  5. 两级臭氧一活性炭组合工艺净化太湖水中试研究%Pilot Study on Two-stage Ozonization and Activated Carbon Process for Taihu Lake Water Purification

    Institute of Scientific and Technical Information of China (English)

    刘洋; 崔云霞

    2011-01-01

    采用两级臭氧-活性炭组合工艺在以太湖水为水源的某水厂进行深度处理中试研究.结果表明:该组合处理工艺对有机污染物有稳定的去除效果,在预臭氧投加重为0.5 mg/L、主臭氧投加量为0.7 mg/L下,相对于原水对CODMn,UV254(紫外吸光度),DOC,THMEP,氨氮,亚硝酸盐氮和硝酸盐氨的平均去除率分别为47.06%,80%,31.92%,58.9%,65.5%,81.25%和9.1%,出永满足GB 5749-2006《生活饮用水卫生标准》的要求,炭滤池出水中臭氧消毒副产物均低于标准限值,组合工艺对有害物质冲击负荷有一定的抵抗能力.%The pilot experiments were carried out to investigate the advanced treatment by the combined process of two-stage ozonization and activated carbon in a plant using Taihu Lake water as raw water. The results showed that the removal of organic pollutants by the combined process was stable. Relative to the raw water, the average removal rates of CODmns UV254, DOC, THMEP, ammonia nitrogen, nitrite nitrogen and nitrate nitrogen were 47.06%, 80%, 31.92%, 58.9%, 65.3%, 81.25% and 9.1% respectively, when the pre-ozonizaiton dosage was 0.5mg/L and the main ozonization dosage was 0.7mg/L. The effluent could meet "Standards of Drinking Water Quality "(GB 5749-2006). The disinfection by-products of ozone were lower than the standard limit in the effluent from carbon filter. The combined process has some resistibility to the impact load of hazardous substances.

  6. Salting our freshwater lakes.

    Science.gov (United States)

    Dugan, Hilary A; Bartlett, Sarah L; Burke, Samantha M; Doubek, Jonathan P; Krivak-Tetley, Flora E; Skaff, Nicholas K; Summers, Jamie C; Farrell, Kaitlin J; McCullough, Ian M; Morales-Williams, Ana M; Roberts, Derek C; Ouyang, Zutao; Scordo, Facundo; Hanson, Paul C; Weathers, Kathleen C

    2017-04-25

    The highest densities of lakes on Earth are in north temperate ecosystems, where increasing urbanization and associated chloride runoff can salinize freshwaters and threaten lake water quality and the many ecosystem services lakes provide. However, the extent to which lake salinity may be changing at broad spatial scales remains unknown, leading us to first identify spatial patterns and then investigate the drivers of these patterns. Significant decadal trends in lake salinization were identified using a dataset of long-term chloride concentrations from 371 North American lakes. Landscape and climate metrics calculated for each site demonstrated that impervious land cover was a strong predictor of chloride trends in Northeast and Midwest North American lakes. As little as 1% impervious land cover surrounding a lake increased the likelihood of long-term salinization. Considering that 27% of large lakes in the United States have >1% impervious land cover around their perimeters, the potential for steady and long-term salinization of these aquatic systems is high. This study predicts that many lakes will exceed the aquatic life threshold criterion for chronic chloride exposure (230 mg L(-1)), stipulated by the US Environmental Protection Agency (EPA), in the next 50 y if current trends continue.

  7. Experimental study on phosphorus release from sediments of shallow lake in wave flume

    Institute of Scientific and Technical Information of China (English)

    SUN; Xiaojing; ZHU; Guangwei; LUO; Liancong

    2006-01-01

    Influence of wave on sediment resuspension and nutrients release from sediments, collected from Lake Taihu and Lake Chaohu, was studied in flume experiments. Under strong-wave conditions, concentrations of suspended solids (SS), total phosphorus (TP) and dissolved total phosphorus (DTP) in overlying water were increased significantly following the sediments re-suspension. During the experiments on sediments of Lake Taihu and Lake Chaohu, TP concentrations increased 6 times and 3 times, and DTP concentration increased 100% and 70% more than it in presuspension, respectively. Concentration of soluble reactive phosphorus (SRP) of experiment on sediment of Lake Taihu increased 25%. During the massive sediment suspension, the dissolved phosphorus in pore water and much of the phosphorus adsorbed by the sediment particles were released into overlying water. The phenomena in this wave flume experiment are quite similar to the situation observed in situ of Lake Taihu. The critical wave stresses of sediment re-suspension are nearly equal. The change of concentrations of SS, TP, and SRP was the same as that in situ situation.This study showed that concentrations of TP and SRP in lake water could be increased significantly by wave disturbance. Phosphorus release was significantly enhanced by wave disturbance at the beginning of massive sediment re-suspension, but decreased later.

  8. Variations and removal methods of odor substances in Shiba Bay of Lake Taihu%太湖十八湾嗅味物质变化规律及除嗅方法

    Institute of Scientific and Technical Information of China (English)

    李巧霞; 潘纲; 王丹; 代立春

    2012-01-01

    To study the variations of odor substances in lakes and solve odor problems,geosmin and MIB concentrations were investigated in the enclosure of Lake Taihu from Dec.2009 to Aug.2010.Results showed that geosmin and MIB followed similar seasonal trends,the concentrations of geosmin and MIB increased in summer and autumn and decreased in winter and spring,MIB was the main odor substance in summer.In the laboratory study,diatomite was used to manipulate ozone’s stability in water,and ozone-diatomite mixture was made which decreased ozone decompositon rate from 0.036/min to 0.015/min.Using this mixture to remove odor substances in simulated water samples,results showed that 73.4% of geosmin and 46.6% of MIB could be removed in 10 minutes,while only 45.9% of geosmin and 20.5% of MIB were removed in control samples.The removal efficiency increased as the function of time,and it reached 96.1% and 79.7% after 30 minutes.This may provide a new idea for helping solve odor substances problems in natural waters.%为了探索湖泊水体中嗅味物质的变化规律,解决湖泊水体的嗅味问题,本研究选取太湖十八湾围隔水域作为调查对象,从2009年12月到2010年8月,对嗅味物质土臭素(geosmin)和二甲基异茨醇(MIB)的含量进行分析检测,结果表明,geosmin的含量和MIB的含量在冬春季节较低,夏秋季节较高,随季节波动明显,MIB是主要的致嗅物质。为调控臭氧稳定性,降低臭氧衰减速率,室内实验采用硅藻土来吸附夹载臭氧,使臭氧分解速率常数由0.036/min降低到了0.015/min,由此制得了臭氧-硅藻土,并用该材料处理模拟嗅味物质水样。结果表明,10 min时,geosmin和MIB的去除率分别为73.4%和46.6%,高于对照中的45.9%和20.5%,30 min时,geosmin和MIB的去除率进一步提高到96.1%和79.7%,本研究结果为解决湖泊等天然水体的嗅味问题提供了新的思路。

  9. 2016 Lake Michigan Lake Trout Working Group Report

    Science.gov (United States)

    Madenjian, Charles P.; Breidert, Brian; Boyarski, David; Bronte, Charles R.; Dickinson, Ben; Donner, Kevin; Ebener, Mark P.; Gordon, Roger; Hanson, Dale; Holey, Mark; Janssen, John; Jonas, Jory; Kornis, Matthew; Olsen, Erik; Robillard, Steve; Treska, Ted; Weldon, Barry; Wright, Greg D.

    2017-01-01

    This report provides a review on the progression of lake trout rehabilitation towards meeting the Salmonine Fish Community Objectives (FCOs) for Lake Michigan (Eshenroder et. al. 1995) and the interim goal and evaluation objectives articulated in A Fisheries Management Implementation Strategy for the Rehabilitation of Lake Trout in Lake Michigan (Dexter et al. 2011); we also include data describing lake trout stocking and mortality to portray the present state of progress towards lake trout rehabilitation.

  10. Hydrography - Lakes Assessments - Non Attaining

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This layer shows only non attaining lakes of the Integrated List. The Lakes Integrated List represents lake assessments in an integrated format for the Clean Water...

  11. Boat Dwellers of Weishan Lake

    Institute of Scientific and Technical Information of China (English)

    JENNIFER; LIM

    1998-01-01

    IN the south of Shandong Province, Weishan Lake is the largest freshwater lake in northern China. Under the bright blue sky, it gleams like a large mirror. "As the sun is about to set, Weishan Lake is quiet…" Humming

  12. 江苏省环太湖地区有机农业现状调查与发展对策研究%Investigation on Current Situation of Organic Agriculture in Area around Taihu Lake of Jiangsu Province and Strategy on Future Development

    Institute of Scientific and Technical Information of China (English)

    唐剑; 席运官; 刘华周; 亢志华

    2015-01-01

    With the increase of population density and high speed development of economy, the water pollution and eutrophication of Taihu Lake is increasingly serious. Organic agriculture, as an important method to control non-point pollution from agriculture, has been adopted by the government as one of the means of controlling pollution of Taihu Lake. The current situation of organic agriculture around Taihu Lake was taken as studying subject, problems were analyzed from four aspects, i.e., financial support policy, technological level of production, industrial support system, and production cost and benefit. Based on this, 5 developing strategies were put forward, i.e., providing organization guarantee to the development of organic agriculture by scientific planning, providing financial support by establishing motivation mechanism, making technological breakthrough by establishing organic agriculture production technique system, highlighting the priorities by encouraging the development of organic rice, vegetable and fruit production, cultivating domestic and foreign market by strengthening propaganda.%随着人口密度的增加和经济的高速发展,环太湖流域水污染和富营养化日益严重,有机农业作为该地区控制农业面源污染的重要手段之一,被纳入政府治理太湖污染措施中.文章以环太湖地区有机农业发展现状为研究对象,从财政支持政策、生产技术水平、产业支撑体系及生产成本收益等4个方面,分析了该地区有机农业发展存在的问题,并据此提出了:科学规划,为环太湖地区有机农业发展提供组织保障;财政支持,制定发展有机农业的具体激励机制;技术突破,建立有机生产系统产业技术体系;突出重点,鼓励有机水稻、蔬菜和水果产业发展;加强宣传,培育国际国内有机食品市场等对策.

  13. 太湖土著菌 MC-LTH11的筛选及其对藻毒素-RR 和-LR 的生物降解%Biodegradation of microcystin-RR and -LR by an indigenous bacterial strain MC-LTH11 isolated from Lake Taihu

    Institute of Scientific and Technical Information of China (English)

    周远龙; 杨飞; 梁戈玉; 尹立红; 浦跃朴

    2014-01-01

    The indigenous bacterial strain MC-LTH11 with the capability of degrading microcystin-RR MC-RR and microcystin-LR MC-LR was successfully isolated from Lake Taihu.The bacterium was identified as Stenotrophomonas sp. which possessed a mlrA gene. The MC-LTH11 thoroughly degraded MC-RR and MC-LR with the initial concentration of 37.13 mg/L and 18.49 mg /L respectively in the medium containing crude microcystins extract within 6 d.The degradation rates were affected by temperature pH initial MCs concentration and the kinds of media. Additionally the bacterial strain MC-LTH11 also degraded thoroughly microcystins in the water body of Lake Taihu within 1 d.These results suggest that the Stenotrophomonas sp.MC-LTH11 has the capacity to bioremediate water bodies contaminated by microcystins and may contribute to the degradation of microcystins after the outbreak of harmful cyanobacterial blooms in Lake Taihu.%从太湖中成功筛选出一株能够同时降解微囊藻毒素-RR(MC-RR)和微囊藻毒素-LR(MC-LR)的土著细菌 MC-LTH11.经鉴定,该菌属寡养单胞菌属,并含有 mlrA 基因.在含有藻毒素粗提物的培养基中,MC-LTH11能够在6 d 内将初浓度分别为37.13 mg/L 的 MC-RR 和18.49 mg/L 的 MC-LR 完全降解,并且降解速度受到 pH 值、温度、初始微囊藻毒素浓度和培养基种类的影响.此外,MC-LTH11能够在1 d 内完全降解太湖水样中的微囊藻毒素.研究结果表明,寡养单胞菌 MC-LTH11具备对微囊藻毒素污染水体的修复能力,并可能是太湖水华爆发后微囊藻毒素降解的重要因素.

  14. Spatio-temporal Structure Variation of Grain Production and the Evaluation of Grain Security in Taihu Lake Basin%太湖流域粮食生产时空格局演变与粮食安全评价

    Institute of Scientific and Technical Information of China (English)

    潘佩佩; 杨桂山; 苏伟忠; 张健

    2013-01-01

    太湖流域既是中国传统粮食高产区又是当前经济发展的前沿阵地.论文从宏观视角探讨了该区1985-2010年27个县域粮食生产时空变化格局及粮食安全水平,结果表明:时间演化上该区粮食产量不稳定,但总体呈下降趋势,历经波动发展—急剧减少—稳步增长三阶段;空间差异亦较显著,除西北4个县域,其余地区粮食产量均有不同程度下降,粮食生产重心逐渐由中部向西北偏移,县域粮食生产相对优势弱化,整体粮食生产能力降低;粮食总产变异系数和70%以上年份波动系数超全国平均水平,粮食安全风险大;粮食不安全县域增多,2010年59%的县域粮食不安全.未来该区仍受到耕地数量减少和质量退化威胁,完善耕地保护政策并提出保障粮食安全的区域差别化措施具有重要的现实意义.%Taihu Lake Basin is China' s traditional food producing area with high grain yield and the forefront of China' s economic development.With the gradual population increase and rapid urbanization development,the demand for food is increasing rapidly while cropland resources are fast dwindling.Therefore,the supply and demand conflict of food keeps intensifying.From a macro perspective,this paper discusses the temporal and spatial patterns of grain production changes and food security level of 27 county seats in Taihu Lake Basin from 1985 to 2010.The results are as follows:Firstly,the grain production showed instability and a tendency to decline,and it can be divided into three stages which are fluctuant development-sharp drop-stead growth.Secondly,it also showed significant regional differences.The analysis of different regions reveals the reality that all county seats have different degrees of decline other than the four counties in the northwest,especially Suzhou,Wuxi,Changzhou and Hangzhou.Then,the gravity centers of grain production appear the tendency moving from central area to northwest area and

  15. 林带对太湖地区农业非点源的控制效应研究%Controlling effects of forest belts on non-point source pollution of agricultural lands in Taihu Lake area, China

    Institute of Scientific and Technical Information of China (English)

    陈金林; 侍璐璐; 张爱国

    2002-01-01

    太湖地区是高度发达的农业生产区之一,大量使用化肥和杀虫剂加重该地区的环境污染水质污染。本研究选择以油菜-水稻和小麦-水稻为轮作方式的两片农田为农田生态系统,5年生的杨树林带和8年生的水杉林带为研究对象,通过采集水体、作物、林地下的氮和磷的样本,对农田生态系统中 N、P等(主要水污染物)迁移和淋失进行了研究,并对林带作对农业非点源污染的控制效应进行了分析。结果表明:农田生态系统中 N、P等迁移、淋失状况随轮作方式、作物种类及施肥状况而变化;农田与沟渠间的缓冲林带具有截留和净化土壤径流中的N、P等物质的作用,从而在一定程度上控制农业非点源污染。研究表明:当农田与林带宽度比例为100∶40时,在油菜-水稻轮作方式下,50.05%流失N和29.3% 的流失P可以被林带所吸收, 在小麦-水稻的轮作方式下,30.98 %流失N和86.73% P可以被林带所吸收; 当农田与林带宽度比例为150∶40,在油菜-水稻轮作方式下, 33.7%流失N和19.58%P可以被林带吸收,在小麦-水稻的轮作方式下,20.65%流失N和57.82% 流失P可以被林带所吸收。因而,农田与林带宽度比例100∶40或150∶40较为合理,这种模型既能少占耕地,又能净化水质、保护生态环境。杨树生长快、用途广,适于太湖地区营造水环境保护林带。%Taihu Lake area is one of the most developed areas in agricultural production. Application of fertilizers and pesticides in large quantities greatly aggravate environmental pollution of this area, and water pollution has worsened to an unbearable condition. Two sampling farms (respectively 1 hm2) under rape-rice rotation and wheat-rice rotation were selected as studied ecosystem and a 5-yr-old Poplar forest and 8-yr-old Metasequoia forest were chosen in the selected areas. By collecting samples of Nitrogen, Phosphorus

  16. Algae-Removal Efficiency of AS/PDM Used for the Taihu Lake Prechlorination Algae-Rich Water in Summer%AS/PDM对夏季太湖预氯化高藻水的除藻效果

    Institute of Scientific and Technical Information of China (English)

    张跃军; 赵晓蕾; 李潇潇; 刘程; 朱玲玲

    2011-01-01

    The efficiencies of algae-removal for Taihu Lake prechlorination algae-rich water in summer time by using AS/PDM composite coagulants composed of aluminum sulfate (AS) and polydimethyldiallylammonium chloride (PDM) were investigated. The effects of mass percents (5%~20%) and intrinsic viscosity values (0.55~3.99 dL·g-1) of PDM in composite coagulants on algae-removal ratios were studied through coagulation and algae-removal experiments. The results show that, for chlorinated water with temperature of 29~30℃,turbidity of 50~53 NTU and algae content of 6.88×104 cells·mL-1, in order to reach the turbidity of 2 NTU in settled water, which is required by the standard of the water plant, the necessary dosage (based on AI2O3) of AS and AS/PDM(0.55/5%~3.99/20%) composite coagulants are respectively 5.86 mg·L-1 and 4.84~2.97 mg·L-1,and the algae-removal ratios are 90.67% and 91.80%~96.90%, respectively. It was found that, using AS/PDM composite coagulants can evidently enhance the treatment efficiency of AS for Taihu Lake chlorinated water in summer. Compared with using AS solely, the AS dosages in composite coagulants are saved if the required residual turbidities obtained are the same; and the treatment efficiencies are enhanced if the AS dosages in composite coagulants used are the same as the AS dosages used for using AS solely. It was also found that the higher mass percent or intrinsic viscosity of PDM is, the better treatment efficiency of composite coagulant has.The advantages of using composite coagulants also embody the abilities of decreasing COD and NH3-N in settled water, and likely reducing chlorine dosage in finished water.%研究了硫酸铝(AS)与聚二甲基二烯丙基氯化铵(PDM)制成的AS/PDM复合药剂对夏季太湖预氯化高藻水的除藻效果.通过混凝除藻实验,考察了PDM质量分数(5%~20%与特征黏度(0.55~3.99 dL·g-1)对除藻效果的影响.结果表明,对温度29~30℃,浊度50~53

  17. NITROGEN FERTILIZATION RATE RECOMMENDATION INTEGRATING AGRONOMIC, ENVIRONMENTAL, AND ECONOMIC BENEFITS FOR WHEAT SEASON IN THE TAIHU LAKE REGION%太湖地区麦季协调农学、环境和经济效益的荐施肥量

    Institute of Scientific and Technical Information of China (English)

    夏永秋; 颜晓元

    2011-01-01

    Excessive nitrogen (N) fertilization in wheat season in the Taihu Lake region has resulted in serious environmental problems. Previous studies have recommended optimum N fertilization rate. However,so far no holistic evaluation has been made of environmental impacts of N fertilizer. Therefore, based on experiments on fates of various N fractions in relation to N application rate in the region, an evaluation model for knock-on effect of N was developed, integrating agronomic , environmental, and economic benefits in wheat season in the Taihu Lake region. Evaluation with the model show that N application was recommended at N 205 kg hm"2 for wheat season in the Taihu Lake region, which may bring about maximum net benefit 2 621 yuan,which is the balance between 3 722 yuan hm" in yield benefit and 1 101 yuan hm-2 in total environmental loss. The total loss covers the following losses lined in a decreasing sequence in terms of value, acid rain, greenhouse effect and eutrophication. If the net economic benefit is allowed to fluctuate within the range of 10 yuan hm-2, the recommended regional mean N application rate would vary in the range from 193 to 218 kg hm-2,which is 10% to 40% lower than the prevailing N application rate,and nevertheless,would increase the net economic benefit by 5%~ 15% in the Taihu Lake region. This method not only takes into account agronomic, environmental and economic benefits comprehensively, but also provides reference for eco-farming in other regions or other crops. It is easy for decision-makers and farmers to calculate or recommend N fertilizer rate.%基于氮肥用量与各种氮素去向关系的实验数据,构建了太湖地区麦季协调农学、环境和经济效益的氮素连锁效应评价模型.研究表明太湖地区麦季推荐施氮量为205 kg hm-2,最大净收益为2 621元hm-2.此时产量收益为3 722元hm-2,环境总损失为1 101元hm-2,其分量大小依次为酸雨效应损失、温室效应损失、富营养化

  18. 中国太湖流域(江苏南部)人群复合污染经口途径暴露风险评估%Oral exposure risk assessment of combined pollution in Taihu Lake Basin of South Jiangsu Province, China

    Institute of Scientific and Technical Information of China (English)

    杨彦; 王宗庆; 李定龙; 于云江

    2013-01-01

    The pollution of Cu, Pb, Cd and other heavy metals and organic contaminants (DDTs) in oral media (groundwater, soil, crops, 389) from Wuxi, Changzhou and Zhenjiang in the Taihu Lake Basin (south China) were analyzed by laboratory testing. The exposure risk assessment model recommended by U. S. EPA was used. The residents' oral route of exposure risk in Taihu Lake Basin was assessed with the measured exposure parameters and the dietary habits in China were considered. The results showed that the pollution of heavy metals and organic pollutants were serious in Taihu Lake Basin. The population risk of exposure by oral estimated by the traditional way in Taihu Lake Basin showed that the total exposure risk was 9. 07 × 10 to male and 1.00 × 10-2 to female. Considering the oral exposure risk in basin by the factors of the integrated treatment, the total exposure risk was 3.94 × 10-3 to male and 4. 35 × 10 -2 to female. The exposure risks food source by oral media from traditional methods and from post - integrated treatment were both higher than the acceptable level of risk. Carcinogenic risk was significantly higher than non-cancer risk, and the carcinogenic risk of Cd played an important role to the total risk of exposure. The carcinogenic risk of Pb was lower than that of Cd.%对太湖流域(江苏南部)无锡、常州、镇江3市经口介质(地下水、土壤、农作物共389个样品)中Cu、Pb、Cd等8种重金属和有机污染物DDTs的污染状况进行实验室分析,运用US EPA推荐的暴露风险评估模型,对研究区人群进行了暴露参数实测,考虑中国居民膳食习惯,对太湖流域居民经口途径的暴露风险进行评估.研究结果表明:太湖流域重金属、有机污染物污染较严重;传统方式估算的太湖流域人群经口暴露风险,男性总暴露风险为9.07 × 10-3,女性为1.00×10-2;考虑综合处理因素的流域人群经口暴露风险,男性为3.94×10-3,女性为4.35×10-3.食物源经口介质

  19. Great Lakes Teacher's Guide.

    Science.gov (United States)

    Reid, Ron

    The Great Lakes are one of the world's greatest reservoirs of fresh water, the foundation of Ontario's economic development, a primary force in ecological systems, and a base for pleasure and recreation. They are also a magnificent resource for the teachers of Ontario. Study of the Great Lakes can bring to life the factors that shape the ecology…

  20. Marine lakes of Indonesia

    NARCIS (Netherlands)

    Becking, Leontine Elisabeth

    2012-01-01

    The objective of this thesis was to obtain insight into the processes that play a role in biodiversity patterns of tropical marine species by using marine lakes as a model. Marine lakes are landlocked water bodies that maintain a marine character through narrow submarine connections to the sea. Two

  1. The Great Lakes.

    Science.gov (United States)

    Seasons, 1987

    1987-01-01

    The Great Lakes are one of the world's greatest reserviors of fresh water, the foundation of Ontario's economic development, a primary force in ecological systems, and a base for pleasure and recreation. These lakes and their relationship with people of Canada and the United States can be useful as a subject for teaching the impact of human…

  2. Marine lakes of Indonesia

    NARCIS (Netherlands)

    Becking, Leontine Elisabeth

    2012-01-01

    The objective of this thesis was to obtain insight into the processes that play a role in biodiversity patterns of tropical marine species by using marine lakes as a model. Marine lakes are landlocked water bodies that maintain a marine character through narrow submarine connections to the sea. Two

  3. Lake trout in northern Lake Huron spawn on submerged drumlins

    Science.gov (United States)

    Riley, Stephen C.; Binder, Thomas; Wattrus, Nigel J.; Faust, Matthew D.; Janssen, John; Menzies, John; Marsden, J. Ellen; Ebener, Mark P.; Bronte, Charles R.; He, Ji X.; Tucker, Taaja R.; Hansen, Michael J.; Thompson, Henry T.; Muir, Andrew M.; Krueger, Charles C.

    2014-01-01

    Recent observations of spawning lake trout Salvelinus namaycush near Drummond Island in northern Lake Huron indicate that lake trout use drumlins, landforms created in subglacial environments by the action of ice sheets, as a primary spawning habitat. From these observations, we generated a hypothesis that may in part explain locations chosen by lake trout for spawning. Most salmonines spawn in streams where they rely on streamflows to sort and clean sediments to create good spawning habitat. Flows sufficient to sort larger sediment sizes are generally lacking in lakes, but some glacial bedforms contain large pockets of sorted sediments that can provide the interstitial spaces necessary for lake trout egg incubation, particularly if these bedforms are situated such that lake currents can penetrate these sediments. We hypothesize that sediment inclusions from glacial scavenging and sediment sorting that occurred during the creation of bedforms such as drumlins, end moraines, and eskers create suitable conditions for lake trout egg incubation, particularly where these bedforms interact with lake currents to remove fine sediments. Further, these bedforms may provide high-quality lake trout spawning habitat at many locations in the Great Lakes and may be especially important along the southern edge of the range of the species. A better understanding of the role of glacially-derived bedforms in the creation of lake trout spawning habitat may help develop powerful predictors of lake trout spawning locations, provide insight into the evolution of unique spawning behaviors by lake trout, and aid in lake trout restoration in the Great Lakes.

  4. 基于多星遥感影像的太湖北部湖湾春季沉水植被分布动态监测%Dynamic Monitoring of Distribution of Submerged Vegetation in the North of Taihu Lake in Spring Based on Multi-source Remote Sensing Images

    Institute of Scientific and Technical Information of China (English)

    侍昊; 张婷; 李旭文; 牛志春; 王甜甜; 李杨

    2016-01-01

    The distribution and variation of submerged vegetation in the north of Taihu Lake in the spring of 2015 were monitored u-sing multi-source remote sensing images.This paper discussed the key problems in monitoring aquatic vegetation by using the tech -nique.The monitoring results acquired on 28th of April based on the decision tree method showed that the area of submerged vegeta -tion in the north of Taihu Lake was about 11.2 km 2 .Compared with the results obtained from the same period in 2014,the newly e-merged large areas of submerged vegetation were mainly concentrated near the west of Tianji Mountain and around of Xidong Water -works.It was suggested that submerged vegetation should be cleared away and salvaged timely to avoid the death and decay of aquat -ic vegetation,which posed threats to water quality .%利用多星遥感影像动态监测了2015年春季太湖北部湖湾沉水植被分布的变化过程,并对水生植被遥感监测中的几个关键问题展开了探讨。决策树方法获取的水生植被分布结果表明,2015年4月28日太湖北部湖湾发现明显沉水植被分布面积约11.2 km 2,与2014年同期相比,新出现的较大面积沉水植被分布区域主要集中在田鸡山西和锡东水厂附近。提出应及时清理打捞,避免水生植被死亡腐烂,威胁水质安全。

  5. Lake metabolism scales with lake morphometry and catchment conditions

    DEFF Research Database (Denmark)

    Stæhr, Peter A.; Baastrup-Spohr, Lars; Jensen, Kaj Sand;

    2012-01-01

    We used a comparative data set for 25 lakes in Denmark sampled during summer to explore the influence of lake morphometry, catchment conditions, light availability and nutrient input on lake metabolism. We found that (1) gross primary production (GPP) and community respiration (R) decline with lake...... area, water depth and drainage ratio, and increase with algal biomass (Chl), dissolved organic carbon (DOC) and total phosphorus (TP); (2) all lakes, especially small with less incident light, and forest lakes with high DOC, have negative net ecosystem production (NEP ... decreases with lake area and water depth as a consequence of lower input of nutrients and organic matter per unit water volume; (4) the influence of benthic processes on free water metabolic measures declines with increasing lake size; and (5) with increasing lake size, lake metabolism decreases...

  6. 太湖流域水资源能值转换率计算与研究%Calculation of Emergy Transformity of Water Resource in Taihu Lake Watershed

    Institute of Scientific and Technical Information of China (English)

    姚文平; 李翠梅

    2015-01-01

    Water resource is regarded as a complex system and is quantitatively analyzed by using the theory and method of emergy.The water system in Taihu Lake watershed is taken as a research object.Emergy system dia-grams and emergy analytical tables were obtained and the emergy transformity of water supply resource of the water-shed from 2007 to 2011 was calculated.Result shows that the emergy transformity of the watershed’s water re-source has a tendency of increasing over years,which is consistent with the practice of intensifying regulation pro-jects to improve water environment.Besides,the emergy transformity of water resource under human disturbance increased by 24.3% on the average compared with the natural condition,and the increment displays a trend of in-creasing year by year as well,from 4.31% in 2007 to 36.4% in 2011,indicating that safe water supply takes more cost despite the rich water resource of the watershed,and that water shortage of water-quality type is a new chal-lenge of the century.%从水资源复合系统的角度出发,对复合系统进行能量分析,提出运用能值理论与方法对流域水资源定量分析的思路。论述了能值的基本理论与方法,以太湖流域水系为研究对象,绘制了流域水资源能值系统图,并编制能值分析表,对流域2007—2011年供水水资源的能值转换率进行计算。研究表明:流域水资源能值转换率呈逐年增大趋势,与流域近年为改善流域水环境,加大水环境综合整治及系列工程项目的情况吻合;另外,人工干扰下水资源的能值转换率较天然水资源平均增长24.3%,而且这种增长也呈逐年上升趋势,从2007年的4.31%到2011年的36.4%,说明流域水资源量虽丰富,但安全供水的代价却越来越大。水质型缺水将是20世纪面临的新挑战。

  7. 太湖蓝藻水华分级及其时空变化%CHARACTERISTICS OF CYANOBACTERIA BLOOM GRADING AND ITS TEMPORAL AND SPATIAL VARIATION IN TAIHU LAKE

    Institute of Scientific and Technical Information of China (English)

    刘聚涛; 杨永生; 高俊峰; 姜加虎

    2011-01-01

    根据MODIS影像和实地监测叶绿素a浓度数据,采用太湖蓝藻水华分级评估方法,对2004~2008年太湖不同类型蓝藻水华类型进行评估并统计分析,探求太湖蓝藻水华特征及其时空变化规律,以期为太湖蓝藻水华预防和预警提供支持.结果表明:(1)2004~2008年,全湖共发生蓝藻水华414次,以小型蓝藻水华为主,发生333次,占总次数的80.43%;随着蓝藻水华级别的增加,发生次数逐渐减少;(2)空间上,蓝藻水华主要发生在太湖的北部和西部区域,并且蓝藻水华发生级别由高到低基本上沿西北-东南方向分布;(3)年际变化上,蓝藻水华发生次数呈逐渐增加趋势,蓝藻水华级别较高、次数较多的年份主要集中于2006年和2007年;(4)年内变化上,4~8月份,蓝藻水华发生次数呈增加趋势,8~11月,蓝藻水华发生次数逐渐减少.并且,蓝藻水华主要集中于5月和7~10月份,尤其是8~10月.%Using MODIS satellite images and Chlorophyll-a concentration data and adopting cyanobacteria bloom evaluation method, this paper studied different type of cyanobacteria bloom from 2004 to 2008 in Taihu Lake,and explored the characteristics of cyanobacteria bloom and its spatial and temporal variation,which provided pre-prevention and early warning for cyanobacteria bloom. The results showed that from 2004 to 2008,there were 414 cyanobacteria bloom incidents,and small scale cyanobacteria bloom occured 333 times,which occupied 80.43 % of the cyanobacteria bloom incidents. As the grade of the cyanobacteria bloom increased,the number reduced. In the space, cyanobacteria bloom occurred mainly in the northern and western regions. And the distribution of the cyanobacteria bloom grade from high to low was mainly accord with the direction from northwest to southeast. Among the annual change,the number of cyanobacteria bloom gradually increased. The year in which large-scale cyanobacteria bloom happened and the cyanobacteria

  8. Denitrification Study of Elodea nuttallii-Nitrogen Cycling Bacteria Restoration in Meiliang Bay, Taihu Lake%伊乐藻-氮循环菌联用对太湖梅梁湾水体脱氮的研究

    Institute of Scientific and Technical Information of China (English)

    赵琳; 李正魁; 周涛; 吴宁梅; 叶忠香; 刘丹丹

    2013-01-01

    Undisturbed sediment cores were collected from Meiliang Bay,Taihu Lake,and the integrated Elodea nuttallii-nitrogen cycling bacteria technology was applied as a restoration method.The effects of the Elodea nuttallii-nitrogen cycling bacteria technology on sediment denitrification was observed by isotope pairing technique.The highest denitrification rate of 104.64 μmol·(m2· h)-1 was achieved in sediments with Elodea nuttallii-nitrogen cycling bacteria assemblage.The abundance of nirS,nirK and nosZ genes involved in denitrification processes in the sediments (within 2 cm below the water-sediment interface) were measured by real-time quantitative PCR (RT-qPCR).The abundance of nirS and nosZ genes in the sediments with restoration treatments was increased,which was more than one order of magnitudes higher than that in bare sediments.The results indicated that the presence of macrophyte and nitrogen cycling bacteria could increase benthic nitrogen removal by facilitating coupled nitrification-denitrification and uncoupled nitrificationdenitrification.%从太湖梅梁湾采集无扰动泥芯样,分别添加伊乐藻、固定化氮循环菌,模拟生态修复并探讨其机制.采用同位素配对技术测定了伊乐藻-氮循环菌技术对反硝化速率的影响.结果表明,伊乐藻与氮循环菌联合作用的试验柱的反硝化速率(以N计)最高,为104.64 μmol· (m2 ·h)-1,与裸泥试验柱相比增加了150%.采用实时荧光定量PCR技术(RT-qPCR)对沉积物中反硝化菌功能基因nirS、nirK和nosZ进行定量研究,结果显示,反硝化菌的功能基因nirS和nosZ比对照裸泥组高出1~2个数量级,表明较高的微生物量促进了反硝化脱氮的能力.室内模拟实验还表明,沉水植物提高了耦合硝化反硝化的作用,氮循环菌提高了非耦合硝化反硝化的作用,沉水植物与微生物的联合作用提高了沉积物的总反硝化速率,促进了湖泊水体氮素的脱除,起到了净化作用.

  9. Nitrogen balance in paddy fields under different rotation systems in the Taihu Lake Region%太湖地区不同轮作模式下的稻田氮素平衡研究

    Institute of Scientific and Technical Information of China (English)

    胡安永; 刘勤; 孙星; 张亚楠

    2014-01-01

    A field micro-plot (labeled 15N) fertilizer experiment was conducted to investigate the use efficiency of fertilizer N and its residual features under different rice-based cropping systems (Chinese milk vetch-rice rotation, fallow-rice rotation and wheat-rice rotation) in the Taihu Lake Region. Results showed that 20.9%-49.6%of N uptake of rice was derived from the applied fertilizer N. Fallow-rice rotation system largely depended on inorganic N fertilizer to form yield. N fertilizer use efficiency of rice was 25.0%-41.5%of the labeled fertilizer N at harvest. Residual fertilizer N rate in soils was 13.4%-24.6%, over 90%of which was in the 0-20 cm soil layer. The amount of fertilizer N residue in the soil profile decreased rapidly with increasing soil depth. Only 0.2%-0.7%of the fertilizer N was in the soil layer of 30-40 cm. Fertilizer N use efficiency and soil residual N rate were largest at N application rate of 240 kg·hm-2 under Chinese milk vetch-rice rotation and fallow-rice rotation systems. This respectively exceeded by 55.6%and 66.0%over N fertilizer use efficiency under wheat-rice rotation. Fertilizer N use efficiency, soil residual rate as well as total N recovery rate were lowest while N loss rate highest under wheat-rice rotation system at N application rate of 240 kg·hm-2. As for the Chinese milk vetch-rice rotation system, the loss rate of N fertilizer was lowest, which was less than those of fallow-rice rotation and wheat-rice rotation systems by 13.9%and 39.2%, respectively. Under different rotation systems, rice yield increased with increasing urea application rate. Under straw-return application of Chinese milk vetch of Chinese milk vetch-rice rotation system, rice yield was significantly higher compared to those of wheat-rice rotation and fallow-rice rotation at N application of 240 kg·hm-2. Although rice yield under wheat-rice rotation was slightly higher than that under fallow-rice rotation, it was not significantly different. The study

  10. Ecology under lake ice.

    Science.gov (United States)

    Hampton, Stephanie E; Galloway, Aaron W E; Powers, Stephen M; Ozersky, Ted; Woo, Kara H; Batt, Ryan D; Labou, Stephanie G; O'Reilly, Catherine M; Sharma, Sapna; Lottig, Noah R; Stanley, Emily H; North, Rebecca L; Stockwell, Jason D; Adrian, Rita; Weyhenmeyer, Gesa A; Arvola, Lauri; Baulch, Helen M; Bertani, Isabella; Bowman, Larry L; Carey, Cayelan C; Catalan, Jordi; Colom-Montero, William; Domine, Leah M; Felip, Marisol; Granados, Ignacio; Gries, Corinna; Grossart, Hans-Peter; Haberman, Juta; Haldna, Marina; Hayden, Brian; Higgins, Scott N; Jolley, Jeff C; Kahilainen, Kimmo K; Kaup, Enn; Kehoe, Michael J; MacIntyre, Sally; Mackay, Anson W; Mariash, Heather L; McKay, Robert M; Nixdorf, Brigitte; Nõges, Peeter; Nõges, Tiina; Palmer, Michelle; Pierson, Don C; Post, David M; Pruett, Matthew J; Rautio, Milla; Read, Jordan S; Roberts, Sarah L; Rücker, Jacqueline; Sadro, Steven; Silow, Eugene A; Smith, Derek E; Sterner, Robert W; Swann, George E A; Timofeyev, Maxim A; Toro, Manuel; Twiss, Michael R; Vogt, Richard J; Watson, Susan B; Whiteford, Erika J; Xenopoulos, Marguerite A

    2017-01-01

    Winter conditions are rapidly changing in temperate ecosystems, particularly for those that experience periods of snow and ice cover. Relatively little is known of winter ecology in these systems, due to a historical research focus on summer 'growing seasons'. We executed the first global quantitative synthesis on under-ice lake ecology, including 36 abiotic and biotic variables from 42 research groups and 101 lakes, examining seasonal differences and connections as well as how seasonal differences vary with geophysical factors. Plankton were more abundant under ice than expected; mean winter values were 43.2% of summer values for chlorophyll a, 15.8% of summer phytoplankton biovolume and 25.3% of summer zooplankton density. Dissolved nitrogen concentrations were typically higher during winter, and these differences were exaggerated in smaller lakes. Lake size also influenced winter-summer patterns for dissolved organic carbon (DOC), with higher winter DOC in smaller lakes. At coarse levels of taxonomic aggregation, phytoplankton and zooplankton community composition showed few systematic differences between seasons, although literature suggests that seasonal differences are frequently lake-specific, species-specific, or occur at the level of functional group. Within the subset of lakes that had longer time series, winter influenced the subsequent summer for some nutrient variables and zooplankton biomass. © 2016 The Authors. Ecology Letters published by CNRS and John Wiley & Sons Ltd.

  11. Yellowstone Lake Nanoarchaeota

    Directory of Open Access Journals (Sweden)

    Scott eClingenpeel

    2013-09-01

    Full Text Available Considerable Nanoarchaeota novelty and diversity were encountered in Yellowstone Lake, Yellowstone National Park, where sampling targeted lake floor hydrothermal vent fluids, streamers and sediments associated with these vents, and in planktonic photic zones in three different regions of the lake. Significant homonucleotide repeats (HR were observed in pyrosequence reads and in near full-length Sanger sequences, averaging 112 HR per 1,349 bp clone and could confound diversity estimates derived from pyrosequencing, resulting in false nucleotide insertions or deletions (indels. However, Sanger sequencing of two different sets of PCR clones (110 bp, 1349 bp demonstrated that at least some of these indels are real. The majority of the Nanoarchaeota PCR amplicons were vent associated; however, curiously, one relatively small Nanoarchaeota OTU (70 pyrosequencing reads was only found in photic zone water samples obtained from a region of the lake furthest removed from the hydrothermal regions of the lake. Extensive pyrosequencing failed to demonstrate the presence of an Ignicoccus lineage in this lake, suggesting the Nanoarchaeota in this environment are associated with novel Archaea hosts. Defined phylogroups based on near full-length PCR clones document the significant Nanoarchaeota 16S rRNA gene diversity in this lake and firmly establish a terrestrial clade distinct from the marine Nanoarcheota as well as from other geographical locations.

  12. Yellowstone lake nanoarchaeota.

    Science.gov (United States)

    Clingenpeel, Scott; Kan, Jinjun; Macur, Richard E; Woyke, Tanja; Lovalvo, Dave; Varley, John; Inskeep, William P; Nealson, Kenneth; McDermott, Timothy R

    2013-01-01

    Considerable Nanoarchaeota novelty and diversity were encountered in Yellowstone Lake, Yellowstone National Park (YNP), where sampling targeted lake floor hydrothermal vent fluids, streamers and sediments associated with these vents, and in planktonic photic zones in three different regions of the lake. Significant homonucleotide repeats (HR) were observed in pyrosequence reads and in near full-length Sanger sequences, averaging 112 HR per 1349 bp clone and could confound diversity estimates derived from pyrosequencing, resulting in false nucleotide insertions or deletions (indels). However, Sanger sequencing of two different sets of PCR clones (110 bp, 1349 bp) demonstrated that at least some of these indels are real. The majority of the Nanoarchaeota PCR amplicons were vent associated; however, curiously, one relatively small Nanoarchaeota OTU (71 pyrosequencing reads) was only found in photic zone water samples obtained from a region of the lake furthest removed from the hydrothermal regions of the lake. Extensive pyrosequencing failed to demonstrate the presence of an Ignicoccus lineage in this lake, suggesting the Nanoarchaeota in this environment are associated with novel Archaea hosts. Defined phylogroups based on near full-length PCR clones document the significant Nanoarchaeota 16S rRNA gene diversity in this lake and firmly establish a terrestrial clade distinct from the marine Nanoarcheota as well as from other geographical locations.

  13. Ecology of playa lakes

    Science.gov (United States)

    Haukos, David A.; Smith, Loren M.

    1992-01-01

    Between 25,000 and 30,000 playa lakes are in the playa lakes region of the southern high plains (Fig. 1). Most playas are in west Texas (about 20,000), and fewer, in New Mexico, Oklahoma, Kansas, and Colorado. The playa lakes region is one of the most intensively cultivated areas of North America. Dominant crops range from cotton in southern areas to cereal grains in the north. Therefore, most of the native short-grass prairie is gone, replaced by crops and, recently, grasses of the Conservation Reserve Program. Playas are the predominant wetlands and major wildlife habitat of the region.More than 115 bird species, including 20 species of waterfowl, and 10 mammal species have been documented in playas. Waterfowl nest in the area, producing up to 250,000 ducklings in wetter years. Dominant breeding and nesting species are mallards and blue-winged teals. During the very protracted breeding season, birds hatch from April through August. Several million shorebirds and waterfowl migrate through the area each spring and fall. More than 400,000 sandhill cranes migrate through and winter in the region, concentrating primarily on the larger saline lakes in the southern portion of the playa lakes region.The primary importance of the playa lakes region to waterfowl is as a wintering area. Wintering waterfowl populations in the playa lakes region range from 1 to 3 million birds, depending on fall precipitation patterns that determine the number of flooded playas. The most common wintering ducks are mallards, northern pintails, green-winged teals, and American wigeons. About 500,000 Canada geese and 100,000 lesser snow geese winter in the playa lakes region, and numbers of geese have increased annually since the early 1980’s. This chapter describes the physiography and ecology of playa lakes and their attributes that benefit waterfowl.

  14. Rural Residents'Demands And Willingness To Pay For Tributary Ecological Restoration In Lakeshore Zone---Experiences From Zhushan Bay In Taihu Lake%湖滨带农村常住居民支浜生态修复需求与支付意愿--以太湖竺山湾地区为例

    Institute of Scientific and Technical Information of China (English)

    房娟娟; 付文凤; 赵海燕; 管永祥; 吴昊; 梁永红; 姜海

    2015-01-01

    Participation of rural residents in lakeshore zone is important for ecological restoration of tributa-ries and water environment governance in Taihu Lake.The survey of 204 rural residents in Zhushan Bay around Taihu Lake finds that:1)Compared with 2004,the proportion of rural residents that feel water quality very good or very poor significantly reduced.Deterioration of water quality has been temporarily controlled in Taihu lake-shore zone while the improvement of water quality is not obvious.2 )80.88 percent of rural residents have the willingness to pay for ecological restoration of tributaries,of which 62.4 percent are willing to pay one- time with an average WTP 1 63 yuan,27.9 percent are willing to pay by year with an average WTP 136 yuan per year, 9.7 percent are willing to pay by monthly with an average WTP 24 yuan per month.3)Logistic analysis shows that improving of education level would have a significant positive impact on rural residents’WTP for ecological restoration projects.4 )Water environmental governance has favorable social foundation in developed areas as Taihu basin.More attention should be paid to the role of local residents in financing and monitoring of ecological restoration projects.%提升居民参与水平,加快支浜生态修复是改善湖滨带缓冲功能和太湖水环境治理的重要需求.对太湖竺山湾地区204户农村常住居民的调查发现:1)感觉2014年支浜水质比2004年“非常差”或“非常好”的居民比例大幅降低,表明太湖湖滨带水质恶化得到初步控制但总体改善不明显;2)80.88%的湖滨带农村常住居民对支浜生态修复工程具有支付意愿,其中62.4%愿意一次性支付,户均支付意愿163元,27.9%愿意按年支付,户均支付意愿136元/年,9.7%愿意按月支付,户均支付意愿24元/月;3) Logistic 分析表明,受教育水平对湖滨带农村常住居民支浜生态修复工程支付意愿具有显著正向影响;4)在经济相

  15. Can lake sensitivity to desiccation be predicted from lake geometry?

    Science.gov (United States)

    Torabi Haghighi, Ali; Menberu, Meseret Walle; Aminnezhad, Mousa; Marttila, Hannu; Kløve, Bjørn

    2016-08-01

    Declining lake levels (Aral Sea syndrome) can be caused by changes in climate, increased water use or changed regulation patterns. This paper introduces a novel lake geometry index (LGI) to quantify lake hydrological characteristics. The index was developed using a large representative dataset of lake hypsographic characteristics from 152 lakes and man-made reservoirs. Using the LGI index, lakes can be classified into five groups: groups 1-4 when LGI is 0.5-2.5, 2.5-4.5, 4.5-6.5 and 6.5-8.5, respectively, and group 5 when LGI is >8.5. Naturally shallow and vast lakes and wetlands fall into the first group and deep man-made reservoirs in narrow valleys are in group 5. The response of three different lake systems (LGI 0.75, 2.75 and 6.5) to different water flow scenarios was then simulated using the water balance equation. From this, the index 'potential lake area' (Apot) was developed to show lake responses to changed hydro-climatological conditions. Apot and LGI can be used to classify lakes into open or closed systems. Simulations showed that lakes with low LGI have a shorter response time to flow and climate changes. As a result, the impact of water balance restoration is faster for lakes with low LGI than for lakes with high LGI. The latter are also more vulnerable to climate variation and change.

  16. Trends in evaporation of a large subtropical lake

    Science.gov (United States)

    Hu, Cheng; Wang, Yongwei; Wang, Wei; Liu, Shoudong; Piao, Meihua; Xiao, Wei; Lee, Xuhui

    2017-07-01

    How rising temperature and changing solar radiation affect evaporation of natural water bodies remains poor understood. In this study, evaporation from Lake Taihu, a large (area 2400 km2) freshwater lake in the Yangtze River Delta, China, was simulated by the CLM4-LISSS offline lake model and estimated with pan evaporation data. Both methods were calibrated against lake evaporation measured directly with eddy covariance in 2012. Results show a significant increasing trend of annual lake evaporation from 1979 to 2013, at a rate of 29.6 mm decade-1 according to the lake model and 25.4 mm decade-1 according to the pan method. The mean annual evaporation during this period shows good agreement between these two methods (977 mm according to the model and 1007 mm according to the pan method). A stepwise linear regression reveals that downward shortwave radiation was the most significant contributor to the modeled evaporation trend, while air temperature was the most significant contributor to the pan evaporation trend. Wind speed had little impact on the modeled lake evaporation but had a negative contribution to the pan evaporation trend offsetting some of the temperature effect. Reference evaporation was not a good proxy for the lake evaporation because it was on average 20.6 % too high and its increasing trend was too large (56.5 mm decade-1).

  17. Halls Lake 1990

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Salt marsh habitats along the shoreline of Halls Lake are threatened by wave erosion, but the reconstruction of barrier islands to reduce this erosion will modify or...

  18. Sunk Lake Natural Area

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Sunk Lake Natural Area Management Plan guides the long-range development of the Natural Area by identifying and integrating appropriate habitats, management...

  19. Lake Transect : 1986

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document summarizes transect surveys that were done at four different lakes on St. Vincent National Wildlife Refuge in 1986. Lists of the plant species found at...

  20. Lake Transect : 1988

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document summarizes transect surveys that were done at four different lakes on St. Vincent National Wildlife Refuge in 1988. Lists of the plant species found at...

  1. Lake Transect : 1989

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document summarizes transect surveys that were done at four different lakes on St. Vincent National Wildlife Refuge in 1989. Lists of the plant species found...

  2. History of Lake Andes

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Information about the history and management of Lake Andes is compiled in this report. It is intended to help future refuge managers become acquainted with the...

  3. Lake Level Reconstructions

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Records of past lake levels, mostly related to changes in moisture balance (evaporation-precipitation). Parameter keywords describe what was measured in this data...

  4. Great Lakes Ice Charts

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Charts show ice extent and concentration three times weekly during the ice season, for all lakes except Ontario, from the 1973/74 ice season through the 2001/2002...

  5. Chase Lake Wetland Management District, Chase Lake National Wildlife Refuge, Chase Lake Prairie Project: Annual narrative report: 1997

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Chase Lake WMD, Chase Lake NWR, Chase Lake Prairie Project, and Halfway Lake NWR outlines Refuge accomplishments during the 1997...

  6. Is Lake Tahoe Terminal?

    Science.gov (United States)

    Coats, R. N.; Reuter, J.; Heyvaert, A.; Lewis, J.; Sahoo, G. B.; Schladow, G.; Thorne, J. H.

    2014-12-01

    Lake Tahoe, an iconic ultra-oligotrophic lake in the central Sierra Nevada, has been studied intensively since 1968, with the goal of understanding and ultimately controlling its eutrophication and loss of clarity. Research on the lake has included a) periodic profiles of primary productivity, nutrients, temperature, and plankton; b) Secchi depth; c) nutrient limitation experiments; d) analysis of sediment cores; e) radiocarbon dating of underwater in-place tree stumps; g) analysis of long-term temperature trends. Work in its watershed has included a) monitoring of stream discharge, sediment and nutrients at up to 20 stream gaging stations; b) monitoring of urban runoff water quality at selected sites; c) development of a GIS data base, including soils, vegetation, and land use. Based on these studies, we know that a) primary productivity in the lake is limited by phosphorus, and continues to increase; b) the loss of clarity continues, but at a declining rate; c) the lake has been warming since 1970, and its resistance to deep mixing is increasing; d) historically the lake level drops below the outlet elevation about one year in seven; e) 6300 to 4300 yrs BP lake level was below the present outlet elevation long enough for large trees to grow; f) the date of the peak snowmelt runoff is shifting toward earlier dates; g) after accounting for annual runoff, loads of nutrients and suspended sediment have declined significantly in some basin streams since 1980. Downscaled outputs from GCM climatic models have recently been used to drive hydrologic models and a lake clarity model, projecting future trends in the lake and watersheds. Results show a) the temperature and thermal stability will likely continue to increase, with deep mixing shutting down in the latter half of this century; b) the lake may drop below the outlet for an extended period beginning about 2085; c) the annual snowpack will continue to decline, with earlier snowmelt and shift from snowfall to rain; d

  7. WHISKER LAKE WILDERNESS, WISCONSIN.

    Science.gov (United States)

    Schulz, Klaus J.

    1984-01-01

    The mineral-resource potential of the Whisker Lake Wilderness in northeastern Wisconsin was evaluated. Only a strip along the southwest corner of the wilderness is assessed as having probable mineral-resource potential. If mineral deposits exist, they probably are of the massive sulfide type. The geologic terrain precludes the presence of fossil fuel resources. Sand and gravel and peat in swampy lowlands are the only resources of the Whisker lake Wilderness.

  8. Resilience and Restoration of Lakes

    Directory of Open Access Journals (Sweden)

    Kathryn L. Cottingham

    1997-06-01

    Full Text Available Lake water quality and ecosystem services are normally maintained by several feedbacks. Among these are nutrient retention and humic production by wetlands, nutrient retention and woody habitat production by riparian forests, food web structures that cha nnel phosphorus to consumers rather than phytoplankton, and biogeochemical mechanisms that inhibit phosphorus recycling from sediments. In degraded lakes, these resilience mechanisms are replaced by new ones that connect lakes to larger, regional economi c and social systems. New controls that maintain degraded lakes include runoff from agricultural and urban areas, absence of wetlands and riparian forests, and changes in lake food webs and biogeochemistry that channel phosphorus to blooms of nuisance al gae. Economic analyses show that degraded lakes are significantly less valuable than normal lakes. Because of this difference in value, the economic benefits of restoring lakes could be used to create incentives for lake restoration.

  9. Is Lake Chabot Eutrophic?

    Science.gov (United States)

    Pellegrini, K.; Logan, J.; Esterlis, P.; Lew, A.; Nguyen, M.

    2013-12-01

    Introduction/Abstract: Lake Chabot is an integral part of the East Bay watershed that provides habitats for animals and recreation for humans year-round. Lake Chabot has been in danger of eutrophication due to excessive dumping of phosphorous and nitrogen into the water from the fertilizers of nearby golf courses and neighboring houses. If the lake turned out to be eutrophified, it could seriously impact what is currently the standby emergency water supply for many Castro Valley residents. Eutrophication is the excessive richness of nutrients such as nitrogen and phosphorus in a lake, usually as a result of runoff. This buildup of nutrients causes algal blooms. The algae uses up most of the oxygen in the water, and when it dies, it causes the lake to hypoxify. The fish in the lake can't breathe, and consequently suffocate. Other oxygen-dependant aquatic creatures die off as well. Needless to say, the eutrophication of a lake is bad news for the wildlife that lives in or around it. The level of eutrophication in our area in Northern California tends to increase during the late spring/early summer months, so our crew went out and took samples of Lake Chabot on June 2. We focused on the area of the lake where the water enters, known on the map as Honker Bay. We also took readings a ways down in deeper water for comparison's sake. Visually, the lake looked in bad shape. The water was a murky green that glimmered with particulate matter that swirled around the boat as we went by. In the Honker Bay region where we focused our testing, there were reeds bathed in algae that coated the surface of the lake in thick, swirling patterns. Surprisingly enough, however, our test results didn't reveal any extreme levels of phosphorous or nitrogen. They were slightly higher than usual, but not by any significant amount. The levels we found were high enough to stimulate plant and algae growth and promote eutrophication, but not enough to do any severe damage. After a briefing with a

  10. Tewaukon – Clouds LakeLake Elsie – Storm Lake and Wild Rice Refuges Narrative Reports : 1939-1956 : From Sand Lake National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — These narrative reports summarize refuge activities from 1939 to 1956 for Lake Tewaukon Refuge, Clouds Lake Refuge, Lake Elsie Refuge, Storm Lake Refuge, Wild Rice...

  11. TOXAPHENE STUDY OF GREAT LAKES TRIBUTARY SEDIMENTS

    Science.gov (United States)

    The Product is the paper "Pulp and Paper Mills as Sources of Toxaphene to Lake Superior and Northern Lake Michigan" published in the Journal of Great Lakes Research, 25(2):383-394 International Association of Great Lakes 1999.

  12. Glacial lake inventory and lake outburst potential in Uzbekistan.

    Science.gov (United States)

    Petrov, Maxim A; Sabitov, Timur Y; Tomashevskaya, Irina G; Glazirin, Gleb E; Chernomorets, Sergey S; Savernyuk, Elena A; Tutubalina, Olga V; Petrakov, Dmitriy A; Sokolov, Leonid S; Dokukin, Mikhail D; Mountrakis, Giorgos; Ruiz-Villanueva, Virginia; Stoffel, Markus

    2017-08-15

    Climate change has been shown to increase the number of mountain lakes across various mountain ranges in the World. In Central Asia, and in particular on the territory of Uzbekistan, a detailed assessment of glacier lakes and their evolution over time is, however lacking. For this reason we created the first detailed inventory of mountain lakes of Uzbekistan based on recent (2002-2014) satellite observations using WorldView-2, SPOT5, and IKONOS imagery with a spatial resolution from 2 to 10m. This record was complemented with data from field studies of the last 50years. The previous data were mostly in the form of inventories of lakes, available in Soviet archives, and primarily included localized in-situ data. The inventory of mountain lakes presented here, by contrast, includes an overview of all lakes of the territory of Uzbekistan. Lakes were considered if they were located at altitudes above 1500m and if lakes had an area exceeding 100m(2). As in other mountain regions of the World, the ongoing increase of air temperatures has led to an increase in lake number and area. Moreover, the frequency and overall number of lake outburst events have been on the rise as well. Therefore, we also present the first outburst assessment with an updated version of well-known approaches considering local climate features and event histories. As a result, out of the 242 lakes identified on the territory of Uzbekistan, 15% are considered prone to outburst, 10% of these lakes have been assigned low outburst potential and the remainder of the lakes have an average level of outburst potential. We conclude that the distribution of lakes by elevation shows a significant influence on lake area and hazard potential. No significant differences, by contrast, exist between the distribution of lake area, outburst potential, and lake location with respect to glaciers by regions. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. 太湖上游水源保护区生态补偿支付意愿问卷调查——以天目湖流域为例%Questionnaire survey on willingness to pay about ecological compensation of Lake Tianmu catchment, Taihu Basin

    Institute of Scientific and Technical Information of China (English)

    李青; 张落成; 武清华

    2011-01-01

    在天目湖流域建立生态补偿机制,形成上游生态保护激励机制,对于太湖流域水环境改善有着极为重要的作用.本文通过问卷调查的方式,首先,调查了解天目湖流域居民对环境保护和生态补偿的认知状况,得出天目湖流域居民环境保护意识很强,生态补偿需求旺盛.其次,对居民和旅游者的生态补偿支付意愿进行了解.最后,对最大支付意愿公式进行改进,在原有水费反哺的基础上结合了旅游者门票反哺的最大支付意愿,算出天目湖流域生态补偿总额为12924.08万元.同时生态补偿不仅仅是物质或货币的补偿,更重要的是从国家与省市层面上对天目湖这一重要生态功能区给予一定的政策倾斜.%It is important for improving water quality of Lake Taihu that ecological compensation mechanism and incentive mechanism for upstream ecological protection is carried out in Lake Tianmu catchment. Firstly, we acquainted of residents'cognitive status of environmental protection and ecological compensation in Lake Tianmu catchment, and found a strong environmental protection awareness and a great ecological compensation demand. Then, we investigated the willingness to pay for ecological compensation of both local residents and visitors. Finally, we improved the original formula of the greatest willingness to pay. We summed up a total ecological compensation amount of 12924.08 thousand yuan in Lake Tianmu catchment by integrating the greatest back-feeding willingness of tourist tickets to pay into water fee regurgitation-feeding. It was not enough for ecological compensation merely at the material or monetary compensation, and more important way of Lake Tianmu catchment ecological compensation was that some policy inclination of this important eco-function areas from both state and provincial level.

  14. Evidence of Lake Trout reproduction at Lake Michigan's mid-lake reef complex

    Science.gov (United States)

    Janssen, J.; Jude, D.J.; Edsall, T.A.; Paddock, R.W.; Wattrus, N.; Toneys, M.; McKee, P.

    2006-01-01

    The Mid-Lake Reef Complex (MLRC), a large area of deep (> 40 m) reefs, was a major site where indigenous lake trout (Salvelinus namaycush) in Lake Michigan aggregated during spawning. As part of an effort to restore Lake Michigan's lake trout, which were extirpated in the 1950s, yearling lake trout have been released over the MLRC since the mid-1980s and fall gill net censuses began to show large numbers of lake trout in spawning condition beginning about 1999. We report the first evidence of viable egg deposition and successful lake trout fry production at these deep reefs. Because the area's existing bathymetry and habitat were too poorly known for a priori selection of sampling sites, we used hydroacoustics to locate concentrations of large fish in the fall; fish were congregating around slopes and ridges. Subsequent observations via unmanned submersible confirmed the large fish to be lake trout. Our technological objectives were driven by biological objectives of locating where lake trout spawn, where lake trout fry were produced, and what fishes ate lake trout eggs and fry. The unmanned submersibles were equipped with a suction sampler and electroshocker to sample eggs deposited on the reef, draw out and occasionally catch emergent fry, and collect egg predators (slimy sculpin Cottus cognatus). We observed slimy sculpin to eat unusually high numbers of lake trout eggs. Our qualitative approaches are a first step toward quantitative assessments of the importance of lake trout spawning on the MLRC.

  15. Lake Morphometry for NHD Lakes in Ohio Region 5 HUC

    Data.gov (United States)

    U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

  16. Lake Morphometry for NHD Lakes in California Region 18 HUC

    Data.gov (United States)

    U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

  17. Lake Morphometry for NHD Lakes in Tennessee Region 6 HUC

    Data.gov (United States)

    U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

  18. SATELLITE LAKES OF LAKE VICTORIA BASIN (TANZANIAN SIDE)

    African Journals Online (AJOL)

    Studies on phytoplankton species diversity and abundance were carried out in 8 selected satellite lakes within the Lake ... species of blue green algae such as Spirulina spp. are sources of ... scientific and conservation interests. This study ...

  19. Structure and spatial patterns of macrobenthic community in Tai Lake, a large shallow lake, China

    Science.gov (United States)

    Di Li,; Erickson, Richard A.; Song Tang,; Xuwen Li,; Zhichun Niu,; Xia Wang,; Hongling Liu,; Hongxia Yu,

    2016-01-01

    Tai Lake (Chinese: Taihu), the third-largest freshwater lake in China, suffers from harmful cyanobacteria blooms that are caused by economic development and population growth near the lake. Several studies have focused on phytoplankton in Tai Lake after a drinking water crisis in 2007; however, these studies primarily focused on microcystin bioaccumulation and toxicity to individual species without examining the effects of microcystin on macrobenthic community diversity. In this study, we conducted a survey of the lake to examine the effects of microcystine and other pollutants on marcobenthic community diversity. A totally of forty-nine species of macroinvertebrates were found in Tai Lake. Limnodrilus hoffmeisteri and Corbicula fluminea were the most abundant species. Cluster-analysis and one-way analysis of similarity (ANOSIM) identified three significantly different macrobenthic communities among the sample sites. More specifically, sites in the eastern bays, where aquatic macrophytes were abundant, had the highest diversity of macrobenthic communities, which were dominated by Bellamya aeruginosa, Bellamya purificata, L. hoffmeisteri, and Alocinma longicornis. Sites in Zhushan Bay contained relatively diverse communities, mainly composed of L. hoffmeisteri, C. fluminea, L. claparederanus, R. sinicus, and Cythura sp. Sites in the western region, Meiliang Bay and Wuli Bay had the lowest diversity, mainly composed ofL. hoffmeisteri, C. fluminea, Branchiura sowerbyi, and Rhyacodrilus sinicus. In addition, the relationships between macrobenthic metrics (Shannon–Wiener, Margalef, and Pielou) and environmental variables showed that community structure and spatial patterns of macrobenthos in Tai Lake were significantly influenced by chemical oxygen demand (CODCr), biochemical oxygen demand (BOD5), lead (Pb), and microcystin-LR (L for leucine and R for arginine). Our findings provide critical information that could help managers and policymakers

  20. Lake Michigan lake trout PCB model forecast post audit

    Science.gov (United States)

    Scenario forecasts for total PCBs in Lake Michigan (LM) lake trout were conducted using the linked LM2-Toxics and LM Food Chain models, supported by a suite of additional LM models. Efforts were conducted under the Lake Michigan Mass Balance Study and the post audit represents th...

  1. Estimation of the contribution of chromophoric dissolved organic matter to total light absorption by remote sensing in Lake Taihu%太湖有色溶解有机物对水体总吸收贡献的遥感估算

    Institute of Scientific and Technical Information of China (English)

    姜广甲; 马荣华; 段洪涛

    2012-01-01

    Chromophnric dissolved organic matter (CDOM) mainly absorbs light in water which may influence the nature water color in lakes. Its absorption and photochemical degradation products play an important role in the primary productivity of water and carbon cycle. In Lake Taihu, a total of 333 sites were sampled in October 2004, October 2008 , April 2010 and January and March 2011 to analyze the contribution of CDOM to tolal light absorption und estimate [aCDOM/a1] (412 ) from remote sensing. It was found that the average of [ Ocdom/a1] (412) exhibited highly temporal variations during the five cruises. The maximum (0. 369) was determined in 2011 , comparing with all samples in Lake Taihu (0. 295 ±0. 139). The minimum average of [aCDOM\\a1] (412) in the dalaset 201004 was 0. 236 ± 0. 108 , varing from 0.046 to 0.455. No significant difference was observed in the data-set 200410 and 200810. The mean of [aCDOM/a1 ] ( 412) in Zhushan Bay was higher than that in both whole Lake Taihu and Meil lang Bay, For Meiliang Bay, it had almost the same value with the whole lake. A multi-band algorithm was adopted to estimate the [aCDOM/a1] (412) by remote sensing and acceptable results were detected (n =333, RMSE = 34. 60% ). Suspended sediments and pigments had an important impact on determination of [aCDOM/a1] (412) from remote sensing. It was underestimated because of pigments and overestimated as the suspended sediments in water and the latter was worse. Tile results also showed that the CDOM and detritus optically dominate thp water color in Lake Taihu.%有色溶解有机物(CDOM)是决定自然水体水色的主要溶解物质,其吸光能力和光化降解产物对水体初级生产力和碳循环过程具有重要影响.以太湖为研究区,2004年10月、2008年10月、2010年4月和2011年1月和3月共5期实测数据,采集了333个有效样点,分析不同时期CDOM对水体总吸收的贡献,并利用遥感技术估算[aCDOM/a1](412).结

  2. Mono Lake Excursion Reviewed

    Science.gov (United States)

    Liddicoat, J. C.; Coe, R. S.

    2007-05-01

    The Mono Lake Excursion as recorded in the Mono Basin, CA, has an older part that is about negative 30 degrees inclination and about 300 degrees declination during low relative field intensity. Those paleomagnetic directions are closely followed by greater than 80 degrees positive inclination and east declination of about 100 degrees during higher relative field intensity. A path of the Virtual Geomagnetic Poles (VGPs) for the older part followed from old to young forms a large clockwise loop that reaches 35 degrees N latitude and is centered at about 35 degrees E longitude. That loop is followed by a smaller one that is counterclockwise and centered at about 70 degrees N latitude and 270 degrees E longitude (Denham & Cox, 1971; Denham, 1974; Liddicoat & Coe, 1979). The Mono Lake Excursion outside the Mono Basin in western North America is recorded as nearly the full excursion at Summer Lake, OR (Negrini et al., 1984), and as the younger portion of steep positive inclination/east declination in the Lahontan Basin, NV. The overall relative field intensity during the Mono Lake Excursion in the Lahontan Basin mirrors very closely the relative field intensity in the Mono Basin (Liddicoat, 1992, 1996; Coe & Liddicoat, 1994). Using 14C and 40Ar/39Ar dates (Kent et al., 2002) and paleoclimate and relative paleointensity records (Zimmerman et al., 2006) for the Mono Lake Excursion in the Mono Basin, it has been proposed that the Mono Lake Excursion might be older than originally believed and instead be the Laschamp Excursion at about 40,000 yrs B.P. (Guillou et al., 2004). On the contrary, we favor a younger age for the Mono Lake Excursion, about 32,000 yrs B.P., using the relative paleointensity in the Mono Basin and Lahontan Basin and 14C dates from the Lahontan Basin (Benson et al., 2002). The age of about 32,000 yrs B.P. is also in accord with the age (32,000- 34,000 yrs B.P.) reported by Channell (2006) for the Mono Lake Excursion at ODP Site 919 in the Irminger Basin

  3. 高等水生植物对太湖沉积物再悬浮特征的影响%Effects of Aquatic Plants on the Feature ol Sediment Resuspension in Lake Taihu

    Institute of Scientific and Technical Information of China (English)

    许晓伟; 陈昌仁; 万福绪; 谢宇

    2012-01-01

    [Objective] The aim was to study effects of aquatic plants on resuspen- sion of sediment in Lake Taihu. [Method] New resuspension simulator was used in the research. Elodea nuttalli, submerged plant, and Phragmites australis, emergent aquatic plant, were grown in substrate sludge with varied planting density set. Study of simulation experiment on the feature of sediment resuspension was carried on under shearing stress of 0.2-0.5 N/m2 and agitation of 1-30 min. [Result] Aquatic plant growing would effectively reduce seston concentration in water. Concentrations of final Suspended Particulate Matter (SPM) in experimental groups and control groups were as follows: water without plant〉coverage of 30% of Elodea nuttalli〉cov- erage of 60% of Elodea nuttalli〉Phragmites australis with concentration of 50 stock/m2〉 coverage of 90% of Elodea nuttalli〉Phragmites australis with concentration of 80 stock/m2〉Phragmites australis with concentration of 150 stock/m2; SPM concentration showed a tendency from increasing to stable with change of stirring time under dif- ferent shearing stresses: SPM concentration was of severe change at early stage in barrel without aquatic plant while change of SPM concentration in barrel with aquatic plant was quite mild and grew smaller with concentration increasing; SPM concentration was reduced much more if Phragmites australis planted compared with that of Elodea nuttalli; under different shearing stresses, reduction of SPM concen- tration by increase of Phragmites australis area was much more than by increase of Elodea nuttalli area. [Conclusion] It would provide powerful scientific reference for control on aquatic environment through comprehensive research on the feature of sediment resuspension.%[目的]研究高等水生植物对太湖沉积物再悬浮的影响。[方法]采用新型再悬浮模拟器,在底泥中种植沉水植物伊乐藻(Elodeanuttalli)和挺水植物芦苇

  4. Lake Erie Fish Community Data

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Lake Erie Biological Station (LEBS), located in Sandusky, Ohio, is a field station of the USGS Great Lakes Science Center (GLSC). LEBS is the primary federal agency...

  5. Crescent Lake Wilderness Reference Sheet

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Reference sheet includes information about Crescent Lake National Wildlife Refuge, and results of the public hearing for Crescent Lake Wilderness Proposal.

  6. Freshwater lake seabird surveys 2012

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Alaska Peninsula/Becharof NWR complex hosts Becharof Lake, the largest lake within a National Wildlife Refuge system. In addition to this distinction, Becharof...

  7. Great Lakes Environmental Database (GLENDA)

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Great Lakes Environmental Database (GLENDA) houses environmental data on a wide variety of constituents in water, biota, sediment, and air in the Great Lakes area.

  8. Functional microbiology of soda lakes

    NARCIS (Netherlands)

    Sorokin, D.Y.; Banciu, H.L.; Muyzer, G.

    2015-01-01

    Soda lakes represent unique permanently haloalkaline system. Despite the harsh conditions, they are inhabited by abundant, mostly prokaryotic, microbial communities. This review summarizes results of studies of main functional groups of the soda lake prokaryotes responsible for carbon, nitrogen and

  9. Eco-compensation of drinking water source protection region in eastern Lake Taihu based on development right valuation%基于发展权价值评估的太湖东部水源保护区生态补偿标准

    Institute of Scientific and Technical Information of China (English)

    陈江龙; 姚佳; 徐梦月; 陈雯

    2012-01-01

    生态补偿是协调环境保护与区域发展机会公平的重要手段.太湖东部湖区是苏州市、嘉兴市和上海市重要饮用水源供给地.本文分析了苏州市滨湖地区水源地水质保护行为与发展权价值损失的关系.应用区域比较法,在地理要素修正的基础上评价了太湖东部水源保护区发展权价值损失,以此作为生态补偿的标准.研究表明,2009年太湖东部地区水质保护行为的发展权损失为42.39亿元,地方财政收入损失占75.88%;农民收入损失占13.58%;城镇居民收入损失占10.53%.为了缩小城乡居民的收入差距,应优先对农民实施生态补偿.水质保护行为产生的外部收益超出了水源供给价值,需要在更大范围内统筹生态补偿问题.%Ecological compensation is an important means to coordinate the contradiction between environmental protection and regional development fairness. Eastern Lake Taihu is an important source of drinking water for Suzhou, Jiaxing and Shanghai cities. This paper analyzes the connection between water quality protection behavior and loss of development right value in Suzhou city. Based on geographic factor correction, the paper applies regional comparison method to evaluate the loss of development right in drinking water source protection region in eastern Lake Taihu, as the standard of eco-compensation. It shows that the loss of development right in eastern Lake Taihu in 2009 is 4.239 billion yuan, while the loss of local fiscal revenue, farmers' income and urban residents' income accounting for 75.88% , 13.58% and 10.53% , respectively. In order to narrow the income gap between urban and rural residents, fanners should be given priority on the implementation of eco-compensation. The external benefit from water protection behavior has beyond the value of water supply, so overall the eco-compensation police in a greater region is needed.

  10. 太湖康山湾示范区水生植物对水体氮、磷控制的适用性分析%Applicability analysis of aquatic macrophytes on controlling nitrogen and phosphorus from water in the Kangshan Bay demonstration area of Lake Taihu

    Institute of Scientific and Technical Information of China (English)

    宋玉芝; 朱广伟; 秦伯强

    2013-01-01

    为重建湖泊水生植被,改善太湖局部水域水质,在太湖康山湾示范区两个大型围隔进行了两种类型水生植物重建.通过2010年8月-2011年8月的现场采样及分析测定发现,人工控制条件下,浮叶植物荇菜和菱以及沉水植物马来眼子菜的重建效果较好,在其生长季节具有较高的覆盖度;研究表明,控制风浪及提高透明度是恢复水生植被的前提;植被重建区沉水植物氮、磷含量与浮叶植物差别不大,但浮叶植物重建区水体氮、磷浓度的控制比沉水植物重建区好;从经济及水环境效益角度来看,太湖敞水区的沿岸带由于风浪的控制比较困难,恢复水生植被时,应选择浮叶植物荇菜、菱、沉水植物马来眼子菜等抗风浪能力强的物种.本研究为太湖敞水区沿岸带的生态恢复方案制定提供了理论依据.%In order to restore the aquatic vegetation and improve local water quality, reconstruction of two ecological types of aquatic plants were carried out in two large enclosures in the Kangshan Bay demonstration area of Lake Taihu. By annual investigation, results showed that floating-leaved aquatic plants such as Limnanthemun nymphoides and Trapa bicomi, and submerged plant such as Potamogeton macckianus grew better than other plants under controlled conditions. Their coverage was quite high during the growing season. Results also showed that, controlling wind-driven wave disturbance and improving water transparency were the prerequisite for aquatic vegetation restoration; there was no difference about N and P contents between submerged macrophyte and floating-leaved aquatic plants, but floating-leaved aquatic plants performed better than submerged macrophyte in removing water N and P content. Concerning the economic and environmental benefit, aquatic plants including L. nymphoides , T. bicomi and P. macckianus with powerful anti-wave ability could be selected as the pioneering species to rebuild

  11. 太湖及辽河流域表层沉积物中拟除虫菊酯的浓度水平及毒性评估%Levels and toxicity assessment of pyrethroids in the surface sediments of Taihu Lake and Liaohe River

    Institute of Scientific and Technical Information of China (English)

    方淑红; 陈鹏; 卞京娜; 钟文珏; 祝凌燕

    2012-01-01

    Eight widely used pyrethroids,including bifenthrin,lambda-cyhalothrin,permethtin,fenpropathrin,cyfluthrin,esfenvalerate,cypermethrin and deltamethrin,were analyzed in the sediments collected from Taihu Lake and Liaohe River.The total concentration of the 8 pyrethroids in Taihu Lake was relatively low,ranging from 0.02~2.91 ng · g^-1(dry weight,the same in the follows) with a mean value of 0.63 ng · g^-1.In comparison,the concentration in Liaohe River was relatively high and it varied in the range of 0.14~19.6 ng · g^-1 with an average of 6.20 ng · g^-1.Toxic units based on the LC50 of Hyallela Azteca were calculated to estimate the toxicity risk.The ∑TU was in the range of 0-0.40 for the sediments in Taihu Lake,while it was much higher in Liaohe River with a range of 0.10-1.73.The ∑TU was larger than 1 for three sediments in Liaohe River,suggesting pyrethroids in these sediments could present potential toxicity to benthonic organisms.The toxicity was mainly induced by deltamethrin and cypermethrin.%对辽河和太湖流域表层沉积物中8种常见的拟除虫菊酯:联苯菊酯、高效氯氟氰菊酯、氯菊酯、甲氰菊酯、氟氯氰菊酯、氯氰菊酯、氰戊菊酯、溴氰菊酯进行分析测定.结果显示,太湖流域中拟除虫菊酯含量范围为0.02~2.91ng·g^-1(干重,下同),平均含量为0.63ng.g^-1,处于相对较低的水平;辽河流域中的含量相对较高,其范围是0.14~19.6ng·g^-1,平均含量为6.20ng·g^-1.采用毒性单元TU(选用钩虾Hyallela Azteca的LC50)对拟除虫菊酯毒性风险进行估算,太湖流域∑TU值范围是0~0.40,相比之下,辽河流域的∑TU值高出很多,范围在0.10~1.73之间,其中有3个点位的∑TU值大于1,表明其具有一定的生态风险,其毒性主要来源于氯氰菊酯和氰戊菊酯.

  12. Microplastic pollution in lakes and lake shoreline sediments - A case study on Lake Bolsena and Lake Chiusi (central Italy).

    Science.gov (United States)

    Fischer, Elke Kerstin; Paglialonga, Lisa; Czech, Elisa; Tamminga, Matthias

    2016-06-01

    Rivers and effluents have been identified as major pathways for microplastics of terrestrial sources. Moreover, lakes of different dimensions and even in remote locations contain microplastics in striking abundances. This study investigates concentrations of microplastic particles at two lakes in central Italy (Lake Bolsena, Lake Chiusi). A total number of six Manta Trawls have been carried out, two of them one day after heavy winds occurred on Lake Bolsena showing effects on particle distribution of fragments and fibers of varying size categories. Additionally, 36 sediment samples from lakeshores were analyzed for microplastic content. In the surface waters 2.68 to 3.36 particles/m(3) (Lake Chiusi) and 0.82 to 4.42 particles/m(3) (Lake Bolsena) were detected, respectively. Main differences between the lakes are attributed to lake characteristics such as surface and catchment area, depth and the presence of local wind patterns and tide range at Lake Bolsena. An event of heavy winds and moderate rainfall prior to one sampling led to an increase of concentrations at Lake Bolsena which is most probable related to lateral land-based and sewage effluent inputs. The abundances of microplastic particles in sediments vary from mean values of 112 (Lake Bolsena) to 234 particles/kg dry weight (Lake Chiusi). Lake Chiusi results reveal elevated fiber concentrations compared to those of Lake Bolsena what might be a result of higher organic content and a shift in grain size distribution towards the silt and clay fraction at the shallow and highly eutrophic Lake Chiusi. The distribution of particles along different beach levels revealed no significant differences.

  13. A Lake Dream in Asia

    Institute of Scientific and Technical Information of China (English)

    Yang Wei

    2009-01-01

    @@ When William Wordsworth,representative of Lake Poets wrote his Ode to Night ingale nearby the Lake District of England at the turn of the nine-teenth century,he never imagined a century later,a similar romantic lake dream has been created in China,Asia.

  14. Interesting Ziandao Lake

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    LOCATED in Chun’an County, Zhejiang Province, Qiandao Lake (Lake of a Thousand Isles) is a state-level scenic spot and a bright pearl of the golden tourism line between Hangzhou’s West Lake and Anhui’s Huangshan Mountain. Last autumn, we went to Chun’an. It took only three to four hours by coach to travel from Hangzhou to Chun’an. Flanked by mountains on the west, the small county faces water on the east. A street goes across the county; it takes less than half an hour to walk from one end to the other. Small restaurants and shops line the western side of the road,

  15. Viruses in Antarctic lakes

    Science.gov (United States)

    Kepner, R. L. Jr; Wharton, R. A. Jr; Suttle, C. A.; Wharton RA, J. r. (Principal Investigator)

    1998-01-01

    Water samples collected from four perennially ice-covered Antarctic lakes during the austral summer of 1996-1997 contained high densities of extracellular viruses. Many of these viruses were found to be morphologically similar to double-stranded DNA viruses that are known to infect algae and protozoa. These constitute the first observations of viruses in perennially ice-covered polar lakes. The abundance of planktonic viruses and data suggesting substantial production potential (relative to bacteria] secondary and photosynthetic primary production) indicate that viral lysis may be a major factor in the regulation of microbial populations in these extreme environments. Furthermore, we suggest that Antarctic lakes may be a reservoir of previously undescribed viruses that possess novel biological and biochemical characteristics.

  16. Lake Morphometry for NHD Lakes in Great Lakes Region 4 HUC

    Data.gov (United States)

    U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

  17. Technologies for lake restoration

    Directory of Open Access Journals (Sweden)

    Helmut KLAPPER

    2003-09-01

    Full Text Available Lakes are suffering from different stress factors and need to be restored using different approaches. The eutrophication remains as the main water quality management problem for inland waters: both lakes and reservoirs. The way to curb the degradation is to stop the nutrient sources and to accelerate the restoration with help of in-lake technologies. Especially lakes with a long retention time need (eco- technological help to decrease the nutrient content in the free water. The microbial and other organic matter from sewage and other autochthonous biomasses, causes oxygen depletion, which has many adverse effects. In less developed countries big reservoirs function as sewage treatment plants. Natural aeration solves problems only partly and many pollutants tend to accumulate in the sediments. The acidification by acid rain and by pyrite oxidation has to be controlled by acid neutralizing technologies. Addition of alkaline chemicals is useful only for soft waters, and technologies for (microbial alkalinization of very acidic hardwater mining lakes are in development. The corrective measures differ from those in use for eutrophication control. The salinization and water shortage mostly occurs if more water is used than available. L. Aral, L. Tschad, the Dead Sea or L. Nasser belong to waters with most severe environmental problems on a global scale. Their hydrologic regime needs to be evaluated. The inflow of salt water at the bottom of some mining lakes adds to stability of stratification, and thus accumulation of hydrogen sulphide in the monimolimnion of the meromictic lakes. Destratification, which is the most used technology, is only restricted applicable because of the dangerous concentrations of the byproducts of biological degradation. The contamination of lakes with hazardous substances from industry and agriculture require different restoration technologies, including subhydric isolation and storage, addition of nutrients for better self

  18. Lakes on Mars

    CERN Document Server

    Cabrol, Nathalie A

    2014-01-01

    On Earth, lakes provide favorable environments for the development of life and its preservation as fossils. They are extremely sensitive to climate fluctuations and to conditions within their watersheds. As such, lakes are unique markers of the impact of environmental changes. Past and current missions have now demonstrated that water once flowed at the surface of Mars early in its history. Evidence of ancient ponding has been uncovered at scales ranging from a few kilometers to possibly that of the Arctic ocean. Whether life existed on Mars is still unknown; upcoming missions may find critic

  19. Reevaluation of lake trout and lake whitefish bioenergetics models

    Science.gov (United States)

    Madenjian, Charles P.; Pothoven, Steve A.; Kao, Yu-Chun

    2013-01-01

    Using a corrected algorithm for balancing the energy budget, we reevaluated the Wisconsin bioenergetics model for lake trout (Salvelinus namaycush) in the laboratory and for lake whitefish (Coregonus clupeaformis) in the laboratory and in the field. For lake trout, results showed that the bioenergetics model slightly overestimated food consumption by the lake trout when they were fed low and intermediate rations, whereas the model predicted food consumption by lake trout fed ad libitum without any detectable bias. The slight bias in model predictions for lake trout on restricted rations may have been an artifact of the feeding schedule for these fish, and we would therefore recommend application of the Wisconsin lake trout bioenergetics model to lake trout populations in the field without any revisions to the model. Use of the Wisconsin bioenergetics model for coregonids resulted in overestimation of food consumption by lake whitefish both in the laboratory and in the field by between 20 and 30%, on average. This overestimation of food consumption was most likely due to overestimation of respiration rate. We therefore adjusted the respiration component of the bioenergetics model to obtain a good fit to the observed consumption in our laboratory tanks. The adjusted model predicted the consumption in the laboratory and the field without any detectable bias. Until a detailed lake whitefish respiration study can be conducted, we recommend application of our adjusted version of the Wisconsin generalized coregonid bioenergetics model to lake whitefish populations in the field.

  20. Lake whitefish diet, condition, and energy density in Lake Champlain and the lower four Great Lakes following dreissenid invasions

    Science.gov (United States)

    Herbst, Seth J.; Marsden, J. Ellen; Lantry, Brian F.

    2013-01-01

    Lake Whitefish Coregonus clupeaformis support some of the most valuable commercial freshwater fisheries in North America. Recent growth and condition decreases in Lake Whitefish populations in the Great Lakes have been attributed to the invasion of the dreissenid mussels, zebra mussels Dreissena polymorpha and quagga mussels D. bugensis, and the subsequent collapse of the amphipod, Diporeia, a once-abundant high energy prey source. Since 1993, Lake Champlain has also experienced the invasion and proliferation of zebra mussels, but in contrast to the Great Lakes, Diporeia were not historically abundant. We compared the diet, condition, and energy density of Lake Whitefish from Lake Champlain after the dreissenid mussel invasion to values for those of Lake Whitefish from Lakes Michigan, Huron, Erie, and Ontario. Lake Whitefish were collected using gill nets and bottom trawls, and their diets were quantified seasonally. Condition was estimated using Fulton's condition factor (K) and by determining energy density. In contrast to Lake Whitefish from some of the Great Lakes, those from Lake Champlain Lake Whitefish did not show a dietary shift towards dreissenid mussels, but instead fed primarily on fish eggs in spring, Mysis diluviana in summer, and gastropods and sphaeriids in fall and winter. Along with these dietary differences, the condition and energy density of Lake Whitefish from Lake Champlain were high compared with those of Lake Whitefish from Lakes Michigan, Huron, and Ontario after the dreissenid invasion, and were similar to Lake Whitefish from Lake Erie; fish from Lakes Michigan, Huron, and Ontario consumed dreissenids, whereas fish from Lake Erie did not. Our comparisons of Lake Whitefish populations in Lake Champlain to those in the Great Lakes indicate that diet and condition of Lake Champlain Lake Whitefish were not negatively affected by the dreissenid mussel invasion.

  1. Poet Lake Crystal Approval

    Science.gov (United States)

    This September 19, 2016 letter from EPA approves the petition from Poet Biorefining-Lake Crystal, regarding non-grandfathered ethanol produced through a dry mill process, qualifying under the Clean Air Act for renewable fuel (D-code 6) RINs under the RFS

  2. in lake chamo, ethiopia

    African Journals Online (AJOL)

    ADMIN

    zooplankton until they move to the littoral regions and start feeding .... Fish collected during the spawning season (i.e.,. March-June .... females, but sampling in the estuary downstream ... same size could be first-time spawners in Lake. Chamo ...

  3. Reclaiming the lake

    DEFF Research Database (Denmark)

    Rasmussen, Mattias Borg

    2016-01-01

    of individual rights that move well beyond the site of conflict. It is therefore argued that the actions to reclaim Lake Conococha were not only a battle for natural resources and clean water, but more fundamentally an attempt to repossess a citizenship that may be constitutionally secured but all too oft en...

  4. Lake Ontario: Nearshore Variability

    Science.gov (United States)

    We conducted a high-resolution survey with towed electronic instrumentation along the Lake Ontario nearshore (720 km) at a 20 meter contour. The survey was conducted September 6-10, 2008 with a shorter 300 km survey conducted August 14-15 for comparing of temporal variability. ...

  5. Microbiology of Lonar Lake and other soda lakes.

    Science.gov (United States)

    Antony, Chakkiath Paul; Kumaresan, Deepak; Hunger, Sindy; Drake, Harold L; Murrell, J Colin; Shouche, Yogesh S

    2013-03-01

    Soda lakes are saline and alkaline ecosystems that are believed to have existed throughout the geological record of Earth. They are widely distributed across the globe, but are highly abundant in terrestrial biomes such as deserts and steppes and in geologically interesting regions such as the East African Rift valley. The unusual geochemistry of these lakes supports the growth of an impressive array of microorganisms that are of ecological and economic importance. Haloalkaliphilic Bacteria and Archaea belonging to all major trophic groups have been described from many soda lakes, including lakes with exceptionally high levels of heavy metals. Lonar Lake is a soda lake that is centered at an unusual meteorite impact structure in the Deccan basalts in India and its key physicochemical and microbiological characteristics are highlighted in this article. The occurrence of diverse functional groups of microbes, such as methanogens, methanotrophs, phototrophs, denitrifiers, sulfur oxidizers, sulfate reducers and syntrophs in soda lakes, suggests that these habitats harbor complex microbial food webs that (a) interconnect various biological cycles via redox coupling and (b) impact on the production and consumption of greenhouse gases. Soda lake microorganisms harbor several biotechnologically relevant enzymes and biomolecules (for example, cellulases, amylases, ectoine) and there is the need to augment bioprospecting efforts in soda lake environments with new integrated approaches. Importantly, some saline and alkaline lake ecosystems around the world need to be protected from anthropogenic pressures that threaten their long-term existence.

  6. Lake trout rehabilitation in Lake Erie: a case history

    Science.gov (United States)

    Cornelius, Floyd C.; Muth, Kenneth M.; Kenyon, Roger

    1995-01-01

    Native lake trout (Salvelinus namaycush) once thrived in the deep waters of eastern Lake Erie. The impact of nearly 70 years of unregulated exploitation and over 100 years of progressively severe cultural eutrophication resulted in the elimination of lake trout stocks by 1950. Early attempts to restore lake trout by stocking were unsuccessful in establishing a self-sustaining population. In the early 1980s, New York's Department of Environmental Conservation, Pennsylvania's Fish and Boat Commission, and the U.S. Fish and Wildlife Service entered into a cooperative program to rehabilitate lake trout in the eastern basin of Lake Erie. After 11 years of stocking selected strains of lake trout in U.S. waters, followed by effective sea lamprey control, lake trout appear to be successfully recolonizing their native habitat. Adult stocks have built up significantly and are expanding their range in the lake. Preliminary investigations suggest that lake trout reproductive habitat is still adequate for natural reproduction, but natural recruitment has not been documented. Future assessments will be directed toward evaluation of spawning success and tracking age-class cohorts as they move through the fishery.

  7. The petrography features of impact breccias in the Western Taihu Lake,Jiangsu,China%太湖西缘击变角砾岩的岩相学特征及其研究意义--太湖冲击成因又添新证据

    Institute of Scientific and Technical Information of China (English)

    王鹤年; 钱汉东; 黄钟谨; 施贵军

    2015-01-01

    冲击变质作用是变质作用的一种新类型,是指由陨石或彗星高速降落所产生的高压冲击波,瞬间经过或穿过靶岩所引起的岩石及矿物中的所有变化,击变岩是冲击变质作用的典型产物。近年来国外在这一领域发展很快,但国内尚无详细的研究成果报道。近期在太湖西缘发现了这类击变角砾岩。根据国外研究总结提出的诊断性特征和有效的岩相学研究方法,本文对击变角砾岩中面型微裂隙(PFs)、面型微页理(PDFs)、击变矿物玻璃(diaplectic glass)、击变高温矿物玻璃及熔体(焦石英lechatelierite)及岩石相的转变(岩石熔融)等标志性特征的研究,确证了太湖西缘这类击变岩的存在。研究对推动国内击变岩的研究和发展将起到积极促进作用,并为“太湖冲击事件”增添新的证据。%Impact metamorphism is a new type of metamorphism.It refers to all changes in rocks caused by high-speed impact of meteorite or comet,during which high-pressure shockwaves passed by or penetrated through these target rocks.Impactite is a typical product of impact metamorphism.Research of this field has developed rapidly in some countries,yet no detailed research result was reported in China.In recent years the present authors found some impact breccias in the western margin of Taihu Lake.Petrographic features of these impact breccias are studied based on the identification criteria summarized from previous research experience,together with effective petrographic research methods.Some distinguishing characteristics,e.g.planar fissures(PFs),planar deformation features(PDFs),diaplectic glass,impact-induced high-temperature glasses and melts (lechatelierite),and the phase change of rocks (melting)are recognized,which confirm the existence of impactite in western Taihu area.The present study not only provides new evidence for the existence of the “Taihu Lake impact event”,but also actively promotes

  8. DELINEATION OF POLLUTION CONTROL UNITS IN TYPICAL CASE AREA IN THE TAIHU LAKE BASIN AND ITS OVERLOADING RATE OF WATER ENVIRONMENT%太湖流域典型区污染控制单元划分及其水环境载荷评估

    Institute of Scientific and Technical Information of China (English)

    高永年; 高俊峰; 陈垌烽; 许妍; 赵家虎

    2012-01-01

    污染控制单元是流域水质目标管理实施的基本单元。为实现流域水生态健康,针对太湖流域特征和太湖湖泊保护的要求,提出以流域水生态功能区为基础、水系完整性原则、管理可行性和可操作性原则、囊括影响受损水体的主要污染源原则、充分考虑现有控制断面原则等5项原则为太湖流域污染控制单元划分的基本原则,综合考虑汇水区、水生态功能区边界、水系分布及其流向、污染源、控制断面、县级与乡镇级行政边界等多个指标,在GIS空间分析的支持下进行太湖流域污染控制单元划分的总体技术思路;在划分技术体系的指导下,以兼具丘陵山区和平原地貌的湖州市及其上游的安徽省部分地区为案例研究区,在相关基础数据和空间方法的支持下,将其划分为12个污染控制单元,经过专家咨询、地方验证等多轮咨询反馈和实地察看以及管理试运行,表明污染控制单元划分结果具有较好的科学性和可操作性;进而评估了各污染控制单元COD、NH4-N、TN和TP污染物的水环境载荷特征,结果表明各单元污染超载严重。%The pollution control units are the base of the water quality targets management in basin scale.According to the protection requirements for the Taihu Lake and the Taihu Lake basin characteristics,the pollution control unit delineation system in the Taihu Lake basin was discussed.The pollution control unit delineation principles mainly include the principle of aquatic ecoregion being the basis,principle of river integrity,principle of management and operational feasibility,principle of including the most point and nonpoint sources of pollution,principle of trying to include the existing water quality monitoring section,etc.The main indicators of the pollution control unit delineation mainly include the subwatershed,level III aquatic ecoregion,distribution pattern and flow direction of river system

  9. Evolution of alkaline lakes - Lake Van case study

    Science.gov (United States)

    Tillman Meyer, Felix; Viehberg, Finn; Bahroun, Sonya; Wolf, Annabel; Immenhauser, Adrian; Kwiecien, Ola

    2017-04-01

    Lake Van in Eastern Anatolia (Turkey) is the largest terminal soda lake on Earth. The lake sedimentary profile covers ca. 600 ka (Stockhecke et al. 2014) Based on lithological changes, the presence of freshwater microfossils and close-to-freshwater pH value in the pore water, members of ICDP PALEOVAN concluded that Lake Van might have started as an open lake. Here we show paleontological and geochemical evidence in favour of this idea and constrain the time, when Lake Van likely transformed into a closed lake. Additionally we provide the first conceptual model of how this closure may have happened. Our archives of choice are inorganic and biogenic carbonates, separated by wet sieving. We identified microfossil assemblages (fraction > 125 µm) and performed high-resolution oxygen isotope (delta18O) and elemental (Mg/Ca, Sr/Ca) analyses of the fraction food supply. These two aspects point to an increasing salinity in a shallowing lake. The delta18O values of inorganic carbonates are relatively low during the initial phase of Lake Van and increase abruptly (ca. 7‰) after 530 ka BP. At approximately the same time combination of Sr/Ca and Mg/Ca data suggest first occurrence of aragonite. Again, these findings suggest geochemical changes of the lake water concurrent with transition documented by microfossils. Comparison between Lake Van and Lake Ohrid (Lacey et al. 2016) delta18O data, precludes regional climate change (e.g.: increased evaporation) as the main driver of observed changes. With no evidence for increased volcanic or tectonic activity (e.g.: tephra layers, deformation structures, slumping) in the Lake Van sedimentary profile around 530 ka, it seems unlikely that a pyroclastic flow blocked the outflow of the lake. Alternatively, a portion of inflow has been diverged which might have caused a change in the hydrological balance and lake level falling below its outlet. However, as no geomorphological data confirming this scenario yet exist, it is only a

  10. Contributions of phosphatase and microbial activity to internal phosphorus loading and their relation to lake eutrophication

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Phosphatase may accelerate the process of lake eutrophication through improving phosphorus bioavailability. This mechanism was studied in three Chinese eutrophic shallow lakes (Lake Taihu, Lake Longyang and Lake Lianhua). Phosphatase activity was related to the concentration of soluble reactive phosphorus (SRP) and chlorophyll a. Stability of dissolved phosphatase in reverse micelles may be attributed to molecular size, conformation and active residues of the enzyme.At the site with Microcystis bloomed in Lake Taihu, dissolved phosphatase activity was higher and more stable in micelles, SRP concentrations were lower in interstitial water, the contents of different forms of phosphorus and the amounts of aerobic bacteria were lower while respiration efficiency was higher in sediments. Phosphobacteria, both inorganic and organic and other microorganisms were abundant in surface water but rare in sediments. Therefore, internal phosphorus may substantially flux into water column by enzymatic hydrolysis and anaerobic release, together with mobility of bacteria,thereby initiating the bloom. In short, biological mechanism may act in concert with physical and chemical factors to drive the internal phosphorus release and accelerate lake eutrophication.

  11. Radiochronology of lake sediments

    Energy Technology Data Exchange (ETDEWEB)

    Erten, H.N. [Bilkent Univ., Ankara (Turkey). Dept. of Chemistry

    1997-01-01

    Sediment cores from Lakes Zurich, Constance, from the Sea of Marmara and from southern Turkey, northern Cyprus and eastern Spain were dated using natural {sup 210}Pb, fallout {sup 137}Cs and cosmic-ray produced {sup 7}Be radionuclides. Constant activity regions in the uppermost sections of sediments from Lake Zurich and the Sea of Marmara were attributed to post-depositional mobility of {sup 210}Pb in the former case and to bioturbation in the latter. A serious discrepancy exists between the {sup 210}Pb dating of Sea of Marmara sediments and those obtained by organic carbon based methods. The elements Zn, Cu, P and Pb were enriched in the upper sections of the sediment cores corresponding to the last 200 years. The increased metallurgical activities as a result of reforms in the Ottoman Army during the 18th century could be the most likely cause. (Author).

  12. Not so Great Lakes?

    Science.gov (United States)

    Showstack, Randy

    In 1965, Frank Sinatra won the Grammy Award for his album, "September of My Years;" "Early Bird," the first commercial communications satellite, was launched; and Dr. Martin Luther King, Jr. was arrested in Selma, Alabama, during demonstrations against voter-registration rules.The year 1965 was also the last time water levels in the U.S. Great Lakes were as low as they are now.

  13. Archaea in Yellowstone Lake.

    Science.gov (United States)

    Kan, Jinjun; Clingenpeel, Scott; Macur, Richard E; Inskeep, William P; Lovalvo, Dave; Varley, John; Gorby, Yuri; McDermott, Timothy R; Nealson, Kenneth

    2011-11-01

    The Yellowstone geothermal complex has yielded foundational discoveries that have significantly enhanced our understanding of the Archaea. This study continues on this theme, examining Yellowstone Lake and its lake floor hydrothermal vents. Significant Archaea novelty and diversity were found associated with two near-surface photic zone environments and two vents that varied in their depth, temperature and geochemical profile. Phylogenetic diversity was assessed using 454-FLX sequencing (~51,000 pyrosequencing reads; V1 and V2 regions) and Sanger sequencing of 200 near-full-length polymerase chain reaction (PCR) clones. Automated classifiers (Ribosomal Database Project (RDP) and Greengenes) were problematic for the 454-FLX reads (wrong domain or phylum), although BLAST analysis of the 454-FLX reads against the phylogenetically placed full-length Sanger sequenced PCR clones proved reliable. Most of the archaeal diversity was associated with vents, and as expected there were differences between the vents and the near-surface photic zone samples. Thaumarchaeota dominated all samples: vent-associated organisms corresponded to the largely uncharacterized Marine Group I, and in surface waters, ~69-84% of the 454-FLX reads matched archaeal clones representing organisms that are Nitrosopumilus maritimus-like (96-97% identity). Importance of the lake nitrogen cycling was also suggested by >5% of the alkaline vent phylotypes being closely related to the nitrifier Candidatus Nitrosocaldus yellowstonii. The Euryarchaeota were primarily related to the uncharacterized environmental clones that make up the Deep Sea Euryarchaeal Group or Deep Sea Hydrothermal Vent Group-6. The phylogenetic parallels of Yellowstone Lake archaea to marine microorganisms provide opportunities to examine interesting evolutionary tracks between freshwater and marine lineages.

  14. Great Lakes Energy Institute

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, J. Iwan [Case Western Reserve Univ., Cleveland, OH (United States)

    2012-11-18

    The vision of the Great Lakes Energy Institute is to enable the transition to advanced, sustainable energy generation, storage, distribution and utilization through coordinated research, development, and education. The Institute will place emphasis on translating leading edge research into next generation energy technology. The Institute’s research thrusts focus on coordinated research in decentralized power generation devices (e.g. fuel cells, wind turbines, solar photovoltaic devices), management of electrical power transmission and distribution, energy storage, and energy efficiency.

  15. Audubon National Wildlife Refuge, Lake Nettie National Wildlife Refuge, Camp Lake Easement Refuge, Wintering River Easement Refuge, Cottonwood Lake Easement Refuge, Sheyenne Lake Easement Refuge : Narrative report : 1969

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Audubon National Wildlife Refuge (including Lake Nettie National Wildlife Refuge, Camp Lake Easement Refuge, Cottonwood Lake...

  16. Bear Lake-Minidoka - Phragmites Control

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Bear Lake: Phragmites patches were sprayed on the refuge & north of the lake proper. Minidoka: patches along the Snake River & Lake Walcott were treated with...

  17. Environmental Monitoring, Water Quality - Lakes Assessments - Attaining

    Data.gov (United States)

    NSGIC Education | GIS Inventory — This layer shows only attaining lakes of the Integrated List. The Lakes Integrated List represents lake assessments in an integrated format for the Clean Water Act...

  18. Extreme Weather Events and Climate Variability Provide a Lens to How Shallow Lakes May Respond to Climate Change

    Directory of Open Access Journals (Sweden)

    Karl Havens

    2016-05-01

    Full Text Available Shallow lakes, particularly those in low-lying areas of the subtropics, are highly vulnerable to changes in climate associated with global warming. Many of these lakes are in tropical cyclone strike zones and they experience high inter-seasonal and inter-annual variation in rainfall and runoff. Both of those factors strongly modulate sediment–water column interactions, which play a critical role in shallow lake nutrient cycling, water column irradiance characteristics and cyanobacterial harmful algal bloom (CyanoHAB dynamics. We illustrate this with three examples, using long-term (15–25 years datasets on water quality and plankton from three shallow lakes: Lakes Okeechobee and George (Florida, USA and Lake Taihu (China. Okeechobee and Taihu have been impacted repeatedly by tropical cyclones that have resulted in large amounts of runoff and sediment resuspension, and resultant increases in dissolved nutrients in the water column. In both cases, when turbidity declined, major blooms of the toxic CyanoHAB Microcystis aeruginosa occurred over large areas of the lakes. In Lake George, periods of high rainfall resulted in high dissolved color, reduced irradiance, and increased water turnover rates which suppress blooms, whereas in dry periods with lower water color and water turnover rates there were dense cyanobacteria blooms. We identify a suite of factors which, from our experience, will determine how a particular shallow lake will respond to a future with global warming, flashier rainfall, prolonged droughts and stronger tropical cyclones.

  19. Algae Bloom in a Lake

    Directory of Open Access Journals (Sweden)

    David Sanabria

    2008-01-01

    Full Text Available The objective of this paper is to determine the likelihood of an algae bloom in a particular lake located in upstate New York. The growth of algae in this lake is caused by a high concentration of phosphorous that diffuses to the surface of the lake. Our calculations, based on Fick's Law, are used to create a mathematical model of the driving force of diffusion for phosphorous. Empirical observations are also used to predict whether the concentration of phosphorous will diffuse to the surface of this lake within a specified time and under specified conditions.

  20. Great Lakes' regional climate regimes

    Science.gov (United States)

    Kravtsov, Sergey; Sugiyama, Noriyuki; Roebber, Paul

    2016-04-01

    We simulate the seasonal cycle of the Great Lakes' water temperature and lake ice using an idealized coupled lake-atmosphere-ice model. Under identical seasonally varying boundary conditions, this model exhibits more than one seasonally varying equilibrium solutions, which we associate with distinct regional climate regimes. Colder/warmer regimes are characterized by abundant/scarce amounts of wintertime ice and cooler/warmer summer temperatures, respectively. These regimes are also evident in the observations of the Great Lakes' climate variability over recent few decades, and are found to be most pronounced for Lake Superior, the deepest of the Great Lakes, consistent with model predictions. Multiple climate regimes of the Great Lakes also play a crucial role in the accelerated warming of the lakes relative to the surrounding land regions in response to larger-scale global warming. We discuss the physical origin and characteristics of multiple climate regimes over the lakes, as well as their implications for a longer-term regional climate variability.

  1. Limited Regulation of Lake Erie.

    Science.gov (United States)

    1983-11-01

    Ontario,, Cedar Point in Ohio, Presque Isle in Pennsylvania and Hamlin in New York. Recreational boating is a significant activity on Lake Erie . Along...RD-Al47 936 LIMITED REGULATION OF LAKE ERIE (U) INTERNATIONAL LAKE i/i ERIE REGULATION STUDY BOARD NOV 83 UNCLASSIFIED F/G 13/2 N lhhhhh..hEmhhI...o lake Erie ’Governmen of 4,- % * L CTE " 84100400 .- Canad Unite Stte INTRNAIONL OIN COMISIO 4WD’ This document hais been ow for public rleoe and so

  2. THE LAKES IN ROMANIA - AN ACTUAL SYNTHESIS

    Directory of Open Access Journals (Sweden)

    Petre GÂŞTESCU

    2010-06-01

    Full Text Available The article offers a synthesis of the lakes of Romania. We addressed the following questions: genetic types of lakes, geographical distribution and their use in various fields of activities. Thus, in the territory of Romania is a large genetic diversity of lakes distributed on all major forms of relief and recovery in many economic areas. Romania is particularly present fluvial lakes, glacial lakes and anthropogenic lakes (especially reservoirs.

  3. Glacial lakes Buni and Jezerce: Albania

    OpenAIRE

    Milivojević Milovan; Kovačević-Majkić Jelena

    2005-01-01

    The paper presents glacial lakes and glacial relief forms at the foothill of the peak Maja Jezerce in Mt. Prokletije in Albania, near the border with Montenegro. The group of lakes Buni and Jezerce, which consists of six lakes and which genetically belongs to glacial-erosional lakes, is analyzed. Lakes are situated at the cirque bottom, between the moraines and limestone ridges. Except presented morphometric characteristics of lake basins, data about cirque are given, as well as the reconstru...

  4. THE LAKES IN ROMANIA - AN ACTUAL SYNTHESIS

    OpenAIRE

    Petre GÂŞTESCU

    2010-01-01

    The article offers a synthesis of the lakes of Romania. We addressed the following questions: genetic types of lakes, geographical distribution and their use in various fields of activities. Thus, in the territory of Romania is a large genetic diversity of lakes distributed on all major forms of relief and recovery in many economic areas. Romania is particularly present fluvial lakes, glacial lakes and anthropogenic lakes (especially reservoirs).

  5. Lake Charles CCS Project

    Energy Technology Data Exchange (ETDEWEB)

    Leib, Thomas [Leucadia Energy, LLC, Salt Lake City, UT (United States); Cole, Dan [Denbury Onshore, LLC, Plano, TX (United States)

    2015-06-30

    In late September 2014 development of the Lake Charles Clean Energy (LCCE) Plant was abandoned resulting in termination of Lake Charles Carbon Capture and Sequestration (CCS) Project which was a subset the LCCE Plant. As a result, the project was only funded through Phase 2A (Design) and did not enter Phase 2B (Construction) or Phase 2C (Operations). This report was prepared relying on information prepared and provided by engineering companies which were engaged by Leucadia Energy, LLC to prepare or review Front End Engineering and Design (FEED) for the Lake Charles Clean Energy Project, which includes the Carbon Capture and Sequestration (CCS) Project in Lake Charles, Louisiana. The Lake Charles Carbon Capture and Sequestration (CCS) Project was to be a large-scale industrial CCS project intended to demonstrate advanced technologies that capture and sequester carbon dioxide (CO2) emissions from industrial sources into underground formations. The Scope of work was divided into two discrete sections; 1) Capture and Compression prepared by the Recipient Leucadia Energy, LLC, and 2) Transport and Sequestration prepared by sub-Recipient Denbury Onshore, LLC. Capture and Compression-The Lake Charles CCS Project Final Technical Report describes the systems and equipment that would be necessary to capture CO2 generated in a large industrial gasification process and sequester the CO2 into underground formations. The purpose of each system is defined along with a description of its equipment and operation. Criteria for selection of major equipment are provided and ancillary utilities necessary for safe and reliable operation in compliance with environmental regulations are described. Construction considerations are described including a general arrangement of the CCS process units within the overall gasification project. A cost estimate is provided, delineated by system area with cost breakdown showing equipment, piping and materials

  6. Embryotoxicity of an extract from Great Lakes lake trout to rainbow trout and lake trout

    Energy Technology Data Exchange (ETDEWEB)

    Wright, P.J.; Tillitt, D.E. [National Biological Service, Columbia, MO (United States). Midwest Science Center

    1995-12-31

    Aquatic ecosystems such as the Great Lakes are known to be contaminated with chemicals that are toxic to fish. However, the role of these contaminants in reproductive failures of fishes, such as lake trout recruitment, has remained controvertible. It was the objective to evaluate dioxin-like embryotoxicity of a complex mixture of chemicals and predict their potential to cause the lack of recruitment in Great Lakes lake trout. Graded doses of a complex environmental extract were injected into eggs of both rainbow trout and lake trout. The extract was obtained from whole adult lake trout collected from Lake Michigan in 1988. The extract was embryotoxic in rainbow trout, with LD50 values for Arlee strain and Erwin strain of 33 eggEQ and 14 eggEQ respectively. The LOAEL for hemorrhaging, yolk-sac edema, and craniofacial deformities in rainbow trout were 2, 2, and 4 eggEQ, respectively. Subsequent injections of the extract into lake trout eggs were likewise embryotoxic, with an LD50 value of 7 eggEQ. The LOAEL values for the extract in lake trout for hemorrhaging, yolk-sac edema, and craniofacial deformities were 0.1, 1, and 2 eggEQ, respectively. The current levels of contaminants in lake trout eggs are above the threshold for hemorrhaging and yolk-sac edema. The results also support the use of an additive model of toxicity to quantify PCDDs, PCDFs, Non-o-PCBs, and Mono-o-PCBs in relation to early life stage mortality in Lake Michigan lake trout.

  7. LAKE AFDERA: A THREATENED SALINE LAKE IN ETHIOPIA

    African Journals Online (AJOL)

    lake's geological history of having marine inputs from the Red Sea (Gionfiantini et al., 1973). Unlike the other ... area) at the shore where one of the hot springs joins the lake. It is not known ... that goes to the Red Sea port of Assab. One of the ...

  8. Delineation of sympatric morphotypes of lake trout in Lake Superior

    Science.gov (United States)

    Moore, Seth A.; Bronte, Charles R.

    2001-01-01

    Three morphotypes of lake trout Salvelinus namaycush are recognized in Lake Superior: lean, siscowet, and humper. Absolute morphotype assignment can be difficult. We used a size-free, whole-body morphometric analysis (truss protocol) to determine whether differences in body shape existed among lake trout morphotypes. Our results showed discrimination where traditional morphometric characters and meristic measurements failed to detect differences. Principal components analysis revealed some separation of all three morphotypes based on head and caudal peduncle shape, but it also indicated considerable overlap in score values. Humper lake trout have smaller caudal peduncle widths to head length and depth characters than do lean or siscowet lake trout. Lean lake trout had larger head measures to caudal widths, whereas siscowet had higher caudal peduncle to head measures. Backward stepwise discriminant function analysis retained two head measures, three midbody measures, and four caudal peduncle measures; correct classification rates when using these variables were 83% for leans, 80% for siscowets, and 83% for humpers, which suggests the measures we used for initial classification were consistent. Although clear ecological reasons for these differences are not readily apparent, patterns in misclassification rates may be consistent with evolutionary hypotheses for lake trout within the Laurentian Great Lakes.

  9. Simulation and Exploration of the Mechanisms Underlying the Spatiotemporal Distribution of Surface Mixed Layer Depth in a Large Shallow Lake

    Institute of Scientific and Technical Information of China (English)

    ZHAO Qiaohua; SUN Jihua; ZHU Guangwei

    2012-01-01

    The aquatic eco-environment is significantly affected by temporal and spatial variation of the mixed layer depth (MLD) in large shallow lakes.In the present study,we simulated the three-dimensional water temperature of Taihu Lake with an unstructured grid with a finite-volume coastal ocean model (FVCOM)using wind speed,wind direction,short-wave radiation and other meteorological data measured during 13-18 August 2008. The simulated results were consistent with the measurements. The temporal and spatial distribution of the MLD and the possible relevant mechanisms were analyzed on the basis of the water temperature profile data of Taihu Lake. The results indicated that diurnal stratification might be established through the combined effect of the hydrodynamic conditions induced by wind and the heat exchange between air and water.Compared with the net heat flux,the changes of the MLD were delayed approximately two hours.Furthermore,there were significant spatial differences of the MLD in Taihu Lake due to the combined impact of thermal and hydrodynamic forces. Briefly,diurnal stratification formed relatively easily in Gonghu Bay,Zhushan Bay,Xukou Bay and East Taihu Bay,and the surface mixed layer was thin.The center of the lake region had the deepest surface mixed layer due to the strong mixing process.In addition,Meiliang Bay showed a medium depth of the surface mixed layer.Our analysis indicated that the spatial difference in the hydrodynamic action was probably the major cause for the spatial variation of the MLD in Taihu Lake.

  10. Forecasting Lake-Effect Snow in the Great Lakes Using NASA Satllite Data

    Science.gov (United States)

    Cipullo, Michelle; Molthan, Andrew; Shafer, Jackie; Case, Jonathan; Jedlovec, Gary

    2011-01-01

    This slide presentation reviews the forecast of the lake effect snow in the Great Lakes region using models and infrared estimates of Great Lake Surface Temperatures (GLSTs) from the MModerate Resolution Imaging Spectroradiometer (MODIS) instrument on Terra and Aqua satellites, and other satellite data. This study analyzes Lake Erie and Lake Ontario which produce storm total snowfall ranged from 8-18 inches off of Lake Ontario and 10-12 inches off of Lake Erie for the areas downwind.

  11. Feeding competition between larval lake whitefish and lake herring

    Science.gov (United States)

    Savino, Jacqueline F.; Hudson, Patrick L.

    1995-01-01

    The potential for competition for food between larval lake whitefish (Coregonus clupeaformis) and lake herring (C. artedi) 1- to 8-wk of age was explored in a series of 1-h laboratory feeding studies. Feeding started at 2-wk post-hatch. Learning and fish size appear to be more important than prey density at the onset of feeding. Species differed in their feeding behavior and consumption noticeably by 5-wk and substantially by 8-wk. Lake whitefish generally were more aggressive foragers than lake herring, attacking and capturing more prey. At high plankton density at 8-wk, lake herring feeding was depressed in mixed-fish treatments. This difference in competitive food consumption between the two coregonids occurs at a critical life stage, and when combined with other biotic and abiotic factors, may have a significant impact on recruitment.

  12. Analysis of algal bloom risk with uncertainties in lakes by integrating self-organizing map and fuzzy information theory

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Qiuwen, E-mail: qchen@rcees.ac.cn [RCEES, Chinese Academy of Sciences, Shuangqinglu 18, Beijing 10085 (China); China Three Gorges University, Daxuelu 8, Yichang 443002 (China); CEER, Nanjing Hydraulics Research Institute, Guangzhoulu 223, Nanjing 210029 (China); Rui, Han; Li, Weifeng; Zhang, Yanhui [RCEES, Chinese Academy of Sciences, Shuangqinglu 18, Beijing 10085 (China)

    2014-06-01

    Algal blooms are a serious problem in waters, which damage aquatic ecosystems and threaten drinking water safety. However, the outbreak mechanism of algal blooms is very complex with great uncertainty, especially for large water bodies where environmental conditions have obvious variation in both space and time. This study developed an innovative method which integrated a self-organizing map (SOM) and fuzzy information diffusion theory to comprehensively analyze algal bloom risks with uncertainties. The Lake Taihu was taken as study case and the long-term (2004–2010) on-site monitoring data were used. The results showed that algal blooms in Taihu Lake were classified into four categories and exhibited obvious spatial–temporal patterns. The lake was mainly characterized by moderate bloom but had high uncertainty, whereas severe blooms with low uncertainty were observed in the northwest part of the lake. The study gives insight on the spatial–temporal dynamics of algal blooms, and should help government and decision-makers outline policies and practices on bloom monitoring and prevention. The developed method provides a promising approach to estimate algal bloom risks under uncertainties. - Highlights: • An innovative method is developed to analyze algal bloom risks with uncertainties. • The algal blooms in Taihu Lake showed obvious spatial and temporal patterns. • The lake is mainly characterized as moderate bloom but with high uncertainty. • Severe bloom with low uncertainty appeared occasionally in the northwest part. • The results provide important information to bloom monitoring and management.

  13. Conclusion: Ecology of Meromictic Lakes

    NARCIS (Netherlands)

    Gulati, Ramesh D.; Zadereev, Egor S.; Gulati, Ramesh D.; Zadereev, Egor S.; Degermendzhi, Andrei G.

    2017-01-01

    The term meromixis was introduced more than 80 years ago to denote lakes that do not annually mix completely. Since then our understanding of meromictic lakes has considerably advanced. Physical processes support the difference in water density between deep (monimolimnion ) and surface (mixolimnion

  14. Surface seiches in Flathead Lake

    Directory of Open Access Journals (Sweden)

    G. Kirillin

    2014-12-01

    Full Text Available Standing surface waves or seiches are inherent hydrodynamic features of enclosed water bodies. Their two-dimensional structure is important for estimating flood risk, coastal erosion and bottom sediment transport and for understanding shoreline habitats and lake ecology in general. In this work, we present analysis of two-dimensional seiche characteristics in Flathead Lake, Montana, USA, a large intermountain lake known to have high seiche amplitudes. To examine spatial characteristics of different seiche modes we used the original procedure of determining the seiche frequencies from the primitive equation model output with subsequent derivation of the spatial seiche structure at fixed frequencies akin the tidal harmonic analysis. The proposed procedure revealed specific seiche oscillation features in Flathead Lake including maximum surface level amplitudes of the first fundamental mode in straights around the largest island; several higher modes appearing locally in the vicinity of the river inflow; the "Helmholtz" open harbor mode, with the period approximately twice that of the longest seiche mode, generated by a large shallow bay connected to the main lake basin; and several rotating seiche modes potentially affecting the lake-wide circulation. We discuss the lake management problems related to of the spatial seiche distribution, such as shoreline erosion, floods and transport of sediments and invasive species in Flathead Lake.

  15. PYRAMID LAKE RENEWEABLE ENERGY PLAN

    Energy Technology Data Exchange (ETDEWEB)

    HIGH DESERT GEOCULTURE, LLC

    2009-06-06

    The Pyramid Lake Renewable Energy Plan covers these areas: energy potential (primarily focusing on geothermal resource potential, but also more generally addressing wind energy potential); renewable energy market potential; transmission system development; geothermal direct use potential; and business structures to accomplish the development objectives of the Pyramid Lake Paiute Tribe.

  16. Planktonic diatoms of Lake Ontario

    Science.gov (United States)

    Reinwand, Jerry F.

    1969-01-01

    The major species of diatoms in surface collections from Lake Ontario in September 1964 were Asterionella formosa, Fragilaria crotonensis, and Tabellaris fenestrata. Dominant species in the deep-water samples were Stephanodiscus astraea, S. astraea var. mintula, and F. crotonensis. The diatom flora in surface collections varied among several stations in the eastern end of the lake.

  17. Europa's Great Lakes

    Science.gov (United States)

    Schmidt, B. E.; Blankenship, D. D.; Patterson, G. W.; Schenk, P. M.

    2012-04-01

    Unique to the surface of Europa, chaos terrain is diagnostic of the properties and dynamics of its icy shell. While models have suggested that partial melt within a thick shell or melt-through of a thin shell may form chaos, neither model has been able to definitively explain all observations of chaos terrain. However, we present a new model that suggests large melt lenses form within the shell and that water-ice interactions above and within these lenses drive the production of chaos. Our analysis of the geomorphology of Conamara Chaos and Thera Macula, was used to infer and test a four-stage lens-collapse chaos formation model: 1) Thermal plumes of warm, pure ice ascend through the shell melting the impure brittle ice above, producing a lake of briny water and surface down draw due to volume reduction. 2) Surface deflection and driving force from the plume below hydraulically seals the water in place. 3) Extension of the brittle ice lid generates fractures from below, allowing brines to enter and fluidize the ice matrix. 4) As the lens and now brash matrix refreeze, thermal expansion creates domes and raises the chaos feature above the background terrain. This new "lense-collapse" model indicates that chaos features form in the presence of a great deal of liquid water, and that large liquid water bodies exist within 3km of Europa's surface comparable in volume to the North American Great Lakes. The detection of shallow subsurface "lakes" implies that the ice shell is recycling rapidly and that Europa may be currently active. In this presentation, we will explore environments on Europa and their analogs on Earth, from collapsing Antarctic ice shelves to to subglacial volcanos in Iceland. I will present these new analyses, and describe how this new perspective informs the debate about Europa's habitability and future exploration.

  18. Lake-floor sediment texture and composition of a hydrothermally-active, volcanic lake, Lake Rotomahana

    Science.gov (United States)

    Pittari, A.; Muir, S. L.; Hendy, C. H.

    2016-03-01

    Young volcanic lakes undergo a transition from rapid, post-eruptive accumulation of volcaniclastic sediment to slower pelagic settling under stable lake conditions, and may also be influenced by sublacustrine hydrothermal systems. Lake Rotomahana is a young (129 year-old), hydrothermally-active, volcanic lake formed after the 1886 Tarawera eruption, and provides a unique insight into the early evolution of volcanic lake systems. Lake-bottom sediment cores, 20-46 cm in length, were taken along a transect across the lake and characterised with respect to stratigraphy, facies characteristics (i.e., grain size, componentry) and pore water silica concentrations. The sediments generally comprise two widespread facies: (i) a lower facies of light grey to grey, very fine lacustrine silt derived from the unconsolidated pyroclastic deposits that mantled the catchment area immediately after the eruption, which were rapidly reworked and redeposited into the lake basin; and (ii) an upper facies of dark, fine-sandy diatomaceous silt, that settled from the pelagic zone of the physically stable lake. Adjacent to sublacustrine hydrothermal vents, the upper dark facies is absent, and the upper part of the light grey to grey silt is replaced by a third localised facies comprised of hydrothermally altered pale yellow to yellowish brown, laminated silt with surface iron-rich encrustations. Microspheres, which are thought to be composed of amorphous silica, although some may be halloysite, have precipitated from pore water onto sediment grains, and are associated with a decrease in pore water silicon concentration. Lake Rotomahana is an example of a recently-stabilised volcanic lake, with respect to sedimentation, that shows signs of early sediment silicification in the presence of hydrothermal activity.

  19. L-Lake macroinvertebrate community

    Energy Technology Data Exchange (ETDEWEB)

    Specht, W.L.

    1996-06-01

    To characterize the present benthic macroinvertebrate community of L-Lake, Regions 5 and 7 of the reservoir were sampled in September 1995 at the same locations sampled in 1988 and 1989 during the L-Lake monitoring program. The macroinvertebrate community of 1995 is compared to that of 1988 and 1989. The species composition of L-Lake`s macroinvertebrate community has changed considerably since 1988-1989, due primarily to maturation of the reservoir ecosystem. L-Lake contains a reasonably diverse macroinvertebrate community that is capable of supporting higher trophic levels, including a diverse assemblage of fish species. The L-Lake macroinvertebrate community is similar to those of many other southeastern reservoirs, and there is no indication that the macroinvertebrate community is perturbed by chemical or physical stressors.

  20. Phosphorous Loading in Lake Champlain

    Science.gov (United States)

    Hoffman, H.; Halliday, B.; Lane, T.

    2016-12-01

    Phosphate movement from different sources into Lake Champlain is a problem. Excess phosphate generates algae growth causing eutrophication. This excessive growth known as algae blooms leads to poor water quality (State of Lake Report, 2015). Phosphate moves primarily by attachment to soil particles (Busman, Lamb, 09). Historically its movement has been limited to spring, summer and fall. Spring runoff is thought to contribute the most phosphate to Lake Champlain (Jensen, Tiessen, 11). With changes in global and local temperatures effecting weather patterns and the winter season, does phosphate continue to move into Lake Champlain during the winter months? Water samples from two tributaries to Lake Champlain were collected biweekly year around for the past three years. These samples were then tested for total suspended solids and phosphate levels. The results indicate that phosphate loading occurs throughout the year even during the winter months.

  1. Choking Lake Winnipeg

    Science.gov (United States)

    Byrne, J. M.; Little, L. J.; Dodgson, K. A.; MacDonald, R. J.; Graham, J.

    2009-12-01

    The problems of waterway eutrophication and coastal zone hypoxia are reaching epidemic proportions. Fresh water and coastal marine environments around the world are suffering unprecedented pollution loadings. We are developing an education program to address the dramatic need for public, community and K-12 education about the harsh impacts of elevated nutrient loads on fresh and marine water environments. The Lake Winnipeg watershed is adopted as the poster child of fresh water eutrophication in western North America. The watershed, one of the largest on the continent, is in rapid decline due to pollution, population pressures and water diversion. A concerted education program is needed to change personal and society actions that negatively impact the Winnipeg watershed; and the confluence of the watershed - Lake Winnipeg. But the education program goes beyond Lake Winnipeg. Negative impacts of nutrient loads are adversely affecting environments right to the oceans. Major dead zones that are expanding on our continental shelves due to nutrient overloading threaten to coalesce into extensive regions of marine life die-off. This presentation outlines the documentary education production process under development. We are building a series of Public Service Announcements (PSAs) for national television networks. The PSAs will direct educators, stakeholders and citizens to an associated website with educational video clips detailing the issues of eutrophication and hypoxia. The video clips or webisodes, present interviews with leading scientists. The discussions address the causes of the problems, and presents workable solutions to nutrient overloads from a variety of sources. The webisodes are accompanied by notes and advice to teachers on ways and means to use the webisodes in classrooms. The project is fully funed by a group of Canadian Community Foundations, with the understanding the work wil be available free to educators anywhere in the world. Our education

  2. Study of Elodea nuttallii-immobilized nitrogen cycling bacteria restoration in an inflow river channel of water source, Taihu Lake%伊乐藻-固定化氮循环菌技术入湖河道修复研究

    Institute of Scientific and Technical Information of China (English)

    王易超; 李正魁; 周莉; 范念文; 冯露露

    2012-01-01

    从太湖金墅湾水体筛选出包括土著氨化、亚硝化、硝化和反硝化细菌的氮循环菌,固定于多孔性载体内,对伊乐藻固定化氮循环菌联用技术在秋冬季太湖金墅湾水源地入湖河道水体生态修复效果进行了研究.经室内生态修复模拟与原位围隔实验表明,伊乐藻-固定化氮循环菌联用对水质改善效果要优于单独使用伊乐藻或固定化氮循环菌,该技术对原位入湖河道有效去除率为:总氮5.9%~61.2%,氨氮12.4~70.3%,硝氮6.1%~68.0%,COD 4.2%~78.5%;通过氮循环菌释放可明显提高水体氮循环菌数量,MPN值比对照水体高出3~4个数量级;相关性分析表明,差异性显著(P<0.01).经5个月原位围隔试验表明,伊乐藻-氮循环菌联用技术可有效降低秋冬季入湖河道营养盐负荷,有助于控制湖泊水源地富营养化.%Nitrogen cycling bacteria, including ammonifying bacteria, nitrobacteria, nitrosobacteria and denitrifying bacteria were screened and immobilized to the porous carries from nature water of Jinshu Bay, Taihu Lake. The restoration effect of Elodea nuttalliiAmm6b\\\\\\ze& Nitrogen Cycling Bacteria (INCB) assemblage technology applied in one of the inflow river channels of Jinshu bay water source, Taihu Lake was studied in autumn and winter. Lab ecological restoration simulation and in situ enclosure experiment demonstrated that Elodea nuttallii-INCB assemblage technology has better water quality improvement ability than either use INCB or Elodea nuttallii separately. We applied this technology in the inflow river channel water restoration and TN concentration reduced 5.9%~61.2%, NO3 concentration reduced 6.1%~68.0% and COD concentration reduced 4.2%~78.5% during the experiment process. The result also showed nitrogen bacteria quantities increased significantly after releasing INCB, and the MPN values of denitrifying bacteria in the enclosure was 3-4 order of magnitudes higher than the

  3. 78 FR 53675 - Safety Zone; Lake Erie Heritage Foundation, Battle of Lake Erie Reenactment; Lake Erie, Put-in...

    Science.gov (United States)

    2013-08-30

    ... Lake Erie Reenactment; Lake Erie, Put-in-Bay, OH AGENCY: Coast Guard, DHS. ACTION: Temporary final rule... vicinity of Put-In-Bay, OH. This safety zone is intended to restrict vessels from a portion of Lake Erie during Battle of Lake Erie Reenactment near Put-In-Bay. This temporary safety zone is necessary...

  4. The contribution of phytoplankton degradation to chromophoric dissolved organic matter (CDOM) in eutrophic shallow lakes: Field and experimental evidence

    NARCIS (Netherlands)

    Zhang, Y.; Van Dijk, M.A.; Liu, M.; Zhu, G.; Qin, B.

    2009-01-01

    Eight field campaigns in the eutrophic, shallow, Lake Taihu in the summers from 2005 to 2007, and a phytoplankton degradation experiment of 33 days, were carried out to determine the contribution of phytoplankton degradation to CDOM. Significant and positive correlations were found between the CDOM

  5. 太湖水体吸收分解(Ⅱ):浮游植物色素吸收分解%The absorption spectral decomposition of water in Lake Taihu, China (Ⅱ) : the decomposition of absorption due to phytoplankton pigments

    Institute of Scientific and Technical Information of China (English)

    赵晨露; 马荣华; 郝景燕; 段洪涛

    2012-01-01

    Concentrations of pigments could reflect the dominant phyla of algae. Investigations of algae in eutrophic lakes revealed that Chl. B, Chl. C and phycobilin (PC) are the critical pigments of chlorophyta, bacilliariphyta and cyanophyta, respectively. In this study, partial least square ( PLS) regress was used on the retrieval of Chi. A, Chl. B, Chl. C and PC through absorption spectral of phytoplankton. Retrieve of Chl. A was based on the data collected in situ during 2011. Retrieve of Chl. B and Chl. C was based on the data collected in situ in March, since there is no significant dominant phyla of algae in spring. Result shows that PLS is a more effective method than the original least square regress and could be of help for remote sensing of multi-pigments and the distribution of main algae in eutrophic lakes.%蓝藻水华暴发前,浮游植物群类结构的变化可通过其指示型色素的浓度变化来反映.为了同时反演叶绿素a、叶绿素b(绿藻门指示型色素)、叶绿素c(硅藻门指示型色素)和藻蓝素(蓝藻门的指示型色素)的浓度,利用偏最小二乘回归构建线性模型,通过2011年太湖实测吸收数据,较为准确地反演了叶绿素a和藻蓝素的浓度;针对无明显优势藻的春季数据集较为准确地反演了叶绿素b和叶绿素c的浓度.相对于经典最小二乘算法,偏最小二乘法在多色素混合的吸收光谱分析上更为有效.通过反演指示性色素浓度来反映藻类的分布,为富营养化湖泊主要藻类时空分布变化的遥感监测提供了一定的理论与技术支持.

  6. 基于GOCI影像分类的太湖水体叶绿素a浓度日变化分析%Analysis on Diurnal Variation of Chlorophyll-a Concentration of Taihu Lake Based on Optical Classification with GOCI Data

    Institute of Scientific and Technical Information of China (English)

    包颖; 田庆久; 陈旻; 吕春光

    2016-01-01

    spatial and temporal (diurnal)variations,there are still limitations to estimate Chl-a concentration with traditional remote sensing data and single model.In the proposed solution,the first geostationary ocean color satellite sensor,Geostationary Ocean Color Imager (GOCI), which provides an image per hour (eight images per day from 8:1 6 to 1 5:1 6),was used as a data source of Taihu Lake.Based on hierarchical clustering method,water types were identified from in situ normalized spectral reflectance collected in Taihu Lake (21 6 samples in different seasons from 2010 to 2012).Then eight GOCI images which were obtained on May 6 th ,2012 were classified separately according to different water types by calculating spectral angle distance between each spectrum in GOCI ima-ges and the classified spectra.According to the classified remote sensing images and the spectral bands of GOCI data,classed-based models were subsequently developed for the estimation of Chl-a concentration.The results indicated that four water types (Type 1 to Type 4)were identified based on the in situ normalized spectral reflectance in Taihu Lake.The spectra of Type 1 mainly represented the characteristics of floating algae.This type had little significance to in estimating Chl-a concentration be-cause sensors could only receive signal of floating algae.Then Type 1 was usually used as the evidence of algal blooms.Mean-while,two-band semi-analytical algorithms were established for Type 2—Type 4 waters which were separately dominated by Chl-a concentration,high suspended solid,low Chl-a and low suspended solid.Comparing with the two-band algorithms,band 7 and band 6 combination was more suitable for Type 2 and Type 3 while the correlation between Chl-a concentration and b7/b5 was higher than that between b7/b6 for Type 4.The accuracies of classification models (Type 2—Type 4)were higher than that of the overall model,with the reduced average relative errors of 7%,12.3% and 1 5.9%,respectively

  7. 太湖流域电子及光伏行业废水再生回用工程工艺设计和实践%Processes Design and Practice of Wastewater Reclamation and Reuse Project for Electronic and Photovoltaic Industries in Taihu Lake Basin

    Institute of Scientific and Technical Information of China (English)

    祝君乔

    2015-01-01

    针对电子和光伏产业废水成分复杂、可生化性差、氨氮和氟化物浓度高的特点,研发并设计了一套高效化学法除氨氮除氟+超滤、反渗透双膜深度处理制得回用水的资源化集成处理新工艺,该工艺在太湖流域无锡某大型电子企业进行了规模化实践,结果表明运营安全可靠,长期效果良好。该研究可为我国电子及光伏行业废水再生回用和实现节能减排提供重要的借鉴和参考。%On the basis of the electronic and photovoltaic industry wastewater with complex composition,poor biodegradability,high concentration of ammonia nitrogen and fluoride,a set of new process for water resource utilization was developed and designed,which integrated the efficient chemical method for removing ammonia and fluoride with ultrafiltration and reverse osmosis embrane system. Large-scale practice was conducted in an electronic enterprise in Taihu Lake Basin. The results show that the process operation is safe and reliable with the long-term effect. This paper might provide an important reference for the reclamation and reuse of electronic and photovoltaic industry wastewater,as well as the target of energy conservation and emissions reduction in China.

  8. On the Countermeasures to Interest Conflict Among Different Parties in the Process of Cooperative Control---Taking the Case of Water Pollution Control of the Taihu Lake%协作性治理中主体利益冲突的对策研究--以太湖水污染治理为例

    Institute of Scientific and Technical Information of China (English)

    董蕊

    2014-01-01

    由于协作治理过程中存在着同区域和不同区域间合作主体的利益冲突,为了避免各合作主体的利益冲突,以太湖水污染治理为例,集中对水污染治理过程中的相关主体利益进行了分析,并对相关利益主体利益发生冲突的原因进行了剖析,在此基础上探讨了协作参与各方应该如何从转变理念,强调合作共赢、完善利益分享机制、构建利益约束机制和健全利益共享保障机制等4个方面实现协作过程中的主体利益协调。%During the process of cooperative control, there are interest conflict among different parties in the same region or dif-ferent regions.In order to avoid interest conflict among different parties to the cooperation, this paper, taking into account the water pollution control of the Taihu Lake, makes an analysis of the interest of the parties concerned and the causes of interest conflict. On the basis of this, this paper further analyzes how the parties concerned change their ideas proposes to focus on cooperative spirit and win-win effect, perfect the interest distribution mechanism, construct an interest constraiting mechanism and establish an interest sharing mechanism so that interest coodination can be realized during the process of cooperative control.

  9. 14 CFR 93.69 - Special requirements, Lake Campbell and Sixmile Lake Airports.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Special requirements, Lake Campbell and... Anchorage, Alaska, Terminal Area § 93.69 Special requirements, Lake Campbell and Sixmile Lake Airports. Each person operating an aircraft to or from Lake Campbell or Sixmile Lake Airport shall conform to the flow...

  10. Seasonal variations in the diets of Coilia ectenes taihuensis Yen et Lin in Gonghu Bay of Lake Taihu%太湖贡湖湾鲚(Coilia ectenes taihuensis Yen et Lin)食物组成的季节变化

    Institute of Scientific and Technical Information of China (English)

    于谨磊; 何虎; 李宽意; 陈非洲; 刘正文

    2012-01-01

    鲚(Coilia ectenes taihuensis Yen et Lin)是太湖主要的鱼类之一,其产量随水体富营养化程度的加重呈上升趋势.本研究于2009年4-12月用刺网(a=10 mm)在太湖贡湖湾采集了鲚,分析了其胃含物中食物组成的季节变化以及鲚对食物种类的选择性.结果表明,鲚在各月中主要以浮游动物为食,同时也摄食幼鱼、幼虾和水生昆虫等.鲚的食物组成具有明显季节变化,4月份以桡足类为食,其中桡足幼体、汤匙华哲水蚤(Sinocalanus dorrii Brehm)和剑水蚤(Cyclops spp.)所占的平均个数百分比相当;6、8和10月份主要以枝角类为食,其中6月以裸腹溞(Moina spp.)为主,而8和10月以象鼻潘(Bosmina spp.)为主.食物选择性方面,鲚对大型浮游动物表现出主动选择;当环境中出现潘(Daphnia spp.)和透明薄皮溞(Leptodora kindti Focke)时,鲚对它们表现出很强的选择性摄食,但透明薄皮溞只出现在6月鱼类食物中;个体较小的裸腹潘也是鲚主动选择的重要食物,在整个调查期间鲚对裸腹潘都表现出较高的主动选择性;象鼻潘虽然在各月份食物中的出现率最高,但除10月份鲚对其表现出主动选择外,其它月份表现为主动回避或随机选择.本研究结果有助于我们了解鲚对浮游动物群落影响的季节变化,为制定合理的湖泊与渔业管理方案提供依据.%Coilia ectenes taihuensis Yen et Lin ( C. ectenes) is the dominant fish species in Lake Taihu, and the catch has been increasing with the eutrophication of Late Taihu. En this study, in order to investigate the seasonal diets variations of C. ectenes in Gonghu Bay of Lake Taihu, we sampled the fish by gill net and analyzed bimonthly the gut contents of C. ectenes from April to December, 2009. Meanwhile, selectivity for different food items was also analyzed for the purpose to study the food preference of the fish. The results showed that the food composition of C. ectenes varied from month

  11. Less Mixing Can Affect Lake s Ecosystem

    Institute of Scientific and Technical Information of China (English)

    E.Sohn

    2005-01-01

    Lakescanbelikebowlsofsoupinthemicrowave:Theyneedalittlestirringeverynowandthen.Otherwise,alltheheatendsupontop.That’sexactlywhat’shappenedinrecentyearstoAfrica'sLakeTanganyika,scientistsarereporting.Risingwatertemperatureshaveinterferedwiththelake’snormal

  12. TOXAPHENE IN THE GREAT LAKES. (R825246)

    Science.gov (United States)

    This paper presents the most current data for toxaphene in the water, sediments, and biota of the Laurentian Great Lakes of North America. Concentrations in water range from 1.1 ng/L in Lake Superior to 0.17 ng/L in Lake Ontario. Lake Superior has the highest water concentrati...

  13. Analysis of Drought in Poyang Lake

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    [Objective] The drought situation and causes in Poyang Lake were analyzed.[Method] In response to the drought in Poyang Lake in ten years ago and in recent 10 years,the causes of drought in Poyang Lake were discussed.[Result] Drought occurred frequently in Poyang Lake and the consecutive serious drought occurred now and then.The water level in Poyang Lake since 21st century was lower.The drought in Poyang Lake was due to reduction of precipitation,low water level in Yangtze River and "five lakes",hydraulic ...

  14. The Great Lakes' regional climate regimes

    Science.gov (United States)

    Sugiyama, Noriyuki

    For the last couple of decades, the Great Lakes have undergone rapid surface warming. In particular, the magnitude of the summer surface-warming trends of the Great Lakes have been much greater than those of surrounding land (Austin and Colman, 2007). Among the Great Lakes, the deepest Lake Superior exhibited the strongest warming trend in its annual, as well as summer surface water temperature. We find that many aspects of this behavior can be explained in terms of the tendency of deep lakes to exhibit multiple regimes characterized, under the same seasonally varying forcing, by the warmer and colder seasonal cycles exhibiting different amounts of wintertime lake-ice cover and corresponding changes in the summertime lake-surface temperatures. In this thesis, we address the problem of the Great Lakes' warming using one-dimensional lake modeling to interpret diverse observations of the recent lake behavior. (Abstract shortened by ProQuest.).

  15. Rehabilitation of Delavan Lake, Wisconsin

    Science.gov (United States)

    Robertson, Dale M.; Goddard, Gerald L.; Helsel, D.R.; MacKinnon, Kevin L.

    2009-01-01

    A comprehensive rehabilitation plan was developed and implemented to shift Delavan Lake, Wisconsin, from a hypereutrophic to a mesotrophic condition. The plan was threefold: (1) reduce external phosphorus (P) loading by applying Best Management Practices in the watershed, enhance an existing wetland, and short-circuit the inflows through the lake, (2) reduce internal P loading by treating the sediments with alum and removing carp, and (3) rehabilitate the fishery by removing carp and bigmouth buffalo and adding piscivores (biomanipulation). The first and second parts of the plan met with only limited success. With only minor reductions in internal and external P loading, P concentrations in the lake returned to near pre-treatment concentrations. The intensive biomanipulation and resulting trophic cascade (increased piscivores, decreased planktivores, increased large zooplankton populations, and reduced phytoplankton populations) eliminated most of the original problems in the lake (blue-green algal blooms and limited water clarity). However, now there is extensive macrophyte growth and abundant filamentous algae. Without significantly reducing the sources of the problems (high P loading) in Delavan Lake, the increased water clarity may not last. With an improved understanding of the individual components of this rehabilitation program, better future management plans can be developed for Delavan Lake and other lakes and reservoirs with similar eutrophication problems.

  16. Possible temperate lakes on Titan

    Science.gov (United States)

    Vixie, Graham; Barnes, Jason W.; Jackson, Brian; Rodriguez, Sébastien; Le Mouélic, Stéphane; Sotin, Christophe; MacKenzie, Shannon; Wilson, Paul

    2015-09-01

    We analyze southern mid-latitude albedo-dark features on Titan observed by Cassini's Visual and Infrared Mapping Spectrometer (VIMS). In exploring the nature of these features we consider their morphology, albedo, and specular reflectivity. We suggest that they represent candidates for potential temperate lakes. The presence of lakes at the mid-latitudes would indicate that surface liquid can accumulate and remain stable away from Titan's poles. Candidate lakes were identified by looking for possible shorelines with lacustrine morphology. Then, we applied an atmospheric correction that empirically solved for their surface albedo. Finally, we looked for a specular reflection of the sky in the identified candidates. Using this prescription, we find two candidates that remain as potential temperature lakes. If candidate features do represent temperate lakes on Titan, they have implications for formation mechanisms such as clouds and rainfall or, in low elevation areas, percolation and subsurface flow. Clouds were observed near candidate lake locations on the T66 flyby and this latitude band showed many clouds during southern summer. Our techniques can be applied to areas of Titan that lack RADAR coverage to search for mid- and low-latitude lakes in the future.

  17. Monitoring Change in Great Salt Lake

    Science.gov (United States)

    Naftz, David; Angeroth, Cory; Freeman, Michael; Rowland, Ryan; Carling, Gregory

    2013-08-01

    Great Salt Lake is the largest hypersaline lake in the Western Hemisphere and the fourth largest terminal lake in the world (Figure 1). The open water and adjacent wetlands of the Great Salt Lake ecosystem support millions of migratory waterfowl and shorebirds from throughout the Western Hemisphere [Aldrich and Paul, 2002]. In addition, the area is of important economic value: Brine shrimp (Artemia franciscana) residing in Great Salt Lake support an aquaculture shrimp cyst industry with annual revenues as high as $60 million.

  18. Advance and application of lake optics research

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The mainstreams of lake optics research in recent decades include optical properties of lakewater,observation, transmission and calculation of underwater radiation, determination of absorption coefficient S of yellow substance, influence of UV-B radiation of lake primary productivity by bio-optical model. Major lake optics applications, such as calculation of lake primary productivity and chl-a, analysis of factors restricting eutrophication, and protection against lake eutrophication are summarized.

  19. Biogeochemistry of Kenyan Rift Valley Lake Sediments

    Science.gov (United States)

    Grewe, Sina; Kallmeyer, Jens

    2013-04-01

    The numerous lakes in the Kenyan Rift Valley show strong hydrochemical differences due to their varying geologic settings. There are freshwater lakes with a low alkalinity like Lake Naivasha on the one hand and very salt-rich lakes with high pH values like Lake Logipi on the other. It is known that the underlying lake sediments are influenced by the lake chemistry and by the microorganisms in the sediment. The aim of this work is to provide a biogeochemical characterization of the lake sediments and to use these data to identify the mechanisms that control lake chemistry and to reconstruct the biogeochemical evolution of each lake. The examined rift lakes were Lakes Logipi and Eight in the Suguta Valley, Lakes Baringo and Bogoria south of the valley, as well as Lakes Naivasha, Oloiden, and Sonachi on the Kenyan Dome. The porewater was analysed for different ions and hydrogen sulphide. Additionally, alkalinity and salinity of the lake water were determined as well as the cell numbers in the sediment, using fluorescent microscopy. The results of the porewater analysis show that the overall chemistry differs considerably between the lakes. In some lakes, concentrations of fluoride, chloride, sulphate, and/or hydrogen sulphide show strong concentration gradients with depth, whereas in other lakes the concentrations show only minor variations. Fluoride is present in all lakes; the lowest concentration is found in Lake Oloiden (60 - 90 mg/l), the highest one in Lake Bogoria (1,025 - 1,930 mg/l). The lakes show also large differences in sulphate concentrations. The values vary between 2 mg/l in Lake Baringo and 15,250 mg/l in Lake Eight. In all cores, sulphate concentration does not change significantly with depth; however, there is a distinct peak in each core, raising the question of synchronicity. As expected, chloride concentrations correlate with total salinity. There is no hydrogen sulphide present in the porewater of Lakes Naivasha, Baringo, and Oloiden, whereas in

  20. 2010 Great Lakes Restoration Initiative Bathymetric Lidar: Lake Superior

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data contained in this file contain hydrographic and topographic data collected by the Fugro LADS Mk II system along the Lake Superior coast of Minnessota,...

  1. Bathymetric maps of Lake Becharof and the Ugashik Lakes

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — In order to understand the production of smolts in a sockeye salmon nursery lake, it is mandatory to produce a bathymetric map. This must be detailed enough so that...

  2. Lake trout in the Great Lakes: Basin-wide stock collapse and binational restoration

    Science.gov (United States)

    Hansen, Michael J.; Taylor, William W.; Ferreri, C. Paola

    1999-01-01

    The lake trout (Salvelinus namaycush) was important to the human settlement of each of the Great Lakes, and underwent catastrophic collapses in each lake in the nineteenth and twentieth centuries. The timing of lake trout stock collapses were different in each lake, as were the causes of the collapses, and have been the subject of much scientific inquiry and debate. The purpose of this chapter is to summarize and review pertinent information relating historical changes in Great Lakes lake trout stocks, binational efforts to restore those stocks, and progress toward stock restoration. This presentation attempts to generalize patterns across the Great Lakes, rather than to focus within each lake. Lake specific analyses have been used to understand lake specific causes and effects, but there is continuing debate about some of these causes and effects. A basinwide review may suggest mechanisms for observed changes that are not evident by lake specific analysis.

  3. Chase Lake Wetland Management District, Chase Lake Prairie Project: Annual narrative report - 1993

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Chase Lake WMD, Chase Lake Prairie Project, and Halfway Lake NWR outlines Refuge accomplishments during the 1993 calendar year. The...

  4. Chase Lake Wetland Management District, Chase Lake Prairie Project: Annual narrative report: Calendar year 1994

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Chase Lake WMD, Chase Lake Prairie Project, and Halfway Lake NWR outlines Refuge accomplishments during the 1994 calendar year. The...

  5. Annual narrative report 1995: Chase Lake Wetland Management District, Chase Lake Prairie Project

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Chase Lake WMD, Chase Lake Prairie Project, and Halfway Lake NWR outlines Refuge accomplishments during the 1995 calendar year. The...

  6. ANALYSIS OF WATER QUALITY IN SHALLOW LAKES WITH A TWO-DIMENSIONAL FLOW-SEDIMENT MODEL

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The governing equation for sediment pollutions was derived based on the turbulent diffusion of pollutants in shallow lakes. Coupled with shallow water equations, a depth-averaged 2-D flow and water quality model was developed. By means of the conservation law, a proposed differential equation for the change of sediment pollutants was linked to the 2-D equations. Under the framework of the finite volume method, the Osher approximate Riemann solver was employed to solve the equations. An analytical resolution was used to examine the model capabilities. Simulated results matched the exact solutions especially well. As an example, the simulation of CODMn in the Wuli Lake, a part of the Taihu lake, was conducted, which led to reasonable results. This study provides a new approach and a practical tool for the simulation of flow and water quality in shallow lakes.

  7. Restoration in northern Lake Gehu, a eutrophic lake in China

    Science.gov (United States)

    Wu, Xiaodong; Li, Wenchao; Pan, Jizheng; Ma, Shuzhan; Chen, Bingfa; He, Shangwei

    2017-02-01

    Lake Gehu is a severely eutrophic lake in southeast China. A series of restoration measures have been implemented since 2009 in northern Lake Gehu. This study compared aquatic plants, water quality, sediment, and phytoplankton between restoration and control areas to investigate the effect of restoration measures. The results demonstrated that aquatic macrophyte coverage increased from 0% to 10.6%; mean TP, TN, and CODMn concentrations increased by 50.0%, 42.4%, and 40.8%, respectively, compared with those before the measures were carried out; the mean Secchi depth (SD) increased to 42.5 cm, which is 1.4 times higher than that before restoration; the mean euphotic depth (Zeu) in the summer increased from 91 to 130 cm; the mean chl a concentration decreased from 34.8 to 20.2 μg/L, compared with that before restoration; the Shannon-Wiener index of phytoplankton increased by 28.7%. The mean TP and TN concentrations in sediments decreased by 63.8% and 52.4%, respectively, compared with that before dredging. These results indicate that the restoration in northern Lake Gehu was effective. To complete the transformation from an algae- to a macrophyte-stable state within the region, further measures must be adopted. This restoration of a eutrophic lake can serve as a reference for similar eutrophic lakes.

  8. Morphological variation of siscowet lake trout in Lake Superior

    Science.gov (United States)

    Bronte, C.R.; Moore, S.A.

    2007-01-01

    Historically, Lake Superior has contained many morphologically distinct forms of the lake trout Salvelinus namaycush that have occupied specific depths and locations and spawned at specific times of the year. Today, as was probably the case historically, the siscowet morphotype is the most abundant. Recent interest in harvesting siscowets to extract oil containing omega-3 fatty acids will require additional knowledge of the biology and stock structure of these lightly exploited populations. The objective of this study was to determine whether shape differences exist among siscowet populations across Lake Superior and whether these shape differences can be used to infer stock structure. Morphometric analysis (truss protocol) was used to differentiate among siscowets sampled from 23 locations in Lake Superior. We analyzed 31 distance measurements among 14 anatomical landmarks taken from digital images of fish recorded in the field. Cluster analysis of size-corrected data separated fish into three geographic groups: The Isle Royale, eastern (Michigan), and western regions (Michigan). Finer scales of stock structure were also suggested. Discriminant function analysis demonstrated that head measurements contributed to most of the observed variation. Cross-validation classification rates indicated that 67–71% of individual fish were correctly classified to their region of capture. This is the first study to present shape differences associated with location within a lake trout morphotype in Lake Superior.

  9. Holocene lake deposits of Bosten Lake, southern Xinjiang, China

    Institute of Scientific and Technical Information of China (English)

    B. Wünnemann; CHEN Fahu; F. Riedel; ZHANG Chengjun; S. Mischke; CHEN Guangjie; D. Demske; MING Jin

    2003-01-01

    A 9.25-m-long sediment core from Bosten Lake, Xinjiang, provides detailed information about changes in the water budget and biological acticity over the last 8400 calendar years. The chronology is constructed from six AMS radiocarbon dates on the terrestrial plant remains. Based on analyses of TOC, CO3, detrital compounds and biogenic SiO2, lake level fluctuations and periods of remarkably-negative water budget appeared at 8.4-8.2 cal ka, 7.38-7.25 cal ka, 5.7-5.5 cal ka, 3.7-3.4 cal ka and 3.3-2.9 cal ka, respectively. As they are in-phase with low lake levels at Sumxi Co and Bangong Co in western Tibet Plateau and with paleolakes in Inner Mongolia, a climate-induced change to somewhat drier andwarmer conditions is inferred. A further drop in lake level after 1320 AD of about 200 yr duration may be attributed to a negative water balance prior to the main phase of the Little Ice Age. Deep and stable lake phases of 1500 yr and 1800yr duration at 7.2-5.7 cal ka and 5.5-3.7 cal ka coincide with maximum moisture during the Holocene Megathermal in China. The long term trend towards ariditysince about 4.3 cal ka can clearly be recognised. The reduced water budget of Bosten Lake from 640-1200 AD may be attributed to local effects.

  10. Chemical forms and extractability of iron in sediments of three contrasting lakes of China and UK

    Institute of Scientific and Technical Information of China (English)

    ZHOU Qi-xing; Gibson C.E.; Stewart B.M.

    2003-01-01

    Iron is a limiting factor for the eutrophication of lakes, especially those lakes that are enriched with phosphorus. Extractability of iron in sediments of West Lake and Taihu Lake in China and Lower Lough Erne in Northern Ireland of UK was comparatively investigated on the basis of analysing chemical forms of iron using different extractants. It was shown that extractable iron in sediments of the lakes was greatly different using various extractants. Reactive iron or easily released iron such as "active" iron oxides, total free iron oxide and water-soluble iron was not high, only accounting for 0.01%-0.15% of total iron. The efficiency of the extractants for exchangeable iron was decreased in the sequence 0.1 mol/L HCl> DTPA + TEA mixed solution > 1 mol/L NH4OAc > 0.5 mol/L MgCl2 = 0.5 mol/L CaCl2. It seems that the complexion of iron by organic matter was not strong because the concentration of organically bound iron was significantly lower than the concentration it was forecasted. Extractable iron is not entirely consistent with or dependent on total iron in lake sediments. To a certain extent,phosphate can inhibit the release of iron in sediments of the lakes. The selection of extractants is thus the first key step to evaluate bioavailability of iron in lake sediments.

  11. Audubon National Wildlife Refuge, Lake Nettie National Wildlife Refuge, Camp Lake Easement Refuge, Wintering River Easement Refuge, Cottonwood Lake Easement Refuge, Sheyenne Lake Easement Refuge, Lake Otis Easement Refuge : Narrative report : 1970

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Audubon National Wildlife Refuge (including Lake Nettie National Wildlife Refuge, Camp Lake Easement Refuge, Cottonwood Lake...

  12. Aquatic macrophyte richness in Danish lakes in relation to alkalinity, transparency, and lake area

    DEFF Research Database (Denmark)

    Vestergaard, Ole Skafte; Sand-Jensen, Kaj

    2000-01-01

    alkalinity but 12.3 in lakes of high alkalinity due to a greater occurrence of the species-rich group of elodeids. Mean species richness per lake also increased significantly with increasing Secchi depth. No significant relationship between species richness and lake surface area was observed among the entire...... group of lakes or a subset of eutrophic lakes, as the growth of submerged macrophytes in large lakes may be restricted by wave action in shallow water and light restriction in deep water. In contrast, macrophyte species richness increased with lake surface area in transparent lakes, presumably due...

  13. Management recommendations: Sand Lake Complex

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document is a review of land management practices at the Sand Lake National Wildlife Refuge, by a land use specialist. Recommendations, time frame and...

  14. Big Lake Dam Inspection Report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes an inspection of the Big Lake Dam that was done in September of 1983. The inspection did not reveal any conditions that constitute and...

  15. Folsom Lake 2005 Sedimentation Survey

    Data.gov (United States)

    US Bureau of Reclamation, Department of the Interior — The Bureau of Reclamation (Reclamation) surveyed Folsom Lake in the fall of 2005 via an interagency agreement with the U.S. Army Corps of Engineers (Corps of...

  16. Lakes Ecosystem Services Download Package

    Data.gov (United States)

    U.S. Environmental Protection Agency — This data download package contains Esri 10.0 MXDs, file geodatabases and copy of this FGDC metadata record. The data in this package are used in support of the Lake...

  17. Bear study, Karluk Lake, 1956

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Based on observations, 117 bears were estimated to live in the Karluk Lake area. The estimate was lower than estimates from 1952, and 1954-1955. Annual loss to...

  18. Functional microbiology of soda lakes.

    Science.gov (United States)

    Sorokin, Dimitry Y; Banciu, Horia L; Muyzer, Gerard

    2015-06-01

    Soda lakes represent unique permanently haloalkaline system. Despite the harsh conditions, they are inhabited by abundant, mostly prokaryotic, microbial communities. This review summarizes results of studies of main functional groups of the soda lake prokaryotes responsible for carbon, nitrogen and sulfur cycling, including oxygenic and anoxygenic phototrophs, aerobic chemolithotrophs, fermenting and respiring anaerobes. The main conclusion from this work is that the soda lakes are very different from other high-salt systems in respect to microbial richness and activity. The reason for this difference is determined by the major physico-chemical features of two dominant salts - NaCl in neutral saline systems and sodium carbonates in soda lakes, that are influencing the amount of energy required for osmotic adaptation.

  19. Lake Ladora sampling plan, 1993

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Task plan from the U.S. Geological Survey for sampling Lake Ladora on the Rocky Mountain National Wildlife Refuge. During the review of the FY93 Surface-Water...

  20. Great Lakes Environmental Research Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — NOAA-GLERL and its partners conduct innovative research on the dynamic environments and ecosystems of the Great Lakes and coastal regions to provide information for...

  1. Management recommendations: Benton Lake Complex

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document is a review of land management practices at the Benton Lake Complex, by a land use specialist. Recommendations, time frame and additional comments are...

  2. Great Lakes Initiative (GLI) Clearinghouse

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Great Lakes Initiative Toxicity Data Clearinghouse is a central location for information on criteria, toxicity data, exposure parameters and other supporting...

  3. Projecting the future levels of Lake Victoria

    Science.gov (United States)

    Vanderkelen, Inne; van Lipzig, Nicole; Thiery, Wim

    2017-04-01

    Lake Victoria directly sustains 30 million people living in its basin and 200 000 fishermen operating from its shores. As the one of the two sources of the Nile River, it also supports natural resources that impact the livelihood of over 300 million people living in the Nile basin. The outlet to the Nile is controlled by two hydropower dams. The water balance of Lake Victoria is controlled both by climatic conditions (precipitation and evaporation) and human management (dam outflow). Future climate simulations with a high resolution coupled lake-land-atmosphere model project decreasing mean precipitation and increasing evaporation over Lake Victoria. As these two are important factors in the water balance of Lake Victoria, these projected changes may induce a drop in future levels of Lake Victoria. Moreover, as Lake Victoria is also a relatively shallow lake, lake surface area may decrease as well. Here we present a water balance model for Lake Victoria that provides lake level and extent as output. We first force our model with observational input (new satellite products providing high quality precipitation and evaporation data) and evaluate it using measured lake levels. The skill of the model is subsequently assessed by forcing it with present-day regional climate simulations (CORDEX evaluation simulations). In a third step the future lake levels and surface area changes of Lake Victoria are simulated by forcing the model with CORDEX projections under RCP4.5 and 8.5. Finally, the role of human decisions regarding future dam outflow are investigated.

  4. Effects of lake trout refuges on lake whitefish and cisco in the Apostle Islands Region of Lake Superior

    Science.gov (United States)

    Zuccarino-Crowe , Chiara M.; Taylor, William W.; Hansen, Michael J.; Seider, Michael J.; Krueger, Charles C.

    2016-01-01

    Lake trout refuges in the Apostle Islands region of Lake Superior are analogous to the concept of marine protected areas. These refuges, established specifically for lake trout (Salvelinus namaycush) and closed to most forms of recreational and commercial fishing, were implicated as one of several management actions leading to successful rehabilitation of Lake Superior lake trout. To investigate the potential significance of Gull Island Shoal and Devils Island Shoal refuges for populations of not only lake trout but also other fish species, relative abundances of lake trout, lake whitefish (Coregonus clupeaformis), and cisco (Coregonus artedi) were compared between areas sampled inside versus outside of refuge boundaries. During 1982–2010, lake trout relative abundance was higher and increased faster inside the refuges, where lake trout fishing was prohibited, than outside the refuges. Over the same period, lake whitefish relative abundance increased faster inside than outside the refuges. Both evaluations provided clear evidence that refuges protected these species. In contrast, trends in relative abundance of cisco, a prey item of lake trout, did not differ significantly between areas inside and outside the refuges. This result did not suggest indirect or cascading refuge effects due to changes in predator levels. Overall, this study highlights the potential of species-specific refuges to benefit other fish species beyond those that were the refuges' original target. Improved understanding of refuge effects on multiple species of Great Lakes fishes can be valuable for developing rationales for refuge establishment and predicting associated fish community-level effects.

  5. Changes in Rongbuk lake and Imja lake in the Everest region of Himalaya

    Science.gov (United States)

    Chen, W.; Doko, T.; Liu, C.; Ichinose, T.; Fukui, H.; Feng, Q.; Gou, P.

    2014-12-01

    The Himalaya holds the world record in terms of range and elevation. It is one of the most extensively glacierized regions in the world except the Polar Regions. The Himalaya is a region sensitive to climate change. Changes in the glacial regime are indicators of global climate changes. Since the second half of the last century, most Himalayan glaciers have melted due to climate change. These changes directly affected the changes of glacial lakes in the Himalayan region due to the glacier retreat. New glacial lakes are formed, and a number of them have expanded in the Everest region of the Himalayas. This paper focuses on the two glacial lakes which are Imja Lake, located at the southern slope, and Rongbuk Lake, located at the northern slope in the Mt. Everest region, Himalaya to present the spatio-temporal changes from 1976 to 2008. Topographical conditions between two lakes were different (Kruskal-Wallis test, p Lake was located at 623 m higher than Imja Lake, and radiation of Rongbuk Lake was higher than the Imja Lake. Although size of Imja Lake was larger than the Rongbuk Lake in 2008, the growth speed of Rongbuk Lake was accelerating since 2000 and exceeds Imja Lake in 2000-2008. This trend of expansion of Rongbuk Lake is anticipated to be continued in the 21st century. Rongbuk Lake would be the biggest potential risk of glacial lake outburst flood (GLOF) at the Everest region of Himalaya in the future.

  6. Nitrogen and phosphorus budget of different land use types in hilly area of Lake Taihu upper-river basin%太湖上游低山丘陵地区不同用地类型氮、磷收支平衡特征

    Institute of Scientific and Technical Information of China (English)

    韩莹; 李恒鹏; 聂小飞; 徐昔保

    2012-01-01

    The enrichment of nitrogen and phosphorus in soil depends on the soil nitrogen and phosphorus budget of different land use types, which can also influence the strength of nitrogen and phosphorus loss. Understanding this process can help us to know its regional environment effect of different land use types. The study area is Lake Tianmu Basin, located in the hilly area of Lake Taihu upper-river basin. We calculated the soil nitrogen and phosphorus budget of different land use types by questionnaire, experimental analysis of soil and biomass, literature investigation and soil apparent balance model, and chose four land use types, including tea garden, paddy fields, masson pine and bamboo forest. We made a systematic analysis of the import and export elements of nitrogen and phosphorus. The import elements included fertilizer, atmospheric deposition, the straw returned to field or dry branches and leaves, biological nitrogen fixation and manure. The export elements included plant absorption, ammonia volatilization and denitrifying. The above analysis can reveal the water environmental effect of mainly land use types in hilly area of Lake Taihu upper-river basin by comparing with the soil nitrogen and phosphorus content. Results show that the order of soil nitrogen and phosphorus surplus are tea garden, paddy field, masson pine and bamboo forest, with the values of 648. 6, 248.9, 115.5, 53.6 kgN/(ha·a) and 319.9, 29.7, 1.2, -3.4 kgP/(ha·a) , respectively. The nitrogen and phosphorus utilization efficiency of bamboo forest is the highest, while tea garden is the lowest one, only 15.0% and 3. 1% . The soil nitrogen surplus and nitrogen content failed to present a consistent relationship although the soil phosphorus surplus and phosphorus content is similar. This shows that the bamboo forest is more advantageous to the waler environmental protection than masson pine, and the tea garden is worse to the water environmental protection than paddy fields.%不同用地类

  7. 结合卫星遥感技术的太湖蓝藻水华形成温度特征分析∗%Applying remote sensing techniques in analysis of temperature features causing cya-nobacteria bloom in Lake Taihu

    Institute of Scientific and Technical Information of China (English)

    李亚春; 谢小萍; 朱小莉; 杭鑫; 李心怡; 景元书

    2016-01-01

    Air temperature plays an important role in the recruitmen, growth, and formation of cyanobacteria bloom, as well as, the large area outbreak and decline of water bloom in Lake Taihu. In order to find out the relationships between the formation of cy⁃anobacteria bloom in Lake Taihu and surface temperature, meteorological data and satellite observations of the lake and surrounding areas from 2003 to 2013 were used to perform quantitative analysis in this paper. It is found that there is a wide range of daily aver⁃age temperature (0-35.0℃)suitable for cyanobacteria bloom appearing. Specifically, when daily average temperature falls between 15.1 and 35.0℃, the frequency of cyanobacteria bloom occurrences increases, leading to the accumulate frequency and accumulate area of cyanobacteria bloom accounted for 85% and 90%, respectively. The large area of cyanobacteria bloom mainly occurs in the daily average temperature range from 20.1 to 35.0℃, with the accumulate frequency and accumulate area accounted for 72% and 73%, respectively. Meanwhile, the probability of cyanobacteria bloom appearance increases as average temperature rising, showing a quadratic positive correlation. Moreover, single average area of cyanobacteria bloom fluctuates near the mean value of tempera⁃ture, which decreases rapidly when daily average temperature reaches 33℃.It shows that temperature is not the limiting factor for appearance of cyanobacteria bloom after it is resuscitated. Moderate high temperature benefits formation of cyanobacteria bloom, and becomes inhibiting factor when it reaches above 33℃. On the basis of analysis, the relationship to temperature, quantitative in⁃dicators of four stages of cyanobacteria bloom are identified. These four stages include dormant, recruitmen, growth and decline pe⁃ riods, and their initial and final critical temperature are (0℃,5℃),(5℃,15℃),(15℃,30℃) and (30℃,0℃), respectively. Relating to critical temperature, the

  8. Limnology of selected lakes in Ohio, 1975

    Science.gov (United States)

    Tobin, Robert L.; Youger, John D.

    1977-01-01

    Water-quality reconnaissance by the U.S. Geological Survey and Ohio Environmental Protection Agency, to evaluate the status of Ohio's lakes and reservoirs was begun in 1975 with studies of 17 lakes. Spring and summer data collections for each lake included: profile measurements of temperature, dissolved oxygen, pH, and specific conductance; field and laboratory analyses of physical, biological, chemical organic characteristics; (nutrient), and concentrations of major and minor chemical constituents from composites of the water column; and physical and chemical data from major inflows.Light penetration (secchi disk) ranged from 9.4 feet (2.9 meters) in Lake Hope to 0.4 feet (0.1 meter) in Acton Lake. Seasonal thermal stratification or stability is shown for 10 lakes deeper than 15 feet (4.6 meters). Unstable or modified temperature profiles were observed in shallow lakes (depths less than 15 feet) or lakes controlled through subsurface release valves.Dissolved oxygen saturation ranged from 229 percent (20.8 milligrams per liter) in the epilimnion of Paint Creek Lake to zero in the bottom waters of all thermally stabilized lakes. Marked chemical and physical differences and nutrient uptake and recycling developed within different thermal strata. Anaerobic zones were frequently characterized by hydrogen sulfide and ammonia.Calcium was the dominant or codominant cation, and bicarbonate and(or) sulfate were the major anions in all lakes sampled. Only Hope and Vesuvius Lakes had soft water (hardness less than 61 milligrams per liter as CaCO3 ), and both lakes were further characterized by low pH (less than 7.0). Specific conductance ranged from 510 micromhos (Deer Creek and Salt Fork Lakes) to 128 micromhos (Lake Hope). Pesticide residues were detected in Acton Lake, and concentrations of one or more trace metals were at or above Ohio Environmental Protection Agency recommended limits in 11 lakes.Fecal coliform colony counts were below 400 colonies per 100 milliliters in

  9. Present status and changes of the phytoplankton community after invasion of Neosalanx taihuensis since 1982 in a deep oligotrophic plateau lake, Lake Fuxian in the subtropical China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xia; XIE Ping; CHEN Fei-zhou; LI Yan-ling; LI Si-xin; GUO Ni-chun; QIN Jian-hui

    2005-01-01

    Phytoplankton assemblages in the subtrophical oligotrophic Lake Fuxian, the second deepest lake in China, were investigated monthly from September 2002 to August 2003. A total of 113 species belonging to seven phyla were identified, among them, a filamentous green alga, Mougeotia sp., dominated almost throughout the study period and comprised most of the total phytoplankton biomass.Mougeotia sp. has made a substantial development during the past decades: it was absent in 1957, only occasionally present in 1983,increased substantially in 1993, and became predominant in 2002-2003. It is likely that natural invasion of the Taihu Lake noodlefish (Neosalanx taihuensis) has led to a change of dominant herbivorous zooplankton from small to large calanoid, which has increased grazing pressure on small edible algae, and thus has indirectly favored the development of the inedible filamentous Mougeotia sp.

  10. Investigation of the dramatic changes in lake level of the Bosten Lake in northwestern China

    Science.gov (United States)

    Guo, Mengjing; Wu, Wei; Zhou, Xiaode; Chen, Yongmin; Li, Jing

    2015-01-01

    Bosten Lake, located in the arid region of northwest China, is the largest inland freshwater lake in China. Water resources in Bosten Lake are of great importance for the regional drinking water supply, agricultural irrigation, and economic development of Xinjiang province. In this study, the dynamics of the lake level in Bosten Lake were investigated from 1956 to 2010. We found that the lake level experienced three different periods of change due to the combined influences of climate variation and human activities. Generally, the lake level has shown a significant downward trend since the first observation started in 1956 and dropped to its lowest level in 1987. Thereafter, the lake level presented a continuous upward trend and rose to its highest value in 2002. Then, the level decreased dramatically from 2002 to 2010. A water balance model and the climate elasticity method were used to estimate the reasons for the lake level changes of Bosten Lake. The results showed that an increase in lake evaporation led to the continuous decrease in lake level from 1958 to 1987. Then, human-controlled lake outflow and increasing lake inflow together led to the increase in lake level from 1988 to 2002. During 2003 to 2010, the emergency project of transferring water to Tarim River led to the increase in lake outflow, while the lake inflow obviously decreased because of a decrease in precipitation. These factors resulted in a sharp decrease in the lake level from 2003 to 2010. The changes in lake level indicate changes in available water resources from Bosten Lake. This reason for the analysis of the change in lake level in this study is to support the water resources management of Bosten Lake.

  11. A census of colonially breeding waterbirds on Lake Louise and Skilak Lake, Alaska, 21-22 July 1981

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report presents a census of colonial waterbird sites at Lake Louise and Slikak lake on 21 and 22 July 1981 respectively. Both Lake Louise and Skilak Lake are...

  12. Deoxygenation of Lake Ikeda, Japan

    Science.gov (United States)

    Nagata, R.; Hasegawa, N.

    2010-12-01

    Lake Ikeda (Kagoshima prefecture, Japan) is a deep lake with a maximum depth of 233 m. Monitoring data of lake Ikeda exist since 1975. We have analyzed the long-term variability in the water conditions of Lake Ikeda. Recently, Lake Ikeda has exhibited the phenomenon of incomplete overturning because of climate warming. The concentrations of DO (dissolved oxygen) in the deepest parts of the lake have reduced. This phenomenon was observed to have started in the 1980s, and gradually, the deepest parts of the lake became anoxic. Later, the anoxic layer became thicker. Currently, winter mixing in Lake Ikeda reaches to depths of only 100 m. According to our simple estimation, the total volume of oxygen in Lake Ikeda will reduce from approximately 70% in the mid-1980s to 40% by the end of 2010. In addition to this phenomenon, the oxygen concentration appears to vary with several years oscillations. The depths to which mixing occurs depends on the severity of the winter, such as the air temperature during the winter season. The mixing period generally occurs in February; hence, the limnological year is considered to start in February. During our analysis period, the total DO mass showed high values in 1996, 2001, and 2003. Air temperature data obtained for regions near Lake Ikeda (the station name is Ibusuki) are used to clarify the cause of the high DO mass values in the three abovementioned years. During the period prior to the occurrence of the high DO mass in February 1996, i.e., in December 1995 and January 1996, the air temperature was low. Similarly, in 2001 and 2003, the air temperature was low in January (one month before the high DO mass was observed). In January 2001 and 2003, the AO (Atlantic Oscillation) index was negative. When the AO index is negative, there tends to be a greater movement of cold polar air into mid-latitudinal regions including Japan (Yamakawa, 2005). This movement induced a low air temperature in Ibusuki, and consequently, a high DO mass

  13. Effects of Conversion of Paddy Field into Vineyard on Soil Nitrogen Transformation in the Taihu Lake Region of China%太湖地区稻麦轮作农田改葡萄园对土壤氮转化过程的影响

    Institute of Scientific and Technical Information of China (English)

    王敬; 张金波; 蔡祖聪

    2016-01-01

    In response to the growing demand for fruits,farmers in the Taihu Lake region are rushing to convert paddy fields into fruit orchards in recent years. Changes in land-use and management may affect or alter physico-chemical properties of the soil,and hence cycling of soil N and fate of N fertilizer. Up to date, little has been reported on quantification of effects of changes in land use on soil N gross transformation rate, besides some works that have been mainly focused on effects of the conversion of non-agricultural land into agricultural land,and rarely on the effects of the conversion from one type to another type of agricultural land use. In the Taihu Lake region,paddy fields under rice-wheat crop rotation and orchards coverted from paddy fields are the two typical types of agricultural land-use,which differ sharply in water regimes(periodically waterlogged for paddy fields and water-unsaturated for orchards)and fertilizer management (no input of organic manure for paddy fields and combined application of chemical fertilizer and organic manure for orchards). Therefore,gross N processes(e.g.,nitrification and denitrification)in the soils under the two types of land use also differ sharply,as affected by their different aeration conditions and fertilizer managements. The paddy field under rice-wheat crop rotation and the vineyard converted from paddy field under study are located in the upper-streams of the Zhushan Bay Catchment in the Taihu Lake Region of China. Gross transformation rates of soil N under the two types of land use were measured using the15N tracing technique combined with the Markov Chain Monte Carlo(MCMC)algorithm-based numerical optimization model,and effects of the conversion on soil N supply and N retention capacity were investigated. Results show that the conversion reduced soil pH(from 5.74 in paddy field to 5.14 in vineyard,on average) and contents of soil organic C and total N,though not much. In the soils of the paddy field and vineyard

  14. Hutton Lake NWR, Mortenson Lake NWR, and Bamforth Lake NWR : Annual water management plans, 2004 water use report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Water use reports for 2004 and annual water management plans for 2005 for Mortenson Lake National Wildlife Refuge, Hutton Lake National Wildlife Refuge, and Bamforth...

  15. Eutrophication of the St. Lawrence Great Lakes

    Science.gov (United States)

    Beeton, Alfred M.

    1965-01-01

    Lakes Huron, Michigan, and Superior are classified as oligotrophic lakes on the basis of their biological, chemical, and physical characteristics. Lake Ontario, although rich in nutrients, is morphometrically oligotrophic or mesotrophic because of its large area of deep water. Lake Erie, the most productive of the lakes and the shallowest, is eutrophic. Several changes commonly associated with eutrophication in small lakes have been observed in the Great Lakes. These changes apparently reflect accelerated eutrophication in the Great Lakes due to man's activity. Chemical data compiled from a number of sources, dating as early as 1854, indicate a progressive increase in the concentrations of various major ions and total dissolved solids in all of the lakes except Lake Superior. The plankton has changed somewhat in Lake Michigan and the plankton, benthos, and fish populations of Lake Erie are greatly different today from those of the past. An extensive area of hypolimnetic water of Lake Erie has developed low dissolved oxygen concentrations in late summer within recent years.

  16. 伊乐藻和氮循环菌技术对太湖氮素吸收和反硝化的影响%Nitrogen Uptake and Denitrification Study on the Joint Treatment of Aquatic Vegetation and Immobilized Nitrogen Cycling Bacteria in Taihu Lake

    Institute of Scientific and Technical Information of China (English)

    刘丹丹; 李正魁; 叶忠香; 张万广

    2014-01-01

    Undisturbed sediment cores were collected from Meiliang Bay, Taihu Lake. Immobilized nitrogen cycling bacteria (INCB), Elodea nuttallii were added to four groups of restoration incubation chambers respectively to explore the nitrogen removal mechanism in different restoration treatments. 15N tracer and isotope pairing technique were used to determine the rates of plant uptake and denitrification in different treatments. The results showed that denitrification rates were significantly different among the treatments, while cores with addition of both INCB and Elodea nuttallii achieved the highest denitrification rate of 99. 35 μmol·( m2·h) -1 and plant uptake rate of 36. 55μg·( m2·h) -1 . Elodea nuttallii in the cores could assimilate nitrate itself and enhance coupled nitrification-denitrification. Compared with plant uptake, denitrification was the main pathway of nitrogen removal. The results also showed that the combination of Elodea nuttallii and INCB could promote benthic nitrogen removal and purification of water body.%从太湖梅梁湾采集无扰动泥芯样,分别添加固定化氮循环细菌、水生植物伊乐藻建立室内微宇宙,模拟生态修复,探讨不同修复处理下,硝氮的去除机制.采用15N标记结合同位素配对技术测定了各生态模拟柱中的反硝化速率和植物吸收速率.结果表明,不同处理的实验柱反硝化速率差异明显,同时添加了水生植物和固定化氮循环细菌的实验柱反硝化速率最高,为99.35μmol·( m2·h)-1,植物氮吸收速率为36.55μg·( m2·h)-1.沉水植物伊乐藻在自身吸收氮素的同时也提高了耦合硝化反硝化的作用.与植物吸收相比,反硝化过程是主要的氮去除途径.沉水植物与固定化氮循环菌组合生态修复技术促进了湖泊水体氮素的脱除,起到了净化作用.

  17. Lake Naivasha, Kenya

    Science.gov (United States)

    2008-01-01

    If you live in Europe and buy roses, there is a good chance that they were grown in Kenya specifically, in one of the colossal greenhouses that blot out the once wild shores of Lake Naivasha, 90km north-west of Nairobi. Some 25% of Europe's cut flowers come from Kenya. After a tentative start in the 1980s the industry is now the country's third-largest foreign-currency earner, bringing in $120m a year. But the recent violence in Kenya is having a major impact on the flower growers. A local trade union says 3,000 of the 30,000 workers employed in Naivasha's flower farms have abandoned their jobs. Kenya emerged as a flower power when Israel scaled down its own industry. It has since lost business to neighboring Ethiopia, which offers tax breaks and better security, but Naivasha's perfect intensity of sunlight and days of near-constant length should keep it on top. The ASTER image was acquired February 2, 2008, covers an area of 25 x 26.6 km, and is located near 0.8 degrees south latitude, 36.4 degrees east longitude. The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  18. Lake Naivasha, Kenya

    Science.gov (United States)

    2008-01-01

    If you live in Europe and buy roses, there is a good chance that they were grown in Kenya specifically, in one of the colossal greenhouses that blot out the once wild shores of Lake Naivasha, 90km north-west of Nairobi. Some 25% of Europe's cut flowers come from Kenya. After a tentative start in the 1980s the industry is now the country's third-largest foreign-currency earner, bringing in $120m a year. But the recent violence in Kenya is having a major impact on the flower growers. A local trade union says 3,000 of the 30,000 workers employed in Naivasha's flower farms have abandoned their jobs. Kenya emerged as a flower power when Israel scaled down its own industry. It has since lost business to neighboring Ethiopia, which offers tax breaks and better security, but Naivasha's perfect intensity of sunlight and days of near-constant length should keep it on top. The ASTER image was acquired February 2, 2008, covers an area of 25 x 26.6 km, and is located near 0.8 degrees south latitude, 36.4 degrees east longitude. The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  19. 77 FR 23123 - Special Local Regulation; Smokin The Lake; Gulfport Lake; Gulfport, MS

    Science.gov (United States)

    2012-04-18

    ... SECURITY Coast Guard 33 CFR Part 100 RIN 1625-AA08 Special Local Regulation; Smokin The Lake; Gulfport Lake... persons on navigable waters during the Smokin The Lake high speed boat races on May 5 and 6, 2012. Entry... associated with the Smokin The Lake high speed boat races. Basis and Purpose On February 27, 2012, Smokin...

  20. Exploring trends, causes, and consequences of declining lipids in Lake Superior lake trout

    Science.gov (United States)

    The ability of lake trout to forage in deepwater habitats is facilitated by high lipid content, which affords buoyancy. In Lake Superior, lean lake trout historically occupied depths < 80 m, and siscowet lake trout occupied depths > 80 m. Siscowets have been known f...

  1. Exploring trends, causes, and consequences of declining lipids in Lake Superior lake trout

    Science.gov (United States)

    The ability of lake trout to forage in deepwater habitats is facilitated by high lipid content, which affords buoyancy. In Lake Superior, lean lake trout historically occupied depths < 80 m, and siscowet lake trout occupied depths > 80 m. Siscowets have been known f...

  2. Clearing lakes. An ecosystem approach to the restoration and management of shallow lakes in the Netherlands.

    NARCIS (Netherlands)

    Hosper, H.

    1997-01-01

    In the 1950 s and 1960 s, most shallow lakes in the Netherlands shifted from macrophyte-dominated clear water lakes, towards algae-dominated turbid water lakes. Eutrophication, i.e. increased nutrient loading, is the main cause of the deterioration of the lake ecosystems. Other perturbations, such a

  3. Biota - 2011 Vegetation Inventory - Marsh Lake, MN

    Data.gov (United States)

    Army Corps of Engineers, Department of the Army, Department of Defense — 2011 Vegetation Classification for Marsh Lake, MN Vegetation Project Report, OMBIL Environmental Stewardship - Level 1 Inventory. Marsh Lake is located on the...

  4. Thermokarst lakes, drainage, and drained basins

    Science.gov (United States)

    Grosse, G.; Jones, B.; Arp, C.; Shroder, John F.

    2013-01-01

    Thermokarst lakes and drained lake basins are widespread in Arctic and sub-Arctic permafrost lowlands with ice-rich sediments. Thermokarst lake formation is a dominant mode of permafrost degradation and is linked to surface disturbance, subsequent melting of ground ice, surface subsidence, water impoundment, and positive feedbacks between lake growth and permafrost thaw, whereas lake drainage generally results in local permafrost aggradation. Thermokarst lakes characteristically have unique limnological, morphological, and biogeochemical characteristics that are closely tied to cold-climate conditions and permafrost properties. Thermokarst lakes also have a tendency toward complete or partial drainage through permafrost degradation and erosion. Thermokarst lake dynamics strongly affect the development of landscape geomorphology, hydrology, and the habitat characteristic of permafrost lowlands.

  5. Karluk Lake sockeye salmon studies 1984: Draft

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes the findings of a study on Karluk Lake sockeye salmon. The objectives of the study were to: collect sediment core samples from Karluk Lake and...

  6. Limnological monitoring of Lake Becherof, final report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The objectives of this study are to evaluate the major ions of Lake Becharof; to begin to evaluate the trace metals of Lake Becharof; to evaluate the light...

  7. Clarks Hill Lake Water Quality Study.

    Science.gov (United States)

    1982-06-01

    MACROINVERTEBRATE TAXONOMIC LIST CLARKS HILL LAKE 1981 Phylum Platyhelminthes Order Diptera Class Turbellaria Ablabesmyia parajanta unidentified Planariidae A...HILL LAKE 1981 Phylum Platyhelminthes Order Diptera (continued) Planaria sp.,’ Bezzia sp. 2 unidentified Planariidae Chaoborus punctipennis unidentified

  8. Medicine Lake NWR Water Use Report- 1939

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report contains locations and water use at Medicine Lake NWR for 1939. The document provides tabulated data for each area of Medicine Lake NWR, including the...

  9. Medicine Lake NWR Water Use Report- 1944

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report contains locations and water use at Medicine Lake NWR for 1944. The document provides tabulated data for each area of Medicine Lake NWR, including the...

  10. Medicine Lake NWR Water Use Report- 1946

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report contains locations and water use at Medicine Lake NWR for 1946. The document provides tabulated data for each area of Medicine Lake NWR, including the...

  11. Medicine Lake NWR Water Use Report- 1950

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report contains locations and water use at Medicine Lake NWR for 1950. The document provides tabulated data for each area of Medicine Lake NWR, including the...

  12. Medicine Lake NWR Water Use Report- 1951

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report contains locations and water use at Medicine Lake NWR for 1951. The document provides tabulated data for each area of Medicine Lake NWR, including the...

  13. Lake Erie Fish Community Data, 2013 - 2016

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Lake Erie Biological Station (LEBS), located in Sandusky, Ohio, is a field station of the USGS Great Lakes Science Center (GLSC). LEBS is the primary federal agency...

  14. Preparation of aluminium lakes by electrocoagulation

    OpenAIRE

    Prapai Pradabkham

    2008-01-01

    Aluminium lakes have been prepared by electrocoagulation employing aluminium as electrodes. The electrocoagulation is conducted in an aqueous alcoholic solution and is completed within one hour. The dye content in the lake ranges approximately between 4-32%.

  15. Medicine Lake NWR Water Use Report- 1947

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report contains locations and water use at Medicine Lake NWR for 1947. The document provides tabulated data for each area of Medicine Lake NWR, including the...

  16. Medicine Lake NWR Water Use Report- 1952

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report contains locations and water use at Medicine Lake NWR for 1952. The document provides tabulated data for each area of Medicine Lake NWR, including the...

  17. Medicine Lake NWR Water Use Report- 1948

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report contains locations and water use at Medicine Lake NWR for 1948. The document provides tabulated data for each area of Medicine Lake NWR, including the...

  18. Medicine Lake NWR Water Use Report- 1943

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report contains locations and water use at Medicine Lake NWR for 1943. The document provides tabulated data for each area of Medicine Lake NWR, including the...

  19. Medicine Lake NWR Water Use Report- 1955

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report contains locations and water use at Medicine Lake NWR for 1955. The document provides tabulated data for each area of Medicine Lake NWR, including the...

  20. Medicine Lake NWR Water Use Report- 1949

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report contains locations and water use at Medicine Lake NWR for 1949. The document provides tabulated data for each area of Medicine Lake NWR, including the...

  1. Medicine Lake NWR Water Use Report- 1956

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report contains locations and water use at Medicine Lake NWR for 1956. The document provides tabulated data for each area of Medicine Lake NWR, including the...

  2. Togiak National Wildlife Refuge lake surveys, 1984

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Preliminary review of the data reveals that all lakes surveyed can be classified as having low conductibility, ranging from the low 20's for the Goodnews Lakes to...

  3. Global Lake and River Ice Phenology Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Global Lake and River Ice Phenology Database contains freeze and thaw/breakup dates as well as other descriptive ice cover data for 865 lakes and rivers in the...

  4. Medicine Lake NWR Water Use Report- 1945

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report contains locations and water use at Medicine Lake NWR for 1945. The document provides tabulated data for each area of Medicine Lake NWR, including the...

  5. Recent warming of lake Kivu.

    Directory of Open Access Journals (Sweden)

    Sergei Katsev

    Full Text Available Lake Kivu in East Africa has gained notoriety for its prodigious amounts of dissolved methane and dangers of limnic eruption. Being meromictic, it is also expected to accumulate heat due to rising regional air temperatures. To investigate the warming trend and distinguish between atmospheric and geothermal heating sources, we compiled historical temperature data, performed measurements with logging instruments, and simulated heat propagation. We also performed isotopic analyses of water from the lake's main basin and isolated Kabuno Bay. The results reveal that the lake surface is warming at the rate of 0.12°C per decade, which matches the warming rates in other East African lakes. Temperatures increase throughout the entire water column. Though warming is strongest near the surface, warming rates in the deep waters cannot be accounted for solely by propagation of atmospheric heat at presently assumed rates of vertical mixing. Unless the transport rates are significantly higher than presently believed, this indicates significant contributions from subterranean heat sources. Temperature time series in the deep monimolimnion suggest evidence of convection. The progressive deepening of the depth of temperature minimum in the water column is expected to accelerate the warming in deeper waters. The warming trend, however, is unlikely to strongly affect the physical stability of the lake, which depends primarily on salinity gradient.

  6. Zooplankton communities in a large prealpine lake, Lake Constance: comparison between the Upper and the Lower Lake

    Directory of Open Access Journals (Sweden)

    Gerhard MAIER

    2005-08-01

    Full Text Available The zooplankton communities of two basins of a large lake, Lake Constance, were compared during the years 2002 and 2003. The two basins differ in morphology, physical and chemical conditions. The Upper Lake basin has a surface area of 470 km2, a mean depth of 100 and a maximum depth of 250 m; the Lower Lake basin has a surface area of 62 km2, a mean depth of only 13 and a maximum depth of 40 m. Nutrient, chlorophyll-a concentrations and mean temperatures are somewhat higher in the Lower than in the Upper Lake. Total abundance of rotifers (number per m2 lake surface was higher and rotifer development started earlier in the year in the Lower than in the Upper Lake. Total abundance of crustaceans was higher in the Upper Lake in the year 2002; in the year 2003 no difference in abundance could be detected between the lake basins, although in summer crustacean abundance was higher in the Lower than in the Upper Lake. Crustacean communities differed significantly between lake basins while there was no apparent difference in rotifer communities. In the Lower Lake small crustaceans, like Bosmina spp., Ceriodaphnia pulchella and Thermocyclops oithonoides prevailed. Abundance (number per m2 lake surface of predatory cladocerans, large daphnids and large copepods was much lower in the Lower than in the Upper Lake, in particular during the summer months. Ordination with nonmetric multidimensional scaling (NMS separated communities of both lakes along gradients that correlated with temperature and chlorophyll a concentration. Clutches of copepods were larger in the Lower than in the Upper Lake. No difference could be detected in clutch size of large daphnids between lake basins. Our results show that zooplankton communities in different basins of Lake Constance can be very different. They further suggest that the lack of large crustaceans in particular the lack of large predatory cladocerans in the Lower Lake can have negative effects on growth and

  7. Monitoring change in Great Salt Lake

    Science.gov (United States)

    Naftz, David L.; Angeroth, Cory E.; Freeman, Michael L.; Rowland, Ryan C.; Carling, Gregory

    2013-01-01

    Despite the ecological and economic importance of Great Salt Lake, only limited water quality monitoring has occurred historically. To change this, new monitoring stations and networks—gauges of lake level height and rate of inflow, moored buoys, and multiple lake-bottom sensors—will provide important information that can be used to make informed decisions regarding future management of the Great Salt Lake ecosystem.

  8. Estimating the volume of Alpine glacial lakes

    Science.gov (United States)

    Cook, S. J.; Quincey, D. J.

    2015-12-01

    Supraglacial, moraine-dammed and ice-dammed lakes represent a potential glacial lake outburst flood (GLOF) threat to downstream communities in many mountain regions. This has motivated the development of empirical relationships to predict lake volume given a measurement of lake surface area obtained from satellite imagery. Such relationships are based on the notion that lake depth, area and volume scale predictably. We critically evaluate the performance of these existing empirical relationships by examining a global database of glacial lake depths, areas and volumes. Results show that lake area and depth are not always well correlated (r2 = 0.38) and that although lake volume and area are well correlated (r2 = 0.91), and indeed are auto-correlated, there are distinct outliers in the data set. These outliers represent situations where it may not be appropriate to apply existing empirical relationships to predict lake volume and include growing supraglacial lakes, glaciers that recede into basins with complex overdeepened morphologies or that have been deepened by intense erosion and lakes formed where glaciers advance across and block a main trunk valley. We use the compiled data set to develop a conceptual model of how the volumes of supraglacial ponds and lakes, moraine-dammed lakes and ice-dammed lakes should be expected to evolve with increasing area. Although a large amount of bathymetric data exist for moraine-dammed and ice-dammed lakes, we suggest that further measurements of growing supraglacial ponds and lakes are needed to better understand their development.

  9. The Tomb Statues beside Dongqian Lake

    Institute of Scientific and Technical Information of China (English)

    RaoRao

    2005-01-01

    Located 17 kilometers to the City of Ningbo, Dongqian Lake covers an area of 20 square kilometers, which is four only the biggest freshwater lake in Zhejiang Province but atso renowned for its gorgeous scenery. Recently, this beautiful lake once again caught people's eye because a large number of Southern Song Dynasty (1127-1279) gravestone statues were discovered among the mountains beside the lake area.

  10. Comparative Analysis and Comprehensive Evaluation of Fishery Water Quality of the Major Lakes in Jiangsu Province Based on Long-term Monitoring Data

    Institute of Scientific and Technical Information of China (English)

    Wei; WANG; Xiangke; FAN; Chungui; HUANG; Hao; ZHENG; Zhijun; CHEN; Baohong; FAN; Chenwu; XU

    2015-01-01

    The variance analysis of fishery water quality data of five lakes from 2001 to 2011( except 2004) was performed to compare the difference of the monitoring indicators among the five above-mentioned lakes in Jiangsu Province. And TOPSIS method was employed to give comprehensive comparison of water quality of the five lakes. The results indicated that the difference of 14 major water quality indicators was very significant among lakes except copper. In addition,transparency,total nitrogen,total phosphorus had very significant difference among stations for each lake; p H,chemical oxygen demand,oil,total phosphorus,lead,cadmium,mercury had significant or very significant difference among years for each station. The TOPSIS results showed that the fishery water quality of Gaobaoshaobo Lake was the best,and Luoma Lake was just second to it,followed by Hongze Lake,Taihu Lake and Gehu Lake. In combination with the geographic position of each lake,it showed that fishery water quality of the five investigated lakes was basically increasingly better from the south to the north in Jiangsu Province,and the trend revealed high association with the developed industrial economy.

  11. First evidence of successful natural reproduction by planted lake trout in Lake Huron

    Science.gov (United States)

    Nester, Robert T.; Poe, Thomas P.

    1984-01-01

    Twenty-two lake trout (Salvelinus namaycush) swim-up fry, 24-27 mm long, were captured with emergent fry traps and a tow net in northwestern Lake Huron on a small nearshore reef off Alpena, Michigan, between May 10 and June 1, 1982. These catches represent the first evidence of successful production of swim-up fry by planted, hatchery-reared lake trout in Lake Huron since the lake trout rehabilitation program began in 1973.

  12. Groundwater links between Kenyan Rift Valley lakes

    OpenAIRE

    Becht, Robert; Mwango, Fred; Muno, Fred Amstrong

    2006-01-01

    The series of lakes in the bottom of the Kenyan Rift valley are fed by rivers and springs. Based on the water balance, the relative positions determining the regional groundwater flow systems and the analysis of natural isotopes it can be shown that groundwater flows from lake Naivasha to lake Magadi, Elementeita, Nakuru and Bogoria.

  13. Preserving Urmia Lake in a changing world

    NARCIS (Netherlands)

    Shadkam, Somayeh

    2017-01-01

    Urmia Lake, in north-western Iran, is an important internationally recognized natural area designated as a RAMSAR site and UNESCO Biosphere Reserve. Over the last 20 years, the surface area of Urmia Lake has declined by 80%. As a result, the salinity of the lake has sharply increased which is

  14. Lakes: recent research and restoration strategies

    Science.gov (United States)

    Karen L. Pope; Jonathan W. Long

    2014-01-01

    The Sierra Nevada and southern Cascade Range support thousands of montane lakes, from small, remote tarns to iconic destinations such as Lake Tahoe. Their beauty and recreational opportunities instill high social value, in particular by serving as destinations for hiking, camping, swimming, and fishing. Lakes also have high ecological value because they support a...

  15. Determination of phosphite in a eutrophic freshwater lake by suppressed conductivity ion chromatography.

    Science.gov (United States)

    Han, Chao; Geng, Jinju; Xie, Xianchuan; Wang, Xiaorong; Ren, Hongqiang; Gao, Shixiang

    2012-10-01

    The establishment of a sensitive and specific method for the detection of reduced phosphorus (P) is crucial for understanding P cycle. This paper presents the quantitative evidence of phosphite (P, +3) from the freshwater matrix correspondent to the typically eutrophic Lake Taihu in China. By ion chromatography coupled with gradient elution procedure, efficient separation of micromolar levels of phosphite is possible in the presence of millimolar levels of interfering ions, such as chloride, sulfate, and hydrogen carbonate in freshwater lakes. Optimal suppressed ion chromatography conditions include the use of 500 μL injection volumes and an AS11 HC analytical column heated to 30 °C. The method detection limit of 0.002 μM for phosphite was successfully applied for phosphite determination in natural water samples with recoveries ranging from 90.7 ± 3.2% to 108 ± 1.5%. Phosphite in the freshwater matrix was also verified using a two-dimensional capillary ion chromatography and ion chromatography coupled with mass spectrometry. Results confirmed the presence of phosphite in Lake Taihu ranging from 0.01 ± 0.01 to 0.17 ± 0.01 μM, which correlated to 1-10% of the phosphate. Phosphite is an important component of P and may influence biogeochemical P cycle in lakes.

  16. Salt Lake in Chaidamu Basin

    Institute of Scientific and Technical Information of China (English)

    王良华

    2007-01-01

    Chaidamu Basin(柴达木盆地) is in the west of China. It covers an area(地区) of 220,000 square kilometres(平方公里). The number of salt lakes(盐湖) is more than twenty in it. Chaerhan(察尔汗) Salt Lake is the largest in this area. If you get here, you will find that in the lake there is no water but a thick layer(层) of salt. You can walk in it without difficulty, and cars can come and go across it. The thickest layer of salt in this basin is about fifty metres thick. People tried their best to use the salt to build house...

  17. Similarity and disparity of arthropod community compositions among ten tea-intercropping plantations with different species of fruits in the Dongtingshan Mountains, Taihu Lake%太湖洞庭山十种茶果间作茶园节肢动物群落组成的异同性

    Institute of Scientific and Technical Information of China (English)

    季小明; 王梦馨; 江丽容; 韩宝瑜

    2011-01-01

    In order to understand the effect of tea-fruit intercropping on the population density and spatial distribution patterns of arthropod communities, ten types of tea-fruit intercropped plantations were investigated in the East Dongtingshan Mountains, Taihu Lake, during the summer( July) harvesting season of 2009. This mountain is the original production site of the famous tea, Dongtingbiluochun, and has & long history of tea and fruit intercropping. The same experimental design; sampling the same ten types of tea-fruit intercropped plantations, was also implemented in the West Dongtingshan Mountains, Taihu Lake, during the spring( April ) harvesting season of 2010. Data on species composition and population densities of arthropods between the intercropped fruit trees at the upper, middle and lower layers of tea bushes, and on and below ground level, were obtained from each experimental plot for both locations and study periods. Our data indicates that: (1) Overall results from the two locations and sampling periods were virtually the sarae. (2) The tea green leafhopper, Empoasca vitis Cothe, and the citrus spiny whitefly, Aleurocanthus spiniferus( Quainlance) were the most dominant pest species regardless of intercropping types and location; there were no significant differences in the species composition of other major pests and dominant natural enemies. (3) Species richness in the upper and middle layers of tea bushes, abundance ( total number of individuals; dominated by Homopteran insects ) in the lower layer of tea bushes and the biodiversity index of the middle layer of tea bushes, were higher than in the other layers. (4) Among different types of tea-fruit intercropped plantations, tea-citrus and tea-chestnut plantations had a higher arthropod species richness, whereas both species richness and overall arthropod abundance were lower in tea-Japanese allspice plantations. This suggests that the rational intercropping of tea plants with fruit trees can increase

  18. Hydrology of Hunters Lake, Hernando County, Florida

    Science.gov (United States)

    Henderson, S.E.

    1986-01-01

    The size and shape of Hunters Lake, Florida has been significantly altered by development of the surrounding Spring Hill residential community. The lake is the largest in Hernando County, enlarged by lakeshore excavation and connection to nearby ponds to an area of 360 acres at an average stage of 17.2 ft above sea level. Hunters Lake is naturally a closed lake, but development of Spring Hill has resulted in a surface water outflow from the lake in its southwest corner. Inflow to the lake could occur on the east side during extreme high-water periods. The karst terrain of the Hunters Lake area is internally drained through permeable soils, depressions, and sinkholes, and natural surface drainage is absent. The underlying Floridan aquifer system is unconfined except locally near coastal springs. Flow in the groundwater system is to the west regionally and to the southwest in the immediate area of Hunters Lake. Water level gradients in the groundwater system increase from 1.4 ft/mi east of the lake to about 8 ft/mi southwest of the lake. Hunters Lake is hydraulically connected to the groundwater system, receiving groundwater on the northeast side and losing water to the groundwater system on the southwest side. This close relationship with the groundwater system is demonstrated by graphical and numerical comparison of Hunters Lake stage with water levels in nearby groundwater sites. During 1965-84, the stage of Hunters Lake fluctuated between 12.48 and 20.7 ft above sea level. Because area lakes are all directly affected by groundwater levels, they also show a close relationship with water levels in Hunters Lake. Analysis of water quality data for Hunters Lake indicates that the water of the lake is a soft calcium bicarbonate type with ionic concentrations higher than in water from nearby shallow wells and lower than in water from the Upper Floridan aquifer. Samples collected in 1981-1983 indicate slightly higher levels of ionic concentration than in 1965

  19. Mechanism and control of lake eutrophication

    Institute of Scientific and Technical Information of China (English)

    QIN Boqiang; YANG Liuyan; CHEN Feizhou; ZHU Guangwei; ZHANG Lu; CHEN Yiyu

    2006-01-01

    A review about lake naturally eutrophi- cating, the internal loading of nutrients from lake sediment as well as the mechanism of algal blooms and the control practices was made, especially the eutrophication problem of shallow lakes since sev- enty percent of fresh water lakes in China are shallow lakes. It was found that shallow lakes are apt toward eutrophication than deep lakes. Without any influ- ences of human activity, shallow lakes in the middle and lower reaches of Yangtze River are still easily eutrophicated, which may be owing to the effects of flood in this area. In shallow lakes, sediments are frequently disturbed by wind-wave and resuspended, which result in huge nutrients release to overlying water. This may be the major reason for higher in- ternal loading of nutrients in shallow lakes than in deep lakes. Algal bloom is an extreme response of lake ecosystem to the eutrophication. Appearance of algal blooms is related to physical condition of lakes, such as underwater radiation (or transparency), temperature, and hydrodynamic conditions, or related to geochemical conditions of lakes, like concentra- tions of nutrients and ratio of nitrogen to phosphorus, as well as the physiological advantage of cyanobac- teria such as vacuole for moving towards the radiant energy-rich zone and the mycosporine-like amino acids (MAAs) for resisting the harm of ultraviolet ra- diation. In shallow lakes, these advantages of cyanobacteria are favorable in the competition than in deep lakes. Also being the shallowness, it is more difficult to reduce nutrient loading and to control algae blooms in shallow lakes. For the control of eutrophi- cation, people should follow the sequence from pollution sources control, ecological restoration to catchment management. To control the internal nu- trient release, physical, chemical, biological tech- niques, and even bionic techniques could be selected. The idea of ecological restoration for a eutrophic lake is to shift the ecosystem

  20. The Lake and the City

    Directory of Open Access Journals (Sweden)

    Konstantin Lidin

    2013-09-01

    Full Text Available The article considers relations between the city of Irkutsk and Lake Baikal in terms of cultural geography. Baikal is included in the UNESCO world heritage list. Unlike the majority of lakes also included in this list, Baikal’s coast is inhabited, especially its southern part. Similar situation is, for example, in the cluster “the city of Bergen – Geiranger village – Geirangerfjord” in Norway. The comparative analysis shows how Norway’s positive experience of the system “a city – a village – a natural phenomenon” could be used in order to make Irkutsk more attractive for tourists and citizens.

  1. Protecting the endangered lake salmon

    Energy Technology Data Exchange (ETDEWEB)

    Soimakallio, H.; Oesch, P. [ed.

    1997-11-01

    In addition to the Ringed Seal, the labyrinthine Saimaa lake system created after the Ice Age also trapped a species of salmon, whose entire life cycle became adapted to fresh water. In order to improve the living conditions of this lake salmon which - like the ringed seal - is today classified as an endangered species, an intensive research programme has been launched. The partners include the Finnish Game and Fisheries Research Institute, fishing and environmental authorities and - in collaboration with UPM-Kymmene Oy and Kuurnan Voima Oy - the IVO subsidiary Pamilo Oy

  2. Near the Lake and around the Lake: Artists and Baikal

    Directory of Open Access Journals (Sweden)

    Marina Tkacheva

    2013-09-01

    Full Text Available The article considers several aspects of how Lake Baikal influences artists’ work:Baikal as a theme for painting and exhibiting;Creative events at Baikal;Baikal as a place where artists live;Half-amateur paintings for sale.

  3. Post Audit of Lake Michigan Lake Trout PCB Model Forecasts

    Science.gov (United States)

    The Lake Michigan (LM) Mass Balance Study was conducted to measure and model polychlorinated biphenyls (PCBs) and other anthropogenic substances to gain a better understanding of the transport, fate, and effects of these substances within the system and to aid managers in the env...

  4. Crustal structure between Lake Mead, Nevada, and Mono Lake, California

    Science.gov (United States)

    Johnson, Lane R.

    1964-01-01

    Interpretation of a reversed seismic-refraction profile between Lake Mead, Nevada, and Mono Lake, California, indicates velocities of 6.15 km/sec for the upper layer of the crust, 7.10 km/sec for an intermediate layer, and 7.80 km/sec for the uppermost mantle. Phases interpreted to be reflections from the top of the intermediate layer and the Mohorovicic discontinuity were used with the refraction data to calculate depths. The depth to the Moho increases from about 30 km near Lake Mead to about 40 km near Mono Lake. Variations in arrival times provide evidence for fairly sharp flexures in the Moho. Offsets in the Moho of 4 km at one point and 2 1/2 km at another correspond to large faults at the surface, and it is suggested that fracture zones in the upper crust may displace the Moho and extend into the upper mantle. The phase P appears to be an extension of the reflection from the top of the intermediate layer beyond the critical angle. Bouguer gravity, computed for the seismic model of the crust, is in good agreement with the measured Bouguer gravity. Thus a model of the crustal structure is presented which is consistent with three semi-independent sources of geophysical data: seismic-refraction, seismic-reflection, and gravity.

  5. Detecting Magnetosomes in Freshwater Lakes and Lake Sediments

    Science.gov (United States)

    Kodama, K. P.; Kim, B.; Kopp, B.; Chen, A. P.

    2008-05-01

    We will present a summary of the work done to date on detecting magnetosomes in the lake sediments and water column of Lake Ely, a small post-glacial lake in northeastern Pennsylvania. To establish that magnetosomes dominate the magnetic mineralogy of the Lake Ely sediments we sampled the water column every meter down to its maximum depth of 23 m and measured the dissolved oxygen, sulfide, and iron, as well as the ARM of the material filtered from the water. We examined the water samples for magnetotactic bacteria. These results established an increase in the ARM of the filtered material at the oxic-anoxic transition. They also showed that the ARM was carried by magnetosomes produced by magnetotactic bacteria living in the water column at depths from 15-19 m. TEM of magnetic separates collected from the lake sediments show that magnetosomes are transferred to the sediments from the water column and are a significant fraction of the magnetic minerals in the sediments. We used a variety of mineral magnetic techniques to magnetically characterize the magnetosomes in the lake sediments. The delta-delta ratio test of low temperature behavior at the Verwey transition (Moskowitz et al., 1993) gave values of 1.2 to 1.5, lower than the theoretically predicted level of 2 for magnetosomes, but a numeric unmixing technique could resolve higher delta-delta ratios in the dark organic-rich layers in the sediments where magnetosomes were more prevalent. ARM/SIRM ratios of 0.15 to 0.35 with Raf values (the crossover of an IRM acquisition curve versus its alternating field demagnetization curve) of 0.45 to 0.5 are consistent with the presence of magnetosomes in the sediments, the water column, and in a sediment trap located at the bottom of the lake. IRM and ARM acquisition modeling of samples collected from a 160 cm piston core revealed two components of magnetization with coercivities of about 25 mT and 65 mT that are identified as Egli's (2004) biogenic soft (BS) and biogenic

  6. Evaluation of offshore stocking of Lake Trout in Lake Ontario

    Science.gov (United States)

    Lantry, B.F.; O'Gorman, R.; Strang, T.G.; Lantry, J.R.; Connerton, M.J.; Schanger, T.

    2011-01-01

    Restoration stocking of hatchery-reared lake trout Salvelinus namaycush has occurred in Lake Ontario since 1973. In U.S. waters, fish stocked through 1990 survived well and built a large adult population. Survival of yearlings stocked from shore declined during 1990–1995, and adult numbers fell during 1998–2005. Offshore stocking of lake trout was initiated in the late 1990s in response to its successful mitigation of predation losses to double-crested cormorants Phalacrocorax auritus and the results of earlier studies that suggested it would enhance survival in some cases. The current study was designed to test the relative effectiveness of three stocking methods at a time when poststocking survival for lake trout was quite low and losses due to fish predators was a suspected factor. The stocking methods tested during 2000–2002 included May offshore, May onshore, and June onshore. Visual observations during nearshore stockings and hydroacoustic observations of offshore stockings indicated that release methods were not a direct cause of fish mortality. Experimental stockings were replicated for 3 years at one site in the southwest and for 2 years at one site in the southeast. Offshore releases used a landing craft to transport hatchery trucks from 3 to 6 km offshore out to 55–60-m-deep water. For the southwest site, offshore stocking significantly enhanced poststocking survival. Among the three methods, survival ratios were 1.74 : 1.00 : 1.02 (May offshore : May onshore : June onshore). Although not statistically significant owing to the small samples, the trends were similar for the southeast site, with survival ratios of 1.67 : 1.00 : 0.72. Consistent trends across years and sites indicated that offshore stocking of yearling lake trout during 2000–2002 provided nearly a twofold enhancement in survival; however, this increase does not appear to be great enough to achieve the 12-fold enhancement necessary to return population abundance to restoration

  7. Improvement of