Edited by:The Chinese Society of Oceanology and Limnology, 7 Nanhai Road, Qingdao, ChinaEditor-in-ChiefC.K.Tseng Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071Members of the BoardCheng Lanna Scri...Edited by:The Chinese Society of Oceanology and Limnology, 7 Nanhai Road, Qingdao, ChinaEditor-in-ChiefC.K.Tseng Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071Members of the BoardCheng Lanna Scripps Institution of Oceanography, University of California, 92093, USACHEN Shu-peng Institute of Geography, Chinese Academy of Sciences, Beijing 100012C. T. A. Chen Marine Sciences Research Center, National SUN Yat-sen University,Kaohsiung 80424HU Dun-xin Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071JIANG Li-jin Institute of Photographic Chemistry, Chinese Academy of Sciences,Beijing展开更多
Edited by:The Chinese Society of Oasnology and Limnology, 7 Nanhai Road, Qingdao, ChinaEditor-in-ChiefC.K.TSeng Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071Members of the BoardCheng Lanna Scrip...Edited by:The Chinese Society of Oasnology and Limnology, 7 Nanhai Road, Qingdao, ChinaEditor-in-ChiefC.K.TSeng Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071Members of the BoardCheng Lanna Scripps Institution of Oceanography, University of California, 92093, USACHEN Shu-peng Institute of Geography, Chinese Acadrmy of Sciences, Bejing 100012C. T. A. Chen Marine Sciences Research Center, National SUN Yat-sen University,Kaohsiung展开更多
Edited by:The Chinese Society of Oceanology and Linmology, 7 Nanhai Road, Qingdao, ChinaEditor-in-ChiefC.K.Tseng Institute of Oceanology, Chinese Academy of Sciences Qingdao 266071Members of the BoardCheng Lanna Scrip...Edited by:The Chinese Society of Oceanology and Linmology, 7 Nanhai Road, Qingdao, ChinaEditor-in-ChiefC.K.Tseng Institute of Oceanology, Chinese Academy of Sciences Qingdao 266071Members of the BoardCheng Lanna Scripps Institution of Oceanography, University of California 92093, USACHEN Shu-peng Institute of Geography, Chinese Academy of Sciences, Beijing 100012C. T. A. Chen Marine Sciences Research Center, National SUN Yat-sen University,Kaohsiung 80424HU Dun-xin Institute of Oceanology, Chinese Academy of Scieaces, Qingdao 266071JIANG Li-jin Institute of Photographic Chemistry, Chinese Academy of Sciences,Beijing展开更多
Predictive geochemical and limnologic modeling of pit lakes is an important aspect of modern mine-site permitting. One of the key assumptions of many predictive pit-lake models is that open-pit high walls and in-pit b...Predictive geochemical and limnologic modeling of pit lakes is an important aspect of modern mine-site permitting. One of the key assumptions of many predictive pit-lake models is that open-pit high walls and in-pit backfill become geochemically unreactive once submerged by the filling pit lake. Existing pit lakes provide useful data to test this assumption. The Sleeper pit lake (northwestern Nevada, USA) is approaching hydrologic equilibrium and contains good-quality water that generally meets regulatory requirements for pit lakes. Despite the overall stable geochemical composition, seasonal trends in the hypolimnion indicate the generation of dissolved metals associated with the ore deposit (e.g., Mn and Zn) and cyclical variations in pH. This study applies mass balance, analysis of subaqueous pyrite oxidation, and trends in solute concentrations to evaluate the potential causes of long-term solute generation in the hypolimnion of the Sleeper pit lake. Three separate conceptual models (subaqueous pyrite oxidation;redox reactions;and diffusion of solutes from a permanently stratified bottom layer) were tested against the high-quality dataset available for the pit lake. Evaluation of the monitoring dataset for the pit lake indicates that the Sleeper pit lake has variable limnologic behavior, wherein the lake is consistently stratified (meromictic) in some years, while it undergoes full mixing (holomixis) in other time periods. Comparison of the data with the three conceptual models illustrates that none of these models can be completely implicated as causing the seasonal geochemical variations in the bottom of the pit lake, but that a combination of the processes is likely partially responsible. Additional data collection including sediment cores and in-situ pore-water analysis would aid in understanding geochemical processes occurring over time.展开更多
Edited by:The Chinese Society of Oceanology and Limnology, 7 Nanhai Road, Qingdao, ChinaEditor-in-ChiefC.K.Tseng Institute of Oceanology,Chinese Academy of Sciences, Qingdao 266071Members of the BoardCheng Lanna Scrip...Edited by:The Chinese Society of Oceanology and Limnology, 7 Nanhai Road, Qingdao, ChinaEditor-in-ChiefC.K.Tseng Institute of Oceanology,Chinese Academy of Sciences, Qingdao 266071Members of the BoardCheng Lanna Scripps Institution of Oceanography, University of California, 92093, USACHEN Shu-peng Institute of Geography, Chinese Academy of Schaces Boping 100012C. T. A. Chen Marine Sciences Research Ceahe, National SUN Yat-sen University,Kaohsiung 80424HU Dun-xin Institute of Oceanology, Chinase Acatwy of Scences, Qingdao 266071JIANG Li-jin Institute of Photographic Chrmistry, Chinese Acatmy of Sdeaces,Beijing展开更多
The concentrations of heavy metals (Fe > Zn > Cu > Pb > Ag) in bottom sediments and fish gills in Ohana Lake, were found to be significantly high and far exceeded FEPA and WHO environmental standards for w...The concentrations of heavy metals (Fe > Zn > Cu > Pb > Ag) in bottom sediments and fish gills in Ohana Lake, were found to be significantly high and far exceeded FEPA and WHO environmental standards for water quality by 1.5 to 18 times, respectively. Six classes of each of phytoplankton and zooplankton with a total of 35 phytoplankton taxa comprising 46 species i.e. 35(46) and 22(28) faunal were observed. The class Chlorophyceae dominated the phytoplankton community with 18(22) followed by Cyanobacteria 6(10). The aquatic fauna was dominated by the Rotifera 8(11), followed by the Copepoda 6(9). The benthic flora community consisted of five classes of phytoplankton made up of 28(36). The class Bacillariophyceae 11(15) dominated the group followed by Chlorophyceae 10(11). Benthic fauna were made up of seven classes of 13(13). The dominant class Nemata 4(4) was followed closely by Protozoa 2(3). Ohana Lake is fast turning to a eutrophic ecosystem with accompanied algal bloom due to very high nutrient contents. The equitability or evenness indices (J) for both phytoplankton and zooplankton were lowly indicating generally low species diversities as well as predominantly unstable ecosystem. The aquacultural implications of these parameters are discussed.展开更多
Based on reviewing the problems in limnology and watershed sciences in meeting the national demands and the development of theories and methodology, this paper proposed some challeng-ing topics to the sciences, coveri...Based on reviewing the problems in limnology and watershed sciences in meeting the national demands and the development of theories and methodology, this paper proposed some challeng-ing topics to the sciences, covering the process of lake evolution and the quantitative analysis of hu-man impacts, in-lake nutrient cycling an biogeo-chemical process, the process and mechanisms of material flow in lake-watershed system, digital watershed and the modeling of the surface pro-cess of lake-watershed, and ecosystem health and scientific management of lake- watershed.展开更多
Surface lake sediments, 28 from Hoh XU, 24 from northeastern China, 99 from Lake Bosten, 31 from Ulungur and 26 from Heihai were collected to determine δ13C and δ18O values. Considering the impact factors, conductiv...Surface lake sediments, 28 from Hoh XU, 24 from northeastern China, 99 from Lake Bosten, 31 from Ulungur and 26 from Heihai were collected to determine δ13C and δ18O values. Considering the impact factors, conductivity, alkalinity, pH, TOC, C/N and carbonate-content in the sediments, CI, P, S, and metal element ratios of Mg/Ca, Sr/Ca, Fe/Mn of bulk sediments as environmental variables enable evaluation of their influences on δ13C and δ18O using principal component analysis （PCA） method. The closure and residence time of lakes can influence the correlation between δ13C and δ18O. Lake water will change from fresh to brackish with increasing reduction and eutrophication effects. Mg/Ca in the bulk sediment indicates the characteristic of residence time, Sr/Ca and Fe/Mn infer the salinity of lakes. Carbonate formation processes and types can influence the 6~3C--~1So correlation. ~180 will be heavier from Mg-calcite and aragonite formed in a high-salinity water body than calcite formed in freshwater conditions. When carbonate content is less than 30%, there is no relationship with either 613C or 6180, and also none between δ13C and δ18O. More than 30%, carbonate content, however, co-varies highly to δ13C and δ18O, and there is also a high correlation between δ13C and δ18O. Vegetation conditions and primary productivity of lakes can influence the characteristics of δ13C and δ18O, and their co-variance. Total organic matter content （TOC） in the sediments is higher with more terrestrial and submerged plants infilling. In northeastern and northwestern China, when organic matter in the lake sediments comes from endogenous floating organisms and algae, the δ13C value is high. δ13C is in the range of-4‰ to 0‰ when organic matter comes mainly from floating organisms （C/N〈6）; in the range of-4‰ to 8‰ when organic matter comes from diatoms （C/N=6 to 8）; and -8‰ to -4‰ when organic matter comes from aquatic and terrestrial plants （C/N〉8）.展开更多
La Cantera Oriente is a shallow freshwater volcanic water body located at an altitude of 2 270 m above sea level in the Ecological Reserve of San Angel Pedregal of Mexico City （Mexico）. In order to ensure the conser...La Cantera Oriente is a shallow freshwater volcanic water body located at an altitude of 2 270 m above sea level in the Ecological Reserve of San Angel Pedregal of Mexico City （Mexico）. In order to ensure the conservation of its biological heritage including zooplankton, the present work was undertaken to quantify the seasonal changes in the diversity and density of rotifers and the selected physico- chemical variables during 2013-2014. Qualitative analysis of the zooplankton samples yielded 68 rotifer species which represented 24 genera in 15 families. Brachionus calyciflorus Pallas, 1766, B. quadridentatus Hermann, 1783, Polyarthra vulgaris Carlin, 1943, Lecane closterocerca （Schmarda, 1859） and Keratella cochlearis （Gosse, 1851） were the most common species. Preston plots of species frequency-density revealed that as many as 30% of the rotifer taxa were dominant throughout the year. The species with high population densities were Brachionus quadridentatus, Lecane closterocerca, Keratella cochlearis, and Lepadellapatella; their peak densities were 2 000, 1 000, 180 and 90 ind./L, all occurring in summer. Canonical correspondence analysis showed that Platyias quadricornis was related to the concentration of phosphates available in the environment and the conductivity, while B. quadridentatus was positively correlated with chlorophyll-a. The trophic status of the lake was eutrophic based on Chl-a content but oligotrophic with relation to the Braehionus： Trichocerca ratio.展开更多
In this study, the authors carried out the systemic analysis of water quality of Lake Patzcuaro in relationship with the climate change during a period of 85 years. The statistical comparison （medians, ＂t＂ Student ...In this study, the authors carried out the systemic analysis of water quality of Lake Patzcuaro in relationship with the climate change during a period of 85 years. The statistical comparison （medians, ＂t＂ Student test, regressions and correlations） for the precipitation, evaporation, observed temperature, minimum and maximum for the periods 1969-1988 （pre-impact） and 1988-2007 （post-impact） was realized. The ＂t＂ Student test for water quality during the period of 1981-2011, as well as, the regression analysis and multiple linear correlation of water quality from 2006 to 2011 were applied in joint way of the Cluster and Principal Component to observe the effects of climate change on water quality and vulnerability of Lake Patzcuaro. The comparative analysis of the meteorological data for 1921-1960 and 1973-2007 by the KOppen classification showed a climate change. The comparative Box Plots diagrams for 1973-1989 and 1989-2007, as well as, the ＂t＂ Student test, linear regression and correlation indicated significant changes in time for precipitation, evaporation, observed temperature, minimum and maximum （P ≤ 0.05）. The correlation and regression analysis indicated significant positive trends for turbidity, conductivity, total phosphorus, aluminum, oils and grease, in contrast with Secchi disk depth, transparency, Redox potential and dissolved oxygen concentration. The ＂t＂ Student test showed significant differences between 1981 and 2011 for transparency, hardness, alkalinity, conductivity, nitrite, and phosphate. Cluster and Principal Components of the physicochemical and biological of 2006-2011 confirmed the vulnerability of the system by human growth and climate change influence.展开更多
Many experimental studies have contributed to the development of the theory of trophic chains in lacustrine habitats. They have revealed the important role played by fish, a subject that has been mostly ignored by lim...Many experimental studies have contributed to the development of the theory of trophic chains in lacustrine habitats. They have revealed the important role played by fish, a subject that has been mostly ignored by limnological studies for the past few decades. Most of these studies were developed in Europe and in the United States. The general applicability of this theory has not yet been tested in subtropical and tropical habitats. In spite of controversies, the bottom-up: top-down trophic cascade hypotheses are the most adopted conceptual models. In this context, we examined if these hypotheses may be corroborated by data from the subtropical Itaipu Reservoir. A negative effect was verified between water transparency and total suspended solids. The detritivorous fish exerted a controlling effect on chlorophyll-a concentrations. Bottom-up effects were detected in four trophic levels, and top-down was detected in just one trophic level. The limnological variates influenced the chlorophyll-a concentration, which indicated that the lnTKN plus the effect of the quarter and the reservoir zone (and their interaction) were important.展开更多
Considering the great importance of the Itupararanga Reservoir, Upper Alto Sorocaba basin/SP, this study aimed to report the variations of some parameters of water quality in the spatial and temporal gradients in this...Considering the great importance of the Itupararanga Reservoir, Upper Alto Sorocaba basin/SP, this study aimed to report the variations of some parameters of water quality in the spatial and temporal gradients in this multipurpose reservoir. The eutrophication of this reservoir was checked using the Carlson Index Modified and the results indicate that the surface water were classified as eutrophic and mesotrophic in wet and dry periods, being characterized the better quality of water in wet period. In the vertical gradient the results showed a stratiphication in all parameters analyzed, except for the electrical conductivity, with good correlation between total phosphorous and chlorophyll-a, indicating that eutrophication of the reservoir changes the conditions of algal growth, mainly in its initial area. Immediate interventions are needed, which must be directed to planning of land use, domestic effluents treatment, taking to an integrated management of this important watershed located in the Sao Paulo State.展开更多
The knowledge of liminology can be applied in studies of trophic state indexes and morfoedaphic indexes as factors for determining the inference fish production in reservoirs. This work is based on the hypothesis of t...The knowledge of liminology can be applied in studies of trophic state indexes and morfoedaphic indexes as factors for determining the inference fish production in reservoirs. This work is based on the hypothesis of the trophic cascade relations, particularly related to bottom-up and top-down effect in Itaipu Reservoir (Brazil). Using the data available by Itaipu, from 1999 to 2004, analyzes of multiple regressions were accomplished to determine the relationships of the dependent and independent variables. We applied the trophic state indices (TSI) based on readings Secchi disk, total phosphorus and chlorophyll-a density for obtaining TSI medium. Morfoedaphic index was calculated based on the reading of the concentration of dissolved solids and the inference of fishing yield, from this index. The average results of the trophic state indices indicate an oligotrophic status for the entire reservoir as well as for the riverine, transition and lacustrine zones separately. The fish was yieldn Estimated by the relation with cyanobacteria concentration, and this was the best variable que explained this prediction. The use of the morfoedaphic index (MEI), with the recorded catch data, predictive models can generate que estimate the fishing yield in the Itaipu Reservoir. The relations of MEI with chlorophyll-a and water transparency que Indicate this index may be a good predicting factor for future fish captures.展开更多
The present study deals with the assessment of physico-chemical characteristics of Dokan, Derbendikhan and Duhok lakes. The physico-chemical characteristics of these lakes have been studied and analyzed for a year, du...The present study deals with the assessment of physico-chemical characteristics of Dokan, Derbendikhan and Duhok lakes. The physico-chemical characteristics of these lakes have been studied and analyzed for a year, during January-April-July and October 2009. Seasonal variations of two sampling sites of the lakes have been observed. Various parameters including air temperature, water temperature, electrical conductivity, TDS, pH, total alkalinity, total hardness, dissolved oxygen, calcium, magnesium, sodium, potassium, sulfate, chloride, nitrite and phosphate have been analyzed. The study has revealed that there are significant seasonal variations in some physico-chemical parameters and as a whole most of the parameters are different in the three lakes.展开更多
文摘Edited by:The Chinese Society of Oceanology and Limnology, 7 Nanhai Road, Qingdao, ChinaEditor-in-ChiefC.K.Tseng Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071Members of the BoardCheng Lanna Scripps Institution of Oceanography, University of California, 92093, USACHEN Shu-peng Institute of Geography, Chinese Academy of Sciences, Beijing 100012C. T. A. Chen Marine Sciences Research Center, National SUN Yat-sen University,Kaohsiung 80424HU Dun-xin Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071JIANG Li-jin Institute of Photographic Chemistry, Chinese Academy of Sciences,Beijing
文摘Edited by:The Chinese Society of Oasnology and Limnology, 7 Nanhai Road, Qingdao, ChinaEditor-in-ChiefC.K.TSeng Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071Members of the BoardCheng Lanna Scripps Institution of Oceanography, University of California, 92093, USACHEN Shu-peng Institute of Geography, Chinese Acadrmy of Sciences, Bejing 100012C. T. A. Chen Marine Sciences Research Center, National SUN Yat-sen University,Kaohsiung
文摘Edited by:The Chinese Society of Oceanology and Linmology, 7 Nanhai Road, Qingdao, ChinaEditor-in-ChiefC.K.Tseng Institute of Oceanology, Chinese Academy of Sciences Qingdao 266071Members of the BoardCheng Lanna Scripps Institution of Oceanography, University of California 92093, USACHEN Shu-peng Institute of Geography, Chinese Academy of Sciences, Beijing 100012C. T. A. Chen Marine Sciences Research Center, National SUN Yat-sen University,Kaohsiung 80424HU Dun-xin Institute of Oceanology, Chinese Academy of Scieaces, Qingdao 266071JIANG Li-jin Institute of Photographic Chemistry, Chinese Academy of Sciences,Beijing
文摘Predictive geochemical and limnologic modeling of pit lakes is an important aspect of modern mine-site permitting. One of the key assumptions of many predictive pit-lake models is that open-pit high walls and in-pit backfill become geochemically unreactive once submerged by the filling pit lake. Existing pit lakes provide useful data to test this assumption. The Sleeper pit lake (northwestern Nevada, USA) is approaching hydrologic equilibrium and contains good-quality water that generally meets regulatory requirements for pit lakes. Despite the overall stable geochemical composition, seasonal trends in the hypolimnion indicate the generation of dissolved metals associated with the ore deposit (e.g., Mn and Zn) and cyclical variations in pH. This study applies mass balance, analysis of subaqueous pyrite oxidation, and trends in solute concentrations to evaluate the potential causes of long-term solute generation in the hypolimnion of the Sleeper pit lake. Three separate conceptual models (subaqueous pyrite oxidation;redox reactions;and diffusion of solutes from a permanently stratified bottom layer) were tested against the high-quality dataset available for the pit lake. Evaluation of the monitoring dataset for the pit lake indicates that the Sleeper pit lake has variable limnologic behavior, wherein the lake is consistently stratified (meromictic) in some years, while it undergoes full mixing (holomixis) in other time periods. Comparison of the data with the three conceptual models illustrates that none of these models can be completely implicated as causing the seasonal geochemical variations in the bottom of the pit lake, but that a combination of the processes is likely partially responsible. Additional data collection including sediment cores and in-situ pore-water analysis would aid in understanding geochemical processes occurring over time.
文摘Edited by:The Chinese Society of Oceanology and Limnology, 7 Nanhai Road, Qingdao, ChinaEditor-in-ChiefC.K.Tseng Institute of Oceanology,Chinese Academy of Sciences, Qingdao 266071Members of the BoardCheng Lanna Scripps Institution of Oceanography, University of California, 92093, USACHEN Shu-peng Institute of Geography, Chinese Academy of Schaces Boping 100012C. T. A. Chen Marine Sciences Research Ceahe, National SUN Yat-sen University,Kaohsiung 80424HU Dun-xin Institute of Oceanology, Chinase Acatwy of Scences, Qingdao 266071JIANG Li-jin Institute of Photographic Chrmistry, Chinese Acatmy of Sdeaces,Beijing
文摘The concentrations of heavy metals (Fe > Zn > Cu > Pb > Ag) in bottom sediments and fish gills in Ohana Lake, were found to be significantly high and far exceeded FEPA and WHO environmental standards for water quality by 1.5 to 18 times, respectively. Six classes of each of phytoplankton and zooplankton with a total of 35 phytoplankton taxa comprising 46 species i.e. 35(46) and 22(28) faunal were observed. The class Chlorophyceae dominated the phytoplankton community with 18(22) followed by Cyanobacteria 6(10). The aquatic fauna was dominated by the Rotifera 8(11), followed by the Copepoda 6(9). The benthic flora community consisted of five classes of phytoplankton made up of 28(36). The class Bacillariophyceae 11(15) dominated the group followed by Chlorophyceae 10(11). Benthic fauna were made up of seven classes of 13(13). The dominant class Nemata 4(4) was followed closely by Protozoa 2(3). Ohana Lake is fast turning to a eutrophic ecosystem with accompanied algal bloom due to very high nutrient contents. The equitability or evenness indices (J) for both phytoplankton and zooplankton were lowly indicating generally low species diversities as well as predominantly unstable ecosystem. The aquacultural implications of these parameters are discussed.
文摘Based on reviewing the problems in limnology and watershed sciences in meeting the national demands and the development of theories and methodology, this paper proposed some challeng-ing topics to the sciences, covering the process of lake evolution and the quantitative analysis of hu-man impacts, in-lake nutrient cycling an biogeo-chemical process, the process and mechanisms of material flow in lake-watershed system, digital watershed and the modeling of the surface pro-cess of lake-watershed, and ecosystem health and scientific management of lake- watershed.
基金provided by China NSFC grant (41173015, 41202093)the Chinese Ministry of Education Supervision of Ph.D. Degree Fund (20100211110020)
文摘Surface lake sediments, 28 from Hoh XU, 24 from northeastern China, 99 from Lake Bosten, 31 from Ulungur and 26 from Heihai were collected to determine δ13C and δ18O values. Considering the impact factors, conductivity, alkalinity, pH, TOC, C/N and carbonate-content in the sediments, CI, P, S, and metal element ratios of Mg/Ca, Sr/Ca, Fe/Mn of bulk sediments as environmental variables enable evaluation of their influences on δ13C and δ18O using principal component analysis （PCA） method. The closure and residence time of lakes can influence the correlation between δ13C and δ18O. Lake water will change from fresh to brackish with increasing reduction and eutrophication effects. Mg/Ca in the bulk sediment indicates the characteristic of residence time, Sr/Ca and Fe/Mn infer the salinity of lakes. Carbonate formation processes and types can influence the 6~3C--~1So correlation. ~180 will be heavier from Mg-calcite and aragonite formed in a high-salinity water body than calcite formed in freshwater conditions. When carbonate content is less than 30%, there is no relationship with either 613C or 6180, and also none between δ13C and δ18O. More than 30%, carbonate content, however, co-varies highly to δ13C and δ18O, and there is also a high correlation between δ13C and δ18O. Vegetation conditions and primary productivity of lakes can influence the characteristics of δ13C and δ18O, and their co-variance. Total organic matter content （TOC） in the sediments is higher with more terrestrial and submerged plants infilling. In northeastern and northwestern China, when organic matter in the lake sediments comes from endogenous floating organisms and algae, the δ13C value is high. δ13C is in the range of-4‰ to 0‰ when organic matter comes mainly from floating organisms （C/N〈6）; in the range of-4‰ to 8‰ when organic matter comes from diatoms （C/N=6 to 8）; and -8‰ to -4‰ when organic matter comes from aquatic and terrestrial plants （C/N〉8）.
文摘La Cantera Oriente is a shallow freshwater volcanic water body located at an altitude of 2 270 m above sea level in the Ecological Reserve of San Angel Pedregal of Mexico City （Mexico）. In order to ensure the conservation of its biological heritage including zooplankton, the present work was undertaken to quantify the seasonal changes in the diversity and density of rotifers and the selected physico- chemical variables during 2013-2014. Qualitative analysis of the zooplankton samples yielded 68 rotifer species which represented 24 genera in 15 families. Brachionus calyciflorus Pallas, 1766, B. quadridentatus Hermann, 1783, Polyarthra vulgaris Carlin, 1943, Lecane closterocerca （Schmarda, 1859） and Keratella cochlearis （Gosse, 1851） were the most common species. Preston plots of species frequency-density revealed that as many as 30% of the rotifer taxa were dominant throughout the year. The species with high population densities were Brachionus quadridentatus, Lecane closterocerca, Keratella cochlearis, and Lepadellapatella; their peak densities were 2 000, 1 000, 180 and 90 ind./L, all occurring in summer. Canonical correspondence analysis showed that Platyias quadricornis was related to the concentration of phosphates available in the environment and the conductivity, while B. quadridentatus was positively correlated with chlorophyll-a. The trophic status of the lake was eutrophic based on Chl-a content but oligotrophic with relation to the Braehionus： Trichocerca ratio.
文摘In this study, the authors carried out the systemic analysis of water quality of Lake Patzcuaro in relationship with the climate change during a period of 85 years. The statistical comparison （medians, ＂t＂ Student test, regressions and correlations） for the precipitation, evaporation, observed temperature, minimum and maximum for the periods 1969-1988 （pre-impact） and 1988-2007 （post-impact） was realized. The ＂t＂ Student test for water quality during the period of 1981-2011, as well as, the regression analysis and multiple linear correlation of water quality from 2006 to 2011 were applied in joint way of the Cluster and Principal Component to observe the effects of climate change on water quality and vulnerability of Lake Patzcuaro. The comparative analysis of the meteorological data for 1921-1960 and 1973-2007 by the KOppen classification showed a climate change. The comparative Box Plots diagrams for 1973-1989 and 1989-2007, as well as, the ＂t＂ Student test, linear regression and correlation indicated significant changes in time for precipitation, evaporation, observed temperature, minimum and maximum （P ≤ 0.05）. The correlation and regression analysis indicated significant positive trends for turbidity, conductivity, total phosphorus, aluminum, oils and grease, in contrast with Secchi disk depth, transparency, Redox potential and dissolved oxygen concentration. The ＂t＂ Student test showed significant differences between 1981 and 2011 for transparency, hardness, alkalinity, conductivity, nitrite, and phosphate. Cluster and Principal Components of the physicochemical and biological of 2006-2011 confirmed the vulnerability of the system by human growth and climate change influence.
基金part of a postdoctoral report submitted by the senior author to the Programa de Pos Graduacao em Ciencias Biologicas-Zoologia(IB-UNESP,Rio Claro),under MPJr supervisionFAPESP(Processo no.07/50986-9)CNPq,UNESP,UEM/Nupelia and ITAIPUBINACIONAL for their financial support
文摘Many experimental studies have contributed to the development of the theory of trophic chains in lacustrine habitats. They have revealed the important role played by fish, a subject that has been mostly ignored by limnological studies for the past few decades. Most of these studies were developed in Europe and in the United States. The general applicability of this theory has not yet been tested in subtropical and tropical habitats. In spite of controversies, the bottom-up: top-down trophic cascade hypotheses are the most adopted conceptual models. In this context, we examined if these hypotheses may be corroborated by data from the subtropical Itaipu Reservoir. A negative effect was verified between water transparency and total suspended solids. The detritivorous fish exerted a controlling effect on chlorophyll-a concentrations. Bottom-up effects were detected in four trophic levels, and top-down was detected in just one trophic level. The limnological variates influenced the chlorophyll-a concentration, which indicated that the lnTKN plus the effect of the quarter and the reservoir zone (and their interaction) were important.
文摘Considering the great importance of the Itupararanga Reservoir, Upper Alto Sorocaba basin/SP, this study aimed to report the variations of some parameters of water quality in the spatial and temporal gradients in this multipurpose reservoir. The eutrophication of this reservoir was checked using the Carlson Index Modified and the results indicate that the surface water were classified as eutrophic and mesotrophic in wet and dry periods, being characterized the better quality of water in wet period. In the vertical gradient the results showed a stratiphication in all parameters analyzed, except for the electrical conductivity, with good correlation between total phosphorous and chlorophyll-a, indicating that eutrophication of the reservoir changes the conditions of algal growth, mainly in its initial area. Immediate interventions are needed, which must be directed to planning of land use, domestic effluents treatment, taking to an integrated management of this important watershed located in the Sao Paulo State.
文摘The knowledge of liminology can be applied in studies of trophic state indexes and morfoedaphic indexes as factors for determining the inference fish production in reservoirs. This work is based on the hypothesis of the trophic cascade relations, particularly related to bottom-up and top-down effect in Itaipu Reservoir (Brazil). Using the data available by Itaipu, from 1999 to 2004, analyzes of multiple regressions were accomplished to determine the relationships of the dependent and independent variables. We applied the trophic state indices (TSI) based on readings Secchi disk, total phosphorus and chlorophyll-a density for obtaining TSI medium. Morfoedaphic index was calculated based on the reading of the concentration of dissolved solids and the inference of fishing yield, from this index. The average results of the trophic state indices indicate an oligotrophic status for the entire reservoir as well as for the riverine, transition and lacustrine zones separately. The fish was yieldn Estimated by the relation with cyanobacteria concentration, and this was the best variable que explained this prediction. The use of the morfoedaphic index (MEI), with the recorded catch data, predictive models can generate que estimate the fishing yield in the Itaipu Reservoir. The relations of MEI with chlorophyll-a and water transparency que Indicate this index may be a good predicting factor for future fish captures.
文摘The present study deals with the assessment of physico-chemical characteristics of Dokan, Derbendikhan and Duhok lakes. The physico-chemical characteristics of these lakes have been studied and analyzed for a year, during January-April-July and October 2009. Seasonal variations of two sampling sites of the lakes have been observed. Various parameters including air temperature, water temperature, electrical conductivity, TDS, pH, total alkalinity, total hardness, dissolved oxygen, calcium, magnesium, sodium, potassium, sulfate, chloride, nitrite and phosphate have been analyzed. The study has revealed that there are significant seasonal variations in some physico-chemical parameters and as a whole most of the parameters are different in the three lakes.
