• Geomechanics and Engineering
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• v.17 no.5
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• pp.421-427
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• 2019

Coastal erosion is becoming a significant problem in Greece, Bangladesh, and globally. For the prevention and minimization of damage from coastal erosion, combinations of various structures have been used conventionally. However, most of these methods are expensive. Therefore, creating artificial beachrock using local ureolytic bacteria and the MICP (Microbially Induced Carbonate Precipitation) method can be an alternative for coastal erosion protection, as it is a sustainable and eco-friendly biological ground improvement technique. Most research on MICP has been confined to land ureolytic bacteria and limited attention has been paid to coastal ureolytic bacteria for the measurement of urease activity. Subsequently, their various environmental effects have not been investigated. Therefore, for the successful application of MICP to coastal erosion protection, the type of bacteria, bacterial cell concentration, reaction temperature, cell culture duration, carbonate precipitation trend, pH of the media that controls the activity of the urease enzyme, etc., are evaluated. In this study, the effects of temperature, pH, and culture duration, as well as the trend in carbonate precipitation of coastal ureolytic bacteria isolated from two coastal regions in Greece and Bangladesh, were evaluated. The results showed that urease activity of coastal ureolytic bacteria species relies on some environmental parameters that are very important for successful sand solidification. In future, we aim to apply these findings towards the creation of artificial beachrock in combination with a geotextile tube for coastal erosion protection in Mediterranean countries, Bangladesh, and globally, for bio-mediated soil improvement.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.35 no.5
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• pp.95-101
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• 2023

Recent persistent coastal developments have expanded recreational areas and enhanced accessibility. However, this growth has also led to a rise in safety incidents. These accident factors can be divided into human-made and natural types. The latter is comprised of dynamic factors like waves, tides, sea fogs, and winds. While institutions like the Korea Meteorological Administration and the Korea Hydrographic and Oceanographic Agency already offer data on these dynamic factors, the resolution is often insufficient for a precise assessment of localized risks. In this study, to overcome these limitations, we utilized the dynamic information from existing open systems to construct a high-resolution numerical simulation. Through this, we developed an automated module to predict dynamic factors in localized coastal activity areas. Particularly during the module's construction, we compared and reviewed the numerical prediction results for waves with observed wave heights.

• Mycobiology
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• v.49 no.6
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• pp.559-581
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• 2021

The coastal marine ecosystems of Vietnam are one of the global biodiversity hotspots, but the biodiversity of marine fungi is not well known. To fill this major gap of knowledge, we assessed the genetic diversity (ITS sequence) of 75 fungal strains isolated from 11 surface coastal marine and deeper waters in Nha Trang Bay and Van Phong Bay using a culture-dependent approach and 5 OTUs (Operational Taxonomic Units) of fungi in three representative sampling sites using next-generation sequencing. The results from both approaches shared similar fungal taxonomy to the most abundant phylum (Ascomycota), genera (Candida and Aspergillus) and species (Candida blankii) but were different at less common taxa. Culturable fungal strains in this study belong to 3 phyla, 5 subdivisions, 7 classes, 12 orders, 17 families, 22 genera and at least 40 species, of which 29 species have been identified and several species are likely novel. Among identified species, 12 and 28 are new records in global and Vietnamese marine areas, respectively. The analysis of enzyme activity and the checklist of trophic mode and guild assignment provided valuable additional biological information and suggested the ecological function of planktonic fungi in the marine food web. This is the largest dataset of marine fungal biodiversity on morphology, phylogeny and enzyme activity in the tropical coastal ecosystems of Vietnam and Southeast Asia. Biogeographic aspects, ecological factors and human impact may structure mycoplankton communities in such aquatic habitats.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.33 no.6
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• pp.226-237
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• 2021

Coastal safety accidents are characterized by a high proportion of human negligence and repeated occurrences of accidents caused by the same factors. The Korea Coast Guard prepares and implements various countermeasures to prevent accidents at coastal safety accident sites. However, there is a shortage of safety facilities and safety management personnel according to the limited budget. In addition, the ability to be proactively and proactively respond is low due to the limitations of the coastal safety accident risk forecasting system, which relies on the meteorological warning of the Korea Meteorological Administration. In this study, as part of preparing the foundation for establishing a preemptive and active coastal safety management system that can manage accident-causing factors, predict and evaluate risk, and implement response and mitigation measures after an accident occurs before coastal safety accidents occur. The establishment of a risk assessment system was proposed. The main evaluation factors and indicators for risk assessment were established through the analysis of the status of coastal safety accidents. The risk assessment methodology was applied to 40 major hazardous areas designated and managed by the Korea Coast Guard.

• Korean Journal of Medicinal Crop Science
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• v.16 no.1
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• pp.44-50
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• 2008

The cultivation boundary areas and biological activator efficacies of Vitex rotundifolia, Tetragonia tetragonoides and Glehnia littoralis were investigated. Investigation of coastal areas revealed the East and West cultivation boundary areas of Vitex rotundifolia and Gelhnia littoralis to be the Taean Peninsula, Taean-gun and Gangwon-do, Donghae-City. The East and West coastal cultivation boundary areas of Tetragonia tetrragonoides are Jeollanam-do and Kyeongsangbuk-do, Ulleung-gun. The natural habitat is less than 200 m from the coastal area. Most of the Vitex rotundifolia, Tetragonia tetragonoides and Glehnia littoralis grow naturally in a region of mixed sand, clay and loam, in direct sunlight. No dominant vegetation was located. To analyze anti-inflammatory efficacy, RAW 264.7 cells were used. Vitex rotundifolia, Tetragonia tetragonoides and Glehnia littoralis inhibited inflammation by 37%, 12% and 10% in $100{\mu}g/m{\ell}$, respectively. However, the anti-inflammatory efficacy of Glehnia littoralis was invalid. Analysis of anti-cancer activity was accomplished using HL-60 cells. Glehnia littoralis revealed 60% and 72% inhibition activity in $100{\mu}g/m{\ell},\;and\;200{\mu}g/m{\ell}$ respectively. No cytotoxicity inhibition activity was investigated in Vitex rotundifolia and Tetragonia tetragonoides.

• Journal of Forest and Environmental Science
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• v.31 no.3
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• pp.225-234
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• 2015

Mangroves are important coastal ecosystems and are located at the inter-tidal zones of tropical and sub-tropical belts. The global mangrove forests are declining dramatically because of the conversion of forests to shrimp farming, over-exploitation, pollution and freshwater diversion. The Bangladesh Forest Department initiated mangrove afforestation throughout the coastal belts of Bangladesh in 1966 to provide better protection for the coastal communities. Up to 1990, 120,000 ha of mangroves had been planted and it is one of the largest coastal afforestaton programs in the world. The objective of this study is to exploit the spatial extent of mangrove plantation and their dynamics of changes over the last two decades using multispectral Landsat imagery. The study area covers the coastal areas of Bangladesh that is extended over the eastern part of Sundarbans up to Teknaf, the southern tip of mainland Bangladesh. Mangrove plantations were interpreted visually on computer screen and interactive delineation of forest boundary was done. The mangrove plantation area has been estimated as 32,725, 47,636 and 43,166 ha for the year of 1989, 2000 and 2010, respectively. Mangrove deforestation by human activity has increased almost six times in the recent decade in comparison to the previous one. The mangrove forest loss due to coastal erosion has slightly declined in the 2000s. Mangroves have been lost primarily because of agricultural expansion. The result of this investigation will be helpful to understand the dynamics of mangrove plantation and the main drivers of changes in this coastal ecosystem.

• YAKHAK HOEJI
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• v.47 no.5
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• pp.311-318
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• 2003

Eurya emarginata (Thunb.) Makino (Theaceae) is distributed in coastal areas of island. The leaves of Eurya are used in the traditional medicine of the coastal areas of jeju island with the aim of diuresis or to treat ulcers. Nevertheless, there are few reports on the biological activity and constituents of E. emarginata. In this study, we investigated the pharmacological activity of the solvent extracts of E. emarginata on the several inflammatory markers (TNF-$\alpha$, IL-1$\beta$, IL-6, NO, iNOS and COX-2). Also we examined the antioxidizing effect of the solvent extracts by determination of DPPH radical-scavenging activity. Among the solvent fractions, EtOAc and BuOH extracts showed potent radical scavenging activity (RC$_{50}$=10.9 and 12.7 respectively). The subtractions of EF 5-4-6-3-2 and BF 1 potentially inhibited the mRNA expression of pro-inflammatory cytokines (IL-1$\beta$, IL-6 and TNF-$\alpha$) at the concentration of 100 $\mu\textrm{g}$/mι. Also the fractions inhibited the mRNA expression of pro-inflammatory cytokines (IL-1$\beta$, IL-6 and TNF-$\alpha$) and protein expression of iNOS and COX-2 at the concentration of 100 $\mu\textrm{g}$/mι. And then, the inhibition of iNOS was correlated with the decrease of nitrite level. These results suggest that E. emarginata may have anti-inflammatory activity through the inhibition of pro-inflammatory cytokines, iNOS and COX-2.2.

• Journal of Environmental Science International
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• v.17 no.10
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• pp.1169-1182
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• 2008

The chemical and meteorological effects on the concentration variations of air pollutants ($O_3$ and its precursors) were evaluated based on ground observation data in coastal and inland regions, Busan during springs and summers of 2005-2006. For the purpose of this study, study areas were classified into 5 categories: coastal area (CA), industrial area (IA), downtown area (DA), residential area (RA), and suburban area (SA). Two sites of Dongsam (DS) and Yeonsan (YS) were selected for the comparison purpose between the coastal and inland regions. $O_3$ concentrations in CA and SA were observed to be highest during spring (e.g., 40 ppb), whereas those in DA and RA were relatively low during summer (e.g., $22\sim24$ ppb). It was found that $O_3$ concentrations in IA were not significantly high although high VOCs (especially toluene of about 40 ppb) and $NO_x$ ($\geq$ 35 ppb) were observed. On the other hand, the concentration levels of $O_3$ and $PM_{10}$ at the DS site were significantly higher than those at the YS site, but $NO_x$ was slightly lower than that at the YS site. This might be caused by the photochemical activity and meteorological conditions (e.g., sea-land breeze and atmospheric stagnance). When maximum $O_3$ (an index of photochemical activity) exceeds 100 ppb, the contribution of secondary $PM_{10}\;((PM_{10})_{SEC})$ to total observed $PM_{10}$ concentrations was estimated up to 32% and 17% at the DS and YS sites, respectively. In addition, the diurnal variations of $(PM_{10})_{SEC}$ at the DS site were similar to those of $O_3$ regardless of season, which suggests that they are mostly secondary $PM_{10}$ produced from photochemical reactions.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.18 no.4
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• pp.178-185
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• 2013

We measured salinity and $^{222}Rn$ concentration to explore submarine spring along the coastal areas (Mundongri, Icheon-ri, Jukseong-ri, Daebyeon-ri, Yeonhwa-ri, and Dadae-po) including Ilkwang Bay of Busan Metropolitan City in 2009 and 2010. Before field observation, we selected the potential and possible locations of submarine spring based on the lineament distribution and rose diagram analysis. Salinity and radon concentration were measured within the 1~2 km from the coastal lines. Radon activity decreased gradually from onshore to offshore. Vertical profiles of salinity at some stations showed lateral transport of water mass characterized by low salinity. Vertical profiles of salinity in the Ilkwang Bay, which is a unique bay in the south-eastern coastal area of Busan Metropolitan City, also showed the occurrence of low salinity in the bottom seawater. Our results suggest the possible occurrence of submarine discharge of fresh groundwater in the coastal areas around Busan Metropolitan City. In the future, intensive research should be conducted for the exploration methods of submarine spring as well for the possible utility of submarine groundwater as alternative water resources.

• Journal of Environmental Science International
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• v.30 no.8
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• pp.621-628
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• 2021

The characteristics of time changes in air temperature, DI (discomfort index) and WBGT (wet-bulb globe temperature) were investigated for inland city (daegu) and coastal city (pohang) of Gyeongbuk Province during the 2018 consecutive heat wave season. The time when the temperature dropped below 33℃ was around 19h in both regions. As such, the two regions were similar with respect to the time up to which the heatwave warning levels continued. However, the discomfort index (DI) was higher than 27 in Pohang. Most people feel unpleasant when an discomfort index of 27 or higher appears. The results indicated that Korea's night-time thermal environment during the summers is particularly poor in the southern coastal areas. WBGT began at 09:00 and lasted until 21:00, with a score of 31 or higher; this score, in principle, corresponded with the duration of outdoor activity in both regions. Therefore, it was found that outdoor work was at a level where all day long had to be stopped in both areas during the heat wave. Although time changes in temperature and WBGT were similar in both regions, Discomfort Index (DI) differed significantly. The difference refers to the fact that Pohang is strongly affected by the high heat capacity effect and the supply of water vapor from the sea.