• Animal Systematics, Evolution and Diversity
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• v.39 no.1
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• pp.47-52
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• 2023

Thermopolynoe Miura, 1994 is a monotypic genus in Lepidonotopodinae that comprises species endemic to chemosynthesis-based ecosystems. Here, we examined T. branchiata collected from the hydrothermal vents in the North Fiji Basin. For the first time in Thermopolynoe, we report sexual dimorphism detecting nephridial papillae on segments 11-13 in males, additionally describe the morphology on elytra with round to conical microtubercles on the surface, and distinguish presence of small neuropodial lobes on segments 3-26. We also revised couple of errors and ambiguities in the original description: incongruence between the description and figure and existence of individual variation in ratio of tentacular cirri and palps. In addition, three COI sequences of T. branchiata specimens from the North Fiji Basin were newly obtained and sequences divergence with other Lepidonotopodinae species were determined. These results would contribute to the taxonomy of polynoids in a chemosynthesis-based ecosystem.

• Proceedings of the Korea Society of Environmental Biology Conference
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• 2003.11a
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• pp.103-107
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• 2003

Spatial distribution of phytoplankton was investigated in the southwestern sea of Korea in May 2000 in terms of phytohydrography. The sampling was done at the 0m, 30m, 50m of 15 selected stations, and permanent slides of each samples were prepared by QPS method for quantitative and qualitative analyses. Phytoplankton standing crops ranged from 3.23${\times}$10$\^$-4/ to 1.09${\times}$10$\^$-7/ cellsㆍ$\ell$$\^$-1/ in the study area. Dominant species comprised of 9 diatoms and 2 phytoflagellates, showing higher dominance of diatom and most predominance of Skeletonema costatum in all layers of most stations. Phytohydrographic results indicate that the study area might be divided into 4 categories, that is, I area is designated as neritic area where occurrence of terrestrial and coastal species is frequent, II area as intermediate area, III area as offshore area where oceanic species dominate, and IV area as other's. Especially in the II area, Skeletonema costatum was most predominant at both surface and 30m layer in most stations and represent an characteristic of northward expansion with spring massive bloom.

• 한국해양학회지
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• v.24 no.3
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• pp.132-147
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• 1989

A total of 83 surface sediments and 55 sea water samples, collected from the southwestern sea of Cheju Island, were analyzed in order to understand their textural characteristics, geochemical composition and the clay mineralogical features. The sediments were subdivided into ten textural classes, namely clayey sand, slightly gravelly muddy sand, sandy clay, clay and mud. The coarse and fine-grained mixed sediments are distributed in the northern part and around the Island, whereas the fine-grained deposits are mainly distributed in the central and southern parts of the study area; small scale mud patches are distributed in the southwestern and northern parts of Cheju Island. The high concentration of total suspended matter in study area gradually increase toward the southwestern and northwestern offshore area. The concentration of geochemical elements is as follow: the content of Mn, Al, Zn, Cr, Cu and Sn increase toward the southern part which is covered mainly with fine-grained deoposits, whereas the content of Ca, Mg and Ag is higher in the northern area; the elements such as Ni, Na, Fe and Pb are more concentrated relatively in muddy deposits rather than in sandy sediments. The light minerals such as Na-Ca feldspars show a high content around the Socotra Rock, toward the Soheugsan and Cheju Islands, but the K-feldspars are relatively high around the Cheju Island. It was noticed that the provenance of these sediments is partly influenced by the geological characteristics near the island. X-ray diffractogram for clay minerals from the southeastern mud patch and around the Soheugsan Island shows the diagnostic calcite peak indicating that the greater part of these clay fraction may have been derived from present and ancient Hwangho River. The high concentration of smectite in the northern part near the Cheju and around the Soheugsan Islands, eastern side of Socotra Rock probably result from supplies smectite altered from volcanic materials distributed in the Cheju Island and Socotra Rock, whereas the samples near the Chuja and northern parts of the Cheju Island contain weak calcite peak and high concentration of kaolinite and chlorite which is closely related to the geolgical characteristics on the adjacenting land area.

• International Journal of Naval Architecture and Ocean Engineering
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• v.10 no.1
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• pp.85-94
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• 2018

For the design of wind-power facilities, the highest and lowest astronomical tides (HAT and LAT, respectively) are needed for the tidal-water levels regarding international designs; however, the approximate highest high water and approximate lowest low water AHHW and ALLW, respectively, have been used in Korea. The HAT and LAT in the wind-farm test-bed sea should be estimated to satisfy the international standard. In this study, the HAT and LAT are therefore estimated using the hourly tidal-elevation data of the Eocheongdo, Anmado, Younggwang, Gunsan, Janghang, and Seocheon tidal-gauging stations that are located in the adjacent coastal sea. The nodal variation patterns of the major lunar components, such as $M_2$, $O_1$, and $K_1$ are analyzed to check the expected long-term lunar cycle, i.e., 18.61 year's nodal-variation patterns. The temporal amplitude variations of the $M_2$, $O_1$, and $K_1$ clearly show the 18.61-years periodic patterns in the case of the no-nodal correction condition. In addition, the suggested HAT and LAT elevations, estimated as the upper and lower confidence limits of the yearly HAT and LAT elevations, are 50 cm greater than the AHHW and 40 cm lower than the ALLW, respectively.

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.1018-1022
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• 2004

지구온난화에 의해 전세계적으로 평균해수면이 상승하고 있는데, 이는 지반의 융기 또는 침강 등을 비롯한 여러가지 지역적 차이 때문에 지역적으로 적지 않은 차이를 보이고 있다. 분석결과에 따르면 서남해안은 $1\~3mm/yr$ 정도의 비슷한 값을 보이고 있으며 제주도의 경우 $3\~5mm/yr$로 서남해안 지역에 비하여 약간 큰 값을 보이는 등 전지구적 상승량인 $1\~2mm/yr$ 보다는 다소 크게 나타나고 있다. 이와 함께 방조제와 같은 해안구조물 건설에 의해서도 평균해수면 뿐 아니라 고조위 및 저조위의 변화가 유발된다. 서남해안에서는 군산항과 목포항에서 특히 방조제 건설후에 각각 조위상승과 조석확폭현상이 발생하여 만조위 상승이 유발된 것으로 나타나고 있는데, 여기에 기인하여 목포 인근해역에서는 침식현상이 초래되고 있을 뿐 아니라 연중 해수면 변화가 심해짐에 따라 고극조위가 더욱 커져 저지대 범람이 특히 우려되고 있는 실정이다.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.1
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• pp.15-28
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• 1992

Temporal variations of the path of the East Korea Warm Current(EKWC) which flows northward along the east coast of Korea were analysed to investigate whether the EKWC directly influences the existence of the so-called Warm Core in the Ulreung basin. From the 13 years(1975-1987) data of the Fisheries Research and Development Agency(FRDA), the $10^{\circ}C$ isotherm at the 100m depth and the depth of $2^{\circ}C$ isotherm and the temperature field at the 200m depth were used for identification of the path and the central position of the Warm Core. Sea surface winds computed from the surface pressure charts gave the monthly-averaged wind stress curl over the East Sea which was used for determination of the Sverdrup transport. And the mass transport stream functions were computed by use of the Sverdrup balance. The variations of the path show that the EKWC does not always have a fixed path and fluctuates with time. And the existence of the Warm Core is independent upon the presence of the EKWC even when the EKWC doesn't flow northward along the east coast of Korea. In view of the mass transport stream functions, the influences of the sea surface winds on the branching of the Tsushima Warm Currents and the presence of the EKWC were investigated. The presence of the EKWC may be hindered by the southward flow driven by the sea surface winds when the Tsushima currents are rather weak. A very weak correlation exists between the north-south component of the Sverdrup transport and the position of the Warm Core. However, a small but significant part of the southward transport across the latitudinal line of $38^{\circ}N$ indicates that cold water from the northern part of the East Sea may be driven and be forced to flow beneath the permanent thermocline in such a way that the thermal structure of the Warm Core and its position might be changed.

• Journal of the Korean earth science society
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• v.36 no.6
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• pp.533-542
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• 2015

The Gochang beach is located in the southwestern coast of Korea along the eastern part of the Yellow Sea, comprising the Donghori, Gwangseungri, and Myeongsasipri beaches from north to south. The Gochang beach is characterized by macro-tide, open-coast, linear shoreline, and sand substrates. This study has investigated annual and seasonal characteristics of surface topography variation and sediment accumulation rate in the Gochang beach. During the five seasons of winter (Feb.), spring (May), summer (Aug.), and fall (Nov.) in 2014 and winter (Feb.) in 2015, the topographic elevation of total 315 sites was measured along three survey lines. It consists of 21 sites at 30 m intervals in each transverse line perpendicular to the shoreline, respectively. Annual accumulation rate of the Gochang beach in 2014 was -0.081 m/yr, indicative of erosional condition. Annual accumulation rates of the comprising beaches represent -0.091m/yr of the Donghori, -0.051 m/yr of the Gwangseungri, and -0.10 m/yr of the Myeongsasipri.

• Korean Journal of Environmental Biology
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• v.38 no.3
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• pp.461-475
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• 2020

This study was conducted in the southwestern area of Korea using a neuston net in September (14 stations) 2017 to understand the environmental factors affecting neustonic zooplankton. Temperature, salinity, chlorophyll a concentration, suspended solids, and microplastics were included as environmental factors. Based on the density of the copepods, the study area was divided into three regions: the Seomjin River water influence area, the frontal mixing area, and the warm water affected area (Jeju warm current and Tsushima warm current). In the latter two areas, the major species were Pontella chierchiae, Canthocalanus pauper, and Oncaea spp. Also, neustonic zooplankton showed a significant relationship between the density of phytoplankton and microplastics in the frontal mixing area, and temperature and suspended solids in the warm water affected area, respectively (p<0.05). This indicates that microplastics can affect the offshore zooplankton community.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.5
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• pp.583-593
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• 1994

The East Korean Warm Current is known as an anticyclonic circulation in the Ulreung Basin in the southwestern East Sea of Korea. This circulation was approximately estimated by dynamic methods based on the oceanographic observation and remote sensing data. In this study, the existence of circulation in the anticyclonic region of East Korean Warm Current(Tsushima current) in early summer was directly measured by drogue tracking using a global positioning system. At the same time, the velocity was calculated by dynamic method and compared using data collected by remote sensing. As results, these values are shown to be nearly the same, and an anticyclonic circulation was found around Ulreungdo-Tokto. The maximum northward and southward flow speed was deduced to be around 0.6 and one knot, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.40 no.1
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• pp.50-52
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• 2007

The growth of young-of-the-year blue spot mudskipper, Boleophthalmus pectinirostris, was investigated using length-frequency data for 395 individuals collected from a mud flat in southwestern Korea between August and October 2001. Three cohorts were separated by the Bhattacharya method. In October, individuals of cohort-I reached 98 mm in total length, whereas those of cohort-III reached just 66 mm. Each cohort reached hibernation in November, that could be related to the ring formation in the following year.