• Korean Journal of Environmental Agriculture
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• v.41 no.1
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• pp.65-70
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• 2022

BACKGROUND: The Geomunoreum Lava Tube System (GLTS) is both vast and culturally valuable. The Jeju Volcanic Island and Lava Tubes, which are partly composed of the GLTS, have been declared as a United Nations Educational, Scientific, and Cultural Organization (UNESCO) World Heritage Site. Exploration of the caves is strictly regulated to conserve these vulnerable environments. Photographs provide limited information and do not describe the entire environment comprehensively. Therefore, we created several illustrations of the lava tubes to display their environmental features. METHODS AND RESULTS: We explored six lava caves (upstream and downstream) in the GLTS and photographed their geological features and yellow walls, the colors of which are influenced by microbial mats. We compared the hex codes of the wall colors using the Clip Studio v1.10.5 software and created illustrations that accurately represent the scale and features of the caves. CONCLUSION(S): Upstream and downstream caves of the GLTS differ in scale and volcanic features. We illustrated various characteristics of the caves including lava cave features, vegetation, and microbial mats. We also described the internal and external cave environments.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.1
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• pp.29-34
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• 2001

A sweet sorghum [Sorghum bicolor (L.) Moench] cultivar was planted on 9 and 30 June 2000 at plant densities of 4, 6, 8, 10, and 12 plants $m^{-2}$ to determine the optimum plant density in Jeju region. There were no significant planting date x plant density interactions for most traits measured. Delaying planting from 9 to 30 June delayed 21 days in heading date, and significantly decreased plant height, the number of productive stems $m^{-2}$/, and lodging. Fresh stem yield tended to be higher at the 9 June planting date than at the 30 June planting date, but total sugar and ethanol yields were not significantly affected by planting date. Percentage of soluble solid was higher at the 30 June planting date compared with the 9 June planting date. Fresh stem, total sugar, and ethanol yields quadractically increased from 22.9 to 36.7 $t^{-1}$, from 1.66 to 2.54 $t^{-1}$, and from 945 to 1440 $L^{-1}$, respectively, with increasing plant density. The optimal plant densities for the maximum fresh stem, total sugar, and ethanol were estimated to be 10.7, 9.6, and 9.9 plants $m^{-2}$ respectively.

• Microbiology and Biotechnology Letters
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• v.49 no.3
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• pp.384-390
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• 2021

A Gram-negative, aerobic, motile by gliding, and rod-shaped marine bacterium, designated CE67^T was isolated from the marine sponge Callyspongia elegans on Biyang-do in Jeju Island. The CE67^T strain grew optimally at 25℃, pH 7.5, and in the presence of 2-3% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequence showed that strain CE67^T was related to the genus Aureivirga and had the highest 16S rRNA gene sequence similarity to the Aureivirga marina VIII.04^T type strain (96.3%). The primary fatty acids (>10%) of strain CE67^T were iso-C_15:0 (35.3%) and iso-C_17:0 3OH (21.8%). The polar lipid profile of strain CE67^T contained phosphatidylethanolamine, unidentified aminolipids, and unidentified lipids. The predominant menaquinone was MK-6. The DNA G+C content was 29.1 mol%. Based on the polyphasic taxonomic analysis, strain CE67^T was determined to be a representative novel species of the genus Aureivirga for which we propose the name Aureivirga callyspongiae sp. nov., whose strain type is CE67^T (=KCTC 42847^T=JCM 34566^T).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.4
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• pp.478-483
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• 2022

A single specimen (522.0 mm in total length) of the family Muraenidae, collected from the waters off south-western Jeju-do Island in November 2021, was identified as Echidna nebulosa on the basis of morphological and molecular methods (DNA barcoding). This species is characterized by several morphological traits as follows: 10 rounded molar, median intermaxillary, and vomerine teeth; 4 predorsal vertebrae, 50 preanal vertebrae and 123 total vertebrae; and a pale background color with two rows of 17-20 blackish brown starry blotches along the head and body. As this is the first record of E. nebulosa in Korea, we propose the new Korean names, "Dung-Geun-Ni-Gom-Chi-Sog" for the genus Echidna, and "Beol-Kkok-Gom-Chi" for E. nebulosa.

• Korean Journal of Plant Resources
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• v.25 no.4
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• pp.465-472
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• 2012

We examined plants that were used as temple food in Jeju from May 2011 to January 2012. Thirty-six temples participated in the study, and there were 58 questionnaire respondents. Fifty-seven taxa were used as temple food, which belonged to 27 families, 51 genera, 55 species, and two varieties. The most commonly used family-based taxa were eight species of Compositae, six species of Cruciferae, and four species of Umbelliferae. Ten species of woody plants and 25 species of Jeju native plants were also used as temple food. The most useful part was the leaf, followed by the root, leaflet, and fruit. A patent search showed that most of the surveyed plants were covered by intellectual property rights. Forty-eight species had food-related patents, 34 species had cosmetics-related patents, and 38 species had medicine-related patents. The purchase and procurement of Jeju temple food plants usually depended on the market or plant cultivation rather than the use of the plants. Gathering of wild herbs for temple food has been performed on a limited basis. Therefore, collecting traditional knowledge for the use of Jeju plant resources should be conducted under different conditions rather than through a temple-related study.

• Journal of the Korean Society for Marine Environment & Energy
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• v.11 no.2
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• pp.105-112
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• 2008

The surface and bottom water were sampling in ten stations of the coastal area of Chagwi-Do, Jeju Island, which was repeated 6 times in several different months(September, November, 2004 and March, May, August, and November 2005) in order to examine the physico-chemical characteristics of water. The temperature varied by approximately $16^{\circ}C$, ranging somewhere between 1$12.2^{\circ}C$ and $28.9^{\circ}C$. Specifically, the temperature of bottom water was $13^{\circ}C$, implying the emergence of low temperature water. The salinity ranged from 30.2 to 34.9%o, and the lowest salinity in August may be attributable to the effect of land-based water. N/P ratio, the growth factor of phytoplankton, ranged from 5 to 76, which varied depending on the season and station. The ratio, however, was over 22 on the average, suggesting that phosphate phosphorus is an factor that restricts the growth of phytoplankton. TOC in the concentration of organic carbon ranged between $92.5{\mu}M$ and $438.3{\mu}M$, and the mean was $217{\mu}M$. DOC ranged from $82.5{\mu}M$ to $299.2{\mu}M$, and the mean was $130{\mu}M$. The ratio of DOC/POC was 60% with abundant dissolved organic carbon.

• Journal of the Korean Geosynthetics Society
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• v.22 no.2
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• pp.85-92
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• 2023

This paper describes the comparative results of measured and predicted values for the horizontal displacement of earth retaining wall based on two field cases, in order to evaluate the application of lateral earth pressure to earth retaining wall supported by earth anchor in Jeju. The prediction of lateral earth pressure acting on the earth retaining wall was performed by elasto-plastic analysis using Rankine earth pressure, Hong & Yun lateral earth pressure, Terzaghi & Peck modified lateral earth pressure, and Tschebotarioff lateral earth pressure. As a result, the predicted value of the maximum horizontal displacement for site A was about 10 to 12 times greater than the measured value, and in the case of site B, the predicted value was evaluated as about 9 to 12 times greater than the measured value. That is, both sites showed a similar increase rate in the maximum horizontal displacement by the predicted value compared to the measured value. In all field construction cases, the maximum horizontal displacement by measured values occurred in the sedimentary layer, soft rock layer, and clinker layer, and the horizontal displacement distribution was shown in a trapezoidal shape. The maximum horizontal displacement by the predicted value occurred around the clinker layer, and the horizontal displacement distribution was elliptical. In the ground with a clinker layer, the measured value showed a very different horizontal displacement tendency from the predicted value, because the clinker layer exists in the form of a rock layer and continuous layer. In other words, it is unreasonable to apply the existing prediction method, which is overestimated, because the characteristics of the earth pressure distribution in Jeju show a tendency to be quite different from the predicted earth pressure distribution. Therefore, it is necessary to conduct a research on the lateral earth pressure in the realistic Jeju that can secure more economic efficiency.

• Animal Systematics, Evolution and Diversity
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• v.31 no.3
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• pp.146-152
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• 2015

Two scleractinian species are newly recorded in Korea: Leptoseris mycetoseroides Wells, 1954 and Phyllangia hayamaensis (Eguchi, 1968). The two genera Leptoseris Milne Edwards and Haime, 1849 and Phyllangia Milne Edwards and Haime, 1848 are also newly recorded in Korea. The specimens were collected from the subtidal zones of Jeju-do Island, Korea by SCUBA diving from 1991 to 2007. Leptoseris mycetoseroides is characterized by its platelike growth form, intratentacular budding, irregularly developed collines, single styliform columella, and even septa and septocostae. Phyllangia hayamaensis is distinguished by its encrusting and plocoid growth form of corallites basally united with common coenosteum, trabecular columella, and irregular septal arrangements and paliform lobes.

• Animal Systematics, Evolution and Diversity
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• v.30 no.2
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• pp.95-102
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• 2014

The four species of the suborder Holaxonia, Anthogorgia japonica Studer, 1889 of family Acanthogorgiidae, Astrogorgia rubra (Thomson & Henderson, 1906), Euplexaura attenuata (Nutting, 1910), and E. erecta (Kukenthal, 1908) of family Plexauridae have been newly recorded in Korea. They were collected from intertidal and sublittoral zones in the western and southern coasts and Jeju-do Island of Korea by SCUBA diving and fishing nets from 1969 to 2010. This study approaches holaxonians by focusing on external and internal morphologies including size, form, and color of colonies, branches, polyps, coenenchyme, axis, and spicules. Anthogorgia japonica is characterized by its planar growth form, dichotomously branched form, non-retractile polyps, and Astrogorgia rubra by arrangement of calyxes being situated in lateral side at stems and alternately in all sides at branches. Euplexaura attenuata is sparsely and laterally branched colony, and has straight wand-like stems. Euplexaura erecta has branches which run parallel to the main stem.

• Atmosphere
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• v.19 no.3
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• pp.289-296
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• 2009

Measurements of the three-dimensional water vapor distribution in the atmosphere are important for forecast and analysis of meteorological phenomenon. In this study, two Global Positioning System (GPS) campaign networks were installed in Jeju Island and Kangwon-do to construct the vertical water vapor profile solely based on GPS measurements. We implemented a layer model to get the wet refractivity profile and compared the result with radiosonde measurements. The result showed that the vertical profiles from GPS and radiosonde agree well. The bias, root-mean-square error (RMSE) and standard deviation of GPS wet refractivities compared with radiosonde measurements were in the range of 6.6~11.1 mm $km^{-1}$, 11.9~13.9 mm $km^{-1}$, and 4.3~12.3 mm $km^{-1}$, respectively.