• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.2
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• pp.198-203
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• 1999

Gonadal development and reproductive cycle off Gomphina melanaegis collected in the coastal waters of Chumunjin, Korea were investigated monthly from April 1996 to April 1997. G. melanaegis was dioecious, The gonads were located between the digestive diverticula and muscle tissues of the foot, The ovary was composed of a number of ovarian sacs, and the testis was composed of several testicular tubules. The flesh weight rate was reached the maximum in August ($23.0\%$), and then decreased to $19.8\%$ in September. In March, the value was reached the minimum ($17.8\%$) and then increased, The size of mature oocyte was ranged $50\~60\mu$m in diameter and had a germinal vesicle with a nucleolus. Mature oocyte contained a large number of yolk granules and lipid granules in its cytoplasm. The spermatozoon was consisted of a conical nucleus with acrosome, a middle piece containing four mitochondria and proximal and distal centrioles, and a flagellum, Sex ratio (male/female) and minimum size for sexual maturation of G. melanaegis were 0.79 and about 25 mm in shell length, respectively. The reproductive cycle could be classified into five succesive stages: multiplicative (December to March), growing (April and May), mature(June), sprawning (July and August), and degenerative and resting (September to November) stages.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.4
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• pp.303-309
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• 1990

To provide essential information of the role of marine bacteria on the dinoflagellate blooms, distribution of marine bacterial flora and dinoflagellate species was investigated in Chinhae Bay located in southern part of Korea from August 1989 to April 1990. Two hundred and fifty one strains of marine bacteria were isolated from seawater samples collected from the study area. Among them, Flavobacterium spp. and Acinetobacter spp. were the most dominant in bacterial flora. Another 32 strains which comprised 13 percent of total strains were Erythrobacter spp.. Based on the physiological character, Erythrobacter spp. were identified as Erythrobacter longus, Erythrobacter sp.(J-2) and Erythrobacter sp. (J-8). From the phytoplanktonic community, fourteen genera and twenty nine taxa of dinoflagellate species were identified. Based on the spatio-temporal frequence and abundance Gymnodinium sanguneum, Prorocentrum micans and Prorocentrum minimum were the aestival dominent species. However, Heterocapsa triquetra was appeared as predominant species in April. Cell density of about 2,000 cells/ml was prevailed in the bloom of August, but it developed into more intensive bloom of above 500 cells/ml in September. The water quality showed eutrophic or hypereutrophic condition, which was proved by high concentration of dissolved inorganic nitrogen, ortho-phosphate and chemical oxygen demand. Oxygen deficient water mass was found in the bottom overlying waters in August and September. High relationship between abundant bacterial flora and persistent dinoflagellate blooms in eutrophic condition would be approvable.

• Spatial Information Research
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• v.22 no.5
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• pp.99-107
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• 2014

The purpose of this study is to formulate various improved working schemes in determining the definition of non-permissible activities to strengthen the practical implementation and operation of the integrated coastal management plan for regional self-governing authorities In this study, non-permissible activities indicate any activities which should be restricted according to the coastal functions of five different sectors in the regional plan for coastal management. Coastal management plan, are classified into four areas along the coast to use direction. It prohibited and support matters of another coastal exploitation each area. If you want to set the coastal area, has already been specified in the regional and global based on that region Land use planning and urban planning. When additional area settings in some cases may lead to conflicting results. Analyzes the factors to consider about the range and use areas set of in coastal management, It is necessary to strive for deriving a scheme to solve the existing contradiction between the state of the local - area specified problem. With the help of marine spatial planning and pointed out institutional and urban planning system to be utilized in land in the ocean for a more accurate and efficient coastal management, and registered the coastal areas, there is a need to manage. Land -use planning, consideration of another consultation body organization that is able to develop a plan that was comprehensive and marine spatial planning, The contradiction consider to specify the various areas and regions where other specific identification method is determined, Setting the range of coastal waters (within 3 nautical mile), I was exploring the coast registration scheme and registration target, etc.

• Journal of the Korean earth science society
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• v.35 no.2
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• pp.97-103
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• 2014

An isotopic hydrograph separation technique has been able to determine the contribution of new water (event water such as rain or snowmelt) and old water (pre-event water like groundwater) to a stream hydrograph for last several decades using stable water isotopes. It is based on the assumption that the isotopic compositions of both new water and old water at a given instant in time are known and the stream water is a mixture of the two waters. In this study, we show that there is a systematic error (standard error in the new water fraction) in the isotopic hydrograph separation if the average isotopic compositions of new water were used ignoring the temporal variations of those of new water. The standard error in the new water fraction is caused by: (1) the isotopic difference between the average value and temporal variations of new water; (2) the new water fraction as runoff contributing to the stream during rainfall or spring melt; and (3) the isotopic differences between new and old water (inversely). The standard error is large, in particular, when new water dominates the stream flow, such as runoff during intense rainfall and in areas of low infiltration during spring melt. To reduce the error in the isotopic hydrograph separation, incorporation of fractionation in the isotopic composition of new water observed at a point should be considered with simultaneous sampling of new water, old water and stream water.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.383-386
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• 2005

CCW(China Coastal Water) is different each year. It appears clearly from June to October in the neighboring sea of Jeju island. It appears in June, and it's strong most in August, after tat disappears in October. CCW appeared clearly at 1996 and 1999 during investigation period(1995 to 1999). SLA and SST appear annual variations(about 365day), semi-annual variations(about 180day) from power spectral density. After PCA(Principal component analysis), it's different. PCA of SLA shows 43day variations and PCA of SST shows 259day variations. SLA and SST appear annual variation, semi-annual variation and seasonal variation from power spectral density. SLA appeared that summer and fall of 1996 and 1999 is higher than other years. It seem to be being the relationship which is close with the severe rain strom. Temperature distribution of sea surface according to season is different, but clearly water temperature boundary divides this area into Yellow Sea and East China Sea. It considered that CCW follow according to boundary of temperature. The variation which it follows at time of SLA and SST is faster about one month to three month at Yangtz.

• Development and Reproduction
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• v.10 no.3
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• pp.177-184
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• 2006

Retinol-binding protein(RBP) plays an important role in the specific transport of retinol to target cells through the blood stream in higher vertebrates. In order to clarify the effects of 4-nonylphenol(4-NP) on RBP mRNA expression in the rockfish, Sebastes schlegeli which is common in coastal waters of Korea and commercially important species, the cDNA library was constructed from the liver, and a partial fragment of the RBP gene was cloned. The deduced amino acid sequence from the RBP mRNA showed a high homology to the amino acid sequence from Sparus aurata(80%), Oncorhynchus mykiss(72%) or Anguilla anguilla(78%). Effects of 4-NP on RBP and vitellogenin(VTG) mRNA expression level in rockfish were examined by the northern blot analysis. In female and male rockfish injected with 4-NP(10 mg/kg BW, lower dose), there was no changes in the levels of VTG mRNA expression in the liver. The RBP mRNA levels, however, decreased at 48 hours after the injection in male. In the rockfish injected with 4-NP(25 mg/kg BW, higher dose), the level of VTG mRNA expression increased after 24 hours, regardless of sex. The level of RBP mRNA expression decreased at 48 hours after the injection in both sexes. These data indicate that estrogenic mimics such as 4-NP exhibit a contrasting effect on RBP and VTG gene expression in rockfish.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.2
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• pp.101-108
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• 2013

Ara Canal is the first artificial canal in Korea that connects the Han River and the Yellow Sea. Due to mixture of waters with different salinity and water quality, complicated hydrodynamic and water quality distributions are expected to occur inside the canal. An integrated hydrodynamic and water quality modeling system was developed using the 3 dimensional hydrodynamic model, EFDC (Environmental Fluid Dynamics Code) and the water quality model WASP (Water Quality Analysis and Simulation Program). According to the modeling results, BOD, TN, TP and Chl-a concentrations inside the canal were lower at the West Gate side than the Han River side since influent concentrations of the West Gate side are significantly lower. Chemical stratification due to salinity difference were more evident at the West Gate side as vertical salinity difference were more pronounced in this area. On the other hand, Chl-a concentrations showed more pronounced vertical distribution at the Han River side as Chl-a concentrations were higher in this area. It was notable that Dissolved Oxygen concentrations can be lower than 2 mg/L occasionally in the middle part of the canal. While major factor affecting DO concentrations in the canal are inflows via both gates, the other important factor was found to be BOD decay in the canal due to extended hydraulic residence time. This study can be used to predict hydrodynamic conditions and water quality in the canal during the year and thus can be helpful in the development of gate operation method of the canal.

• Korean Journal of Environmental Biology
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• v.32 no.1
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• pp.75-87
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• 2014

This study describes about the spatio-temporal distributions in phytoplankton community such as species composition, standing crop and dominant species from May 2006 to February 2007 in the Jangsu bay and the northwestern parts of Gamak bay. Based on the principal component analysis (PCA) of the environmental factors as well as biological parameters, the bio-oceanographical characteristics were analysed. A total of 83 species of phytoplankton belonging to 47 genera were identified. Whereas diatoms and dinoflagellates occupied more than 65% and 30% of total species, respectively. The annual dominant species were Chaetoceros affinis, Paralia sulcata and Bacillaria paxillifera in spring, Chaetoceros didymus, Ch. affinis and Octactis octonaria in summer, Skeletonema costatum-like species and B. paxillifera in autumn. Moreover phytoplankton cell density was ranged between 3.1 $cells{\cdot}mL^{-1}$ in spring and 521.0 $cells{\cdot}mL^{-1}$ in winter. It fluctuated with an annual mean of 76.0 $cells{\cdot}mL^{-1}$ between the lowest value of 7.6 $cells{\cdot}mL^{-1}$ in spring and the highest value of 220.2 $cells{\cdot}mL^{-1}$ by Skeletonema costatum-like species in winter. Briefly, the phytoplankton cell density in the mixing seasons was higher in comparison with the other seasons. According to the PCA, the biological oceanographic characteristics of the Jangsu bay was affected by the introduction of outside seawater particularly in temperature increasing seasons, and the other seasons, it may be described the light intensity, and mix between inner and outer bay sea waters.

• Journal of Preventive Medicine and Public Health
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• v.22 no.4 s.28
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• pp.495-505
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• 1989

This study was conducted as a nationwide survey In Korea to determine the THM (trihalomethane) concentration levels in the drinking water of 14 selected cities. The survey was underdtaken in one city (Kwangju) during September and October of 1988 and 14 cities in January through February of 1989. The results were as follows : 1. The $KMnO_4$ consumption was 10.6mg/l-11.6mg/l in Pusan and Ulsan, exceeding the drinking water standard of 10mg/l. Pusan, Inchon, Kwangju, Ulsan, Mokpo and Junju areas also exceeded the ammonia nitrate standard of 0.5mg/l. Other tap waters surveyed were detected below the drinking water standards. 2. The THM concentrations of tap water measured in January and February of 1989 were detected in the range $1.20{\mu}g/l-150.8{\mu}g/l$. 3. In the comparative study of the THM concentration of tap water measured in the Kwangju area during September and October of 1998, the average THM concentation of $145.63{\pm}70.72{\mu}g/l$ showed a sixfold increase compared to that of $23.8{\pm}8.31{\mu}g/l$ surveyed in January and February 1989. 4. The proportion of the four THM compounds found in tap water was bromoform, 47% ; chloroform, 30% ; chlorodibromomethane, 13% ; and dichlorobromomethane, 10%. 5. Since the results indicate that the concentration of bromoform was 2-10 times higher than that of chloroform measured in the seaside district of Pusan, Ulsan and Cheju Island, it is reasonable to assume that the raw water was somehow Influenced by seawater. 6. The average lifetime cancer rate of the population exposed to chloroform measured in the surveyed areas was 17 cancer incidences per 1 million population. From the above results, the existence of THM in the distribution systems seems to be inevitable, since chlorine disinfection is performed in water treatment plants In our country. There seems to be a trend of increasing. THM cncentrations due to the contamination of raw water. In order to establish my form of regulations, health risk assessment is an imminent subject.

• Korean Journal of Ecology and Environment
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• v.36 no.2 s.103
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• pp.108-116
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• 2003

To investigate bacteria with algal Iytic activities against Anabaena cylindrica when water blooming occurs and to study enzyme profiles of alga-Iytic bacteria, various bacterial strains were isolated from surface waters and sediments in eutrophic lakes or reservoirs in Korea. Abacterial strain AK-07 was characterized and identified as Acinetobacter johnsonii based on its16S rDNA base sequence. When AK-07 was co-cultivated with A. cylindrica, bacterial cells propagated to $8\;{\times}\;10^8$ cfu $ml^{-1}$ and Iyses algal cells. However, culture filtrates of AK-07 did not exhibit algal Iytic activities. That suggesting the enzymes on the surfaces of the bacterium might be effective algal Iytic agents to cause Iyses of cells. Acinetobacter johnsonii AK-07 exhibited high degradation activities against A. cylindrica, and formed alginase, caseinase, lipase, fucodian hydrolase, and laminarinase. Moreover, glycosidases for example ${\beta}$-galatosidase, ${\beta}$-glucosidase, ${\beta}$-glucosaminidase, and ${\beta}$-xylosidase, which hydrolyzed ${\beta}$-0-glycosidic bonds, were found in cell-free extracts of A. johnsonii AK-07. Other glycosidase such as ${\alpha}$-galctosidases, ${\alpha}$-N-Ac-galctosidases, ${\alpha}$-mannosidases, and ${\alpha}$- L-fuco-sidases, which cleavage ${\alpha}$-0-glycosidic bondsare not detected. In the results, enzyme systemsof A. johnsonii AK-07 were very complex to do-grade cell walls of cyanobacteria. The polysaccharides or peptidoglycans of A. cylindrica maybe hydrolyzed and metabolized to a range of easily utilizable monosaccharides or other low molecular weight organic substances by strain AK-07 of A. johnsonii.