• Journal of Microbiology
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• v.42 no.3
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• pp.181-187
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• 2004

Cyanobacteria are the dominant phototrophic bacteria in water environments. Here, the diversity of cyanobacteria in seven Korean reservoir waters where different levels of algal blooms were observed during the summer of 2002, was examined by T-RFLP analysis. The number of T-RF bands in the HaIII T-RFLP profiles analyzed from those water samples ranged from 20 to 44. Of these, cyanobacteria accounted for 6.1 to 27.2％ of the total bacteria. The water samples could be clustered into 2 groups according to the Dice coefficient of the T -RF profiles. The eutrophic Dunpo and oligotrophic Chungju reservoirs were selected, and several representative clones from both reservoir waters analyzed for the nucleotide sequences of their 16S rDNA. The major clones were found to belong to the Microcystis and Anabaena species in the waters from the Dunpo and Chungju reservoirs, respectively, which was in agreement with the T-RFLP result. That is, the Microcystis and Anabaena species were dominant in the eutrophic and polluted Dunpo and oligotrophic Chungju reservoir waters, respectively. These results indicated that there is a correlation between prevalence of cyanobacterial species and levels of pollution in reservoir waters.

• Journal of environmental and Sanitary engineering
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• v.20 no.2 s.56
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• pp.1-11
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• 2005

Cyanotoxin, microcystins commonly produced by cyanobacterial affect various aquatic organisms and even human health. Kinds, structures, measurement analysis, toxicity and removal of Microcystin-LR were explained and discussed.

• Journal of Environmental Science International
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• v.15 no.10
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• pp.961-966
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• 2006

An algal assay procedure using an indigenous phytoplankton assemblage was tested to estimate the propagation of red tide phytoplankton species and determine the optimal time interval at which to measure growth yield in eutrophic marine waters where red tides frequently occur. Various red tide phytoplankton species were propagated on a large scale by adding nitrogen or phosphorous. This procedure was useful for estimating the limiting nutrient, elucidating the mechanisms underlying red tides, and determining the levels of increases in organic matter in eutrophic coastal waters. The algal assay using indigenous C. polykrikoides showed that this species did not always propagate, apparently because of very low concentrations of trigger elements that are necessary for its growth, rather than as a result of other environmental characteristics, e.g., water temperature or stress from sampling. In the winter, when water temperatures are lower than in spring, summer, or autumn, maximum propagation and the limiting nutrient could be estimated by measuring phytoplankton biomass at 2 - 3-day intervals. However, in the other seasons, when water temperatures are higher, phytoplankton biomass should be measured at 2-day intervals. In particular, daily monitoring will be required to determine precise growth yields in warm seasons.

• Korean Journal of Ecology and Environment
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• v.41 no.4
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• pp.519-529
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• 2008

Recent studies reveal one of the representative endocrine disrupters of nonylphenol affects on the composition of a planktonic community. Since nonylphenol is sometimes discharged into eutrophic waters, we monitored planktonic community composition of a eutrophic pond after receiving nonylphenol when cyanobacterium Microcystis aeruginosa mainly dominated. The experiment was carried out two times using small-scale microcosms in a laboratory. In both two experiments, ciliate abundances significantly decreased when nonylphenol was added. On the seventh day, the ciliate abundances in $10{\mu}g\;L^{-1}$ added treatments decreased by 36.9% in the first experiment and 33.6% in the second, when compared to the control. The response of other planktonic groups was less obvious to nonylphenol addition. In particular, in the first experiment, Chl. b/Chl. $\alpha$ and Chl. c/Chl. $\alpha$ significantly increased with the addition of nonylphenol, while total Chl. $\alpha$ concentration did not change. Indeed, bacillariophyceae and chlorophyceae abundances tended to increase with nonylphenol dosing. From these results, we tentatively hypothesized that nonylphenolloading positively affects on abundances of edible phytoplankton such as Scenedesmus spp. and diatoms by releasing from grazing pressure due to decrease in ciliate abundances. The present study emphasizes that the indirect effect of endocrine disrupters should be paid more attention when freshwater resources are polluted by them.

• Environmental Engineering Research
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• v.7 no.2
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• pp.93-101
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• 2002

The seasonal patterns of dissolved organic matter (DOM) in Lake Kasumigaura, a shallow, eutrophic lake, and serveral DOM sources in its catchment area were investigated. DOM was fractionated using three resin adsorbents into classes: aquatic humic substances (AHS=humic acid+fulvic acid), hydrophobic neutrals (HoN), hydrophilic acids (HiA), bases (BaS) and hydrophilic neutrals (HiN). The DOM produced significantly different fraction distributions depending on the origin of sample. AHS and HiA prevailed over AHS in the lake while AHS and HiA existed at almost the same concentration levels in the rivers. AHS seems to be a more dominant component in rever water than lake water. The dominance of organic acids was also observed in the DOM sources: forest stream (FS), plowed field percolate (PFP), domestic sewage (DS) and sewage treatment plant effluent (STPE).

• Proceedings of the Korea Society of Environmental Biology Conference
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• 2001.12a
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• pp.84-84
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• 2001

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.9 no.4
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• pp.179-195
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• 2004

The trophic state of the coastal waters of the southern part of Korea was assessed using biogeochemical data obtained from the National Marine Environmental Monitoring Program conducted by the National Fisheries Research and Development Institute for six years. The trophic state of different areas, analyzed by non-metric multi-dimensional scaling (MDS) analysis, could divide the areas into three groups. Masan Bay, with suboxic water masses and/or the highest concentrations of dissolved inorganic nitrogen and phosphorus occurred, was assessed as being in a hypertrophic state. Ulsan Bay, Onsan Bay, Busan and Jinhae Bay, located near strong point sources, were in a eutrophic state. Other areas, including Tongyong, Yosu, Mokpo and Jeju island, were evaluated as being in a mesotrophic state. During 1997 to 2002, the average values of excess nitrogen, which is the difference between the measured dissolved inorganic nitrogen (DIN) and the corrected DIN using the Redfield ratio, were positive at Ulsan, Onsan, and Busan, where there were inflows from polluted rivers. In contrast, those were negative values in Haengam Bay, Gwangyang Bay and nearby Yosu. This suggests that the limiting element for phytoplankton growth differed among sites. The time series data of excess nitrogen showed gradual decrease over time in the hypertrophic waters, but the opposite trend in the mesotrophic waters. This indicated that the ratio of nitrogen to phosphate varied according to the trophic state of the coastal waters. The enrichment of organic matter in sediment in eutrophic waters would disturb the normal pattern of biogeochemical cycling of nitrogen and phosphate. In order to assess the condition of the coastal environment, the benthic boundary layer should be considered.

• Ocean and Polar Research
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• v.24 no.4
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• pp.359-365
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• 2002

The qualitative and quantitative composition of the phytoplankton of the coastal waters off Vladivostok during the period 1991-1994 was studied. The following trends in the phytoplankton composition with decreasing distance from the source of eutrophication were revealed: 1) total density and bio-mass increased; 2) the density of the diatom Skeletonema costatum, which reflects a decrease in the Shannon-Weaver species diversity index during the summer microalgal bloom, increased significantly; and 3) the density of the non-diatom component of the phytoplankton increased.

• Ocean Science Journal
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• v.42 no.2
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• pp.81-88
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• 2007

The paper reviews data available on euglenophycean algae of the genus Eutreptiella from the Russian waters of East/Japan Sea. Five species (such as E. braarudii, E. eupharyngea, E. gymnastica, E. cf. marina, and E. pascheri) were identified in our study. E. cf. marina and E. pascheri were found for the first time in the fare astern seas of Russia (including East/Japan Sea, Bering and Okhotsk seas). Morphological descriptions of species are based on light and electron microscopical studies and supplied with information on ecology and distribution. Original micrographs of these species obtained by light and electron microscopy are presented. It was established that E. eupharyngea, E. gymnastica, and E. pascheri cause water "blooms" in spring and summer in eutrophic coastal areas of Peter the Great Bay (East/Japan Sea), where their cell concentrations at these periods exceed $1\times10^6\;cells\;l^{-1}$.

• Journal of Korean Society on Water Environment
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• v.29 no.3
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• pp.428-437
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• 2013

Physico-chemical water quality parameters and the phytoplankton communities from 12 sites in Oship-stream, Songchunstream, and Namdae-stream, located Gyeongsangbukdo Uljin-gun, Yeongdeok-gun, and Pyeonghae-eup respectively, were investigated from April 2009 to February 2010. Oship-stream, which is an open estuary, was easily affected by ocean current compared to that of Songchun-stream and Namdae-stream. OS3 and OS4 conductivity was higher with a season average of 3,397 ${\mu}s/cm$. The streams were mesotrophic to hypertrophic. Biological oxygen demand (BOD) was about 3mg/L, which was level 2 on the water quality ratings, but a concentration of 5mg/L in April 2009 indicated increased pollution due to drought. A total of 118, 117, and 124 phytoplankton taxa were found in Oship-stream, Songchun-stream, and Namdae-stream, respectively. The apparent dominant species in the polluted waters included Cryptomonas ovata, Fragilaria construens var. venter, Oscillatoria limnetica, O. limosa, and Phormidium tenue. All of Oship-stream, SC2 and SC4 of Songchun-stream, and ND3 of Namdae-stream were eutrophic as a result of standing crop analysis. BOD was highly correlated with chlorophyll-a content(r=0.52). Phosphorus concentration and proliferation of phytoplankton were thought to most affect BOD concentration in all three streams.