The dynamics of N & P nutrient inputs and the consequent epilimnetic concentration during 1969-2018 in Lake Kinneret was studied. The consequences of their availability on algal composition were also studied. Two prominent periods were indicated: 1) Sufficient supply of N accompanied by Peridinium enhancement; 2) N deficiency and P sufficiency-induced Peridinium reduction and Cyanobacterium enhancement. The impact of Anthropocene conditions and dust deposition on N & P availability is evaluated.
{"title":"The Replacement of Peridinium by Cyanobacteria in Lake Kinneret (Israel): A Commentary Review","authors":"M. Gophen","doi":"10.4236/ojmh.2019.94009","DOIUrl":"https://doi.org/10.4236/ojmh.2019.94009","url":null,"abstract":"The dynamics of N & P nutrient inputs and the consequent epilimnetic concentration during 1969-2018 in Lake Kinneret was studied. The consequences of their availability on algal composition were also studied. Two prominent periods were indicated: 1) Sufficient supply of N accompanied by Peridinium enhancement; 2) N deficiency and P sufficiency-induced Peridinium reduction and Cyanobacterium enhancement. The impact of Anthropocene conditions and dust deposition on N & P availability is evaluated.","PeriodicalId":70695,"journal":{"name":"现代水文学期刊(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70315034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The research has been conducted to analyze the distribution of underground water physical parameters of the housing around Asahan Indah palm oil factory area Rokan Hulu District with radial method within ±300 meters radius from the factory location. The levels of underground water physical parameters include conductivity, resistivity, and salinity measured based on coordinate points amounted of 50 points. The data obtained from the measurement results were then inputted into “surfer 11” software to be processed in order to obtain the contour map of underground water physical parameters level. The results of this research indicated that the highest conductivity level came from the ring well type with 5 meter depth; it was 0.0964 (1/ohm·m) exceeded the standard threshold of underground water quality standard and the lowest conductivity was 0.00342 (1/ohm·m) which came from a ring well type with 10 meter depth. The lowest resistivity level was 10.37 ohm·m which came from the ring well type with 5 meter depth and the highest was 292.4 ohm·m which came from the ring well with 10 meter depth. The highest salinity level was 448 mg/l which exceeded the baseline threshold of underground water quality which came from the ring well type with 5 meter depth and the lowest was 175 mg/l from the ring well with 10 meter depth. The results of this research found that underground water in wells with 5 meters depth has been polluted with palm oil waste and at the depth of 10 meters, it has not been contaminated.
{"title":"The Interpretation of Underground Water Physical Parameters of Housing in the Region of Asahan Indah Palm Oil Factory Area Rokan Hulu District","authors":"M. Juandi","doi":"10.4236/ojmh.2018.84009","DOIUrl":"https://doi.org/10.4236/ojmh.2018.84009","url":null,"abstract":"The research has been conducted to analyze the distribution of underground water physical parameters of the housing around Asahan Indah palm oil factory area Rokan Hulu District with radial method within ±300 meters radius from the factory location. The levels of underground water physical parameters include conductivity, resistivity, and salinity measured based on coordinate points amounted of 50 points. The data obtained from the measurement results were then inputted into “surfer 11” software to be processed in order to obtain the contour map of underground water physical parameters level. The results of this research indicated that the highest conductivity level came from the ring well type with 5 meter depth; it was 0.0964 (1/ohm·m) exceeded the standard threshold of underground water quality standard and the lowest conductivity was 0.00342 (1/ohm·m) which came from a ring well type with 10 meter depth. The lowest resistivity level was 10.37 ohm·m which came from the ring well type with 5 meter depth and the highest was 292.4 ohm·m which came from the ring well with 10 meter depth. The highest salinity level was 448 mg/l which exceeded the baseline threshold of underground water quality which came from the ring well type with 5 meter depth and the lowest was 175 mg/l from the ring well with 10 meter depth. The results of this research found that underground water in wells with 5 meters depth has been polluted with palm oil waste and at the depth of 10 meters, it has not been contaminated.","PeriodicalId":70695,"journal":{"name":"现代水文学期刊(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49252151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Genale-Dawa River Basin is one of the largest and most drought prone re-gions in Ethiopia. As a result a search for alternative source of water has always been a major issue in the region. This study therefore, aims at characterizing and evaluating the ground water potential resource of the river basin. The delineation and numerical discretization of the river basin were primarily done for the proper development of the problem domain. And the groundwater governing equation was solved at individual nodal points of the discretized region using a 3-D numerical ground water model called TAGSAC. This resulted in monthly average groundwater table fluctuation and replenishable ground water potential estimation. Hydrogeological classification was also done based on hydraulic conductivity values obtained from model calibration.
{"title":"Groundwater Potential Assessment and Characterization of Genale-Dawa River Basin","authors":"Nebiyou Kassahun, M. Mohamed","doi":"10.4236/OJMH.2018.84010","DOIUrl":"https://doi.org/10.4236/OJMH.2018.84010","url":null,"abstract":"Genale-Dawa River Basin is one of the largest and most drought prone re-gions in Ethiopia. As a result a search for alternative source of water has always been a major issue in the region. This study therefore, aims at characterizing and evaluating the ground water potential resource of the river basin. The delineation and numerical discretization of the river basin were primarily done for the proper development of the problem domain. And the groundwater governing equation was solved at individual nodal points of the discretized region using a 3-D numerical ground water model called TAGSAC. This resulted in monthly average groundwater table fluctuation and replenishable ground water potential estimation. Hydrogeological classification was also done based on hydraulic conductivity values obtained from model calibration.","PeriodicalId":70695,"journal":{"name":"现代水文学期刊(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47685152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The availability of long-term rainfall records is essential to conduct a serious frequency analysis in order to estimate the effective precipitation depth. The development of the process of elaboration of IDF (Intensity-Duration-Frequency) curves for a given location requires very precise data, at least with daily frequency, obtained through the use of rainfall records. The present study presents a method used to merge historical precipitation data with the latest data collected by satellite in order to perform graphs with IDF curves in places where rainfall records are scarce. The homogeneity of the data used is analyzed in order to guarantee its statistical utility and the frequency analysis was performed with the statistical distributions of Extreme Values Type I (Gumbel), Gamma, Pearson Type III and finally with Log-Pearson Type III, in order to verify which one of them applies better to the sites chosen for this analysis: the cities of Benguela and Lobito in the south of Angola. Daily rainfall data from the TRMM mission and historical daily data were used to derive the relationships between the maximum daily precipitation and the sub-daily precipitation values. From the observed daily data, techniques of disaggregation of the collected data were used, in order to generate a synthetic precipitation sequence with the extreme values in periods of time inferior to the daily one, with statistical properties similar to the registered data. Then IDF equations are established, with which the occasional storm depth is calculated for various return periods and various durations and, after them, the IDF curves are drawn for these two geographic stations.
{"title":"Generic Method for Merging Satellite and Historical Ground Station Data to Design Rainfall Intensity Duration Frequency (IDF) Curves in Recordless Sub-Saharian Countries","authors":"J. E. Matos","doi":"10.4236/OJMH.2018.84008","DOIUrl":"https://doi.org/10.4236/OJMH.2018.84008","url":null,"abstract":"The availability of long-term rainfall records is essential to conduct a serious frequency analysis in order to estimate the effective precipitation depth. The development of the process of elaboration of IDF (Intensity-Duration-Frequency) curves for a given location requires very precise data, at least with daily frequency, obtained through the use of rainfall records. The present study presents a method used to merge historical precipitation data with the latest data collected by satellite in order to perform graphs with IDF curves in places where rainfall records are scarce. The homogeneity of the data used is analyzed in order to guarantee its statistical utility and the frequency analysis was performed with the statistical distributions of Extreme Values Type I (Gumbel), Gamma, Pearson Type III and finally with Log-Pearson Type III, in order to verify which one of them applies better to the sites chosen for this analysis: the cities of Benguela and Lobito in the south of Angola. Daily rainfall data from the TRMM mission and historical daily data were used to derive the relationships between the maximum daily precipitation and the sub-daily precipitation values. From the observed daily data, techniques of disaggregation of the collected data were used, in order to generate a synthetic precipitation sequence with the extreme values in periods of time inferior to the daily one, with statistical properties similar to the registered data. Then IDF equations are established, with which the occasional storm depth is calculated for various return periods and various durations and, after them, the IDF curves are drawn for these two geographic stations.","PeriodicalId":70695,"journal":{"name":"现代水文学期刊(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41305650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Drought events across the world are increasingly becoming a critical problem owing to its negative effects on water resources. There is need to understand on-site drought characteristics for the purpose of planning mitigation measures. In this paper, meteorological drought episodes on spatial, temporal and trend domains were detected using Standardized Precipitation Index (SPI) and Effective Drought Index (EDI) in the upper Tana River basin. 41 years (1980-2016) monthly precipitation data from eight meteorological stations were used in the study. The SPI and EDI were used for reconstruction of the drought events and used to characterize the spatial, temporal and trend distribution of drought occurrence. Drought frequency was estimated as the ratio of a defined severity to its total number of events. The change in drought events was detected using a non-parametric man-Kendall trend test. The main drought conditions detected by SPI and EDI are severe drought, moderate drought, near normal, moderate wet, very wet and extremely wet conditions. From the results the average drought frequency between 1970 and 2010 for the south-eastern and north-western areas ranged from 12.16 to 14.93 and 3.82 to 6.63 percent respectively. The Mann-Kendall trend test show that drought trend increased in the south-eastern parts of the basin at 90% and 95% significant levels. However, there was no significant trend that was detected in the North-western areas. This is an indication that the south-eastern parts are more drought-prone areas compared to the North-western areas of the upper Tana River basin. Both the SPI and the EDI were effective in detecting the on-set of drought, description of the temporal variability, severity and spatial extent across the basin. It is recommended that the findings be adopted for decision making for drought-early warning systems in the river basin.
{"title":"Detection of Spatial, Temporal and Trend of Meteorological Drought Using Standardized Precipitation Index (SPI) and Effective Drought Index (EDI) in the Upper Tana River Basin, Kenya","authors":"R. Wambua, B. Mutua, J. Raude","doi":"10.4236/OJMH.2018.83007","DOIUrl":"https://doi.org/10.4236/OJMH.2018.83007","url":null,"abstract":"Drought events across the world are increasingly becoming a critical problem owing to its negative effects on water resources. There is need to understand on-site drought characteristics for the purpose of planning mitigation measures. In this paper, meteorological drought episodes on spatial, temporal and trend domains were detected using Standardized Precipitation Index (SPI) and Effective Drought Index (EDI) in the upper Tana River basin. 41 years (1980-2016) monthly precipitation data from eight meteorological stations were used in the study. The SPI and EDI were used for reconstruction of the drought events and used to characterize the spatial, temporal and trend distribution of drought occurrence. Drought frequency was estimated as the ratio of a defined severity to its total number of events. The change in drought events was detected using a non-parametric man-Kendall trend test. The main drought conditions detected by SPI and EDI are severe drought, moderate drought, near normal, moderate wet, very wet and extremely wet conditions. From the results the average drought frequency between 1970 and 2010 for the south-eastern and north-western areas ranged from 12.16 to 14.93 and 3.82 to 6.63 percent respectively. The Mann-Kendall trend test show that drought trend increased in the south-eastern parts of the basin at 90% and 95% significant levels. However, there was no significant trend that was detected in the North-western areas. This is an indication that the south-eastern parts are more drought-prone areas compared to the North-western areas of the upper Tana River basin. Both the SPI and the EDI were effective in detecting the on-set of drought, description of the temporal variability, severity and spatial extent across the basin. It is recommended that the findings be adopted for decision making for drought-early warning systems in the river basin.","PeriodicalId":70695,"journal":{"name":"现代水文学期刊(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46738669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Agmon is a small, shallow man-made lake (area: 1.1 km2; mean depth 0.45 m), excavated in the peat soils of the Hula Valley in northern Israel, that was filled with water in August 1994. We followed the seasonal variations in phytoplankton and metaphyton biomass, primary production and related environmental conditions between December 1995 and July 1997. Water temperature ranged between 9.5°C - 30.8°C; pH ranged between 7.2 - 8.6. The algae in Lake Agmon were characterized by seasonal alterations between summer-fall phytoplankton blooms and spring proliferation of benthic algal mats, with a winter clear-water phase. Chlorophyll a content in the water, as a measure of planktonic algal biomass, was low in winter (1.75 - 5 μg·L-1) and high in summer (>100 μg·L-1), when planktonic cyanobacteria (Microcystis spp.) bloomed. Metaphyton biomass varied between 3.5 and 970 g·dry·wt·m-2, with chlorophyll a content ranging from 5 - 701 mg·m-2. The dominant benthic algal genera were Spirogyra and Oedogonium in 1996 and Cladophora in 1997. Phytoplankton primary production was high in summer-fall, with a maximum of 1200 mg·O2·m-2·h-1. Benthic primary production was high from March till May, with a peak of 2173 mg·O2·m-2·h-1 in April 1997. The rate of benthic algal primary production was positively correlated to benthic chlorophyll a (r2 = 0.90). Diel measurements of water column dissolved oxygen (DO) concentration, conducted monthly from January to May 1997, revealed that DO concentration ranged from a nighttime minimum of 5.3 to a noon peak of 15.3 mg·L-1. Only during January to February, no significant changes in DO with depth were found, suggesting that at that time the water column was well mixed. The most salient feature of primary production in the lake was the seasonal partitioning between its benthic and planktonic components. This was most evident in the significant inverse relationship between benthic and planktonic primary productivity rates (r2 = 0.78).
{"title":"Seasonal Partitioning of Primary Production and Biomass between Phytoplankton and Metaphyton in a Shallow Lake Agmon, Hula Valley (Israel)","authors":"Y. Yehoshua, M. Gophen","doi":"10.4236/OJMH.2018.82006","DOIUrl":"https://doi.org/10.4236/OJMH.2018.82006","url":null,"abstract":"Agmon is a small, shallow man-made lake (area: 1.1 km2; mean depth 0.45 m), excavated in the peat soils of the Hula Valley in northern Israel, that was filled with water in August 1994. We followed the seasonal variations in phytoplankton and metaphyton biomass, primary production and related environmental conditions between December 1995 and July 1997. Water temperature ranged between 9.5°C - 30.8°C; pH ranged between 7.2 - 8.6. The algae in Lake Agmon were characterized by seasonal alterations between summer-fall phytoplankton blooms and spring proliferation of benthic algal mats, with a winter clear-water phase. Chlorophyll a content in the water, as a measure of planktonic algal biomass, was low in winter (1.75 - 5 μg·L-1) and high in summer (>100 μg·L-1), when planktonic cyanobacteria (Microcystis spp.) bloomed. Metaphyton biomass varied between 3.5 and 970 g·dry·wt·m-2, with chlorophyll a content ranging from 5 - 701 mg·m-2. The dominant benthic algal genera were Spirogyra and Oedogonium in 1996 and Cladophora in 1997. Phytoplankton primary production was high in summer-fall, with a maximum of 1200 mg·O2·m-2·h-1. Benthic primary production was high from March till May, with a peak of 2173 mg·O2·m-2·h-1 in April 1997. The rate of benthic algal primary production was positively correlated to benthic chlorophyll a (r2 = 0.90). Diel measurements of water column dissolved oxygen (DO) concentration, conducted monthly from January to May 1997, revealed that DO concentration ranged from a nighttime minimum of 5.3 to a noon peak of 15.3 mg·L-1. Only during January to February, no significant changes in DO with depth were found, suggesting that at that time the water column was well mixed. The most salient feature of primary production in the lake was the seasonal partitioning between its benthic and planktonic components. This was most evident in the significant inverse relationship between benthic and planktonic primary productivity rates (r2 = 0.78).","PeriodicalId":70695,"journal":{"name":"现代水文学期刊(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42363497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Shannon-Wiener Biodiversity Index was implemented for Zooplankton Diversity (BDI) in Lake Kinneret (1970-2001). It was computed based on monthly mean densities in relation to Epilimnetic temperatures. 4, 5 and 9 species of Copepoda, Cladocera and Rotifera, respectively, were included. Direct relations between Epilimnetic temperatures and Zooplankton Bio-Diversity Indexes (BDI) were indicated: Matching was found between low BDI and the high summer temperature and between higher BDI and the low winter temperature as well. Similar correspondence did not indicate annual means of BDI values. Zooplankton density and temperature probably resulted from smoothed confound of the averaged temperature changes. Conclusively, in themonomicticLakeKinneret located in the temperate zone with a high degree of temperature fluctuation, causation of seasonal BDI fluctuations is possible. The consistence of global warming trend might, therefore, enhance the seasonality of BDI values changes with implications for water quality.
{"title":"Temperature Impact on the Shannon-Wiener Biodiversity Index (BDI) of Zooplankton in Lake Kinneret (Israel)","authors":"M. Gophen","doi":"10.4236/OJMH.2018.82004","DOIUrl":"https://doi.org/10.4236/OJMH.2018.82004","url":null,"abstract":"The Shannon-Wiener Biodiversity Index was implemented for Zooplankton Diversity (BDI) in Lake Kinneret (1970-2001). It was computed based on monthly mean densities in relation to Epilimnetic temperatures. 4, 5 and 9 species of Copepoda, Cladocera and Rotifera, respectively, were included. Direct relations between Epilimnetic temperatures and Zooplankton Bio-Diversity Indexes (BDI) were indicated: Matching was found between low BDI and the high summer temperature and between higher BDI and the low winter temperature as well. Similar correspondence did not indicate annual means of BDI values. Zooplankton density and temperature probably resulted from smoothed confound of the averaged temperature changes. Conclusively, in themonomicticLakeKinneret located in the temperate zone with a high degree of temperature fluctuation, causation of seasonal BDI fluctuations is possible. The consistence of global warming trend might, therefore, enhance the seasonality of BDI values changes with implications for water quality.","PeriodicalId":70695,"journal":{"name":"现代水文学期刊(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48441101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Due to precipitation reduction, nutrient inputs into Lake Kinneret through Jordan river discharge declined. Nitrogen (N) supply into the Kinneret ecosystem is mostly external and that of Phosphorus (P) is partly internal and dust deposition. Therefore, decline of N and slight elevation of P concentrations occurred in the Kinneret Epilimnion. As a result, suppression of Peridinium biomass and enhancement of Cyanophyta, Chlorophyta and Diatoms were recorded. The Peridinium decline caused Primary Production (PP) reduction and although increased later, it accompanied the nano-plankton elevation. It is suggested that the PP enhancement is partly due to the natural photosynthetic capacity of nano-plankton and partly to global increase of atmospheric concentration of CO2. The suggestion of atmospheric CO2 increase and consequently PP, was supported by the pH (and obviously Alkalinity) increase. The enhancement of CO2 diffusion was an incentive factor which enhanced PP capacity.
{"title":"Atmospheric CO 2 Increase: A Potential for Primary Production Enhancement in Lake Kinneret","authors":"M. Gophen","doi":"10.4236/ojmh.2018.82005","DOIUrl":"https://doi.org/10.4236/ojmh.2018.82005","url":null,"abstract":"Due to precipitation reduction, nutrient inputs into Lake Kinneret through Jordan river discharge declined. Nitrogen (N) supply into the Kinneret ecosystem is mostly external and that of Phosphorus (P) is partly internal and dust deposition. Therefore, decline of N and slight elevation of P concentrations occurred in the Kinneret Epilimnion. As a result, suppression of Peridinium biomass and enhancement of Cyanophyta, Chlorophyta and Diatoms were recorded. The Peridinium decline caused Primary Production (PP) reduction and although increased later, it accompanied the nano-plankton elevation. It is suggested that the PP enhancement is partly due to the natural photosynthetic capacity of nano-plankton and partly to global increase of atmospheric concentration of CO2. The suggestion of atmospheric CO2 increase and consequently PP, was supported by the pH (and obviously Alkalinity) increase. The enhancement of CO2 diffusion was an incentive factor which enhanced PP capacity.","PeriodicalId":70695,"journal":{"name":"现代水文学期刊(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49623272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A study was carried out on the impacts of temperature and light/dark regime on the Egg Development Time (EDT) of the cyclopoida copepod, Mesocyclops ogunnus in Lake Kinneret. It was found that EDT was 148, 33 and 20 hours under 15°C, 22°C, and 27°C respectively. EDT was different between the two regimes of 12/12 hrs light/dark and 24 hrs light. Egg hatching and survival were higher under 24 hrs light regime. The results of temperature and light regime impacts on EDT indicate ecological implication on cyclopoida copepod population dynamics in lakes. The implication of the results to the global warming trend is also suggested.
{"title":"Egg Development Time (EDT) in Mesocyclops ogunnus","authors":"M. Gophen","doi":"10.4236/ojmh.2018.81003","DOIUrl":"https://doi.org/10.4236/ojmh.2018.81003","url":null,"abstract":"A study was carried out on the impacts of temperature and light/dark regime on the Egg Development Time (EDT) of the cyclopoida copepod, Mesocyclops ogunnus in Lake Kinneret. It was found that EDT was 148, 33 and 20 hours under 15°C, 22°C, and 27°C respectively. EDT was different between the two regimes of 12/12 hrs light/dark and 24 hrs light. Egg hatching and survival were higher under 24 hrs light regime. The results of temperature and light regime impacts on EDT indicate ecological implication on cyclopoida copepod population dynamics in lakes. The implication of the results to the global warming trend is also suggested.","PeriodicalId":70695,"journal":{"name":"现代水文学期刊(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43580757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The background for the case analysis of the present paper is the landing decline of Sarotherodon galilaeus during 2007-2008 to the annual level of <10 ton whilst normal harvests varied between 170 and 350 t/y. The objectives of the study are aimed at exploring limnological conditions and fishery management which might be the cause for this case. The research methods are focusing at long-term analysis of entire environmental conditions. The results indicatively highlight that, as other fluctuations of limnological parameters (Plankton, Nutrients) in Lake Kinneret, the fishery decline of S. galilaeus is attributed to normal periodical cyclic trends. Therefore, a recommendation that was submitted as a total fishing ban for three years was strongly opposed. The total fishing ban recommendation was rejected because further demolishing processes within the ecosystem were predicted. This conclusion was justified later (2011-2016) when annual landings came to the normal level. Conclusive recommendations considered that the fishing ban was indicated as “Ecological Disorder” and its replacement by controlled fishing policy as “Order Policy” was successfully implemented.
{"title":"Reforming Provisional (2007-2008) Sarotherodon galilaeus Landing Decline in Lake Kinneret (Israel)","authors":"M. Gophen","doi":"10.4236/OJMH.2018.81002","DOIUrl":"https://doi.org/10.4236/OJMH.2018.81002","url":null,"abstract":"The background for the case analysis of the present paper is the landing decline of Sarotherodon galilaeus during 2007-2008 to the annual level of <10 ton whilst normal harvests varied between 170 and 350 t/y. The objectives of the study are aimed at exploring limnological conditions and fishery management which might be the cause for this case. The research methods are focusing at long-term analysis of entire environmental conditions. The results indicatively highlight that, as other fluctuations of limnological parameters (Plankton, Nutrients) in Lake Kinneret, the fishery decline of S. galilaeus is attributed to normal periodical cyclic trends. Therefore, a recommendation that was submitted as a total fishing ban for three years was strongly opposed. The total fishing ban recommendation was rejected because further demolishing processes within the ecosystem were predicted. This conclusion was justified later (2011-2016) when annual landings came to the normal level. Conclusive recommendations considered that the fishing ban was indicated as “Ecological Disorder” and its replacement by controlled fishing policy as “Order Policy” was successfully implemented.","PeriodicalId":70695,"journal":{"name":"现代水文学期刊(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46486173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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