• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.24 no.2
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• pp.208-225
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• 2019

To understand the mean surface circulation and surface currents in the East Sea, trajectories of surface drifters passed through the East Sea from 1991 to 2017 were analyzed. By analyzing the surface drifter trajectory data, the main paths of surface ocean currents were grouped and the variation in each main current path was investigated. The East Korea Warm Current (EKWC) heading northward separates from the coast at $36{\sim}38^{\circ}N$ and flows to the northeast until $131^{\circ}E$. In the middle (from $131^{\circ}E$ to $137^{\circ}E$) of the East Sea, the average latitude of the currents flowing eastward ranges from 36 to $40^{\circ}N$ and the currents meander with large amplitude. When the average latitude of the surface drifter paths was in the north (south) of $37.5^{\circ}N$, the meandering amplitude was about 50 (100) km. The most frequent route of surface drifters in the middle of the East Sea was the path along $37.5-38.5^{\circ}N$. The surface drifters, which were deployed off the coast of Vladivostok in the north of the East Sea, moved to the southwest along the coast and were separated from the coast to flow southeastward along the cyclonic circulation around the Japan Basin. And, then, the drifters moved to the east along $39-40^{\circ}N$. The mean surface current vector and mean speed were calculated in each lattice with $0.25^{\circ}$ grid spacing using the velocity data of surface drifters which passed through each lattice. The current variance ellipses were calculated with $0.5^{\circ}$ grid spacing. Because the path of the EKWC changes every year in the western part of the Ulleung Basin and the current paths in the Yamato Basin keep changing with many eddies, the current variance ellipses are relatively large in these region. We present a schematic map of the East Sea surface current based on the surface drifter data. The significance of this study is that the surface ocean circulation of the East Sea, which has been mainly studied by numerical model simulations and the sea surface height data obtained from satellite altimeters, was analyzed based on in-situ Lagrangian observational current data.

• Animal Systematics, Evolution and Diversity
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• v.8 no.2
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• pp.163-176
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• 1992

Three species of foreign barnacles were found to invade into Korean interitidal seashores: Balanus amphitrite, B. ebumeus and B. improvisus. The southeastern coast of Korea, near Pusan, is the area where all the specimens of three species were discovered and the populations of these species were well establishe. B. amphitrite is the earliest invader(probably invaded around early 1970's) and most widely distributed in Korea. It is now distributed all around Korea, except the Yellow Sea coast, north of Mokpo. B. improvisus has been successful to expand its reange to the northern part of Korean coast of the East Sea, whereas B. eburneus is restricted to the southeastern coast. B. amphitrite is successfully competing with the native barnacle, B. albicostatus, and in several areas where the mixed populations of the two species occur, the latter species is found to excluded. The Yellow Sea coast has not been invaded by the foreign barnacles, the reason of which is not known.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.7
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• pp.909-917
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• 2017

In this study, we investigated the relationship between catches of yellowtail and water temperature at the set net fisheries of Gyeongsangbuk-do (Gyeongbuk) and Gangwon-do (Gangwon) off the east coast of Korea from May-November, 1980-2010. We also analyzed the water temperature and fluctuation of catches during the northward moving period (May-August) and southward moving period (September-November) using NOAA satellite images. Although the total catches fluctuated year by year, catches increased during the southward moving period when the water alongside the coast warmed. Yellowtail catches during the southward period in fall were higher than those during the northward period in spring or summer. The catch when the water temperature decreased was larger in Gyeongbuk than in Gangwon for all periods However, the catch when the water temperature increased was much larger in Gangwon than in Gyeongbuk. This indicates that high summer temperatures (> $25^{\circ}C$) affected the coast of Gangwon, with high water temperature ($20^{\circ}C$) maintained in the region during fall. Therefore, the increased catch in Gangwon was due to longer yellowtail presence caused by increased water temperature.

• Korean Journal of Remote Sensing
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• v.39 no.5_2
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• pp.785-798
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• 2023

Recently, forest fires have become frequent due to climate change, and the size of forest fires is also increasing. Forest fires in Korea continue to cause more than 100 ha of forest fire damage every year. It was found that 90% of the large-scale wildfires that occurred in Gangwon-do over the past five years were concentrated in the east coast area. The east coast area has a climate vulnerable to forest fires such as dry air and intermediate wind, and forest conditions of coniferous forests. In this regard, studies related to various forest fire analysis, such as predicting the risk of forest fires and calculating the risk of forest fires, are being promoted. There are many studies related to risk analysis for forest areas in consideration of weather and forest-related factors, but studies that have conducted risk analysis for forest-friendly areas are still insufficient. Management of forest adjacent areas is important for the protection of human life and property. Forest-adjacent houses and facilities are greatly threatened by forest fires. Therefore, in this study, a grid-based forest fire-related disaster risk map was created using factors affected by forest-neighboring areas using national branch numbers, and differences in risk ratings were compared for forest areas and areas adjacent to forests based on Gangneung forest fire cases.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.58 no.4
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• pp.310-316
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• 2022

Giant pacific octopus, Enteroctopus dofleini, is a large mollusk distributed in the East Sea of Korea. In this study, the catch status of giant pacific octopus by drift line fishery and the effect of sea temperature on fishing ground were investigated in Goseong-gun, Gangwon-do, which is the central coast of the East Sea. The average catch of giant pacific octopus in Gangwon-do was 1,570 tons over the past ten years, and it accounted for 21% in 2008 and 44% in 2021 compared to the total catch in the East Sea during the same period. Such data indicates that the catch in Gangwon-do has recently increased. In this study area, giant pacific octopus weighing 1.1-5.0 kg dominated accounting for 56% of the total individuals, and followed by those weighing 1 kg or less. However, the ratio of catch of giant pacific octopus over 5.1 kg tended to increase in 2021, which is thought to be related to the sea temperature that affected the fishing ground. The main depth of fishing ground was from 21 m to 50 m in this area and fishing grounds were widely distributed throughout the season except summer. Fishing ground was formed with the conditions of bottom sea temperature under 10℃ and was diminished by moving of giant pacific octopus to deeper depth with conditions of bottom sea temperature over 18℃.

• ALGAE
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• v.19 no.3
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• pp.257-270
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• 2004

In order to clarify the structure and seasonal dynamics of warm tolerant benthic marine algal community in Korea, the species composition and biomass of marine algae at the discharge canal of Uljin nuclear power plant on the East Coast of Korea were investigated seasonally from February 1992 to October 2000. 107 species of marine algae were found at the discharge canal during the past nine years. In general, the number of species observed was abundant in spring or summer and less in autumn or winter. 27 species (4 blue-green, 5 green, 6 brown and 12 red algae) of marine algae occurred more than 1/ 6 frequency and thus can be categorized as warm tolerant species. Among these, one brown (Dictyota dichotoma) and four red algae (Gelidium amansii, Anphiroa ephedraea, Hydrolithon sargassi, Marginisporum crassissimum) are recorded as warm tolerant marine algae for the first time in Korea. Padina arborescens, Anphiroa zonata and Corallina pilulifera were common species found more than 75% frequency. Seasonal fluctuations of mean biomass were 0-1,330 g dry wt m^(-2) and dominant species in biomass were Corallina pilulifera (contribution to a total biomass proportion 34%), Anphiroa zonata (23%), Padina arborescens (18%) and Sargassum micracanthum (11%). The red algae appeared as predominant algal group at the discharge canal of Uljin nuclear power plant in the qualitative and quantitative aspects. The green algae such as Enterornorpha compressa appeared rather frequently at the discharge canal, but the biomass proportion was very low, in contrast to Kori nuclear power plant where there was definite green algal dominance. Differences in algal communities developed at the discharge canals of Uljin and Kori nuclear power plant on the East Coast of Korea, particularly biomass proportions of green algae, can probably be related to local environmental factors such as water velocity through the canal and natural seawater temperatures.

• Journal of Environmental Science International
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• v.12 no.6
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• pp.677-688
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• 2003

The purpose of this study was to predict occurrence of earthquakes in Korea by measuring the concentration of radon radioactivity in the air and in the underground water. Two monitoring systems of radon concentration detection in the air were installed in Seoul, East Coast area, whereas of radon concentration in the underground water in Kyungju area during December, 1999 to June, 2001. The distribution of radon concentration in the air in Seoul is as follows Winter(10.10 $\pm$ 2.81 Bq/㎥), autumn(8.41 $\pm$ 1.35 Bq/㎥), summer(5.83 $\pm$ 0.05 Bq/㎥) and spring (5.34 $\pm$ 0.44 Bq/㎥), whereas the distribution of radon in the air in the East Coast area showed some difference as follows : autumn (14.08 $\pm$ 5.75 Bq/㎥), Summer (12.04 $\pm$ 0.53 Bq/㎥), Winter (12.02 $\pm$ 1.40 Bq/㎥) and spring (8.93 $\pm$ 0.91 Bq/㎥). In the meanwhile, the distribution of radon in the water is as follows : spring (123.59 $\pm$ 16.36count/10min), Winter (93.95 $\pm$ 79.69counter/10min), autumn (68.96 $\pm$ 37.53counter/10min) and spring (34.45 $\pm$ 9.69counter/10min). The daily range of the density of radon concentration in Seoul and East Coast area was between 5.51 Bq/㎥ - 9.44 Bq/㎥, 7.15 Bq/㎥ - 15.27 Bq/㎥, respectively. Correlation of the distributions of radon concentrations in the air and in underground water with earthquake showed considerable variations of radon concentration before the occurrence of the earthquake. The results suggested that radon radioactivity seemed to be helpful for the prediction of the occurrence of earthquake.

• ALGAE
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• v.21 no.4
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• pp.453-461
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• 2006

This study is intended to clarify the structure and seasonal dynamics of warm tolerant benthic marine algal community in Korea. The species composition and biomass of marine algae at the discharge canal of Wolseong nuclear power plant on the East Coast of Korea were investigated seasonally from February 2001 to October 2005. As a result, 43 species (6 blue-green, 8 green, 9 brown and 20 red algae) of marine algae were found at the discharge canal during the past five years. In general, the number of species observed was abundant during winter to summer and less in autumn. Lyngbya confervoides and Enteromorpha compressa always occurred at the discharge canal during the past five years, and Oscillatoria brevis, Padina arborescens and Caulacanthus ustulatus were common species found more than 80% frequency during the study period. Seasonal fluctuations of mean biomass were 2-659 g dry wt m–2 and dominant species in biomass were Caulacanthus ustulatus (contribution to a total biomass proportion 37%), Enteromorpha compressa (26%) and Padina arborescens (24%). Results showed that, in the floristic composition, the green algae occurred as common algal group at the discharge canal of Wolseong nuclear power plant. In the quantitative aspect, however, the red algae such as Caulacanthus ustulatus and Ahnfeltiopsis flabelliformis appeared as predominant group at the discharge canal, in contrast to Kori nuclear power plant where there was a definite green algal dominance. Differences in algal communities developed at the discharge canals of three nuclear power plants on the East Coast of Korea can probably be related to local environmental factors.

• ALGAE
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• v.20 no.3
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• pp.217-224
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• 2005

The species composition and biomass of marine algae at the discharge canals of three (Gori, Wolseong and Uljin) nuclear power plants on the east coast of Korea were investigated seasonally from February 1992 to October 2000. As a result, 103-107 species of marine algae were found at the discharge canals during the past nine years. In general, algal communities established at the discharge canals were less diverse than those at the intake canals and control sites. 43 species (6 blue-green, 9 green, 10 brown and 18 red algae) of marine algae occurred more than 1/6 frequency and thus can be categorized as warm tolerant species. Among these, two green (Urospora penicilliformis, Cladophora albida), four brown (Sphacelaria divaricata, S. rigidula, Sargassum coreanum, S. fulvellum) and four red algae (Stylonema alsidii, Bangia atropurpurea, Hypnea charoides, Chondria crassicaulis) are recorded as warm tolerant marine algae for the first time in Korea during this study. Enteromorpha compressa, Padina arborescens, Amphiroa zonata and Ahnfeltiopsis flabelliformis were common species found more than 50% frequency at the discharge canals of all three nuclear power plants investigated. Dominant species in biomass were Padina arborescens and Amphiroa zonata. Results showed that, as a whole, the red algae appeared as predominant algal group at the discharge canals of all three nuclear power plants on the east coast of Korea. However, the biomass proportion of dominant algae at the discharge canals of each nuclear power plant varied over the year during the past nine years.

• Journal of Microbiology and Biotechnology
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• v.30 no.12
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• pp.1927-1936
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• 2020

Tunicates are known to contain biologically active materials and one species in particular, the sea peach (Halocynthia aurantium), has not been thoroughly studied. In this study we aimed to analyze the fatty acids profile of the H. aurantium body wall and its immunomodulatory effects on RAW264.7 macrophage-like cells. The fatty acids were classified into three categories: saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs), and polyunsaturated fatty acids (PUFAs). Omega-3 fatty acid content, including EPA and DHA, was higher than omega-6 fatty acids. H. aurantium body wall fatty acids exhibited enhanced immune response and anti-inflammatory effects on RAW264.7 macrophage-like cells. Under normal conditions, fatty acids significantly increase nitric oxide (NO) and PGE2 production in a dose-dependent manner, thereby improving the immune response. On the other hand, in LPS-treated RAW264.7 cells, fatty acids significantly decreased nitric oxide (NO) and PGE2 production in a dose-dependent manner, thereby enhancing anti-inflammatory effects. Fatty acids transcriptionally control the expression of the immune-associated genes, iNOS, IL-1β, IL-6, COX-2, and TNF-α, via the MAPK and NF-κB signaling cascades in RAW264.7 cells. However, in LPS-stimulated RAW264.7 cells, H. aurantium body wall fatty acids significantly inhibited expression of inflammatory cytokine; similarly, production of COX-2 and PGE2 was inhibited. The results of our present study provide insight into the immune-improving and anti-inflammatory effects of H. aurantium body wall fatty acids on macrophages. In addition, our study demonstrates that H. aurantium body wall is a potential source of immune regulatory components.