• Animal Systematics, Evolution and Diversity
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• 제33권1호
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• pp.8-16
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• 2017

We firstly described a box jellyfish, Carybdea brevipedalia collected from the southern coasts of Korea. It is morphologically characterized by gastric phacellae, a special digestive system of cubozoan jellyfish, and velarium, the thin muscle flap forming the opening of the subumbrellar cavity. The phacellae are linear-shaped, comprising numerous cirri branched from multiple roots. Each root also has multiple numbers of cirrus bundles. Basis of velarial cannels parts into two branches in each octant of velarium. Its geographic distributions were limited to Jeju-do and the middle-southern coasts where the organisms are seriously hazardous to bathers in summer. Numerous individuals and/or large-sized populations were observed specifically from beaches at Jeju-do, Namhae-do and a small fishing port of Namildae, while only a small amount of the individuals was observed in Gamak Bay, Jaran-Goseung Bay, and Geoje-do. We confirmed molecular identity of the Korean C. brevipedalia with comparison of nuclear ribosomal DNA sequences. Until now, Carybdea brevipedalia is the only cubozoan species reported to be distributed in Korean waters.

• Journal of the korean society of oceanography
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• 제33권4호
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• pp.196-204
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• 1998

$^{14}$C uptake experiments were carried out in and around the cold water mass in the southern part of the Korean East Sea in August and October 1995 to assess spatial and seasonal variability of primary productivity and its relation to physical and chemical factors. The cold and high saline water mass in the bottom layer extended upward to the surface layer and developed along the eastern coast of Korea in August. Chlorophyll-a concentration was maintained high in the cold water mass through August to October and its maximum concentration was 6.3 ${\mu}$g 1$^{-1}$ at Stn. 209-4 in August. Primary productivity and daily primary productivity ranged from 0.29 to 8.02 mgC m$^{-3}$ hr$^{-1}$ and from 58.3 to 63.1 mgC m$^{-2}$ d$^{-1}$, respectively, throughout the study period. Primary productivity of the cold water mass was higher than that of offshore waters in both summer and autumn seasons. P$_{max}$ and I$_{max}$ of the cold water mass in August were higher than those in October, except Stn. 208-5. These results suggest that high primary productivity in the cold water mass may be established by the upwelled nutrients and light adaptaion to convected phytoplankton due to upwelling of the bottom waters.

• Ocean and Polar Research
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• 제34권1호
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• pp.65-71
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• 2012

Gambierdiscus toxicus, Adachi et. Fukuyo, is a benthic ciguatoxin-producing armored dinoflagellate, often attached to macroalgae. This organism is the primary causative agent of ciguatera fish poisoning which occurs in tropical and subtropical regions. However, regardless of the fact that the population of Gambierdiscus spp. has expanded to such temperate areas from sub-trophic and trophic areas, monitoring of G. toxicus has been lacking in the Korean coastal waters of temperate areas. This study was performed at the uninhabited Baekdo Islands off the southern coast of Korea and at Seopsom Island in the vicinity of Seogwipo, Jeju Province during April and May, 2011. Cell densities of Gambierdiscus spp. on macroalgae at Baekdo and Jeju Island ranged from zero to 56.4 cells $g^{-1}$. Maximum density was recorded on the brown alga Cladophora japonica at St. 3 of Jeju Island. In particular, the cell densities of Gambierdiscus spp. were influenced by the substrate characteristics of macroalgae. In the future, the continuous monitoring of toxic benthic dinoflagellate is necessary to predict and prevent ciguatera poisoning in Korean coastal waters.

• Environmental Analysis Health and Toxicology
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• 제25권4호
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• pp.287-294
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• 2010

Objectives : The aim of this study was to verify the intersexuality of Crassostrea gigas and Ruditapes philippinarum in southern coastal waters of Korea. Methods : Specimens of Crassostrea gigas (n=363) were collected from six areas of Tongyeong, Geoje and Yeosu. Ruditapes philippinarum (n=221) was collected from five areas of Yeosu. The sex ratio and intersexuality were determined after observing gonad preparations. Results : The rate of intersexuality in Crassostrea gigas was 16.25%, with females (24.79%; n=30/121) exhibiting a higher rate than males (11.98%; n=29/242). The rate of intersexuality in Ruditapes philippinarum was 24.43%, with females (37.76%; n=37/98) exhibiting a higher rate than males (13.82%; n=17/123). Conclusions : The results of this study suggest that intersexuality is induced by aquatic pollutants such as endocrine disrupting chemicals (EDCs).

• Environmental Engineering Research
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• 제25권4호
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• pp.515-521
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• 2020

Nowadays, due to various pollution sources, it is essential for environmental scientists to monitor water quality. Phytoplanktons form the end of the food chain in water bodies and are one of the most important biological indicators in water pollution studies. Chlorophyll-A, a green pigment, is found in all phytoplankton. Chlorophyll-A concentration indicates phytoplankton biomass directly. Therefore, Chlorophyll-A is an indirect indicator of pollutants, including phosphorus and nitrogen, and their refinement and control are important. The present study, Moderate Resolution Imaging Spectroradiometer (MODIS) satellite images were used to estimate the chlorophyll-A concentration in southern coastal waters in the Caspian Sea. For this purpose, Multi-layer perceptron neural networks (NNs) were applied which contained three and four feed-forward layers. The best three-layer NN has 15 neurons in its hidden layer and the best four-layer one has 5 in each. The three- and four- layer networks both resulted in similar root mean square errors (RMSE), 0.1($\frac{{\mu}g}{l}$), however, the four-layer NNs proved superior in terms of R² and also required less training data. Accordingly, a four-layer feed-forward NN with 5 neurons in each hidden layer, is the best network structure for estimating Chlorophyll-A concentration in the southern coastal waters of the Caspian Sea.

• 한국양식학회지
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• 제6권2호
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• pp.63-69
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• 1993

여러 규모의 적조 현상이 1970년대 말부터 우리나라 대부분의 패류 및 어류 양식장이 있는 남해안에서 일어나고 있다. 경남 충무의 북신만도 이곳 중의 하나로 1980년대 초부터 매년 적조가 나타나고 있다. $1990\~1991$년 사이에 양식 생물의 대량 폐사가 이곳에 나타났고 이때의 우점 적조 생물 종은 90년 11월과 91년 6월에 Leplocylindrus danicus, 90년 12월과 91년 8월에는 Skeletonema costatum, 그리고 91년 8월에는 Nitzschia seriata, 91년 7월에는 Gymnodinium splendens로 기록되었으며 적조 시기의 최대 클로로필-a 량은 $265.7{\mu}/l$였다. 이렇게 빈번하게 발생하는 적조 현상은 부근 해역의 부영양화와 관계 있으며 적조와 부영양화의 상관 관계에 대하여 본 논문에서 논의하였다.

• 한국수산과학회지
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• 제44권6호
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• pp.689-694
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• 2011

Age and growth of whitespotted conger Conger myriaster were estimated using right sagittal otoliths from 495 fish collected from February, 2004, to January, 2005, in the southern coastal waters of Korea. Examination of the outer margin of the otoliths showed that opaque zones formed once a year and annual rings formed from April to June. The ages of the specimens examined ranged from 3 to 8 years. Whitespotted conger spawn from December to March. Allometry between preanal length and total weight can be expressed as $TW=0.0350{\times}PL^{2.9173}$ ($R^2=0.89$). There was no significant difference in allometry between females and males (P>0.05). The estimated VBF growth equation was $L_t=415.2(1-e^{-0.1457(t+0.4654)})$.

• 한국어류학회지
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• 제32권4호
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• pp.251-256
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• 2020

우리나라 연안성 어류자원 미발굴 분류군 탐색을 위해 제주도 남부 연안해역에서 SCUBA를 이용한 수중조사 과정 중 2015년 9월 수심 약 15미터에서 망둑어과 한국첫기록종인 Callogobius shunkan 2개체(표준 체장 54.9~66.1 mm)를 채집하였다. 본 종은 살아있을 때 암갈색 바탕에 등지느러미 기저부에서 시작하는 3개의 흑갈색 안상반문이 있는 점, 두부 감각관과 잘 발달된 피습에 공기열이 배열되어 있는 점(특히 비공과 안와 후방에 공기열이 있는 점), 배지느러미막이 잘 발달된 점, 흑갈색 바탕의 체색에 백색 반점이 산재하는 특징이 있다. 본 종의 신한국명으로 '주름망둑'을 제안한다.

• 한국수산과학회지
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• 제55권2호
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• pp.146-153
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• 2022

The vertical distribution and abundance of icthyoplankton in the southern waters of Jeju Island during June 2020 were investigated. Fish eggs and larvae were identified using the mitochondrial DNA cytochrome c oxidase subunit I (mtDNA COI) and the 16S rRNA gene. During this period, fish eggs of 23 taxa belonging to 21 families and larvae of 27 taxa belonging to 25 families were collected. Fish eggs were located mostly from the surface to 30 m depth of the water column. Larvae were located from the surface to 80 m depth of the water column. Vertical distributions of fish eggs and larvae were influenced by oceanography conditions such as temperature, salinity, and thermocline depth. No discernible difference in mean thermocline depth was observed between day and night.

• 한국미생물·생명공학회지
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• 제20권4호
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• pp.483-490
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• 1992

수계 환경에서 일어나는 유전자의 전이행방을 이해하기 위하여, conjugation에 의하여 전이되는 kanamycin 내성 ($Km^r$) 유전자에 대하여 DNA probe를 이용하여 Southern hybridization 방법으로 추적하였다. 자연계로부터 분리한 $Km^r$ 세균과 $Km^r$ 유전자를 유전자 조작기법으로 변형시킨 GMM 균주들을 donor로 하여 conjugation을 했을 때, $Km^r$ 유전자는 자연계 분리 균주에서보다 수질환경에 관계없이 10~00배 잘 전이되었다. LB 배지에서 GMM 균주의 $Km^r$ 유전자가 전이된 conjugant에서는 새로 생성되는 plasmid가 많이 나타났고 AW와 FW에서는 conjugation 시간에 따라 plasmid의 재배열 현상이 다양하였다. LB에서 얻은 conjugant들의 plasmid에 대하여 $Km^r$ DNA probe로 Southern analysis를 한 결과, plasmid의 재배열이 다양함에도 불구하고 conjugant들의 $Km^r$ plasmid는 donor에서와 같은 위치에서 hybridization signal이 나타났다. 그러나 AW에서 50시간 conjugation시켰을 때 DKI의 pDK101과 DKC601의 pDT529, 그리고 AW에서 30시간 conjugation 시켰을 때 DKC600의 pDK101은 전혀 나타나지 않고, 소실되었다. 또 전이된 $Km^r$ plasmid의 크기는 AW와 FW의 수질에 따라 약간 변화되어 나타났다. 그러므로 DNA probe에 의한 Southern hybridization 방법은 수질환경에서 특정 유전자의 전이행방을 추적하는데 매우 유용하다고 판단된다.