• Journal of the korean society of oceanography
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• 제37권3호
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• pp.169-177
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• 2002

An eddy-resolving free-surface primitive-equation model with nonlinear terrain-following coordinates is established to study the exchange of water masses among the Asian marginal seas and their adjacent waters. A curvilinear coordinate system is used to generate the horizontal grid with a variable resolution for the regional oceans from $5^{\circ}$S to $45^{\circ}$N and $100^{\circ}$E to $155^{\circ}$E. The higher resolution region has about a 10 km by 10 km grid covering the complex geometry of the coastal marginal seas, while the lower resolution region has about a 30 km by 30 km grid covering the eastern Pacific. The model is initialized by the Levitus annual climitology and forced by the monthly mean air-sea fluxes of momentum, heat, and freshwater derived from the Comprehensive Ocean-Atmosphere Data Set. High-resolution and low-viscosity are identified as the key factors for a better representation of the exchange of waters through narrow straits and passages between the marginal seas and their adjacent waters. The dynamics of the loop currents and eddies in the South China Sea and Celebes Sea are examined in detail. It has found that the anticyclonic loop and detached eddies from the Kuroshio through the Luzon Strait play an important role in transporting warm and salty water into the South China Sea, while the cyclonic circulation of the Mindanao Current in the Celebes Sea plays a role in contributing cold water to the Indonesian throughflow. The deep undercurrent of the western Pacific is shown to provide fresher water to the South China Sea and Celebes Sea. These modeling results suggest that the exchange processes via the narrow straits and passages are of fundamental importance to the maintenance of water masses for the marginal sea region.

• 수산해양기술연구
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• 제52권3호
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• pp.197-208
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• 2016

The WCPFC CMMs related to tropical tunas have been strongly restricting fishing capacity and operating activities of main fisheries, especially purse seine fishery. In terms of changes in fishing trend by implementing relevant measures of FAD set, the number of FAD set by Korean purse seine fleet showed a decreasing pattern with the lowest level of FAD set proportion among major distant water fishing nations. With regards to the FAD closure, there was no significant change in fishing effort but a drop in catch, especially bigeye tuna during the period of FAD closure. Moreover, it showed closely similar trends between the number of FAD set and bigeye tuna catch. In terms of measures related to the high sea area including a ban on fishing on the HSP and limitation of fishing days on the high sea by flag state, proportions of catch and effort on the high sea had sharply declined after implementing those measures. As relevant measures are expected to be strengthened, it should pay attention to change of coastal nations policies and focus on improving fishing efficiency of unassociated school set with multi-pronged efforts.

• 한국해양학회지
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• 제25권4호
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• pp.189-204
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• 1990

태평양 클라리온-클리퍼톤 균열대 서부의 KODOS(Korea Deep Ocean Study)지역에 분포하는 망간단괴의 성인과 분포, 그리고 분포 원인을 규명하기 위하여 망간단괴와 퇴적물을 채취하여 화학 및 광물학적 분석을 하였다. 이 지역의 망간단괴는 Mn/Fe 비 가 크고 구리, 니켈, 아연, 마그네슘, 토도로카이트 함량이 높으며 표면조직이 거친 속성기원의 망간단괴(S-형 망간단괴)와 철, 코발트, 버나다이트 함량이 높고 표면조직 이 매끈한 수성기원의 망간단괴(S-형 망간단괴) 그리고 화학 및 광물조성과 표면조직 이 두 기원의 중간성격을 띄는 망간단괴(R-S-형 망간단괴)로 구분된다. 성인 및 부존 밀도 등의 특성에 따라 KODOS-89 지역은 크게 4지역으로 구분된다. 즉, 부존밀도가 10 kg/m$^2$이하이고 수성기원의 망간단괴가 분포하는 최북단지역, 부존밀도가 1 kg/m$^2$ 내 외이고 속성기원의 망간단괴가 분포하는 남부 지역, 그리고 부존밀도가 10 kg/m$^2$ 이 상으로 높고 수성기원의 망간단괴가 분포하는 해저산지역으로 구분된다. 이러한 망간 단괴의 분포특성은 주로 위도에 따른 수층의 생산성 및 해저지형의 차이에 의해 기인 되었다고 생각된다.

• 한국해양학회지:바다
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• 제2권1호
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• pp.42-47
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• 1997

북동 태평양 심해저 퇴적물에 서식하는 중형저서생물의 군집조성 및 분포양상을 보기 위하여, 다중 주상 시료 채취기(Multiple corer) 및 상자형 시료 채취기(Box corer)를 사용하여 10개 정점에서 시료를 채집하였다. 전 정점에서 18개 분류군이 출현하였다. 각 군집의 비율을 보면 Sarcomastigophora가 가장 우점하여 35.8%, 그 다음 Nematoda가 30.8%, Crustacea의 Naup1ius larvae가 그 다음으로 11.9%의 조성비율을 보였다. 또, benthic Harpacticoida, Ciliophora가 주요 생물군으로 이 5개의 주요 동물군이 전 정점의 중형저서동물 전체의 약 90%를 차지하였다. 총 개체 수는 정점 4(수섬 4960 m)에서 가장 높은 196 inds./10 $cm^2$을 보였고 정점 1(수심 4969 m)에서 가장 낮은 85 inds./10 $cm^2$을 보였다. 각 정점의 평균 개체 수는 $1.34{\times}10^5\;inds./m^2$ 이였다. 수평분포는 수심의 증가에 따라 서서히 감소하는 경향을 보였고, 수직분포는 표층 0~1 cm에서 집중적으로 분포하고 퇴적물내의 심도의 증가에 따라 서서히 감소하는 경향을 보였다.

• 미생물학회지
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• 제46권3호
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• pp.255-261
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• 2010

남태평양에 서식하는 두 종의 해면 Hyrtios sp. 604와 Callyspongia sp. 612로부터 16S rDNA DGGE 방법을 이용하여 공생세균 군집의 다양성을 분석하였다. DGGE band로부터 염기서열 분석 결과, Hytrios sp. 604의 공생세균은 Alphaproteobacteria, Gammaproteobacteria, Acidobacteria, Actinobacteria, Chloroflexi, Cyanobacteria, Firmicutes로 나타났으며, Callyspongia sp. 612의 공생세균 그룹은 Alphaproteobacteria, Gammaproteobacteria, Chloroflexi, Cyanobacteria로 나타났다. 풍부한 이차대사산물의 생산자로 보고된 Hyrtios 해면 속의 Hyrtios sp. 604는 Callyspongia sp. 612에 비해 더 다양한 공생세균 군집을 나타내었으며 주요 공생세균 군집으로 Actionobacteria가 포함되었다. 동일 지역에 서식하나 화학적 특성이 다른 두 해면 종의 세균 군집은 서로 다른 것으로 나타났다. 발견된 공생세균의 염기서열은 90% 이상이 uncultured clone들과 높은 상동성을 나타내었다.

• Ocean and Polar Research
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• 제32권3호
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• pp.229-236
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• 2010

A study was conducted to investigate the effect of water temperature and photoperiod on the oxygen consumption of the fasting juvenile Pacific cod Gadus macrocephalus (mean body weight 79.9${\pm}$2.0 g) in order to quantify metabolic response of the species under given conditions. The oxygen consumption rate (OCR) of G. macrocephalus was measured under a combination of four different water temperatures (7, 10, 13 and $16^{\circ}C$) and three different photoperiods (24L:0D, 12L:12D and 0L:24D) with an interval of 5 minutes over a 24-hour period using a closed recirculating respirometer. Three replicates were set up in each treatment. OCRs increased with increased water temperatures under all photoperiod conditions (P<0.001). Mean OCRs at 7, 10, 13 and 16oC ranged from 793.7~1108.4, 1145.7~1570.3, 1352.8~1742.5 and 1458.2~1818.6 mg $O_2$ $kg^{-1}$ $h^{-1}$, respectively. Under all water temperature conditions except $7^{\circ}C$ (P<0.001), mean OCRs of G. macrocephalus were the highest in continuous light (24L:0D) followed by 12L:12D and 0L:24D photoperiods. Mean OCRs of fish exposed to the 12L:12D photoperiod were significantly higher during the light phase than during the dark phase under all temperature conditions (P<0.001). $Q_{10}$ values ranged from 3.19~5.13 between 7 and $10^{\circ}C$, 1.41~1.74 between 10 and $13^{\circ}C$ and 1.15~1.35 between 13 and $16^{\circ}C$, respectively. Based on overall results, water temperature, photoperiod and their combinations exerted a significant influence on the metabolic rate of juvenile cod. This study provides empirical data for estimating the amount of oxygen demand and managing the culture of cod under the given water temperatures and photoperiods.

• 한국수산과학회지
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• 제36권6호
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• pp.578-585
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• 2003

The chum salmon (Oncorhynchus keta) is an anadromous fish distributed all around the North Pacific. Artificial production and release of the juveniles are being made by Korea, Japan, Russia, Canada and the United States. It is important to set up some criteria identifying each stock in order to clarify each nation's right of harvest for the chum salmon resource. As an attempt to build such criteria, we analyzed sequences of a microsatellite DNA Ogo5 and the COIII-ND3-ND4L region of the mitochondrial DNA from chum salmons of Korea, Japan, and the United States. Ogo5 has 4 different alleles: allele A, B-1, B-2, and B-3. Allele B-3 is found only in 3 individuals out of 12 Korea salmons. The Japan salmons have the other 3 alleles and the America salmons have only 2 allots, A and B-1. Heterozygosity index (Ho/He) distinguishes the Korea (1.61) and Japan salmons (1.63) from the America ones (1.09). Seventeen different haplotypes are found in the COIII-ND3-ND4L region from 60 individuals,20 from each stock. The gene genealogy of the haplotypes revealed by TCS program shows that the Korea and Japan salmons are genetically closely linked, but that they are clearly distinguished from the America ones. Ten and eleven individuals of the Korea and Japan salmons have an identical haplotype. Nine individuals of the Korea salmons $(45\%),$ however, are separable from the Japan salmons by their own specific nucleotides. This result presents usefulness of the COIII-ND3-ND4L region as a genetic marker for identification of the chum salmon stocks.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2013년도 춘계학술대회
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• pp.218-222
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• 2013

우리나라와 중국을 비롯한 아시아권과 브라질 칠레 등 남미 간 무역거래량이 지속적으로 증가하고 있으며, 그 주요 품목은 농수산물, 공산품, 광물 등 원자재를 비롯하여 매우 다변화 되고 있는 추세에 있다. 이에 따른 국제물류수단은 주로 항공 및 컨테이너 라이너에 의존하고 있으나 대부분 여러 기항지를 경유하고 있으므로 소요시간이 많이 길고 환적 등 다소 복잡한 수송루트를 거쳐야 하는 애로사항이 있어 화주들이 물류비절감에 애로를 겪고 있다. 이에 본 연구에서는 태평양을 마주하며 대권항법에 따라 지리적으로 인접하고 특히 동북아시아와 남미의 허브로 기능할 수 있는 한국과 에콰도르의 주요 항만을 이용한 두 지역 간의 직항물류망을 개설함으로써 물류에 소요되는 시간과 비용을 절감할 수 있는 방안을 모색해 보고자 한다.

• Journal of the korean society of oceanography
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• 제32권4호
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• pp.171-180
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• 1997

Daily mean sea level variability and its response to atmospheric pressure along the coasts of the northwestern Pacific Ocean are investigated. Daily values of sea level and atmospheric pressure covering the period 1976-1986 from 72 stations are analyzed. The sea level and the air pressure in all the data set have a definite seasonal signal, and higher frequency oscillations at time scales of several days to several weeks are also observed. Among the short-period oscillations of sea level with periods shorter than six months, the period of around 3 or 4 months is dominant in most study stations. According to the statistical analysis of sea level and air pressure, the length scale of sea level variability is smaller than that of air pressure for the present study area. The overall variability of sea level is found to be the smallest around Hokkaido, Japan and the largest in the China coasts. Large short-period (< 6 months) sea level variability is found in the southern coasts of China and Hokkaido, and large long-period (> 6 months) variability in the southern coasts of Japan and Korea along Tsushima Current and Kuroshio. The patterns of air pressure are very similar to those of sea level. The air pressure field is found to account for 31% of the overall sea level variability in the study area. Conside.ins the fact that the results (40%) of Pang and Oh (1995) were obtained through monthly sea level, the present result implies that the short-period sea level variability is less affected by air pressure. Generally the sea level response to air pressure are found to be isostatic, but significantly nonisostatic for the periods around 4 months and for those of 2 to 4 days. In particular, nonisostatic response for higher frequencies seem to be due to the restrictions to water transport necessary for barometric responsein the Korea Strait.

• Ocean and Polar Research
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• 제44권4호
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• pp.319-329
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• 2022

The paramyxean parasite Marteilioides chungmuensis infects the cytoplasm of the eggs of Pacific oysters Crassostrea gigas , resulting in spawning failure of the infected females. Such infected eggs appear as bump-like nodules on the body in late fall when most of the uninfected females complete spawning. In this study, we estimated the quantity of the infected eggs using an enzyme-linked immunosorbent assay (ELISA), which is destroyed by M. chungmuensis parasitism. In December, the infected oysters collected from Tongyoung on the south coast exhibited numerous yellowish bump-like nodules as signs of infection. In histology, the infected oysters exhibited mature eggs in the follicle, which were heavily infiltrated by hemocytes. ELISA indicated that the infected egg mass accounted for 7.52±5.50 percent of the body weight, suggesting the ovarian parasite causes substantial reproductive loss. Histology also indicated that the infected oysters are in a poor nutritional condition, as the digestive gland atrophy (DGA) level is comparatively higher than the uninfected oyster. The total carbohydrate contents in the infected oysters (108.68±44.41 mg/g dry wt) were significantly lower than in uninfected oysters (269.76±50.97 mg/g dry wt), suggesting that M. chungmuensis parasitism also affected the energy storage capacity of the host during the resting stage.