• Journal of the Korean earth science society
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• v.30 no.5
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• pp.581-587
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• 2009

This study intended to the optimal conservation method and to make an application scheme for the fossil locality of the Quaternary Hamori Formation at the northeastern coast of Mt. Songak. Many kinds of innumerable fossils are found from the Hamori Formation in the study area: Footprints of hominid, trace fossils of invertebrates, bird, artiodactyla, proboscidea, carnivores, unclassified footprints, and body fossils (arthropoda, gastropoda, mollusca, and plants). The formation has been outcropped and eroded out with innumerous fossils by the strong wave action of storm and typhoon. Korean government recognized the dangerous situation of the important fossils and decided to conserve the formation for the national heritage. Method D1 (conservation hall or museum on the fossil locality) may be the best way to protect the fossil locality from all the natural activities and to do the research, exhibition, education, and sightseeing together. The application of the geologic materials from the fossil locality should preferentially focus on the collection and research which should be accompanied by exhibition, education, and sightseeing. The application scheme may be stepped into three stages during 10 years: (1) systematic conservation and publicity during 2005-2007, (2) establishment of wellorganized museum during 2008-2010, and (3) international museum with the optimized roles 2011-2014.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.3
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• pp.354-365
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• 2019

Megabenthos samples were collected using 10-min trawls towed at 17 stations from 2015 to 2016. The dominant species (>1% of the total density) were Stegophiura sterea (10.4%) and two subtropical species, Mactrinula dolabrata (9.0%) and Acila divaricate (8.3%), respectively. The community structure of the megabenthos fell into four groups: the southeast, the southernmost region off Jeju Island, the frontal zone of the South Sea with C3, and a diagonal area from the south coast to the western side of Jeju Island. The total numbers of species, diversity, density and biomass were higher in the C3 region of the South Sea. Environmental factor analysis showed that differences in the megabenthos community were related to depth, gravel contents, and sorting value (${\sigma}$). These results indicate that changes in the marine environmental conditions in the South Sea of Korea affect the megabenthos species' composition and diversity.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.58 no.1
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• pp.59-67
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• 2022

This study assessed the levels of water qualities and microbials contamination of inland olive flounder farms in Jeju in the summers from 2015 to 2017. Three farms (A-C) located in a concentrated area using mixing coastal seawater and underground seawater and one farm (D) located in an independent area using only coastal seawater were selected. Total ammonia nitrogen (TAN) reached a maximum of 0.898 ± 1.024 mg/L as N in the coastal seawater of A-C, which was close to the limit of the water quality management goal of the fish farm. TAN in the influent from A-C was up to three times higher than that of D, so that the discharged water did not spread to a wide range area along the coast and continued to affect the influent. TAN of the effluent in A-C increased by 2.7-4.6 times compared to the influent, resulting in serious self-pollution in the flounder farm. Heterotrophic marine bacteria in the influent of A-C was about 600 times higher than D, and the discharge of A-C was increased by about 30 times compared to the influent.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.08a
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• pp.26-26
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• 2020

Daphne L. (Thymelaceae) comprises about 95 species distributing worldwide from N Africa, N India, SE Asia to E Asia and the coast of the Mediterranean of Europe. In Korea, five species of this genus have been described. In this study, we included four species (D. genkwa, D. pseudomezereum, D. kiusiana, D. jejudoensis) from Korea, excluding cultivated D. odora. The morphological characters through local surveys and the re-classification of the specimens collected in the Korea National Herbarium (KH) were carried out and distribution maps for each taxon were also prepared. The major characters include habit, trichomes in winter bud, leaf, and twig, phyllotaxis, inflorescence, size of calyx lobe and trichomes in the calyx tube, etc. The distribution map showed that D. genkwa is mainly distributed in the coastal area of Hwanghaenam-do, Pyeongannam-do, Jeollabuk-do and Jeollanam-do, whereas D. pseudomezereum is distributed in the limestone zone of Gangwon-do, Jeollabuk-do, and Gyeongsangbuk-do. Similarly, D. kiusiana is mostly found in Jeollanam-do, Gyeongsangnam-do, and Jeju-do. In addition, D. jejudoensis is known to be distributed in forests of Murueng, Andeok, and Seonheul-ri in Jeju-do, but recently, new habitat is discovered in the island forest areas of Jeollanam-do. However, some of these individuals showed the characteristics of D. kiusiana, thus before come to any conclusion detailed taxonomic review of D. jejudoensis and D. kiusiana is required.

• Journal of Species Research
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• v.13 no.1
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• pp.89-99
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• 2024

Larger benthic foraminifera (LBF) are a group of marine organisms that inhabit oligotrophic subtropicaltropical photic zones, commonly possess relatively large shells (i.e., tests) with a complex internal structure and host photosynthetic endosymbionts. In this study, we provide a new report of a LBF species belonging to the genus Sorites Ehrenberg, 1839, with a brief description and images of the test. The sediment samples were collected by SCUBA diving from the east coast of Jeju Island (South Korea). The discoidal test shape and annular series of chamberlets with a single row of apertures surrounded by rim indicate that these specimens belong to the genus Sorites, and this is the first record of the genus in Korea. The arrangement of early chamberlets, septular disposition, and the aperture details suggest that the specimens can be assigned to Sorites orbiculus(Forsskål in Niebuhr, 1775). Only three LBF species, including the present species, have been reported from Korean waters. The present study provides additional information for the evaluation of foraminiferal diversity including LBF in Korea and suggests the necessity of continuous investigations to understand the diversity of Sorites species in Korea.

• Korean Journal of Environment and Ecology
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• v.36 no.6
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• pp.627-638
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• 2022

This study was conducted at a village fishing farm on 4 peaks on the main island of Jeju Island and 2 peaks on an inhabited island to compare the distribution characteristics of seaweeds along the coast of Jeju Island from May to December 2018. A total of 101 species of seaweeds were surveyed, including 13 species (12.9%) of green algae, 24 species (23.8%) of Phaeophyta, and 64 species (63.4%) of Rhodophyta. The largest number of seaweeds appeared in May and the fewest in October, showing typical features of a temperate sea area. The number of seaweed species that appeared was 66 and 65 species at the water depths of 5 m and 8 m, respectively, and the largest was 74 species at 12 m. The number of seaweeds that appeared by area was the largest at 66 species on Udo Island, an eastern island near Jeju Island, and the lowest at 27 species in Pyoseon-ri, an eastern part of Jeju Island. The important values of emerging species were high in the order of, Ecklonia cavaand Corallina crassissima at 21.1% and 20.3%, respectively, Corallina aberransat 9.2%, Amphora ephedraeaat 6.2%, and Sargassum macrocarpumat 4.4%. Among seaweeds, an average of 11.2 species of coralline algae appeared, and the mean importance value was 32.6% in the sear area. The lowest importance value was 14.7% on Udo Island, and the highest was 41.0% in Pyoseon-ri. The mean ecological evaluation index (EEI) of seaweed colonies ranged from 2.1 to 10. It was the lowest at the water depth of 12 m in Pyoseon-ri in May and June and was 7.3 or higher in other areas, indicating good condition. This study rated the standardized ecological grade I for the water depth of 12 m on Udo Island and grade II for the water depths of 5 m and 8 m in Sagye-ri and on Chujado Island. Grade III was the water depth of 5 m and 12 m in Pyoseon-ri and Guideok 2-ri and the water depth of 5 m and 8 m in Pyeongdae-ri, and grade IV was the water depth of 8 m in Guideok 2-ri.

• Korean Journal of Environmental Biology
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• v.28 no.4
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• pp.223-230
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• 2010

To investigate the variations of physico-chemical factors in four stations (Hanlim, Aewol, Sinchon, Hamdeok) at Jeju coastal area, Water temperature, Salinity, dissolved oxygen (DO), pH, chemical oxygen demand (COD), suspended solid (SS), ammonia-nitrogen ($NH_4-N$), nitrite-nitrogen ($NO_3-N$), nitrate-nitrogen ($NO_2-N$) were analysed. The ranges of water temperature were from 26.23 to $28.6^{\circ}C$, the salinity were from 31.4 to 32.88‰, the pH were from 8.15 to 8.35, the chemical oxygen were from 0.48 to 0.91 mg $L^{-1}$. A total of 52 strains of marine actinomycetes was isolated from Jeju Island coastal area. They were characterized by determining morphological and physio-biochemical properties, the API kit and confirmed by molecular methods including partial sequencing of 16S rRNA. A neighbor-joining tree of partial 16S rRNA sequences divided the 52 isolates in 2 major groups, 22 strains of Gram positive bacteria/Actinobacteria (division)/Actinomycetales (order)/Streptomycineae (suborder)/Streptomycetaceae (family)/Streptomyces (93.1%) and 2 strains of Streptospotangineae (suborder)/Nocardiopsaceae (family)/Nocardiopsis (6.9%).

• Korean Journal of Environmental Biology
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• v.32 no.4
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• pp.377-381
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• 2014

In this study, we report for the first time a hybridization between Caretta caretta and Chelonia mydas in South Korea. On 7th May 2012, a sea turtle (Jeju sea turtle 01, JST01) was found in the east coast of Jeju Island, South Korea. The morphological characteristics of JST01 were compared with those of C. caretta and C. mydas that were frequently observed in Korean Seas. Interestingly, JST01 showed similar morphological characters such as body color, appearance of carapace, shape of upper beak, serration on marginal scute, and two claws with those of C. caretta. On the other hand, JST01 showed also similar patterns in several characteristics including the numbers of marginal, inframarginal and costal scute, smooth carapace without keel, no contact between costal scute and nuchal scute with those of C. mydas. From these results, we suggest that JST01 is one of hybrid animals bred between C. caretta and C. mydas, because JST01 has species-specific characters from both species. We anticipate that our study would be useful and have significant impact onto study inter-specific hybridization in the groups of sea turtle.

• The Journal of the Acoustical Society of Korea
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• v.34 no.1
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• pp.12-19
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• 2015

In this paper, temporal variations of acoustic transmission loss (TL) affected by internal tide are studied by computer simulation using oceanic data measured in the southern sea of Jeju Island in summer. Temperature was measured with depth (bottom depth are nearly 80 m) in two sites near Seogwipo coast every one hour for 25 hours during July 27 and 28, 2009. The periodic fluctuation of temperature due to the internal tide was observed and its vertical displacement was more than 10 m. In order to investigate temporal variation of TL by internal tide, acoustic propagation between two measurement sites (3.8 km distance) was simulated with a source depth of 10 m. TL variation for 1/3 octave band of 100 Hz center frequency highly coincided with tidal period but more complex variation with indistinct tidal period was observed for 1 kHz. Maximun standard deviation of TL variation was 4.2 dB for 100 Hz at 2.8 km distance from a source and it was 3.7 dB for 1 kHz. The tidal variation was also shown in detection range and its maximum variance was less than 1 km. These results imply that temporal variation of TL should be considered for acoustic researches at the southern sea of Jeju Island.

• Journal of Navigation and Port Research
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• v.46 no.3
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• pp.209-215
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• 2022

On the Jeju coast, international cruise ships, passenger ships, and other ships pass frequently, as well as many fishing boats. Thus, there is a high risk of marine accidents and frequent ship collisions. Accordingly, it is urgent to establish a coastal VTS for systematic safety management of ships passing through the coastal waters of Jeju. The purpose of this study was to set the area of the VTS to be newly established. In this study, to calculate the workload of the VTS operators, a formula was proposed that reflects the monitoring workload considering the monitoring frequency and required time for target as well as non-target ships and the workload for ship collision situations. The proposed formula was applied to the newly established VTS area in Jeju. Three control sectors were set up in each VTS center. The average number of workstations per hour was approximately 1, so the division between sectors was appropriate. Thus, it was deduced that there would be no workload for the VTS operators. It is expected that the method proposed in this study can be used as primary data for calculating the appropriate number of workstations for the current VTS, and setting the VTS area for a new coastal VTS in the future.