• 수산해양기술연구
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• 제7권1호
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• pp.8-8
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• 1971

Oceanography of the Subarctic North Pacific Ocean is reviewed. The submarine topography and the current systems in the region are explained. Recent serial observation data reveals that. though the upper mixed layer of low salinity is relatively thick. the pattern of the property distribution in winter is essencially similar to that in summer. Alaskan Stream Extension Water. which influences the abundance and the location of demersal fishes. extends northward to 58${\circ}$ N Lat in the Bering Sea. A southeastward intrusion of the Bering Borcal Cold Water causes the formation of a sharp oceanic front. where the demersal fishes such as Alaska pollacks and cods arc concentrated. The Alaska pollacks seem to avoid the low salinity water of the Alaskan Coastal Water.

• Ocean and Polar Research
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• 제30권4호
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• pp.379-399
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• 2008

Spatial-temporal variations in physiochemical water qualities (temperature, salinity, DO, SPM, POC and nutrients) of surface and bottom waters were investigated along the mid-western coastal area (Taean Peninsula to Gomso Bay) of Korea. Spatial distribution patterns of temperature and salinity were mostly controlled by the physical mixing process of freshwater from Geum River and/or Gyunggi Bay with nearby coastal water. A strong tidal front is formed off Taean Peninsula during spring and summer. Seasonal variations in nutrient concentrations, lower in spring and summer and higher in fall and winter, are primarily regulated by magnitude of phytoplankton occurrence rather than freshwater loadings into the bay. Based on seasonal and spatial variability of physicochemical parameters, water quality of the study area can be divided into four water masses; Gyunggi Bay-influenced Water Mass (GBWM), Geum River-influenced Water Mass (GRWM), Yellow Sea Bottom Cold Water Mass (YSBCWM) and Cheonsu Bay Water Mass (CBWM). Water quality of the GBWM (Taean Peninsula coastal area), which has relatively low salinity and high concentrations of nutrients, is strongly controlled by the Gyunggi Bay coastal water, which is under influence of the Han River freshwater. In this water mass, the mixed layer is always developed by strong tidal mixing. As a result, a tidal front is formed along the offshore boundary of the mixed layer. Such tidal fronts probably play an important role in the distribution of phytoplankton communities, SPM and nutrients. The GRWM, with low salinity and high nutrients, especially during the flood summer season, is closely related to physiochemical properties of the Geum River. During the flood season, nutrient-enriched Geum River water mass extends up to 60 km away from the river mouth, potentially causing serious environmental problems such as eutrophication and unusual and/or noxious algal blooms. Offshore (<$30{\sim}40m$ in water depth) of the study area, YSBCWM coupled with a strong thermocline can be identified in spring-summer periods, exhibiting abundant nutrients in association with low temperature and limited biological activity. During spring and summer, a tidal front is formed in a transition zone between the coastal water mass and bottom cold water mass in the Yellow Sea, resulting in intensified upwelling and thereby supplying abundant nutrients to the GBWM and GRWM. Such cold bottom water mass and tidal front formation seems to play an important role in controlling water quality and further regulating physical ecosystem processes along mid-western Korean coastal area.

• 한국수산과학회지
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• 제35권1호
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• pp.46-56
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• 2002

황해남부해역에 근원을 갖고 있는 저온 $\cdot$ 저염의 저밀도수가 춘계인 1998년 3월 중순부터 4월 초순까지 표층에서부터 약 20m층까지 분포하며 연취되는 북서계절풍에 편승하여 제주도 연안천해역으로 Ekman 수송되어 제주도 북부 연안천해역에 영향을 미쳤다. 따라서 이러한 자료의 축적을 통하여 해양환경의 Realtime monitoring을 위한 기초자료의 제공과 어$\codt$해황예보의 정도를 향상시킬 수 있는 중요한 자료를 제공하게 된다.

• Journal of Advanced Marine Engineering and Technology
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• 제38권2호
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• pp.208-216
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• 2014

In case of any coastal ocean near the mouth of huge rivers, low salinity water can be formed due to its large amount of freshwater discharge. For the acoustic analysis on the low salinity environment, some oceanographic data of the East China Sea and the Atlantic Ocean were collected through KODC (Korea Oceanographic Data Center) and NODC (National Oceanographic Data Center) online service. In this paper, the T-S gradient diagram is introduced to show a relation between the gradients of temperature and salinity in view of acoustic surface channel formation. Existence of haline channel, quantitative contribution of gradients of salinity and temperature, effectiveness of the channel formation can be known by the T-S gradient diagram. After applying the collected data into the diagram, tropical regions of the Atlantic Ocean show strong haline channel due to its nearly invariant temperature and drastic change of salinity with depth. The averaged transmission loss in the channel is about 5.7 ~ 7.5 dB less than that out of the channel by the results of acoustic propagation model (RAM: Range independent Acoustic Model). On the other hand, the East China Sea and temperate region of the Atlantic ocean have weaker haline channel with less difference of the averaged transmission loss between in and out of the channel as 3.2 ~ 6.0 dB. Although data samples used in this study have limitation to represent the general physical structures of the three ocean regions, the T-S gradient diagram is shown to be useful and acoustic field affected by low salinity environment is investigated in this study.

• 해양환경안전학회지
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• 제11권2호
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• pp.97-102
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• 2005

목포항 주변 해역의 6개 정점에서 1997년부터 2004년까지 수질의 계절 및 년간 변동에 대해 조사하였다. 염분, pH, 용존무기질소와 용존무기인은 년간 다양하게 나타났다. 염분은 1998년에 유의하게 나타났으나, 영양염 농도들은 1998년이 다른 년도보다 유의하게 높았다. 수온, DO, COD와 DIP의 농도는 계절 변동이 명확하게 나타났으며, 이러한 계절적인 변화는 영산강하구언에서 유입되는 담수의 계절적인 특징에 영향을 받았다. 수온, COD와 DIP는 8월에 유의하게 높았으나, 염분과 DO는 8월에 최소로 나타났다. 정점 1(영산강 하구언)의 수질은 영산강의 유입에 따른 낮은 염분과 높은 영양염의 특성을 보였으나, 정점 6(목포항 외해)은 주로의 외해의 특성을 보였다. 목포항 주변 해역에서 수질 인자간의 관계에서 염분은 COD, DO, pH, Chlorophyll a와 영양염 농도에 주요한 요인으로 나타났다.

• Ocean and Polar Research
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• 제34권1호
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• pp.37-51
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• 2012

We investigated the distribution and species composition of zooplankton in relation to hydrographical characteristics in the Korea Strait during the winter (February) and summer (July) of 2009. Satellite images of sea surface temperatures and in situ CTD data showed that the southeastern water zone (St3-5) off Jeju Island was strongly influenced by the Tsushima Current during both the winter and summer, whereas the Changjiang Diluted Water, characterized as water with relatively low salinity, was evident in the coastal waters of Jeju Island during the summer. During winter, zooplankton abundance was significantly higher than in the summer, with dominance by copepods, ostracods, siphonophorans, appendicularians, and nauplii. In both seasons, copepods represented >70% of the total zooplankton population. Calanus sinicus, a large calanoid copepod, was dominant in near the coast, and that may be associated with the intrusion of low salinity water (i.e., the Changjiang Diluted Water) along the coast. The abundance of P. parvus s.l. and A. omorii, known as neritic copepods, was mainly associated with the Korea Southern Coastal Water. Foraminiferans, Ostracods, O. plumifera, and P. aculeatus were concentrated in the southeastern water off Jeju Island during both seasons; showing their association with the Tsushima Current, which is characterized warm, high salinity water. Our results suggest that the distribution, abundance, and species composition of zooplankton are highly influenced by different water masses in the Korea Strait.

• 한국패류학회지
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• 제30권2호
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• pp.101-106
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• 2014

인공종묘로 생산된 동죽, Mactra veneriformis의 크기, 수온, 염분 변화에 대한 여수율과 먹이섭이량의 차이를 조사하였다. 수온의 경우 소형, 대형그룹의 여수율은 $5^{\circ}C$에서 최소값을 보였으며 $20^{\circ}C$에서 가장 높은 값을 보였으나, $25^{\circ}C$에서 급격한 감소 경향을 보였다. 염분에 대한 소형그룹의 여수율은 26‰에서 가장 높은 값을 보였고 8‰에서 가장 낮은 값을 보였다. 대형그룹은 32‰에서 가장 높은 값을 보였고, 8‰에서 가장 낮은 값을 보였다. 본 연구를 통해 동죽의 최적 수온, 염분 환경은 $20^{\circ}C$, 27-32‰이며, $10^{\circ}C$ 이하 또는 $25^{\circ}C$ 이상의 수온과 20‰ 이하의 저염분에서 여수율이 낮아진다는 사실을 확인할 수 있었다.

• Journal of the korean society of oceanography
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• 제34권1호
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• pp.43-48
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• 1999

The latest-Quaternary paleoceanographic history of the Ulleung Basin, the East Sea (the Sea of Japan) is reconstructed on the base of planktonic foraminifera, oxygen and carbon isotopes, and accelerator mass spectrometer radiocarbon (AMS-$^{14}$C) data from two cores. Sinistral populations of Neogloboquadrina pachyderma are dominant during the last glacial period while dextral forms of Neogloboquadrina pachydeyma are abundant in the Holocene. An abrupt increase in ${\delta}^{18}$O values in both cores that began about 11 ka B.P may indicate the Younger Dryas cooling episode. A low-salinity event, marked by light ${\delta}^{18}$O values (0-1 %), is observed before the Younger Dryas event. As previous works suggested, the low-salinity event is probably due to the freshening of surface water caused by fresh water input from Huang Ho river and/or the excess of precipitation over evaporation. The lowest salinity water in the Ulleung Basin was probably continued from approximately 18 ka B.P. to 15 ka B.P. The ${\delta}^{18}$O values have gradually decreased since the Younger Dryas as a result of the continuous inflow of the warm Tsushima Current into the East Sea.

• 수산해양기술연구
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• 제34권2호
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• pp.117-134
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• 1998

The study on the Assembling Mechanism of the Hairtail, Trichiurus lenpturus, at the Fishing Grounds of the Cheju Strait had been investigated by analyzing the relationship of the oceanographic conditions and the fishing ground of the Hairtail in the Cheju Strait. 1. The fishing grounds of the hairtail at the Cheju Strait are formed at the bottom of a high temperature of the tidal front at the coast. area of northern Cheju Island, the tip of the linguiform is high in salinity at the eastern and western entrances of Cheju Island, low salinity eddy on the surface and its surrounding front, various water masses in the Strait and coastal waters of the South Sea in Korea. 2. The fishing grounds of the Hairtail at the Cheju Strait begins with the sea surface temperature higher than $15^{\circ}C$ and the incoming of low salinity water now from the East China Sea. 3. Estimation of optimum temperature and salinity per season based upon analysis for relationship between temperature of water and salinity of the bottom layer and the catch is : 15.2~$16.4^{\circ}C$, 34.20~34.40${\textperthousand}$ in spring(June); 14.4~ $17.0^{\circ}C$, 33.70~34.30${\textperthousand}$ in summer(July~September); and 15.7~ $18.6^{\circ}C$, 33.70~34.50$\textperthousand$ in autumn(October~December). Hairtail are mostly caught at the Yellow Sea Warm Current and Tsushima Current with temperature over $14.5^{\circ}C$ and salinity over 33.70${\textperthousand}$ at the bottom layers of the Cheju Strait. 4. Considering the relationship between the amount of hairtail catch and the water temperature of bottom layer, when the bottom water being above $14.0^{\circ}C$ flowed into Cheju Strait through the western entrance of the strait in summer, the ca-h appears to have been abundant. In contrast, the catch has been poor when the temperature of such water was recorded to be below $13^{\circ}C$ Therefore, distribution patterns of water at the bottom layer can be used as a forecast index whether the catch of a certain year will be good or poor.

• 한국패류학회지
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• 제29권3호
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• pp.225-232
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• 2013

본 연구는 저염분 해수에 노출된 전복의 폐사 원인을 구명하고자, 수온별 (15, 20 및 $25^{\circ}C$) 염분별 (30, 25, 20 및 15 psu) 노출시간별 (3, 6, 12, 24 및 48 h) 북방전복, Haliotis discus hannai 치패의 회복률 및 아가미의 조직학적 변화를 조사하였다. 모든 수온조건에서 20 psu 이하의 저염분 해수에 6시간 이상 노출시킨 전복은 회복기간 동안 생존율이 감소하였으며, 15 psu 해수에 24시간 이상 노출시킨 전복은 회복되지 못하고 전량 폐사하였다. 이를 조직학적으로 관찰한 결과, 20 psu 이하의 저염분 해수에 6시간 이상 노출시킨 전복의 아가미 조직은 팽창 또는 손상되었으며, 15 psu 해수에 24시간 이상 노출시킨 전복의 아가미 조직은 대부분 파괴되었다. 이와같은 결과는 수온이 높을수록, 염분이 낮을수록, 노출시간이 길수록 확연히 나타났다. 따라서 저염분 해수에 노출된 전복이 폐사하는 직접적인 원인 중의 하나는 아가미 조직의 손상으로 인한 질식으로 판단된다.