• Journal of Ocean Engineering and Technology
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• v.30 no.5
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• pp.389-399
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• 2016

This paper presents the explorations of hydrothermal vents located in the Marina Arc and Back Arc Basin using the deep-sea ROV Hemire. These explorations were conducted by KRISO and KIOST to demonstrate the capability of Hemire in various applications for deep-sea scientific research. The missions included the following: (1) to search the reported vents, (2) conduct visual inspections, (3) deploy/recover a sediment trap and bait traps, (4) sample sediment/water/rock, (5) measure the magnetic field at the vent site, and (6) acquire a detailed map using multi-beam sonar near the bottom. We installed three HD cameras for precise visual inspection, a high-temperature thermometer, a three-component magnetometer, and a multi-beam sonar to acquire details of the bottom contour or identify vents in the survey area. The explorations were performed in an expedition from March 23 to April 5, 2016, and the missions were successfully completed. This paper discusses the operational process, navigation, and control of Hemire, as well as the exploration results.

• Nuclear Engineering and Technology
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• v.56 no.2
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• pp.389-401
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• 2024

In recent decades, numerous instances of blockages have been reported in coastal nuclear power plants globally, leading to serious safety accidents such as power reduction, manual or automatic power loss, or shutdown of nuclear power units. Loss or shortage of cooling water may compromise the reliability of the cooling water system, thus threatening the operational safety of power plants and resulting in revenue reduction. This study provides a comprehensive review of the current state of cooling water system safety in coastal nuclear power plants worldwide and the common challenges they face, as well as the relevant research on cooling water system safety issues. The research overview and progress in investigation methods, outbreak mechanisms, prevention and control measures, and practical cases of blockages were summarized. Despite existing research, there are still many shortcomings regarding the pertinence, comprehensiveness and prospects of related research, and many problems urgently need to be solved. The most fundamental concern involves understanding the list of potential risks of blockages and their spatially distributed effects in surrounding waters. Furthermore, knowledge of the biological cycles and ecological habits of key organisms is essential for implementing risk prevention and control and for building a scientific and effective monitoring system.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.3
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• pp.185-191
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• 2012

Most of Korean farms have been developed in the semi-closed bay, and its position is very vulnerable to the coastal contamination due to the long term and the high density. So, mariculture management is very essential for the sustainable aquaculture. Some of the specific ways would be the assessment of the optimal stocking density for mariculture management zone and this has to consider both the suitable site selection and the assessment of ecological carrying capacity. Habitat suitability index(0.0 totally unsuitable habitat, 1.0 optimum habitat) and ecological indicator(Filtration pressure indicator) was used to assess the stocking density for oyster farms in Geoje-Hansan Bay. Geoje Bay showed the higher habitat suitability index value 0.75 than Hansan Bay 0.53, indicating that Geoje Bay is more suitable for oyster farming. Ecological indicator showed different stocking density according to the coastal characteristics in Geoje-Hansan Bay. Consequently, it is desirable that the stocking density in Geoje Bay should reduce average 40% and Hansan Bay, average 60% than present, in order to meet the ecological carrying capacity. The assessment of the stocking density could solve various problems such as the coastal contamination, environmental aggravation and the productivity decrease and this study could be a scientific basis to establish the policies for mariculture management.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.5
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• pp.430-438
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• 2013

In this study, the seasonal field survey was conducted in Goseong Jaran Bay(22 stations), Geoje Hansan Bay(15 stations) and Jinhae Bay(18 stations). We analyzed the sediment environmental parameters(Chemical Oxygen Demand, Ignition Loss, Acid Volatile Sulfides, Total Organic Carbon) and biotic parameters of macrobenthic polychaetes(number of species, density, diversity, evenness). It had a good correlation between total organic carbon and polychaete diversity(R=0.61, P<0.01), and we made a decision them as representative environmental indices. As a result of that, regarding the criteria in the assessment of farm environment, we suggest concentrations of total organic carbon : Peak Point = 15 mg/g dry, Warning Point = 26 mg/g dry, Contaminated Point = 31 mg/g dry and polychaete diversity : ~2.6(Good), 2.6~2.1(Moderate), 2.1~1.2(Poor) and 1.2~(Bad). This could be a scientific basis to establish the environmental standards for fishery management.

• Journal of the Korean Association of Geographic Information Studies
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• v.15 no.1
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• pp.1-15
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• 2012

Marine scientific monitoring, including monitoring of oil pollution, marine ecosystems, and the marine environment in general, has been being carried out continuously in order to assess the impact of oil pollution since the Hebei Spirit oil spill in December 2007. GIS thematic maps containing visual and summarized information are very useful for conducting exploratory analyses on the spatio-temporal variability of the marine environment and marine ecosystems due to oil pollution. Defining map types and building a legend in accordance with data characteristics are essential elements for mapping. In the present study, map types were defined according to the data attributes and GIS data types for each data item and classification of data intervals for the legend was defined by using two data distribution types through a histogram analysis. The data interval method was defined as follows: If the histogram of data has a uniform distribution, an equal interval method is applied; in the case of a normal distribution, a standard deviation method is applied. In addition, thematic map templates were made for each map type through the definition of marginal elements. Through the establishment of systematic mapping methods and procedures in this study, it was possible to effectively make standardized thematic maps for various kinds of marine scientific data.

• The Korean Journal of Quaternary Research
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• v.17 no.2
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• pp.1-7
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• 2003

Environmental changes caused by the abrupt climatic change are one of the important issues in the scientific community. In the East Sea, abrupt climatic shift, called Younger Dryas, is identified. The age of the Younger Dryas cold episode occurred at 11.2 ka. Overall, changes in circulation and bottom water conditions occurred during the Younger Dryas cold episode in the study area. Especially, climatic transition from meltwater spike to the Younger Dryas cold episode is characterized by significant shifts of oxygen isotope values, the coiling ratios of Neogloboquadrina pachyderma, and the planktonic foraminifers abundances. The impact of abrupt climate change on the ecosystem is very significant. In the East Sea, the calcium carbonate secreting organism(foraminifers) is replaced by silicon dioxide secreting organisms(diatom, radiolarian) after the abrupt and severe cold climatic event. Based on the Doctrine of Uniformitarianism, at least climate change for the next 100 years would be severely influence on the marine ecosystem.

• Korean Journal of Ichthyology
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• v.35 no.2
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• pp.136-140
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• 2023

A single opah specimen (705 mm SL) was collected from Samcheok, South Korea on November, 2014, and firstly reported as Lampris guttatus by Jeong et al. (2015). Thereafter Lampris lauta was revived and three additional species (Lampris australensis, Lampris incognitus, Lampris megalopsis) were newly reported (Underkoffler et al., 2018). Therefore, it needs to review the scientific name of the Korean opah. The first reported opah specimen from Korea is now preserved as stuffed specimen at the Seodaemun Museum of Natural History in Seoul. We re-investigated the morphological features of stuffed specimen. It was characterized by having the following morphological combinations; orbital diameter is greater than 5% of fork length, whole body including head with white irregular spots, all fins are deep red. In addition, L. guttatus is confined to North Atlantic Ocean, whereas L. megalopsis is distributed worldwide from temperate to tropical waters. Therefore, our comprehensive study suggests that the scientific name of opah (L. guttatus) reported in Korea must be changed to L. megalopsis based on morphological characteristics and distribution area.

• Ocean and Polar Research
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• v.40 no.3
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• pp.145-160
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• 2018

The Paguroidea is an important group in terms of marine biodiversity. In Korea, paguroids have been studied by many taxonomists and recently we conducted comprehensive taxonomic studies on hermit crabs from the southern part of the Korean Peninsula. As a result, a checklist of 61 species of Paguroidea in South Korean water with their geographical distribution was prepared. Remarks on taxonomy, geographical distribution, and the Korean scientific names of each applicable species were also provided.

• The Journal of Fisheries Business Administration
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• v.49 no.4
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• pp.99-108
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• 2018

Maintaining a certain level of fisheries production is due to the increase in aquaculture production. In recent years, aquaculture plays an important role in fishery production in Korea. Nevertheless, aquaculture should be carefully managed by regulations because it also causes environmental load which can threat sustainability of aquaculture. For this reason, Korean government has regulated density of culturing facilities with the Fisheries Law and its adjective decrees. The regulatory compliance of fisheries businesses is very low because the criteria for the regulation of the density were not enacted with scientific research. Thus, this research was aimed to obtain scientific criteria for the regulation of oyster aquaculture in Jaran Bay with economic assessment. For this research, we collected the data necessary for the assessment on five investigation points in the bay for two years. With the data, simulation for the growth rate of oyster was performed and the result showed that at least 25.5% of facilities should be reduced. Also, it was revealed that removing 2 long lines would be most beneficial. The NPV of the best measurement was 35,120,300 won and IRR was 11.7%. With this research, the government will gain more accurate regulatory compliance due to the scientific approach. Moreover, fisheries businesses in oyster aquaculture can obtain flexibility to cope with market fluctuation.

• Fisheries and Aquatic Sciences
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• v.17 no.3
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• pp.369-376
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• 2014

I provide an overview of the application of hydroacoustic methods in South Korea to understand the current research status in relation to fisheries acoustics and to determine which areas require further study. One main purpose for using a scientific echosounder, a representative tool using the hydroacoustic method, is to evaluate the abundance of fisheries resources. Thus, two representative methods for abundance estimation are described. The history of fisheries acoustics worldwide is also summarized.