• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.14 no.3
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• pp.155-162
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• 2009

To characterize the initiation, propagation and termination of Cochlodinium polykrikoides blooms in the southeast coastal waters of Korea, 2008, we analyzed the data set of phytoplankton composition, physical and chemical water properties, and meterological data. C. polykrikoides bloom in 2008 were long lasting and restricted to the coastal area with a low density. Our results indicate that C. polykrikoides blooms were affected by the atypical cold waters occurring in east-south coastal water in the early July. The cold water masses probably protected the free living cells of C. polykrikoides from entering into the coastal area from offshore waters as a pelagic seed population. The low density blooms of small scale established possibly by the germination of C. polykrikoides cyst in shallow coastal bottom could have not spread over because of the weak wind and low nutrient concentrations caused by severe drought in July and September.

• Economic and Environmental Geology
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• v.30 no.1
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• pp.25-33
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• 1997

The purpose of this study is to examine the feasibility of using stable isotopes as a hydrologic tracer, and to elucidate the groundwater circulation system and the source of S component dissolved in thermal water of the Chonju Jukrim thermal spring district based on the O, H and S isotopic variabilities of environmental materials including bedrock, rainwater, surface water, shallow subsurface water and thermal spring water. The ${\delta}^{18}O$ and ${\delta}D$ of subsurface waters and surface water show highly restricted range and plotted on the same meteoric water line as a ${\delta}D=8{\delta}^{18}O+19$ line, and derivate from the mean annual isotopic composition of the rain water but are analogous to those of rain waters precipitated during winter season, indicating that ground waters are originated from the meteoric water and are strongly affected by the seasonal variation of air mass. Thermal spring waters are more depleted in ${\delta}^{18}O$ and ${\delta}D$ than those of shallow ground water and surface water. It can be explained by the difference of recharge area. The hydrochemical properties of subsurface waters and surface water devide into two groups: $Ca(HCO_3)_2$ type including shallow subsurface water and surface water, and $Na(HCO_3)$ type of thermal spring waters. The ${\delta}^{34}S$ values of thermal spring water show very high positive and quitely distinct from those of shallow subsurface water and surface water that are similar to those of bed rocks, indicating that sulfate dissolved in thermal spring water has not only a terrigenic origin, but also originates partially from the foreign source containing very heavy ${\delta}^{34}S$ component such as an ancient sea water. However, the presence of $H_2S$ can not be ignore the affact of the isotopic fractionation to explaine the heavy ${\delta}^{34}S$ of thermal spring water. Overall, the Oxygen and Hydrogen stable isotopes can identify the source and the circulation system of the natural waters and the S-isotopes can provide a crucial clue on tracing the dissolved material transports in the circulation system of the natural water.

• Journal of Navigation and Port Research
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• v.27 no.6
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• pp.639-643
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• 2003

The emphasis is put on the detailed knowledge on manoeuvring characteristic for the safe navigation while avoiding terrible collision between ships and on the guideline to the design and operation of the ship-waterway system The numerical simulation of manoeuvring motion was carried out parametrically for different ship types, ship-velocity ratios, separation and stagger between ships. As for the calculation parameters, the ratios of velocity difference (hereafter, $U_2$/$U_1$ ) between two ships were considered as 0.6, 1.2, 1.5. From the inspection of this investigation, it indicates the following result. Considering the interaction force only as parameter, the lateral distance between ships is necessarily required for the ship-velocity ratio of 1.2, compared to the cases of 0.6 and 1.5 regardless of the ship types. Furthermore, regardless of the ship-velocity ratio, an overtaking and overtaken vessel can be manoeuvred safely without deviating from the original course under the following conditions: the lateral distance between two vessels is approximately kept at 0.5 times of ship-length and 5 through 10. degrees of range in maximum rudder angle. The manoeuvring characteristic based on this investigation will be very useful for keeping the safety of navigation from the practical point of ships design and traffic control in restricted waterways.

• Korean Journal of Ichthyology
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• v.2 no.1
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• pp.1-27
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• 1990

Twenty four species belonging to 10 genera and 4 families in the suborder Tetraodontoidei in Korea were reviewed and provisional keys to species, genera and families are provided. Among them available specimens of seventeen species in this taxa collected during 1986 to 1990 from Korean waters were examined and recorded on the morphometric characters, their body color and collection sites. And two species are reported for the first time to Korea with their descriptions and figures : Lagocephallus gloveri Abe et Tabeta, 1983 and L. wheeleri Abe,Tabeta et Kitahama, 1984. Taki/ugu chiηensis Abe, previously recorded from Pusan, Korea as paratype locality but not included in the list of Chyung, 1977, is listed in the present paper with the new korean name, "Chambok". Many of this taxa are also distributed throughout the waters of China and Japan. But it is found that the distribution of three species of genus Takifugu are restricted only to the west coast of Korea as well as to the adjacent waters of China in the Yellow Sea ; T. obscurus, T. flavidus and T. basilevskianus. Taxonomy and distribution of this taxa were discussed with references to the information obtained so far.

• Korean Journal of Ichthyology
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• v.22 no.2
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• pp.105-114
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• 2010

A taxonomic review of the family Sillaginidae was carried out based on two species (Sillago japonica and S. parvisquamis) collected in the coastal waters of Korea from 2008 to 2009 and three species (S. parvisquamis, S. aeolus and S. sihama) kept in the museum. Sillago japonica was easily distinguished from S. parvisquamis and S. sihama by lateral line scales (70~73 in S. japonica vs. 77~81 in S. parvisquamis vs. 67~70 in S. sihama) and scales above lateral line (3~4 vs. 7 vs. 5~6, respectively). Sillago aeolus differed from the other three species in having dark brown blotches on the side of body. We newly found morphological differences in some measurements (snout length, pectoral fin length and $2^{nd}$ anal spine length) and the number of vertebrae between Korean and Japanese S. parvisquamis, suggesting the two may be different populations. Although four sillaginid species are known from Korea, only two species (S. japonica and S. parvisquamis) were found in this study; accordingly, the distribution of the remaining two species (S. sihama and S. aeolus) may be restricted to subtropical waters.

• Fisheries and Aquatic Sciences
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• v.4 no.3
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• pp.120-129
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• 2001

Thirty-six dinoflagellate cysts, representing 15 genera were identified in the surface sediments obtained from the northwestern East China Sea. Three cyst morphotypes found in this survey have not previously been described in the East China Sea and adjacent waters: Seleno­pemphix sp. 2, Selenopemphix sp. 3 and Trinovantedinium sp. 1. In the northwestern East China Sea, Operculodinium centrocarpum, Spiniferites bulloideus and ellipsoidal cysts of Alexandrium were commonly observed. Moreover, it was recognized that the ellipsoidal cysts of Alexandrium, whose motile cells of A tamarense and/or A catenella are responsible to paralytic shellfish poisoning, distributed not only restricted to the coastal areas but also to the offshore stations far from the Changjiang River mouth.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2013.06a
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• pp.169-171
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• 2013

The ships always have had the risk of collision. There are also a number of near-miss situations especially in the congested area such as port entrance, restricted waters and crossing point of the ship's route. In those areas, the navigator might have more stress than other areas. If the collision risk of decided area is calculated, it might be possible to analyse the human factors by using this data. It is also helpful for deciding a position of aids to navigation or any other system for the safety navigation. For this purpose, the model of collision risk with AIS data has been explained in this paper. The calculated result from the proposed model has been examined by using the simulation.

• Economic and Environmental Geology
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• v.33 no.5
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• pp.367-377
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• 2000

The purpose of this study is to elucidate the source of U anomaly formed in stream water of the drainage system around the Shinbo talc mine area based on the O, H, S and Sr isotopic characteristics of water masses and wall rocks. The ${\delta}$D and ${\delta}^{18}O$ of surface and ground waters show highly restricted range and plotted on the same meteoric water line, indicating that they are all originated from the meteoric water. The ${\delta}^{34}S$value of the ground water containing high U shows slightly negative (-0.2${\textperthousand}$) and quite distinct from those of the other surface and ground waters that are similar to those of wall rocks (>5.8${\textperthousand}$), indicating that they have a different S isotopic fractionation or less probably, source. The $^{87}Sr/^{86}{Sr}$ratios of water masses around the Shinbo talc mine area show a variable range from 0.724325 to 0.744928, but tend to increase with increasing U concentration of water mass. Although it is not possible to determine precisely the source rock of U anomaly formed in the hydrologic system around the Shinbo talc mine, the evidence obtained from the Sr isotopic compositions strongly suggests that coal schist and/or pegmatite vein could be the most likely candidate for the source rock.

• 한국해양학회지
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• v.22 no.2
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• pp.87-104
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• 1987

The middle Cretaceous stratigraphec section of Deep Sea Drilling Project (DSDP) Site 530 in the Angola Basin is characterized by cyclic interbeds of organic-carbon-rich black shales and organic-carbon-poor red and green claystones, namely the black shale sequence. A number of samples from the black shale sequence were analyzed for the typesand distribution of insoluble sedimentary organic matter(kerogen) in order to give more information on the depositional conditions of the black shales in the Angola Basin. The dominant type of kerogen in the black shale sequence at Site 530 is amorphous organic matter mainly of marine planktonic algal origin. It probably consists of remains of some unfossiliqed dinoflagellates. The cyclic preservation of organic-carbon-rich black shales in the Angola Basin during the mid-Cretaceous could be explained by the low dissolved-oxygen concentration in the warm, saline deep and bottom waters combined with the sluggish circulation within the highly restricted basin, and the periodic high productivity in the surface waters.

• Korean Journal of Ichthyology
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• v.28 no.3
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• pp.175-178
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• 2016

The karyotype analysis of Liobagrus somjinensis, an endemic Korean freshwater fish with restricted waters and a new species of torrent catfish was carried out from nine females and eight males of Somjingang River, Sikjeong-dong, Namwon-si, Jeollabuk-do, Korea. The diploid number of chromosomes was 42, and its karyotype was composed of 28 metacentrics and 14 submetacentrics; 84 FN (fundamental number). Polyploidy and sex dimorphism were not observed in the present species. The chromosome number of L. somjinensis was the same as its congeners, but there was a difference in karyotypes.