• Journal of Fisheries and Marine Sciences Education
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• v.24 no.4
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• pp.507-515
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• 2012

Jungmun beach was confirmed only one beach as a nesting place of seaturtles in Jeju of South Korea. We investigated the environment conditions for nesting of seaturtles (sites 1, 2) to target as the spawning grounds of accidental nesting place. Sand temperatures of beaches at 5 cm above and 10, 30 and 50 cm below the surface of beach were measured at intervals of approximately 10 days during June to December. These data indicated that the optimum (over $25^{\circ}C$) sand temperature for spawning and hatching of seaturtles in the sites 1 and 2 from June 23 to September 29, 2008 and from June 23 to October 17, 2008, respectively. Also, maintained the optimum coastal water temperature (above $20^{\circ}C$) for seaturtles maintained from June 23 to November 17, 2008. Therefore, Jungmun beach could be the possible spawning grounds of accidental nesting place, where the landed seaturtles and hatched young seaturtles could be survived successfully.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.5
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• pp.584-593
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• 2021

The sediment makes up the sea floor and plays an important role as a habitats for living things in the sea. However, pollution of coastal sediment due to internal and external factors such as inflow of contaminants from land and self-pollution becoming more serious, the needs for management of sediment that play an important role in ecology, is increasing. In particular, the review and evaluation of the effects of sediment in marine development projects including reclamation and dredging, have significance in terms of proactive protection and management of surrounding ecosystems. This study proposed the improvement measures for marine sediment management standards on the sea area utilization consultation for the development of public water. For the purpose, The evaluation and management standards of domestic and overseas marine sediments were reviewed and compared. The sediment environment guidelines under the Marine Environment Management Act of Korea were reviewed. Accordingly, the cases of Canada and NOAA, which have various evaluation standards consist of comprehensive factors, were analyzed. For analysis of operational cases, the port and fishing port development projects for the last five years (2016-2020) that are considered to have the greatest impact on sediments among the sea area use consultations were also reviewed. Finally, this study suggested that the assessment factors for ecological hazards and potential human risks should be considered in the sediment environmental standards in the sea area utilization consultation system.

• Journal of Life Science
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• v.29 no.3
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• pp.287-294
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• 2019

Calystegia soldanella is distributed in coastal sand dunes and has high environmental adaptability; it is also known to be effective for anti-oxidant, anti-pyretic, anti-septic, and diuretic action. This study investigated the effect of crude extracts and organic solvent fractions of C. soldanella on MMP-2 and MMP-9 expression, MMP activity, and cell mobility in phorbol-12-myristate-13-acetate (PMA)-induced fibrosarcoma HT-1080 cells. C. soldanella was twice extracted, once with methylene chloride (MC) and once with methanol (MeOH). After the MC and MeOH extracts were combined, their suppressive effects on MMP-2 and MMP-9 expression, MMP enzymatic activity, and gene and protein expression were measured by gelatin zymography, enzyme-linked immunosorbent assay, reverse-transcription polymerase chain reaction, and western blot method. Cell mobility for the HT-1080 cells was observed by wound healing assay. The combined crude extracts showed a significant suppressive effects on MMP-2 and MMP-9 expression. To explore active inhibitory elements, the combined extracts were fractionated according to polarity into with n-hexane, 85% aqueous methanol, n-butanol, and water. Across these four solvent fractions, MMP-2 and MMP-9 activity and cell mobility in the HT-1080 cells were all strongly inhibited by the n-hexane fraction. These results suggest that C. soldanella extract and organic solvent fractions could be used as potent MMP inhibitors for effective anti-cancer treatments to suppress cancer invasion and metastasis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.142-149
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• 2019

In this study, the past erosion history and current status in the CHUNG-UI beach of Eulwang-dong, Jung-gu, Incheon-Si, South Korea were investigated and analyzed the wave with wave-induced current to investigate the causes of coastal erosion. As a result, the significant wave height ($H_{1/3}$) was in the range of 0.07~1.57 m and the mean value was 0.21 m. The maximum wave height ($H_{max}$) was in the range of 0.02-4.76m and the mean value was 0.27m. The vertical wave height and cycles were estimated through numerical model experiments of wave transformation. The 50-year frequency design wave height ranged from 0.82m to 3.75m. As a result of the experiment of wave-induced current, wave-induced current in the CHUNG-UI beach was decreased after the installation of the Detached breakwater and the Jetty. On the other hand, when the crest elevation was increased up to 5 m, there was no significant change, but when the crest elevation was increased to 8m, strong wave-induced current occurred around the submerged breakwaters due to lowered depth of water. In addition, the main erosion of the CHUNG-UI beach is due to the intensive invasion of the wave characteristics coming from the outer sea into the white sandy beach. The deformation of the wave centered on the front of the sandy beach caused additional longshore currents flowing parallel to the sandy beach and rip currents in the transverse direction, thus confirming that the longshore sediment was moved out of the front and out of the sea. The results of this study can be used as preliminary data for the recovery of the sand and the selection of efficient erosion prevention facilities.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.7
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• pp.902-908
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• 2017

To determine the horizontal and temporal distribution of firefly squid, Watasenia scintillans (W. scintillans), larvae, we conducted surveys using IKMT (mesh size: $500{\mu}m$) and CTD (SBE9plus) with Fisheries Research Vessel (FRV, TAMGU 21) in the southern part of the East Sea in summer (August) and autumn (September and November) 2015. A total of 238 larvae, ranging in mantle length (ML) from 0.6 mm to 18.5 mm, were collected at 28 stations. Abundance and larval distribution density were significantly higher in summer than in autumn during the study period. Especially, the highest density of W. scintillans was observed in the coastal waters of the East Sea from Pohang to Pyunghae where cold water masses were distributed in summer. Optimum embryo survival temperature ($6-16^{\circ}C$) 40 to 180 m depth ranges for stations which larvae were collected.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.1
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• pp.74-80
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• 2019

In this study, pyrolyzed oyster shells at a low temperature ($350^{\circ}C$) were applied for a mesocosm experiment to confirm resulting changes in the properties of sediment. After creating a covering of oyster shells, an increase in ORP and decrease in ammonia in the overlying water was observed in an experimental case. The decrease of TOC in this experiment was due to the dilution of organic matter due to the addition of inorganic matter (pyrolyzed oyster shells). The decrease in the concentration of AVS was observed due to the adsorption of AVS by the surface of the oyster shells. From the results obtained in this experiment, it has been concluded that pyrolyzed oyster shells at a low temperature can be used for remediation of polluted sediment.

• Convergence Security Journal
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• v.17 no.5
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• pp.41-47
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• 2017

The Marine Environment Observation Information System supplies oceanographic information elements such as water temperature, chlorophyll, float, etc. based on satellite images to consumers. The data produced by the Korean marine environmental observatories are located in the coastal areas of Korea. But if the range is too far from a particular area of interest, due to distance or spatial constraints, the accuracy and up-to-dateness of the data can not be relied upon. Therefore, it is necessary to perform fusion and complex operation to solve the difference between the field observation and the marine satellite image. In this study, we develop a system that can process marine environmental information in the user's area of interest in the form of layered character (numeric) information considering the readability and light weight rather than the satellite image. In order to intuitively understand satellite image information, we characterize (quantify) the marine environmental information of the area of interest and we process the satellite image band values into layered characters to minimize the absolute amount of transmitted / received data. Also we study modular location-based interest information service method to be able to flexibly extend and connect interested items that diversify various observation fields as well as application technology to serve this.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.4
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• pp.483-491
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• 2021

The identification of regional collision risks in water areas is significant for the safety of navigation. This paper introduces a new method of collision risk assessment that incorporates a clustering method based on the distance factor - hierarchical clustering - and uses real-time data in case of several surrounding vessels, group methodology and preliminary assessment to classify vessels and evaluate the basis of collision risk evaluation (called HCAAP processing). The vessels are clustered using the hierarchical program to obtain clusters of encounter vessels and are combined with the preliminary assessment to filter relatively safe vessels. Subsequently, the distance at the closest point of approach (DCPA) and time to the closest point of approach (TCPA) between encounter vessels within each cluster are calculated to obtain the relation and comparison with the collision risk index (CRI). The mathematical relationship of CRI for each cluster of encounter vessels with DCPA and TCPA is constructed using a negative exponential function. Operators can easily evaluate the safety of all vessels navigating in the defined area using the calculated CRI. Therefore, this framework can improve the safety and security of vessel traffic transportation and reduce the loss of life and property. To illustrate the effectiveness of the framework proposed, an experimental case study was conducted within the coastal waters of Mokpo, Korea. The results demonstrated that the framework was effective and efficient in detecting and ranking collision risk indexes between encounter vessels within each cluster, which allowed an automatic risk prioritization of encounter vessels for further investigation by operators.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.26 no.3
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• pp.248-262
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• 2021

Marine planktonic ciliates include two major groups, loricated tintinnids and naked oligotrichs. The study of marine ciliate plankton in Korea began with taxonomic efforts on tintinnids based on the morphology of lorica, a vase-shaped shell. Despite polymorphism in the lorica, it is utilized as a key characteristic in identification of tintinnid species. However, oligotrichs have been studied only recently in Korea due to challenges associated with the observation of ciliary arrangements and the technical development for cell staining. Species diversity and phylogenetic classification of the ciliates have been informed by recent advances in morphological and molecular analyses. Illustrations of the planktonic ciliate in Korea have been published on the basis of taxonomic data of tintinnids and oligotrichs. Planktonic ciliates acting as the major consumers of pico- and nanoplankton as well as the prey of mesozooplankton, has been monitored by spatial and temporal investigations in Korean coastal waters. A practical approach addressing the limitations and potential of marine ciliate studies in Korea is proposed here to improve the data quality of planktonic ciliates, providing an enhanced basis for quality control of ciliate monitoring.

• Journal of the Korean earth science society
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• v.42 no.6
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• pp.677-687
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• 2021

In this study, we analyzed diatoms from core RS15-GC41 collected in Iselin Bank, Ross Sea. A total of 24 genera and 35 species of diatoms are identified, and the having valve abundance of diatoms varies from 0.2 to 28.6×10⁶/g. Four diatom assemblage zones are established by the vertical distribution of diatoms, and changed with a cycle of 100 kyrs. RS15-GC41 were deposited over the last 400 kyrs (corresponding to Marine Isotope Stages 1-11). The open-water species Fragilariopsis kerguelensis, Rhizosolenia styliformis, and Thalassionema nitzschioides abundantly occurred in interglacial periods. Whereas, Actinocyclus actinochilus abundantly dominant during the glacial periods. The distribution of these diatoms indicated, it can be seen that the sea-ice extent was larger and lasted longer during MIS 7, 9, and 11 than that of MIS 1, 3, and 5. Moreover, Paralia sulcata was abundantly predominant in MIS 7, 9, and 11; this finding suggests likely indicating that P. sulcata was transported from the coastal/inner shelf area to the study site, during accumulated in the sediments, reworked with the influx of ice-rafted debris by the currents