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The objectives of this study were to establish a method of classifying plants as indicator species of eutrophication, as a key metric for assessing lake ecosystem health, and to select sensitive and tolerant plant species among aquatic macrophytes and hygrophytes. Thus, 38 natural and artificial lakes throughout Korea were investigated. The distribution and abundance of plant species were investigated. As a measure of eutrophication, the modified trophic state index (TSIKO), derived from total phosphorus and chlorophyll a, was used. Using TSIKO criteria and the response curves of plants to TSIKO, a selection method of classifying sensitive and tolerant species was developed. Overall, 15 sensitive and 11 tolerant species among 117 macrophytes and hygrophytes were classified. The applicability of the selected indicator species was verified by a comparison with the results of a multimetric analysis using eight variables. The results suggest that the selected indicator species is expected to be useful as a metric for assessing lake ecosystem health. 相似文献
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Sooyong Shim Bomchul Kim Yoshihiko Hosoi Takanori Masuda 《Paddy and Water Environment》2005,3(4):211-218
The aim of this study is to quantify the dissolved organic carbon (DOC) of drainage water from paddy fields in agricultural
areas of Tottori prefecture, Japan. In four experimental paddy fields, DOC concentration varied much from 1.1 to 10.1 mg C l−1, and was the highest during heavy runoff that occurred in April when there was a non-agricultural period. However, variation
in DOC concentration did not always correspond to rainfall, but depended more on cultivation-activity events such as tilling,
planting, draining in summer, and final draining in autumn. The water discharge rate from each experimental field was estimated
by using a hydrologic model (the Tank Model and a genetic algorithm). Daily DOC export rate per unit area of three experimental
paddy fields was calculated to be 0.0074, 0.0052, and 0.0081 kg a−1 day−1, respectively. The daily DOC export rate showed large seasonal variation with the highest value in May and June. It can be
concluded that DOC export from paddy fields can be a substantial source of DOC in receiving waters, and the export rate depends
much on cultivation method practice. It might be suggested that DOC export from paddy fields can be controlled by a better
water management practice of farmers. 相似文献
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The concentrations of nitrogen (N) and phosphorous (P) species and relevant hydrographic parameters were determined in main stream and tributary waters of the Nakdong River system during the periods of May through October 1994. During the entire period, the total N (TN) and total P (TP) concentrations in surface waters were found within the ranges of 0.4–7.0 (N=241) and 0.02–1.536 mg L-1 (N=241), respectively. To help derive meaningful interpretations of temporal and geographical variabilities in the nutrient bahavior, the entire data were evaluated for each individual parameter after employing several different grouping schemes. The results of this comparative analysis can be expressed in terms of: (1) high summer/fall ratios for most of nutrient species; and (2) low summer/fall ratios for most of nutrient-to-nutrient ratios and relevant hydrographic parameters. Interestingly, while the former case was found to be more significant in tributary waters than main stream waters, such geographical dependence was not strongly evident for the latter case. A z-statistic test, conducted to check the significance of temporal (between summer and fall) and spatial (between tributary and main stream regions) differences, confirm that the observed variabilities are in most cases strong enough for most of variables studied – nutrient species, their ratios, and relevant hydrographic parameters. In addition, comparison of nutrient species between dissolved and particulate phases reveals several interesting features. Unlike dissolved nutrient species, the concentrations of particulate N or P (PN or PP) exhibited quite extraoridanry behavior. While PN appears to be rather minor component of the total N budget for the Nakdong river, PP seems to make rather strong contributions to its total P budgets with its strong input from tributary waters during rainy summer season. Through an application of correlation analysis, relationships between different parameters were investigated for both before and after the grouping of data sets. The overall picture of this analysis showed that nutrient species were strongly correlated with each other, while the strongest correlations were among such hydrographic parameters as DO, BOD, COD, and conductivity. This analysis was further conducted to more deliberately divided data groups. The results of analyses on these sub-grouped data sets indicate that the occurrences of significant corelations were common from tributary waters relative to main streams for both (1) between different nutrient species and (2) between nutrient and hydrographic parameters. Using the line of evidence gathered from the statistical tests and from the correlation analysis, we conclude that the environmental health of the Nakdong river system is affected by the combined effects of various factors and processes. 相似文献
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This study investigated the effect of extracts with time (a range of extraction periods: 0.2 days to maximum 150 days) of rice and rye straw on the growth of Microcystis aeruginosa (a cyanobacterium). The effect was assessed by an effective concentration 50 (EC50) of extracts measured by a carbon (C) content, when 50% normalized maximum growth yield (50% inhibition effect) of M. aeruginosa occurred. We found that extracts of rice and rye straw inhibited the growth of M. aeruginosa. Extracts from the earliest incubation phase (0.2 days) for rice straw and the 40-day extract for rye straw showed the most inhibitive EC50 value of 28.0 mg C L?1 and 18.9 mg C L?1, respectively. The inhibition effect was positively related to the extraction period of the rye straw, but inversely of the rice straw. Our results suggested that the long-term decomposition of extracts during straw extraction be linked with the formation of allelochemicals. These results provided information on how allelochemicals derived from agricultural by-products affect algal growth in aquatic ecosystems. 相似文献
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The objectives of this study were to determine the trophic state of agricultural reservoirs within the four major watersheds and evaluate ecosystem health using a multi-metric fish modeling approach of the lentic ecosystem health assessment (LEHA) in South Korea. Fish survey for the LEHA model was sampled twice from 12 reservoirs (oligotrophic to hypereutrophic reservoirs) during 2008–2010 along with data analysis of water quality monitored by the Ministry of Environment, Korea. The fish sampling gears used in the field were fyke net, trammel net, casting net, and kick net. A regression analysis of N:P ratios showed a negative linear function with total phosphorous (TP) values but not with total nitrogen. The greater relationship to TP was due to low variability and high ambient concentrations of N relative to P. The plots of “TSI (CHL)–TSI (TP)” and “TSI (CHL)–TSI (SD)” suggest that other factors other than phosphorus limited algal biomass (CHL–TP < 0), and that non-algal particles dominated light attenuation (CHL–SD < 0). Nutrients input into the reservoirs during the Asian monsoon exceeded actual nutrient availability for phytoplankton growth. A regression model of the fish trophic components against log-transformed TP showed that the proportions of omnivore and insectivore fish had a positive linear function and negative relationship with TP, respectively. According to the multi-metric LEHA model for agricultural reservoirs, the model value averaged 26 ± 6.5, indicating a “Fair” condition. Overall, ecosystem health was directly influenced by organic matter pollution and high algal production. This new tool appeared particularly relevant to detect the contamination effects on fish communities in reservoirs. The new national biological monitoring methodology in lentic ecosystem would be used as a key tool for ecological restorations and species conservations in Korean lentic ecosystems. 相似文献
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Lee Yunkyoung Kim Jai-Ku Jung Sungmin Eum Jaesung Kim Chulgoo Kim Bomchul 《Paddy and Water Environment》2014,12(1):19-28
Lake water quality and trophic state are evaluated using various parameters which may have different interpretations. Therefore, it is useful to adopt a proxy index that shows normalized values of parameters having different units and distribution characteristics. In this study, a model for integrated water quality index was developed for lakes and reservoirs in Korea. Water quality and phytoplankton were examined in 36 lakes, two natural lakes and 34 artificial lakes. The study lakes were selected to represent the range geographic regions and lake morphology in Korea. After investigating the interrelationships among water quality parameters, four parameters (total organic carbon, chlorophyll-a, total phosphorus, and turbidity) were selected as surrogate indicators of overall water quality. A relative evaluation system was developed by adopting a logistic function index that describes a cumulative distribution function and reflects the relative position of each parameter among the study lakes. The cumulative distribution probability ranging from 0 to 1 was multiplied by 100 and then transformed into the Korean Lake Water Quality Index (LQI) ranging from 0 to 100. A score of 50 was assigned to the median value of the dataset, 0 to the highest concentration value and 100 to the lowest concentration value. Thus, the LQI is an integrated easy-to-understand index that provides information about the relative status of each lake. The results of this study can represent a model to provide a relative evaluation system for lake and reservoir water quality, which can be useful for ecosystem management within an ecoregion or a jurisdictional district. 相似文献
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Lee Ji Min Park Youn Shik Kum Donghyuk Jung Younghun Kim Bomchul Hwang Soon Jin Kim Hyun Bae Kim Chulgoo Lim Kyoung Jae 《Paddy and Water Environment》2014,12(1):169-183
Aquatic ecosystems are threatened by increasing variability in the hydrologic responses. In particular, the health of river ecosystems in steeply sloping watersheds is aggravated due to soil erosion and stream depletion during dry periods. This study suggested and assessed a method to improve the adaptation ability of a river system in a steep watershed. For this, this study calibrated soil and water assessment tool (SWAT) for runoff and sediment, and quantified the changes in hydrologic responses such as groundwater recharge rate soil erosion and baseflow according to two scenarios for adjustment of the watershed slope (steep to mild). Here, one scenario was set by three measured slopes, and the other was set by fixing the entire watershed slopes with 5 %. Moreover, SWAT and web-based hydrograph analysis tool (WHAT) models were applied to estimate groundwater recharge, soil erosion, and baseflow in the Haean-myeon watershed in South Korea. The results show that the reduction of watershed slope increased groundwater recharge and baseflow, and decreased sediment. Specifically, groundwater recharge rate was increased from 257.10 to 364.60 mm, baseflow was increased from 0.86 to 1.19 m3/s, and sediment was decreased from 194.6 to 58.1 kg/km2. Based on these results, the suggested method will positively contribute to aquatic ecosystems and farming environments in a steeply sloping watershed due to improvements in the quantity and quality of river water. 相似文献
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