• Journal of the Korean Society for Marine Environment & Energy
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• v.17 no.2
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• pp.153-165
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• 2014

Carbon dioxide capture and storage (CCS) technology is recognizing one of method responding the climate change with reduction of carbon dioxide in atmosphere. In Korea, due to its geological characteristics, sub-seabed geological $CO_2$ storage is regarded as more practical approach than on-land storage under the goal of its deployment. However, concerns on potential $CO_2$ leakage and relevant acidification issue in the marine environment can be an important subject in recently increasing sub-seabed geological $CO_2$ storage sites. In the present study effect data from literatures were collected in order to conduct an effect assessment of elevated $CO_2$ levels in marine environments using a species sensitivity distribution (SSD) various marine organisms such as microbe, crustacean, echinoderm, mollusc and fish. Results from literatures using domestic species were compared to those from foreign literatures to evaluate the reliability of the effect levels of each biological group and end-point. Ecological effect guidelines through estimating level of pH variation (${\delta}pH$) to adversely affect 5 and 50% of tested organisms, HC5 and HC50, were determined using SSD of marine organisms exposed to the $CO_2$-induced acidification. Estimated HC5 as ${\delta}pH$ of 0.137 can be used as only interim quality guideline possibly with adequate assessment factor. In the future, the current interim guideline as HC5 of ${\delta}pH$ in this study will look forward to compensate with supplement of ecotoxicological data reflecting various trophic levels and indigenous species.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.18 no.4
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• pp.206-213
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• 2013

Glass eels (Anguilla japonica) are caught in the west coast of Korea on their migratory route from the breeding grounds in the Mariana Trench along the North Equatorial Current and the Kuroshio Current. To identify the food source of natural glass eels, we analyzed the stable C and N isotopes of glass eels caught in April 2012 and investigated possible food sources in the survey area. In particular, with respect to the stable C and N isotopes of particulate organic matter, we extended the surveying area to the northern parts of East China Sea as well as the west coast of Korea. The stable C and N isotope ratios of the glass eels caught in the west coast were found to be $-20.7{\pm}0.1$‰ and $5.0{\pm}0.2$‰, respectively. The stable C and N isotope ratios of the particulate organic matter in the west coast of Korea, in which the glass eels are assumed to eat the particulate organic matter as food source, were estimated to be $-24.0{\pm}0.3$‰ and $2.8{\pm}0.4$‰, respectively. Similar data were obtained from the northern part of the East China Sea, $-24.5{\pm}0.5$‰ and $0.8{\pm}0.3$‰. The stable isotope ratios showed values differing from the stepwise increasing rates up the food web in natural aquatic ecosystem, showing that particulate organic matter in the west coast of Korea and East China Sea was not served as the glass eels food source. This result suggested that the glass eels caught in the west coast might not assimilate nutrition from the marine environment during long migration.

• Journal of Environmental Impact Assessment
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• v.27 no.6
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• pp.548-561
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• 2018

The objectives of this study were to construct a three-dimensional (3D) hydrodynamic and water quality model (EFDC) for the river reach between the Daecheong dam and the Sejong weir, which are directly affected by Gap and Miho streams located in the middle of the Geum River, and to evaluate the trophic status and water quality improvement effect according to the flow control and pollutant load reduction scenarios. The EFDC model was calibrated with the field data including waterlevel, temperature and water quality collected from September, 2012 to April, 2013. The model showed a good agreement with the field data and adequately replicated the spatial and temporal variations of water surface elevation, temperature and water quality. Especially, it was confirmed that spatial distributions of nutrients and algae biomass have wide variation of transverse direction. Also, from the analysis of algal growth limiting factor, it was found that phosphorous loadings from Gap and Miho streams to Sejong weir induce eutrophication and algal bloom. The scenario of pollutant load reduction from Gap and Miho streams showed a significant effect on the improvement of water quality; 4.7~18.2% for Chl-a, 5.4~21.9% for TP at Cheongwon-1 site, and 4.2~ 17.3% for Chl-a and 4.7~19.4% for TP at Yeongi site. In addition, the eutrophication index value, identifying the tropic status of the river, was improved. Meanwhile, flow control of Daecheong Dam and Sejong weir showed little effect on the improvement of water quality; 1.5~2.4% for Chl-a, 2.5~ 3.8% for TP at Cheongwon-1 site, and 1.2~2.1% for Chl-a and 0.9~1.5% for TP at Yeongi site. Therefore, improvement of the water quality in Gap and Miho streams is essential and a prerequirement to meet the target water quality level of the study area.

• Korean Journal of Ichthyology
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• v.34 no.3
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• pp.179-185
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• 2022

The feeding habits of Largehead hairtail Trichiurus japonicus was studied using 377 specimens collected in the Yellow Sea of Korea. The specimens ranged from 4.5 to 33.7 cm in Anal length (AL). T. japonicus consumed mainly a piscivore, such as Engraulis japonicus [percent index of relative importance (%IRI) =74.1%]. We calculated the trophic level as 3.84 for T. japonicus. Fishes were the main prey items for all seasons. The main fish prey during autumn and winter was E. japonicus, whereas those during spring and summer was Larimichthys polyactis. Fishes were the main prey items for all size groups (<15 cm, 15~20 cm, 20~25 cm, ≥25 cm). T. japonicus also showed size-related dietary shift from Spratelloides gracilis and E. japonicus to L. polyactis and T. japonicus. As the anal length of T. japonicus increased, the mean number of preys per stomach (mN/ST) and the mean weight of preys per stomach (mW/ST) tended to increased (One-way ANOVA, P<0.05). Seasonal and size-related shifts in dietary composition were investigated by PERMANOVA analysis, which showed significant variations among size classes and seasons.

• Korean Journal of Ichthyology
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• v.35 no.4
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• pp.354-360
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• 2023

The diet composition of Tanaka's snailfish, Liparis tanakae were collected by bottom trawl net in the Yellow Sea of Korea during 2022 (April, August, October, and November). The size of the specimens ranged from 3.8 to 52.2 cm in total length. L. tanakae were primary consumed caridea shrimps (Crangon hakodatei, Eualus spathulirostris, etc.) and specialist feeder mainly consumed caridea shirmps (C. hakodatei). The L. tanakae's trophic level is 3.63. Caridea shrimps were the primary prey items for all size groups (<20 cm, 20~30 cm, 30~40 cm, ≥40 cm). The proportion of E. spathulirostris has increased as the body size of L. tanakae increased, whereas the proportion of C. hakodatei decreased gradually. As the body size of L. tanakae increased the mean weight of prey per stomach (mW/ST) tended to increase significantly (One-way ANOVA, P<0.05). The caridea shrimps were the primary prey items throught all seasons. In summer, the main prey items were the C. hakodatei, however, in autumn, the proportion of C. hakodatei decreased while the proportion of E. spathulirostris increased.

• Korean Journal of Agricultural Science
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• v.9 no.1
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• pp.303-313
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• 1982

The study was conducted to find out the concentrations of sex hormones and the contents of metabolites in serum, and the changes of weights and tissues on ovary, thyroid gland and adrenal gland according to gestation period in rabbit. The results were summarized as follows: 1. The ovary weights were increased significantly with the time e lapse after gestation and recovered normally at 5 days after parturition. In the histological changes of ovary, the lutein cells were hypertrophied and the secretory granules were increased actively until 3 weeks after gestation, and then a trophied thereafter. 2. The thyroid gland weights at all observation times were higher than those in control group, and the significance was recognized at 1, 3 and 4 weeks after gestation. The histological features of the secretory epithelium were the hyper trophic and columnar condition stimulating the functional state from 1 week after gestation. 3. The adrenal gland weights in experimental group were recognized significantly at 4 weeks after gestation, but showed higher than those in control group at all observation times. The zona fasciculata and zona reticularis of the gland showed the slight hypertrophic condition, but the zona glomeerulosa and adrenal medulla did not find out any particular changes. 4. The serum concentrations of progesterone and LH reached a peak level at 2 weeks and 1 week after geestation respectively, and rapidly began to decline thereafter. 5. The serum concentrations of estradiol-$17{\beta}$ and FSH were not detected below 20.0 pg/ml and 1.3 mIU/ml respectively. 6. The contents of total protein and non-protein nitrogen nitrogen were decreased gradually with the time elapse after gestation, but the significant differences were recognized from 3 weeks. 7. The total lipids were not changed markedly until 3 weeks, but increased significantly at 4 weeks after gestation and at 5 days after parturition. 8. The serum cholesterol tended to be decreased until 3 weeks, but increased at 4 weeks after gestation and at 5 days after parturition. 9. The serum calcium showed a continuous decrease during the gestation period, but the significant differences were recognized at 3 and 4 weeks. The serum phosphorus also had a significant decrease at 4 weeks after gestation.