• ALGAE
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• v.17 no.3
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• pp.135-144
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• 2002

Scytosiphonaceae is an acetocarpalean brown algal family, that is a recent focus of synstematics and marine biodiversity. We describe Petalonia zosterifolia and Scytosiphon gracilis from Korea for the first time. P. zosterifolia occurred on the East coast, and had flat, linear and solid thalli. S. gracilis was found in Jeju, and had cylindircal to flat and hol-low thalli. However, these two species are so similar that it is difficult to identify by morphology alone. In order to determine if the nuclear DNA reveals the distinctness of both species and to know their phylogenies, the ITS region sequences were newly detrmined in 22 samples of P. zosterifolia, Scytosiphon gracilis, and other three members of the genera from Korea. We found 0.12% variation among samples of P. zosterifolia from different locations, and no variation between S. gracilis samples from diferent years, but extensive interspecific divergences (13.62-22.83%) of each species to other members in Petalonia and Scytosiphon . The ITS sequence dta consistently showed a close relationship between P. zosterifolia and S. gracilis. This result is congruent with morphology and with the published data of plastid rbc and partial nrDNA large subunit gene sequences, and suggests that P. zosterifolia and S. gracilis might have diverged from the most recent common ancestor.

• Korean Journal of Agricultural Science
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• v.40 no.4
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• pp.425-434
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• 2013

Nowadays, the korean peninsula has endured weather changes toward to the subtropical climate. Also demographical structure has changed into multi-cultural society in which many people from subtropical areas have immigrated into Korea. Therefore, consumption and production of subtropical vegetables become important. For the analysis, we choose eight important subtropical crops. EDM (Equilibrium Displacement Model) with many parameters and elasticities is used for the forecast of consumption and required cultivation area. The simulation focuses on the changes of the number of foreign workers and immigrated women in Korea to predict the quantity of consumption and required area in Korea. The results show that we need additional land area about 581~1,065 ha for the cropping subtropical vegetables in Korea. Finally, these required area can be provided by the cities and counties in coast area in Gyeongsangnam-Do, Jeonranam-Do and Jeju-Do. Climate change will be continued in the future. Together with climate change, the change of demographical structure into multi-culture may increase consumption and production of subtropical vegetables. Forecasting of increased consumption and required cultivation area for subtropical vegetables is significant.

• Environmental Analysis Health and Toxicology
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• v.19 no.1
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• pp.73-80
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• 2004

숭어의 생식주기를 밝히기 위해 2002년 2월부터 2003년 3월까지 제주도 동남부 연안에서 채집하였고, 난모세포의 발달과정을 조직학적 방법으로 관찰하였다. 난모세포의 발달과정은 GSI변화와 밀접하였다. GSI는 9월에 급격히 증가하여 12월에 최고 값을 나타내었다. 난소의 조직학적 관찰결과, 염색인기와 주변인기의 난모세포는 연중 관찰되었으며,8월에는 일부에서 난황을 포함하는 난모세포가 관찰되었다. 대부분의 난모세포가 10월과 12월에는 난황구기 단계의 난모세포로 발달했다. 10월과 12월에 난황구기 난모세포들을 가진 개체의 출현이 가장 높았으며, 잔존여포와 퇴화 난모세포는 2월부터 관찰되었다. 숭어의 주 산란기는 11월에서 1월이고, 난군동기발달형의 난소를 가지며 외양으로 이동하여 산란하는 어류에 속한다.

• Journal of Species Research
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• v.7 no.4
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• pp.354-362
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• 2018

Population genetic assessment is essential for the conservation and management of endangered and rare plants. Neofinetia falcata is endangered epiphyte orchid and protected by law in Korea. In Korea, this species is only found on islands in the South Sea of Korea (including Jeju-do) and the southern coast of the Korean Peninsula. We developed nine microsatellite makers to assess the genetic diversity and population genetic structure of three populations of N. falcata. The genetic diversity at the species level was low, which can be attributed to inbreeding or fragmentation into small, isolated populations. A recent bottleneck was detected in one population, likely due to overcollection. N. falcata exhibited moderated levels of differentiation among populations, with the three populations were divided into two clusters based on genetic structure. The genetic diversity and structure of N. falcata are affected by restricted gene flow by pollen or seeds due to isolation and geographic distance. Strategies for in situ and ex situ conservation of this species are been proposed based on the results of our study.

• Atmosphere
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• v.20 no.2
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• pp.195-210
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• 2010

This study uses mesoscale model WRF to investigate characteristics of wind fields in South Korea, a region with a complex terrain. Hourly wind fields were simulated for one year representing mean characteristics of an 11-year period from year 1998 to year 2008. The simulations were performed on a nested grid from 27 km down to 1 km horizontal resolution. Seasonal variation of wind speed indicates that wind is strongest during the spring and winter seasons. Spatial distribution of mean wind speed shows wind energy potential at its peak in mountainous region of Gangwon-do, the east coast, and Jeju Island. Wind speed peaks at night in mountainous and eastern coastal regions, and in the afternoon inland and in the southwestern coastal region. The simulated wind map was verified with four upper-air sounding observations. Wind speed was shown to have a more pronounced overestimation tendency relative to observation in the winter rather than summer. The results of this wind mapping study help identify locations with the highest wind energy potential in South Korea.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.6
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• pp.856-861
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• 2016

This study compared the density of fish determined using three different echogram methods: the frequency-difference, time variable, and threshold modification methods. An acoustic survey was conducted off the coast of Jeju Island after sunset. Data at 38 and 120 kHz frequencies were collected using a commercial fishing vessel. As a reference point, the value of ${\Delta}MVBS_{120-38kHz}$ that distinguished fish from zooplankton using the 38 and 120 kHz frequencies was set at < 2 dB. The estimated density of fish along the survey line was 0.1-30.4, 0.1-64.3, and $0.1-51.7m^2/nmi^2$ using the frequency difference, time variable threshold, and threshold modification methods, respectively. The results of this study constitute basic research for estimating fish densities.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.60 no.1
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• pp.18-26
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• 2024

In this study, we estimated the distribution density of giant jellyfish in coastal waters of Korea in 2023 and compared the occurrence of giant jellyfish over four years. In May, the giant jellyfish were mainly distributed in the waters of the Yangtze River outflow, and in July, they were highly distributed in the west of Jeju Island and near the south coast of Korea. In addition, when comparing the distribution densities of giant jellyfish in Korea over four years, both acoustic and sighting surveys showed that the highest density of jellyfish occurred in 2021.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.4
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• pp.315-326
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• 2013

This study investigated the temporal-spatial distribution and variations in water quality parameters (temperature, salinity, pH, DO, COD, SPM, DIN, DIP, silicate, TN, TP, and chlorophyll-a) in the coastal area of Jeju, Korea, adjacent to aquaculture ponds (Aewol-ri, Haengwon-ri, Pyosun-ri, and Ilkwa-ri). Data were collected bimonthly from February 2010 to December 2011. A principal component analysis (PCA) identified three major factors controlling variations in water quality during the sampling period. Aquaculture effluent water led to large changes in nutrient levels. The highest nutrient values were observed during the investigation period. The relatively large increase in organic matter at the sampling stations coupled with sea area runoff events during the summer rainy period. Variation in chlorophyll-a concentration was mainly driven by meteorological factors such as air temperature and rainfall in the coastal areas of Aewol and Haengwon. In the coastal areas of Pyosun and Ilkwa, pollution was caused by anthropogenic factors such as discharge of aquaculture effluent water. High nutrient concentrations at the majority of the coastal stations indicate eutrophication of coastal waters, especially within a distance of 300 m and depth of 10m from drainage channels. Coastal eutrophication driven by aquaculture effluent may be harmful inshore. Events such as eutrophication may potentially influence water pollution in aquaculture ponds when seawater intake is detected because of aquaculture effluent water.

• Korean Institute of Interior Design Journal
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• v.26 no.4
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• pp.42-56
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• 2017

In Korea, which has three sides of the sea, various waterfront spaces are being developed and developed along with various coastal landscapes. However, there are a lot of cases that do not consider the regional characteristic of the coast or the characteristic of the coastal landscape. In many cases, the street facilities cause the landscape degradation and the use inconvenience because of incongruity with the scenery, aging and lax management. Therefore, it is necessary to reflect the specificity of the coastal landscape in planning and directing the street facilities, harmonizing with the surrounding natural environment, and consideration of sustainability. However, there is no research or planning index for sustainable street facilities considering the coastal characteristics. Therefore, this study suggests plan elements to improve the sustainability of the street facilities on the shore and proposes them as basic plan elements, and suggests what kind of improvements should be made to improve the sustainability of coastal facilities in Korea. Based on the plan elements derived from the plan, we checked the problems and complementary points of coastal street facilities in Korea by analyzing the current status of the street facilities around the Jeju Island beach from a sustainable point of view, and suggested plan indicators that should be supplemented to improve sustainability. We surveyed the street facilities such as walkway blocks, benches, pagoda, drinking fountain, trash cans, bicycle shelters, fences, guide maps, streetlights, and shower rooms in 10 beaches in Jeju Island. This study analyzed the sustainability characteristics of the each factor of these facilities by surveying the reflectivity of the 23 plan indicators from the six aspects derived from the sustainability planning factor as conformity, partial reflection, non - reflection, and nonconformity. The results of the analysis showed that the functional aspect was the highest with 68.3%, the material aspect (53%), the landscape aspect (22.3%), the productive aspect (14.7%) and the morphological aspect (12.2%), and maintenance / management (10.6%). In addition, the facilities with the lowest fitness in each aspect are bicycle shelter in landscape aspect, bicycle storage box and trash can in form aspect, shower room in material aspect, trash can in functional aspect, showroom, guide maps and drinking fountain in product aspect, showroom In maintenance aspect. In order to improve the sustainability of coastal facilities in the future, it is necessary to complement the administrative and landscape aspects. In coastal facilities, it is necessary to consider the sustainability planning index, especially for showers, taking into account the specificity of beaches. Consideration should be given to various aspects of sustainability for bike shelters and trash facilities. Through this study, we have proposed the plan elements to systematize, supplement, and improve the planning index for sustainability improvement in coastal facilities planning.

• ALGAE
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• v.21 no.1
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• pp.141-148
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• 2006

Benthic diatoms are known as a good food for shellfish in nature and in commercial hatchery of Jeju Island, Korea. Grammatophora marina is commonly found as dominant benthic micro-algae in Jeju coastal waters throughout the year. To know the best growth conditions of this species, culture was done in terms of three parameters; water temperature, salinity and nutrients. Each parameter was controlled by temperature of 15, 20 and 25°C; salinity of 25, 30 and 35 psu; and nutrient concentrations of 50, 100 and 200%. F/2 media was used with artificial seawater for the culture, which was continued for two weeks with L:D cycle 12:12 by using fluorescent light. Maximum specific growth rate was recorded 1.68 d–1 at temperature of 25°C with salinity of 35 psu and nutrient concentration of 200% on 6th day during the culture period. Maximum biomass was also observed 4.9 × 105 cells mL–1 in the same condition. This species may belong to the euryhaline and eutrophic habitat with warm condition. For nutritional aspects of this species, protein, lipid and carbohydrate were measured. The value of protein, lipid and carbohydrate was 4.96%, 15.82% and 5.65%, respectively. The antioxidant activities of 80% methanolic extract were 46.7%, 23.7% and 23.8% on DPPH (1,1-Diphenyl-2-picrylydrazy) radical, superoxide anion radical and hydrogen peroxide scavenging, respectively. Percentage metal chelating activity was 81.2%. Enzymatic extracts of Alcalase and Ultraflow showed remarkable scavenging activities on DPPH radical (86.5% and 57.2%, respectively), and superoxide anion scavenging activities were 45.3% and 41.4% from Kojizyme and Viscozyme extracts, respectively. Extract of Protomex revealed 24.8% activity on hydrogen peroxide and Neutase showed 30.8% on hydroxyl radical scavenging effects. Celluclast and Viscozyme extracts showed 33.2% and 32.1% activities on nitric oxide scavenging, respectively, while Alcalase showed 61.5% on metal chelating. This species contains higher lipids among the biochemical compounds and higher metal chelating activities from both 80% methanolic and enzymatic extracts.