• Fisheries and Aquatic Sciences
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• v.23 no.7
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• pp.17.1-17.4
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• 2020

Six specimens of Bathygobius hongkongensis were collected for the first time from the eastern coast of Jeju Island, Korea, in September-November 2017. This species is characterized by a pectoral fin with free rays and the division of the first dorsalmost pectoral free ray into three branches; a lower jaw with a mental frenum; and an anterior nostril with a tiny flap. Bathygobius hongkongensis is similar to B. fuscus but differs in having more dorsalmost free pectoral fin rays. The new Korean name proposed for B. hongkongensis is "Nam-bang-mu-nui-mang-duk."

• 한국균학회소식:학술대회논문집
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• 2014.05a
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• pp.49-49
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• 2014

South Korea is covered primarily by temperate vegetation; therefore, foliicolous lichens may not be expected to play an important role in its lichen flora. Indeed, more than 100 years after the first lichen record from South Korea reported by Hue, the paper "Pyrenocarpous lichens in Korea" published by Moon and Aptroot, reported on the presence of two foliicolous lichens, Strigula nemathora Mont, and S. smaragdula Fr., for the first time in South Korea. No detailed reports on foliicolous lichens have since been published in South Korea. In Japan, the neighboring country, approximately 83 foliicolous lichen species are distributed at the southernmost part under temperate to subtropical climatic conditions. However, a large number of foliicolous lichens, with many recent records, have been reported in neighboring countries like China and Taiwan. According to Thor et al., studies on foliicolous lichen flora of Asia are comparatively poor compared to those reported from America. There are six lichenogeographical regions: the Neotropics, Valdivia, Tethyan, African Paleotropics, eastern Paleotropics, and Neozelandic-Tasmanian, which are demarcated based on the known worldwide distribution pattern of foliicolous lichen flora. South Korea belongs to the eastern paleotropic region, where a higher number of local endemic foliicolous lichens have been reported. So far, there are a total of six known foliicolous lichen taxa from South Korea; S. concreta, S. macrocarpa, S. melanobapha, S. nemathora, S. smaragdula, and S. subelegans from Jeju Island. So far, the genus Strigula is the only known representative of the foliicolous lichen flora in South Korea. Among the recorded species, S. concreta, S. smaragdula, and S. subelegans are abundant and widespread. Japan, the closest area to Jeju Island, has the same distribution pattern of foliicolous lichens, with S. smaragdula, S. melanobapha, and S. subtilissima. Pollen studies conducted by Chung reported that changes in vegetation on Jeju Island, due mainly to deglacial warming and the influence of geographical change, resulted from sea-level rises. In general, all of the foliicolous lichens observed so far were restricted to the southernmost part of South Korea, particularly Jeju Island. Island might be influenced by its geographical setting. One reason could be the close dispersal distances of spores and vegetative propagules from areas such as the southern part of Japan and eastern part of China, where more foliicolous lichens can be found. Thor et al. also showed that the southern part of Japan harbors more foliicolous lichens than the northern part. Considering that China is close to Jeju Island, many foliicolous lichens, including S. concreta, S. macrocarpa, S. nemanthora, and S. smaragdula, have been reported from Yunnan province, the southernmost part of China. Geographically, this province is far away from Jeju Island. In other provinces, such as Shandong, Jiangsu, Shanghai, and Zhejiang, which are closer to Jeju Island, no foliicolous lichens have been recorded so far. Therefore, the chance of spores and propagules coming from such closer areas is questionable. Thus, the location of origin of ancestors of foliicolous lichens of South Korea and the time and means of their invasion of this island is controverisial. The current study would lead the way to finding answers to the above mentioned questions.

• Journal of Environmental Science International
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• v.28 no.4
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• pp.423-433
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• 2019

This study was carried out to identify the problems of the underground watersheds on Jeju Island, and to establish the hydraulic groundwater basin to be used as basis for the analysis of the groundwater model. In order to evaluate the adequacy of the groundwater basin on Jeju Island, a correlation analysis between elevation and groundwater level was conducted using data from 125 observation wells. The analysis, conducted with an elevation step of 100 m, exhibited values of R2 in the range 0.1653-0.8011. No clear correlation was observed between elevation and groundwater level. In particular, the eastern and western areas showed an inverse proportionality between elevation and groundwater level. The Kriging technique was used to analyze the underground water level data and to define the equipotential lines for all areas of Jeju Island. Eight groundwater watersheds were delineated by considering the direction of groundwater flow, the positions of the observation wells, and the long and short axes of the watersheds.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.15 no.3
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• pp.1-6
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• 2019

The basalt fiber, which is found to be non-toxic and harmless to the human body, is expected to become a trend for industrial fibers as they have better properties of non-combustion, heat-resistant, soundproof, absorbent, moistureproof, wear-resistant, corrosion resistant, lightweight, and high strength properties. Thus, in this study, we analyzed the chemical compositions of basalt produced at seven sites on Jeju Island for making a high value inorganic insulation material. The results showed that the MgO content of basalt collected from the eastern part of Jeju Island was higher than 7.5 percent, while that of the western region was less than 6 percent.

• Journal of Fisheries and Marine Sciences Education
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• v.29 no.1
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• pp.297-305
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• 2017

This study was analysed the species composition of demersal fishes caught by a bottom trawler, KAYA, in the winter season during 4 years and the study area was the eastern fishing ground in depth of about 110m, 40 miles eastward from Jeju Island, Korea. A total of 54 species were collected, including 40 species of Pises, 9 species of Mollusks, 5 species of Crustaces. The number of individuals and biomass of unit area was $7,978ind/km^2$ and $1,800kg/km^2$, respectively. The dominant species in winter season were Dentex tumifrons, Carangoides equula, Callanthias japonicus, Thamnaconus modestus and Pagrus major. And these also were caught every year. The ranges of the diversity index(H') were 1.97 to 2.40, the richness(R) 1.91~4.59, the evenness(E) 0.54~0.83 and the dominance(D) 0.42~0.61.

• Proceedings of the Korea Society of Environmental Biology Conference
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• 2006.06a
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• pp.9-10
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• 2006

• Journal of Environmental Science International
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• v.22 no.5
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• pp.609-623
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• 2013

Fluctuation patterns of groundwater level as a factor that reflects the characteristics of groundwater system can be categorized as the various types of aquifer with the time-series data. Time-series data on groundwater level obtained from 115 monitoring wells in Jeju Island were classified according to variation types, which were largely affected by rainfall(Dr), rainfall and pumping(Drp), and unknown cause(De). Analysis results indicate that 106 wells belong to Dr and Drp and the ratio of the wells with the wide range of fluctuation in the western and northern regions was higher than that in the eastern and southern regions. From the results that Drp is relatively higher than Dr in the western region which has the largest agricultural areas, groundwater level fluctuations may be affected significantly due to the intensive agricultural use. Non-parametric trend analysis results for 115 monitoring wells show that the increasing and decreasing trends as the ratio of groundwater levels were 14.8% and 22.6%, respectively, and groundwater levels revealed to be increased in the western, southern and northern regions excluding eastern region. Results of correlation analysis that cross-correlation coefficients and the time lags in the eastern and western regions are relatively high and short, respectively, indicate that the rainfall recharge effect in these regions is relatively larger due to the gentle slope of topography compared to that in the southern and northern regions.

• Journal of Soil and Groundwater Environment
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• v.26 no.3
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• pp.1-13
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• 2021

Groundwater monitoring is commonly practiced with real-time sensors placed in several depth spots in aquifer. However, this method only provides monitoring data at the point where the sensors are installed. In this study, we developed a vertical line monitoring system (VLMS) that can provide continuous data of groundwater parameters along the vertical depth. The device was installed in a well located on the coast of the eastern part of Jeju island to monitor electrical conductivity, temperature, salinity, pH, dissolved oxygen, and oxidation-reduction potential over approximately 3 months from September 11 to December 3, 2020. The results indicated that the groundwater levels fluctuated with the tidal change of seawater level, and the upper and lower boundaries of the freshwater and saltwater zone in the groundwater were located at below 16 m and 36 m of mean sea level, respectively. There was a large variation in EC values during the high tide and temperature change was the greatest during flow tide. Although further investigation is needed for improvement of the device to obtain more accurate and reliable data, the device has a potential utility to provide fundamental data to understand the seawater intrusion and transport mechanisms in coastal aquifers.

• Journal of the Korean Solar Energy Society
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• v.33 no.5
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• pp.60-68
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• 2013

This paper presents the characteristics of lightning over established and scheduled wind farms of Jeju island as well as over specific range of entire Jeju Island. The lightning data for 5 years from 2008 to 2012 was obtained from IMPACT ESP which detects lightning. Lightning frequency, lightning strength and regional lightning events were analyzed in detail, and then the lightning maps of Jeju Island were created. The evaluation of lightning rate was made for all the wind farms of this study. Damage to wind turbines by lightning was found in the existing wind farms. As a result, the eastern part of Jeju Island had more lightning frequency than the western part of the Island. Also, the evaluation of lightning rate was good for all established and scheduled wind farms of Jeju Island. Hankyung is the best place for lightning safety, while precaution should be taken against lightning damage in Kimnyung. Lightning damage to wind turbines occurred in Samdal and Haengwon wind farms, which had the first and the second highest lightning rate of the five existing wind farms.

• ALGAE
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• v.34 no.4
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• pp.253-266
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• 2019

Several species classified to the genus Ulva are primarily responsible for causing green tides all over the world. For almost two decades, green tides have been resulted in numerous ecological problems along the eastern coast of Jeju Island, Korea. In order to characterize the species of Ulva responsible for causing the massive blooms on Jeju Island, we conducted DNA barcoding of tufA and rbcL sequences on 183 specimens of Ulva from eight sites on Jeju Island. The concatenated analysis identified five bloom-forming species: U. australis, U. lactuca, U. laetevirens, U. ohnoi and a novel species, U. pseudo-ohnoi sp. nov. Among them, U. australis, U. lactuca, and U. laetevirens caused to the blooms coming mainly from the substratum. U. ohnoi and U. pseudo-ohnoi sp. nov. were causative the free-floating blooms. Four species, except U. australis, are characterized by marginal teeth. A novel species, U. pseudo-ohnoi sp. nov., is clearly diverged from the U. lactuca, U. laetevirens, and U. ohnoi clade in the concatenated maximum likelihood analysis. Accurate species delimitation will contribute to a management of massive Ulva blooms based on this more comprehensive knowledge.