• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.5
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• pp.759-770
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• 1997

The general flow patterns in the Cheju Strait have been investicated by analyzing the current observations measured in $1986\~1989$ by current meter mooring in 3 north-south sections in the Cheju Strait and at 4 observation points around Cheju Harbour, and measured in $1981\~1987$ by drogue tracking. 1. In the Cheju Strait, there are eastward or northeastward residual currents, which implies that sea waters flow into through the whole western section and flow out through the whole eastern section in the Cheju Strait. The velocity of residual currents are $5.2\~30\;cm/sec$ in 10 m layer and $1.3\~24cm/sec$ in mid-bottom layer. Generally, the flow is strong along the deepest through and the northern part, and weak in the shallow areas near Chuja Islands and Bogil Island. 2. In the western entrance of the Cheju Strait, the observed mean residual velocity is 6.93 cm/sec and the volume transport is 0.384 Sv. There are a big discrepancy between the observed residual currents and the geostrophic currents. 3. Near the frontal areas northwest to Chuja Islands, warm and saline offshore waters, flow northward about 5 miles into the southern coastal areas of the Korean Peninsula in flood, and flow back rather eastward or southeastward than southward in ebb. So, warm and saline waters flow along coastal areas, being mixed with coastal waters. As a result, the northwestern area of Chuja Islands plays a role of the entrance of influx of warm and saline offshore water to the southwestern coastal areas of the Korean Peninsula. It should be stressed that this flow pattern is not due to the residual flows, but to the temporal (tidal) flows.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.2
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• pp.106-117
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• 2006

We measured the concentrations of organic matter and metallic elements (Al, Fe, Cr, Mn, Ni, Cu, Zn, As, Cd, Pb and Hg) in the surface sediments of Masan Harbor (in the southern sea, Korea) to evaluate the geochemical characters of sediment and the pollutions by organic matter and metallic elements. The mean grain size of the surface sediments in the study area ranged from $5.6{\phi}$ to $7.8{\phi}$, indicating silt sediment. The water content of the surface sediments exceeded 60% except at some stations. The contents of ignition loss (IL), total organic carbon (TOC) and total nitrogen (TN) ranged from 7.2-14.3%, 1.2-3.2%, and 0.10-0.28%, respectively. Based on the C/N ratios, the organic matter in the surface sediments of Masan Harbor may originate from terrigenous sources including fluvial inputs (mainly sewage in urban areas). The chemical oxygen demand (COD) and acid volatile sulfide (AVS) ranged from $11.3-29.9\;mgO_2/g\;dry$ and 0.20-4.47 mgS/g dry, respectively, and low concentrations were observed near a shipping route. In addition, the concentrations of metallic elements showed large spatial variations in Masan Harbor and the distributions of metallic elements were also comparable to those of organic matter. This implies that the distributions of organic matter and metallic elements in the surface sediments of Masan Harbor are mainly controlled by biogenic matter and artificial action (mainly dredging). In addition, we calculated the enrichment facto. (EF) and geoaccumulation index (Igeo) in order to evaluate pollution by metallic elements. The enrichment of metallic elements relative to Al was three to eighteen times higher at the study sites, compared to levels in the Earth's crust except for Fe, Ni and Mn. In addition, the Igeo class indicated that the surface sediments in the study area were moderately to strongly polluted in terms of metallic elements.

• Korean Journal of Ecology and Environment
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• v.46 no.3
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• pp.367-379
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• 2013

The distribution of Coreoperca kawamebari was known to be restricted to the Tamjin River and several small streams flowing into the southern part of the West Sea, while C. herzi was widely distributed throughout South Korea except the areas inhabited by C. kawamebari: the two species were known to be allopatric. However, we found that both species were sympatric in the Boseong River, a tributary of the Seomjin River, and the Jiseok Stream, a tributary of the Yeongsan River. Local-scale distribution of the two Coreoperca species, fish assemblages, and environmental variables were surveyed to investigate effects of environmental factors on fish community structures in the Boseong River. Rank abundance distribution of fish community at the study sites indicated that fish species diversity and distribution pattern of the two Coreoperca species were closely related to habitat diversity. The result of canonical correspondence analysis showed that C. kawamebari was distributed in pool areas while C. herzi was found in the areas with higher water velocity and boulder substrate. These results suggested that species diversity of fish community decreased and only one of the two Coreoperca species inhabited at the sites with less diverse habitat, but on the other hand, high habitat diversity increased species diversity and allowed the two species to coexist.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.2
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• pp.127-135
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• 1999

Grain-size distribution and accumulation rate of surface sediments on the tidal flats in Hampyong Bay, southwestern coast of Korea, were investigated in a sequential interval of 2 months for the period of 27 months (1994. 10~1996. 12). Seasonal variation of grain-size distribution is prevalent on the Shimock tidal flat in the southern side of the innerbay, rather than the Anarc tidal flat in the northern side around the baymouth. This variation, in particular, more distinctive in the areas around the both high and low tide water levels. The Shimock tidal flat shows typical seasonal variation of sedimentary processes, expected under monsoonal climate. Deposition of tine-grained sediments in summer dominates over erosion in winter, resulting in an annual accumulation rate of 3.7 mm/yr. In contrast, sedimentary processes on the Anarc tidal flat is abnormal that have experienced slight deposition of fine-grained sediments in the winter and severe erosion in the summer time, showing a negative annual accumulation rate of -49.6 mm/yr. Erosional processes in this area is interpreted due mainly to change of strength and direction of tidal currents, caused by the artificial construction of dyke for reclamation in the mid-tidal flat. As a result, It is immoderate to conclude whether sedimentary processes of Hampyong Bay is erosional or depositional at current situation. Further studies on sedimentary budget at the entrance to the bay are needed.

• Korean Journal of Microbiology
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• v.52 no.3
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• pp.313-318
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• 2016

Bacteria in the viable but nonculturable (VBNC) state fail to produce colonies on routine bacteriological media, but are still alive in the state of very low metabolic activity. The aim of the present study was to induce the VBNC state of the Edwardsiella tarda using sea water microcosm under starvation conditions at $10^{\circ}C$ and to investigate resuscitation of the VBNC cells in temperatures changed from 10 to $25^{\circ}C$, with and without additives. E. tarda entered into the VBNC state within about 42-84 days of incubation in the microcosm. Throughout this period, the total cell counts as determined using acridine orange direct counting remained near the original inoculum level of ${\sim}10^8cells/ml$. The live cell counts measured with direct viable counting, on the other hands, declined to ${\sim}10^4cells/ml$. When the VBNC cells were incubated with addition of yeast extract, fish muscle extract or serum at $25^{\circ}C$, the ratios of resuscitated samples were 37%, 23%, and 37%, respectively. The characteristics of resuscitated E. tarda were consistent with those of the original E. tarda. When the resuscitated E. tarda were intraperitoneally injected into olive flounders, all fishes died within 5 days, indicating that the VBNC E. tarda might retain its pathogenic potential. Therefore, E. tarda under starvation conditions in the winter enter into the VBNC state and the VBNC E. tarda cells resuscitated at summer and autumn seawater temperature are considered to be pathogen continuously to olive flounder on the southern coast of Korea.

• Journal of the Korean association of regional geographers
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• v.2 no.2
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• pp.93-102
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• 1996

The Korean Peninsula is located on the east coast of monsoon Asia of the midlatitude, where the Pacific polar front moves. As a result variations of spatial and temporal distribution of precipitation occur. A great variation of precipitation during the summer months created frequent droughts and floods. The purpose of this study is to identify distributional characteristics and to analyze synopic characteristics of summer droughts in Korea. The research methods used are ; (1) to identify droughts based on the anomaly of monthly precipitation during summer of 1994. (2) to analyze correlations between drought and weather systems by using the calender of rain days. (3) to compare a synoptic mechanism of summer droughts with that of typical normal summer. The characteristics of summer droughts of 1994 may be summarized as follows ; 1) While most regions were affected by the droughts some regions displayed specific characteristics. The southern part of the Korean Peninsula was severely affected during the month of June. August droughts severely affected east part of the Sobek Mountains, thus showing that the droughts of June and August are highly localized. 2) In the pressure anomaly of surface field. the positive anomaly appears in June around Korean Peninsula, but in July when all parts of the South Korea were under severe droughts, the anomaly changes and becomes negative. 3) Extracyclones occurred less frequently in the summer of 1994. Those that did occur were located in areas far off the Korean Peninsula having little consequences on the drought patterns. 4) The trough of westerly wave at 500hPa height patterns in June is located far from the eastern sea of Korean Peninsula, but in July and August Korean Peninsula belongs to ridge of westerly wave. 5) In June the positive height anomaly at 500hPa surface appears zonally from Siberia to the western Parts of North Pacific Ocean, and in July and August, the strong positive anomaly appears around Korean Peninsula. As a result the zonal index of westerlies at during each month of summer in Korean sector has a large value, which in turn implies that drought will prevails when zonal flow is strong.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.25 no.4
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• pp.255-265
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• 2013

In the coastal region of Korea, historical tide harmonic constants were collected. Long-term tides and short-term tides observed by the KHOA were analyzed by a tide harmonic analysis method. Based on the harmonic constants, tidal characteristics such as tide asymmetry in Korean coastal waters were investigated. The harmonic constants obtained from the long-term tide data in the western coast have been used to show the relation between tide variation and reclamation project. $M_2$ amplitudes in the western coast have been decreased and $M_2$ phases were faster. $M_4$ amplitudes also were reduced and $M_4$ phases were faster in overall. In Mokpo and Kunsan tidal nonlinearity is relatively conspicuous. Overall, non-linearity of tidal currents is higher in the tidal channels flowing fast. The tidal non-linearity has increased by the development projects including large reclamation. The flood dominant characteristic in the northern and central part of Korean western coastal waters and the ebb dominant characteristic in the southern part have been intensified. The construction of Saemangeum sea dike has significantly changed the tidal characteristic in Korean western coastal waters.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.37 no.4
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• pp.267-274
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• 2001

A prototype experiment on the anchovy boat seine was carried out in the southern sea of korea to analyze the vertical opening and the underwater geometry. The vertical opening and the underwater geometry of the prototype net were determined by distance of Minilog position with the combinations of the distance between paired boats and the towing speed. The results osbtained can be summarized as follows; 1. Vertical opening of the protype net was gradually lowered according to the increase of the distance between paired beats and the towing speed. 2. Vertical opening of Wing net, Inside wing net, Square, Fore bag net, Flapper and After bag net of the prototype net according to the distance between paired boats were varied in the range of 8.4~9.0, 15.7~17.4, 12.9~17.9, 13.6~19.0, 8.3~8.4, 11.1~14.7m respectively, varied in the range of 12~16, 22~24, 27~38, 59~83, 92~93, 41~54% of the normal opening respectively. 3. Vertical opening of Wing net, In side wing net, Square, Fore bag net, Flapper and After bag net of the prototype net according to the towing speed were varied in the range of 7.7~10.5, 19.6~21.6, 12.2~16.9, 15.4~17.1, 8.0~8.2, 13.7~14.7m respectively, varied in the range of 14~19, 27~30, 32~36, 67~74, 89~91, 51~54% of the normal opening respectively. 4. Prototype net was appeared apparent the pocket shape, because Wing net and Inside wing net was opened 20% of the normal opening. 5. Working depth of the prototype net was gradually shallow according to the increase of the distance between paired boats and the towing speed.

• Journal of Korean Society for Geospatial Information Science
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• v.22 no.3
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• pp.129-136
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• 2014

This study deals with red tide detection by using the remote sensing imagery from the Geostationary Ocean Color Imager (GOCI), the world's first geostationary orbit satellite, around the southern coast of Korea where the most severe red tide occurred recently. The red tide zone was determined by the available data selection from the GOCI imagery during the period of red tide occurrence and also the severe red tide zone was detected through the spatial analysis by temporal change out of the red tide zone. This study results showed that the coast in the vicinity of the Hansan and Yokji in Tongyeong-si was classified into the severe red tide zone, and that the red tide was likely to spread from the coast of Hansan and Yokji to the one of Sanyang-eub. In addition, the comparative analysis between the area of red tide occurrence, the prevention activities of Gyeongsangnam-do provincial government and the amount of the damage cost over time showed close correlation among them. It is still early to conclude that the study is showing the severe red tide zone and the spread path exactly due to various factors for red tide occurrence and activities. In order to improve the reliability of the results, the more data analysis is required.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.3
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• pp.198-207
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• 1990

Among the biodegradable liquid waste treatment and disposal methods, ocean dumping is a cost-effective and productive manner considering reuse point of view However, when biodegradable liquid waste is dumped in the ocean, oxygen consumption by the decomposition of organic matter must be considered. The purpose of this study is to determine the maximum allowable concentration and dumping rate in the southern waters of the East Sea based on dissolved oxygen level. Streeter and Phelps' model has been used to determine the maximum allowable concentration. Factors in this model, deoxygenation constants and reaeration coefficients, have been determined by appling oxygen consumption method and closed system model. Deoxygenation constants and reaeration coefficients from surface to each standard depth are $0.24\~0.29/day\;and\;0.03\~0.39/day$ in summer, $0.17\~0.20/day\;and\;0.04\~0.56/day$ in winter, respectively. The allowable organic matter concentration($mgBOD/\iota$) to the dissolved oxy-gen sag value of $5mg/{\iota}$ is represented $17.23\times(H)^{-0.37}$ in summer, and $64.96\times(H)^{-0.52}$ in winter by mixing depth(H, m). Csanady's experiment has been applied to estimate the optimum dumping rate. The optimum dumping rate($R,\;m^3/sec$) can be written as a product of the beam(b, m) and the draft(h, m) of vessel, and biochemical oxygen demand of waste($L_n,\;mg/{\iota}$) $R=275{\times}bh^{0.63}L_n^{-1}$ in summer $=745{\times}bh^{0.48}L_n^{-1}$ in winter. The difference of dumping rate between in summer and winter is due to the oxygen distribution.