• Journal of the Korean earth science society
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• v.31 no.3
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• pp.214-224
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• 2010

Gravity and Magnetic survey data were analyzed to investigate the geophysical characteristics and regional geological structures of the southwestern Yellow Sea. The set of data about the southwestern part of the Yellow Sea in Korea was one collected by the Korea Ocean Research and Development Institute (KORDI) in 2003, 2004, and 2005. The Yellow Sea has a few basins and the study area also includes parts of the Heuksan Basin and the East China Sea Basin. The bathymetry of the study area ranges from about ?40 m southwestward near China to about 150 m northeastward near Korea. The bathymetry has the gentle rise and fall and the smooth slope. The gravity anomalies, from sea surface gravity and satellite gravity data, reflect the basement rocks rather than the smooth bathymetry. The gravity anomalies are higher on Northeastern part of the study area and lower over the South of the Heuksan Basin. The analytic signal from the Bouguer anomaly shows higher anomalous zones near the boundaries of the basins. The magnetic anomalies and the analytic signal, from the magnetic data, suggest that the complex anomalies on the Northern part are attributed to the volcanic intrusions and that the smooth patterns in the Southern part are based on the lack of the intrusions. The power spectrum analysis of the Bouguer anomalies and the magnetic anomalies indicate that the depth to the Moho discontinuity varies from about 30.2 to 28.3 km and that the depths of the basement rocks and the Eocene discontinuity range from about 8.4 to 8 km and from about 1.5 to 1.7 km, respectively. The inversion of the Bouguer anomaly shows that the Moho depth to the Western part of the study area near China is slightly deeper than the Eastern part near Korea. The result of 2-D gravity modeling has a good coherence with the results of the analytic signal, the power spectrum analysis, and the inversion.

• Animal Systematics, Evolution and Diversity
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• v.24 no.3
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• pp.251-263
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• 2008

Eight species and four genera belonging to two families of antipatharians have been reported in Korea. In the present study, the major specimens were collected from the coastal areas of Jejudo Island from 2005 to 2006, and the other ones which have been deposited in the Natural History Museum and the Department of Life Science, Ewha Womans University during the period from 1965 to 2004 were reexamined. As a result of this work, four species, Myriopathes bifaria, M. stechowi, M. ulex and Plumapathes pennacea are new to Korean antipatharian fauna. In this study, total six species including previously recorded species of the family Myriopathidae were described. And the distribution range of Myriopathes lata was turned out to be expanded from southwestern sea to the eastern sea, up to Ulleungdo Is. of Korea. Especially, the sexuality and the gonadal stage of M. lata which are collected during their reproduction period were also determined by means of histological analysis.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.4
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• pp.312-322
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• 1999

We have studied both submarine morphology and sediment characteristics of waste disposal sites in the southwestern Ulleung Basin, East Sea, as part of a marine environmental preservation program. The Jung waste disposal site in the outer shelf is characterized by the thick accumulation of coarse-grained palimpsest sediments and fine-grained sediments from various sources. The Byung waste disposal site in the continental slope is generally characterized by hemipelagic muds with intermittent sandy sediments originated from the outer shelf and upper slope. The hemipelagic sediments, draping the seafloor, consist of fluidized muds. The core sediments show numerous bioturbation structures which cause vertical mixing of sediments. The surface sediments can be divided into four sand types (S-1, S-2, S-3, and S-4) and two mud types (M-1 and M-2) based on relative contents of reworked coarse-grained palimpsest sediments and fine-grained sediments. sorting and heavy mineral contents. The sands are probably relict sediments reworked during high-energy conditions such as typoon or storm. On the other hand, the muds were originated from various sources such as recent input from the Nakdong River, reworked fine-grained sediment from the shelf or suspended particulate matter from the East Sea Warm Current.

• Journal of Species Research
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• v.8 no.4
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• pp.389-394
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• 2019

Foraminifera are protists that inhabit diverse marine environments and show high abundance and diversity. However, previous studies on foraminifera in Korea mostly focused on geological and paleoecological fields and were conducted in a limited area. Therefore, there is a high possibility for discovering new and unrecorded species. Here we describe three newly recorded foraminiferal species from the southwestern part of Jeju Island during a survey on the meiofaunal community, which belongs to three different genera (Ammobaculites, Cylindroclavulina, Saracenaria), three families (Lituolidae, Vaginulinidae, Valvulinidae), and three orders (Lituolida, Textulariida, Vaginulinida): Ammobaculites formosensis Nakamura, 1937, Cylindroclavulina bradyi (Cushman, 1911), and Saracenaria hannoverana (Franke, 1936). These species have been reported from Chinese region in the East China Sea, however this is the first report from Korean waters. Particularly, Cylindroclavulina bradyi is the first report of the genus Cylindroclavulina in Korean waters. The present study supports the diversity of foraminiferal species in Korea, and the necessity of further surveys in Korean waters.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.1
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• pp.39-49
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• 2014

Morphological and positional characteristics of anchovy aggregations, confirmed by trawling, were examined in two locations of the southern part of theWest Sea (T1) and the western side of South Sea (T11) of South Korea. Morphological characteristics (mean length, height and area) of the anchovy aggregations at T1 were smaller than those at T11, however the positional characteristics (distributional depth and bottom depth) of the aggregations at T1 were larger than those at T11. Diverse dataset such as the ship's cruise track, the cruse map, and interpolated three-dimensional-like water temperature were visualized in multiple dimensions. For a comprehensive understanding of the anchovy aggregations within their surrounding circumstances, the interpolated water temperature transferred to the location of anchovy aggregations at both stations were visualized based on geospatial information. Using quantitative investigation, the overall range of change in water temperature and salinity of anchovy aggregations at stations was considerably small. However, the water temperature and salinity of anchovy aggregations at T11 were somewhat higher than those at T1.

• Journal of the Korean earth science society
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• v.35 no.2
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• pp.131-146
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• 2014

Multi-beam echosounder data and grain size analysis data of surface sediment were acquired and analyzed in order to investigate the shelf-to-slope morphology, geological character, and their geological controlling factors in the southwestern margin of the Ulleung Basin. According to the morphological character, the continental shelf can be divided into two parts: (1) shallow (~100 m) and steep ($0.5^{\circ}$) inner shelf, (2) deep (100-300 m) and gentle ($0.2^{\circ}$) outer shelf. The continental slope is featured with eight distinct topographic depressions of various spatial dimension (~121 $km^2$ in area) and head wall gradient (${\sim}24.3^{\circ}$). They are developed adjacent to each other and presumably formed by submarine landslides which have recurred under the strong influences of earthquakes and eustatic sea-level change. The inner continental shelf and the continental slope are dominated by fine-grained sediment, whereas the outer continental shelf is dominated by coarse-grained sediment. The surface sediment distribution seems dominantly influenced by eustatic sea-level change. The outer continental shelf is mostly covered by coarse relict sediment deposited during lowstand sea-level, while the inner shelf is covered with recent sediment during highstand sea-level. The surface of the continental slope is covered with fine-grained sediments which were supplied by hemipelagic advection process.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.2
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• pp.85-93
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• 2012

We study on the distribution characteristics of antifouling agents such as Sea-nine 211, Irgarol 1051, Diuron using HS-SPME method in southwestern coast of Korea. Short half-life of Sea-nine 211 was distributed in very low concentrations and/or below detection limits in all of the sampling points, both water and sediments samples. Irgarol 1051 was detected to have the highest concentration respectively $6.98{\mu}g/L$, 28.50 ng/g-dry wt in the seawater and sediments, and regional distribution characteristics did not appeared. Strong bioaccumulation and long half-life of Diuron was distributed higher concentration than in all sampling point and was analyzed to have the highest concentration(3882.22 ng/g-dry wt) Mo7(Mokpo)'s sediment. Irgarol 1051 and Diuron distributed in the shipbuilding industry and ship marina are located just at the point to found in high concentrations. In addition, the distribution of the antifouling agent materials were lower in concentration than in inner bay to outter bay in sediments. Antifouling agent materials from these results were contaminated high potential from port and shipbuilding industry located in inner bay.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.4
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• pp.499-508
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• 2016

We investigated regional differences in the growth and maturation rate of Pacific cod in the East and Yellow Seas. Significant regional differences were detected in the von Bertalanffy growth equation and mean length at maturity (L₅₀). Cod in the East Sea grew at a faster rate than those in the Yellow Sea, with females growing faster than males in both populations. Cod of both sexes matured earlier in the Yellow Sea (age of maturity: 2.3 years for males, 2.6 years for females) than in the East Sea (age of maturity: 3.9 years for males, 4 years for females). These regional differences suggest that Pacific cod in the Yellow Sea, which is at the southwestern extremity of global cod distribution and thus likely to be an inhospitable habitat for this species, have adapted to their environment by developing earlier maturation and slower growth than cod in the East Sea or the Korea Strait. These regional differences must be taken into account when setting biological reference points for management of the Pacific cod fishery in Korean waters.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.57 no.2
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• pp.134-148
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• 2021

During the ichthyoplankton survey around the Chilsan Island (previously known as the biggest spawning ground of the Sciaenidae) in the southwestern sea of Korea from April to June in 2019 using ring nets, we collected a total of 12 individuals belonging to the family Sciaenidae. Using molecular methods, we identified five sciaenid species (Collichthys lucidus, Collichthys niveatus, Johnius grypotus, Nibea albiflora, and Pennahia argentata), and described and compared them on the basis of the preflexion larval stage. C. lucidus was well distinguished by the presence of occipital crests at preflexion stage. Although there were no occipital crests, preflexion larva of C. niveatus was distinguished by the absence of melanophore except for the upper part of the abdominal cavity. J. grypotus and N. albiflora were very similar morphologically, but were distinguished by myomere height (15.22-15.53% in J. grypotus vs. 11.66-12.78% in N. albiflora) in the percentage of notochord length, and eye diameter (32.58-33.37% in J. grypotus vs. 40.32-42.53% in N. albiflora) in the percentage of head length between specimens of similar size (J. grypotus: 3.22-3.23 mm, N. albiflora: 3.04-3.13 mm). P. argentata were distinguished by distribution of ventral caudal melanophore (one row of small spot in P. argentata vs. irregular patches on the central part of caudal in J. grypotus and N. albiflora). Comparative morphological studies using more diverse species must be conducted for more comprehensive understanding of the morphogenesis of Sciaenidae.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.3
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• pp.177-184
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• 1991

We have investigated geographical distribution and physico-chemical properties of water masses or water types at mid-bottom depth in the neighbouring sea of Cheju Island in August 1986. In 50m layer the Yellow Sea Bottom Cold Water(YSBCW) below $12^{\circ}C$ was observed in the northwestern area of Cheju Island, while the Tsushima Warm Water(TWW) with relatively high temperature$(>16^{\circ}C)$ and salinity more than 34.0 in its southeastern area extended as far as the coast of about 15km. Also, 50m layer at the outside stations of its southwestern area indicated relatively cold water temperature$(11-30^{\circ}C)$, probably due to southward transport of the Yellow Sea Bottom Cold Water(YSBCW . The Yellow Sea Warm Water(YSWW), the mixed water of the YSBCW and the TWW, ranged $13^{\circ}C$ to $16^{\circ}C$ in water temperature and was appeared mainly in the coastal and intermediate area of Cheju Island. And the relatively cold water in the southwestern area and the Tsushima Warm Water were more extensively distributed in 50m layer than the deeper layer. Horizontal distributions of nitrate and phosphate showed a pattern similar to that of water temperature. As it were, the Yellow Sea Bottom Cold Water had the highest concentration of nutrients, while southwestern outside stations had the lowest nutrient contents. Especially, the concentration of nitrate in the latter was remarkably low compared with the value at the other stations. It may be attributed to intensive vertical mixing by collision of the northward driven Tn with the southward driven YSBCW. Also, it was particular that the Tsushima Warm Water indicated relatively high silicate content corresponding to that of the Yellow Sea Bottom Cold Water. Based on the data of $\Delta Si/\Delta P$ ratio, it seems that the mid-bottom waters in this study area are younger than the surface or intermediate water in the Korean East Sea.