• Ocean and Polar Research
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• 제26권2호
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• pp.361-365
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• 2004

Deep-sea Resources Research Center (DRRC) has been using a free-fall grab (FFG) for the resource evaluation of polymetallic nodules in the KODOS (Korea Deep Ocean Study) area, NE Pacific, since 1992. A FFG model (Model 4200, Benthos) adapting one glass buoy system (diameter 17 inch, net buoyance 25.4 kg) has been used until 1993. Since then, DRRC has carried out a study to increase the recovery rate of FFG and it was found that a revised system adapting an additional buoy (diameter 10 inch, net buoyance 4.5 kg) gives improved results. The nodule sampling tests were performed using two different models for the same study area and the resulting recovery rates were compared. The result shows no distinct difference in recovery time between two models, but average recovery rate of the revised model was increased to 99.44% from 96.06% of the original model.

• Ocean and Polar Research
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• 제36권4호
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• pp.515-524
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• 2014

The Korea Institute of Ocean Science and Technology has acquired detailed biological, chemicophysical, and geological data in the northeastern Pacific through a manganese nodule program since 1983. Plenty of manganese nodules were collected to estimate the amount of resources by free-fall grab and box corer. The collected manganese nodules have been archived systematically in the rock and mineral storage section of the Library of Marine Samples (LIMS) since 2012. The LIMS provides essencial information on the stored samples including sample name, nodule type, sampling location, depth, and equipment. Although a high quality database of the information system is under construction, the samples have tagged information for manganese nodules like chemical composition, morphology, weight, size, abundance, and photograph. In this study, we attempted to provide information on the well-organized and easily accessible archived manganese nodule samples for future studies and to introduce the usefulness of the LIMS.

• 수산해양기술연구
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• 제46권3호
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• pp.248-256
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• 2010

Acoustic side-aspect target strength (TS) of living Japanese anchovy (Engraulis japonicus) was measured at 120kHz during in situ experiments. The data were collected by lowering and horizontally projecting the splitbeam transducer into the anchovy school. For analysis and interpretation of the side-aspect TS data, acoustic theoretical model, based on the fish morphology, and dorsal-aspect TS data were used. Total length of the anchovy ranged from 6.6 to 12.8cm (mean length 9.3cm). The side-aspect TS distributed between -40 and -55dB, has an obvious length dependency. The mean side-aspect TS of the anchovy was -47.8dB, and the TS was about 2dB higher than mean TS generated from dorsal-aspect measurements. With reference to maximum TS, the results of the side-aspect TS were distributed within the range of the theoretical and dorsal-aspect TS. Apparently these tendency indicates that side-aspect TS measured from the study is useful data. These in situ measurements of side-aspect TS can be applied to improve acoustic detection and estimates of the anchovy, and is necessary to measure with a various frequency and length for making enhance data.

• 한국패류학회지
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• 제23권1호
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• pp.65-104
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• 2007

This catalogue is the result of a four-year survey of the mollusks of Jeju Island, the southernmost island in the Republic of Korea. Forty-eight survey stations were visited, with a total of 82 specific localities being sampled. Literature records were also obtained. Local and world distribution of each species is included. This survey reports a total of 1,072 mollusk species and subspecies; 1,015 marine and 57 land and freshwater. There are 812 gastropods, of which 755 are either entirely marine or have marine affinities. The best represented of the marine families are the Pyramidellidae, Trochidae, and Ovulidae. There are 225 bivalves, none being freshwater species, with the Veneridae, Mytilidae, and Arcidae having the largest number of species. Among the smaller classes there are sixteen Cephalopoda, eleven Polyplacophora, and eight Scaphopoda. Compared to mainland Korea, Jeju Island has a rather small terrestrial mollusk fauna and a depauperate freshwater one, with mainly Palearctic connections. The Helixarionidae and Bradybaenidae are the largest terrestrial families. The marine faunal affinities with the neighboring Japonic and Indo-West Pacific provinces are also discussed, revealing that this island's mollusk fauna is a blend of warm-temperate and subtropical-tropical species.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2007년도 특별 심포지엄 논문집
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• pp.73-83
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• 2007

We interpreted marine seismic profiles in conjunction with swath bathymetric and magnetic data to investigate rifting to breakup processes at the eastern Korean margin that led to the separation of the southwestern Japan Arc. Analysis of rift fault patterns suggests that rifting at the Korean margin was primarily controlled by normal faulting resulting from extension rather than strike-slip deformation. Two extension directions of E-W and NW-SE for rifting are recognized. We interpret that the E-W direction represents initial rifting at the inner margin and the NW-SE direction probably represents the extension in response to tensional tectonics associated with the subduction of the Pacific Plate in the NW direction. No significant volcanism was involved in rifting. In contrast, the inception of sea floor spreading documents a pronounced volcanic phase which appears to reflect asthenospheric upwelling as well as rift-induced convection particularly in the narrow southern margin. We suggest that structural and igneous evolution of the Korean margin, although it is in a back-arc setting, can be explained by the processes occurring at the passive continental margin with magmatism influenced by asthenospheric upwelling.

• Ocean and Polar Research
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• 제32권3호
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• pp.291-297
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• 2010

In the summer of 2008 (August 4-14), vertical and horizontal distributions of inorganic nutrients and dissolved organic carbon (DOC) were measured in the southwestern East Sea. Concentrations of DOC were determined for the first time in the southwestern East Sea using the high-temperature combustion oxidation (HTCO) method, and results were compared with those measured by another laboratory. Concentrations of DOC ranged from 58 to 104 ${\mu}M$ in the upper 200 m, showing a typical decreasing pattern with depth. Generally, concentrations of DOC were relatively lower, with higher nutrient concentrations, in the upper layer of the coastal upwelling zone. Concentrations of DOC ranged from 54 to 64 ${\mu}M$ in the deep Ulleung Basin (200-1500 m), and were higher than those in the Pacific and Atlantic oceans. In association with rapid vertical ventilation of the euphotic, this difference indicates a larger accumulation of semi-labile DOC in the deep East Sea than in the major oceans. A correlation between apparent oxygen utilization (AOU) and DOC in the deep ocean of the East Sea revealed that only a small portion (<10%) of the sinking DOC, relative to the sinking particulate organic carbon (POC), contributes to microbial degradation. Our results present an important data set of DOC in the East Sea, which plays a critical role in carbon cycle modeling and sequestration.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2002년도 추계학술대회 논문집
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• pp.167-173
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• 2002

For moving cargo between the North Pacific region and Northern European ports, the Northern Sea Route, along Russia's coastline, is 35-60% shorter than the traditionally used routes through the Suez and Panama Canals. In addition to its shorter distance, there exists and extensive ports and shipping infrastructure, and the potential for developing new markets in Russia and other northern countries including Korea and Japan. These incentives attracted considerable attention from the international shipping and shipbuilding industries and have formed a cooperative international research program, called as the International Northern Sea Route Programme (INSROP). This paper is a general compilation of the historical usage, recent trade developments, the physical environment, and the practical considerations that may shape future operational mode of shipping in the NSR based on results from INSROP reports. This study focuses mainly on an operation of commercial icebreaking vessels that may be utilized along the NSR.

• 한국어류학회지
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• 제34권1호
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• pp.1-7
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• 2022

북서태평양 표층에서 채집한 후기 자어 (2.2 mm BL)의 미토콘드리아 전장 유전체를 근거로 Himantolophus groenlandicus로 동정하였다. 후기 자어는 둥근 몸통, 작은 이빨, 발달하기 시작한 등 지느러미, 아래 부분이 들어간 눈, 그리고 지느러미, 정수리, 등 부분에 분포하는 흑색소포를 가졌다. 이러한 특징은 크기가 유사한 동종으로 보고된 자어(2.1 mm BL)와 차이가 컸다. 본 연구 자어의 유전적, 형태적 특징은 유사종의 동정에 유용할 것이다.

• 대기
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• 제20권3호
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• pp.247-260
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• 2010

A recent dramatic increase of natural hazards in the Korean peninsular (KP) due to typhoons have raised necessities for the accurate typhoon prediction. Ieodo ocean research station (IORS) has been constructed in June 2003 at the open ocean where typhoons pass frequently, aiming to observe typhoons before the landfall to the KP and hence to improve the prediction skill. This paper investigates the importance of measurements at the IORS in the typhoon research and forecast. Analysis of the best track data in the N. W. Pacific shows that about one typhoon passes over the IORS per year on the average and 54% of the KP-landfall typhoons during 59 years (1950-2008) passed by the IORS within the range of the 150-km radius. The data observed during the event of typhoons reveals that the IORS can provide useful information for the typhoon prediction prior to the landfall (mainland: before 8-10 hrs, Jeju Island: before 4-6 hrs), which may contribute to improving the typhoon prediction skill and conducting the disaster prevention during the landfall. Since 2003, nine typhoons have influenced the IORS by strong winds above 17m/s. Among them, the typhoon Maemi (0314) was the strongest and brought the largest damages in Korea. The various oceanic and atmospheric observation data at the IORS suggest that the Maemi (0314) has kept the strong intensity until the landfall as passing over warm ocean currents, while the Ewiniar (0603) has weakened rapidly as passing over the Yellow Sea Bottom Cold Water (YSBCW), mainly due to the storm's self-induced surface cooling. It is revealed that the IORS is located in the best place for monitering the patterns of the warm currents and the YSBCW which varies in time and space.

• 한국환경과학회지
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• 제17권4호
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• pp.461-468
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• 2008

Competitive power of pelagic fishery in Korea has been weakened by the domestic and international problems such as wage increase and exclusive economic zone. To make it worse, fishing fleet spends more than 80% of fishing time on searching fishing grounds. Real-time information on oceanographic data, temperature in particular, are likely to contribute to raise efficiency of fishing. However, available data obtained by satellite remote sensing, fixed buoy and drifting buoy, limited to sea surface or fixed positions. ARGO (Array for Real-time Geostrophic Oceanography), an international program, has delivered vertical profiles of temperature and salinity in the upper 2000m of the world ocean every 10 days using freely moving floats. We have developed real-time oceanographic information system for pelagic fishery based on the Argo data which has the contents of vertical profile, horizontal distribution and vertical section of temperature around fishing grounds and searched data can be download unrestrictedly. Comparison of skipjack catch with sea surface temperature and depth of $20^{\circ}C$ derived from Argo data in the West Equatorial Pacific revealed that Argo data are able to help fishing fleet to find fishing grounds and to increase catch.