• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.32 no.3
• /
• pp.338-344
• /
• 1999

Floating debris was recorded from a training ship, $\sharp$1 Kwanaksan, of Pukyong National University with about 10 knots speed at July 15th and 20th of 1997. The sampled area is the middle of southern sea of Korea, divided into 44 unit segments on survey routes. Debris fabrication materials were categorized with 6 items using the following; man-made or natural wood items, paper and cardboard, nylon netting and rope, styrofoam, plastics, floating metal and glass containers. All identified items within a 100 $\pm$ 2 m wide band were recorded but ignored if beyond this boundary. The results of distribution and transport of floating debris in the area are as follows: 1. The quantities of debris during the survey were distributed from $1.6\~369.7\;items/km^2$. The most obvious trend is the widespread distribution of all debris. The highest densities of all debris were discovered in the coastal waters of Namhae and Yokji island, and of about 50 km off from the southward of Yokji and about 74 km off from the eastward of Komun island. Especially many of small styrofoams within $\phi$20 cm were observed in these segments. 2. Styrofoams and plastics were composed of $83.5\%$ among all debris, next woods items, $9.8\%$. 3. The quantities, distribution shapes and composition of debris were varied as the observed duration and the natures of each items. 4. These phenomena are concluded that firstly they depend on the river discharges included debris due to precipitation falls, secondly inflow or dumping debris are drifting to the off-shore by Kuroshio currents present at their adjacent sea, But on the basis of the observed data it is difficult that source position, quantities and inflow items of debris are identified, and also the transport processes is pursue. further more surveys are continuously being investigated, and from this it is hoped that a much wider coverage can be achieved, perhaps on all sites of the Coast of Korea and contributed to the stationary area, finding of sources, removal method of debris and resistants of marine productivity.

• Journal of Wetlands Research
• /
• v.9 no.1
• /
• pp.79-89
• /
• 2007

This paper provides a comprehensive overview of the present status of several environmental problems caused by emerging toxic substances such as persistent organic pollutants (POPs), endocrine disrupting chemicals (EDCs), and arsenic in various environmental media in Vietnam. Monitoring data reported during the 1990s demonstrated elevated contamination of DDTs in most of these compartments in Vietnam. Studies in frame of the Asia-Pacific Mussel Watch Program revealed that fish, mussels and resident birds from Vietnam contained higher concentrations of DDTs as compared to other countries in region, suggesting the role of Vietnamese environment as a significant emission source of DDT in the Southeast Asian region. The estimated dietary intakes of PCBs and DDTs for Vietnamese were relatively high among Asian developing countries, suggesting potential risk for humans posed by thesechemicals. Widespread contamination of some endocrine active compounds such as alkylphenols and phthalates was observed at various sites along the coasts of northern and middle Vietnam. The presence of significant source of bisphenol-A along Red River estuary was revealed with the concentrations comparable to those reported for developed nations. A case study on seasonal variation of alkylphenols and phthalates in surface water of river delta and estuary of north and middle Vietnam indicated the differences in distribution of these compounds between dry and rainy seasons. Higher concentrations of alkylphenols and phthalates were found in dry season in estuary; while the contrasting pattern was observed in the river delta, showing elevated residues in rainy season. This result suggests the different behavior of alkylphenols and phthalates in river delta and coastal environment. From ecotoxicological perspectives, concentrations of bis-phenol A and di(2-ethylhexyl)phthalates [DEHP] in surface water from some locations in Vietnam exceeded the guideline values for Ecotoxicological Effects and the Environmental Risk Limit, respectively, suggesting potential for toxic implications on aquatic wildlife. Widespread and elevated arsenic contamination was discovered inour recent surveys in groundwater in a large area of suburban areas of Hanoi city, the capital of Vietnam. The most recent investigation in 4 villages showed about more than 50 % of groundwater samples contained As concentrations exceeding 50 g/L (the WHO and Vietnamese standard). In particular, in Son Dong villages, 58 % of samples analyzed contained As concentrations higher than 200 g/L. Good correlations were found in As concentrations in water and hair and urine of peoples in corresponding families, suggesting the chronic exposure to As by people living in As-contaminated ground water areas. In Son Dong village, As levels in hair (mean: 1.7 mg/kg dry wt) and urine (g/g creatinine) exceeding the reference values recommended by WHO, suggesting potential for human risk posed by long term accumulation of As in human body. Future studies should be focused on the time trends of POPs and EDCs in biota in Vietnam in order to predict future trend of contamination and to reveal new clues for understanding possible toxic impacts on aquatic organisms. The issues of arsenic contamination in groundwater and their chronic toxic implications on human health should be systematically investigated in the future.

• Journal of the Korean earth science society
• /
• v.28 no.1
• /
• pp.75-86
• /
• 2007

In Korea, it is significantly deficient in the study about tourism geology, which is a new branch of applied geology that would support the growth of ecotourism world-wide. The objectives of this study include (1) the promotion in geodiversity of tourism geology using the data for type and distribution patterns of geological and geomorphological landscape resources and (2) the redoubling of diversity in the environmental interpretation programs offered by the Korea National Parks Service (KNPS). Our field study discovered 212 geological and geomorphological landscape resources distributed in the area of Taean seashore national park. Coastal topography is the most discovered type followed by weathering topography. It is our belief that the aforementioned resources can be utilized as a tourism geological site in assisting the public to understand geological science and to draw their attention and interests after sorting and filtering it out through discussions with geologists and geomorphologists of a consortium. Furthermore, in order to promote the activation of developing user-oriented geotourism sites, it is recommended to keep monitoring on demographical characteristics of geotourists, behavioral characteristics of geotouconrists within the geotourism site and ducting analysis for developing geotourism program and events. And, the research support of geological engineering dealing with the estimation of weathering degree and the development of conservation techniques for the object of geotourism along with the research of environmental science aspects will improve the activation of tourism geology.

• Korean Journal of Soil Science and Fertilizer
• /
• v.30 no.2
• /
• pp.200-207
• /
• 1997

In order to evaluate the soil microbiological characteristics of paddy fields in Korea, surface soils were sampled from 63 sites in different agroclimatic zones before submersion of the fields. The distribution of microorganisms and the microbial diversity indices were examined. Soil microbial populations were generally higher in southern area than in northern area. The colony forming units(cfus) of fluorescence Pseudomonas sp. showed the greatest regional differences, among the microbes investigated. On the topographical differences, the cfus of aerobic bacteria, fluorescence Pseudomonas sp. and Azotobacter sp. maintained high level in coastal plains; and on the sail textural difference, fungus was the highest in clay soil, but Bacillus sp., Azotobacter sp and denitrifiers were the highest in silty clay loam soil at 0.05 probability level based on the multiple range test. The numbers of ammonium oxidizers and Azotobacter sp. were increased with soil pH. Microbial diversity indices of paddy fields which calculated from the percentages of Bacillus sp. fluorescence Pseudomonas sp. Azotobacter sp. denitrifiers, ammonium oxidizers, nitrite oxidizers, actinomycetes and fungus to these total microbial numbers were between 0.109 and 0.661. On the soil textures, the microbial diversity indices of sandy, sandy loam, silty clay loam, clay loam and clay soil were 0.443, 0.427, 0.414, 0.405 and 0.362 respectively.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.33 no.6
• /
• pp.501-507
• /
• 2000

Distribution and habitat characteristics of Zostera (Zosteraceae) in the eastern coast of Korea were examined along with plant monohology, sediment composition and physicochemical factors of seawater from June 1998 to July 2000, The results showed that three species, Zostera marina, Z. asiatica and Z, caespitosa were found in specific habitats. The depth of habitat for Z. asiatica was deeper ($8.5{\~}15.0 m$) than that of Z. marina ($1.3{\~}5.6 m$) and Z. caespitosa ($3.2{\~}5.2 m$). Z. marina beds were observed at brackish-water, port and inner bay with the sediment type of sand or muddy sand. Habitats of Z. asiatica were restricted to the open bay with the sediment type of sand, Zostera have been described with regard to different growth forms of vegetation, flowering shoot and life history. Vegetation and flowering shoot length varied significantly with habitats; values ranged $66.8{\~}110.0 cm$ and $128.0{\~}217,8 cm$, respectively. Morphology of Z. marina varied with water depth and different substrates. Morphological characteristics of Z. asiatica showed a new phenotype at the deeper water depth. Vegetation and flowering shoots of Z. caespitosa were not significantly different between study sites (values ranged from 64.9 cm to 70.3 cm). Nutrient concentrations of seawater were higher at southern part than at middle part of the eastern coast of Korea. Distribution of Zostera in the eastern coast of Korea was dependent upon differences in water depth and habitat environments, by which affected the morphological differences were affected.

• Journal of Korean Society of Forest Science
• /
• v.83 no.3
• /
• pp.380-390
• /
• 1994

This study was conducted to investigate the effects of the topographical factors (16 items), physico-chemical properties of soil (13 items) and meteorological factors(9 items) on the height growth of Pinus thunbergii stands along the coastal area in Korea. According to the coefficients by partial correlation analysis in total area, it was found that tree height growth was considerably affected by local topography, soil hardness, soil B-horizental depth, effective soil depth, soil moisture, parent rock, soil texture, and etc.. And the soil factors were available $P_2O_5$, total nitrogen, base saturation, exchangeable $Ca^{{+}+}$, and etc.. In partial correlation analysis, annual relative humidity, annual precipitation, index of aridity, and etc. were found to be the most important factors influencing on tree height growth of Pinus thunbergii stands. In conlusion, the topographical, soil and meteorological factors have multiplex influence on the tree height growth in the Pinus thunbergii stands. They promise to provide the basis of improving not only the selection of suitable sites and the management of soil fertilizer but also the estimation of growth and yield. Hence these results would be used successfully for the design in the scientific forest working plan.

• Ocean and Polar Research
• /
• v.30 no.1
• /
• pp.109-117
• /
• 2008

Application of biomarkers for assessing marine environmental health risk is a relatively new field. According to the National Research Council and the World Health Organization, biomarkers can be divided into three classes: biomarkers of exposure, biomarkers of effect, and biomarkers of susceptibility. In order to assess exposure to or effect of the environmental pollutants on marine ecosystem, the following set of biomarkers can be examined: detoxification, oxidative stress, biotransformation products, stress responses, apoptosis, physiological metabolisms, neuromuscular responses, reproductions, steroid hormones, antioxidants, genetic modifications. Since early 1990s, several biomarker research groups have developed health indices of marine organisms to be used for assessing the state of the marine environment. Biomarker indices can be used to interpret data obtained from monitoring biological effects. In this review, we will summarize Health assessment Index, Biomarker Index, Bioeffect Assessment Index and Generalized Linear Model. Measurements of biomarker responses and development of biomarker index in marine organisms from contaminated sites offer great a lot of information, which can be used in environmental monitoring programs, designed for various aspects of ecosystem risk assessment.

• Korean Journal of Ecology and Environment
• /
• v.50 no.4
• /
• pp.432-440
• /
• 2017

Compound specific isotope analysis of amino acids (CSIA-AAs) is being highlighted as an alternative approach for overcoming some restrictions in application of stable isotope analysis of bulk tissue (SIA) for trophic position (TP) estimation. However, this approach has rarely been applied in Korea. The present study determines TP of two Polychaeta (Nephtyidae and Glyceridae) and two fish species(Platycephalus indicus and Lophius litulon) collected from the Geum River estuary using nitrogen isotope ratio of amino acid and compared with the TP values estimated by SIA. The Polychaeta species, sampled in two sites, showed similar TP between SIA(2.7 and 3.1) and CSIA-AAs (2.6 and 3.1). However, for both fish species, TP values displayed a large difference between SIA (3.1 and 2.3) and CSIA-AAs (3.8 and 3.7). In this study TP values estimated by CSIA-AAs showed more similar to the previously reported gut content analysis of both fishes compared with the results of SIA. Current study suggests the applicability of nitrogen isotope ratio of amino acid to understand coastal ecosystem structure and trophic ecology.

• Korean Journal of Environmental Biology
• /
• v.36 no.2
• /
• pp.165-173
• /
• 2018

We sampled vomit of black-faced spoonbills(Platalea minor) during the brood-rearing season (from June 2011 to June 2014) at the Namdong reservoir in Incheon and analyzed the food components in the vomit using microscopy and next-generation sequencing (NGS). Microscopic observations primarily helped in identifying osteichthyes (bony fishes), crustaceans, and polychaetes. In particular, species belonging to the families Mugilidae and Gobiidae among the fish, and Macrophthalmus japonicas among the crustaceans, were observed at high frequency. Results of NGS analysis revealed the predominant presence of bony fish (42.58% of total reads) and crustaceans (40.75% of total reads), whereas others, such as polychaetes (12.66%), insects (0.24%), and unidentified species (3.78%), occurred in lower proportions. At the species level, results of NGS analysis revealed that Macrophthalmus abbreviates and Macrobrachium sp. among the crustaceans, and Acanthogobius hasta, Tridentiger obscurus, and Pterogobius zacalles among the bony fish, made up a high proportion of the total reads. These food species are frequently found at tidal flats in the Songdo and Sihwa lakes, emphasizing the importance of these areas as potential feeding sites of the black-faced spoonbill. Feed composition of the black-faced spoonbill, as evaluated by analyzing its vomit, differed when the evaluations were done by microscopic observation or by NGS analysis. Evaluation by microscopic observation is difficult and not error free, owing to the degradation of the samples to be analyzed; however, NGS analysis is more accurate, because it makes use of genetic information. Therefore, accurately analyzing food components from morphologically indistinguishable samples is possible by using genetic analysis.

• Korean Journal of Ecology and Environment
• /
• v.49 no.1
• /
• pp.22-30
• /
• 2016

Environmental changes exert harmful effects on organisms inhabiting coastal regions. These changes are also associated with reduced production in aquaculture farms. In this study, we investigated internal and external responses of two Bivalvia species (Crassostrea gigas and Mytilus galloprovincialis) in Gamak Bay under stressful environmental conditions in aquaculture farms. We investigated external responses such as weight, size, and environment exposure time, and analyzed the expression of the HSP70 gene. C. gigas HSP70 gene expression level was significantly high in the C3 aquaculture farm site, but the weight and size of C. gigas were high in the C2 aquaculture farm site. The response of C. gigas HSP70 mRNA was associated with the environmental exposure time in each aquaculture farm. Expression of M. galloprovincialis HSP70 gene was found to be significantly higher in the M2 aquaculture farm site than in the M1 site, whereas the weight of M. galloprovincialis was observed to be higher in the M1 site. The size and environmental exposure time of M. galloprovincialis were similar between M1 and M2 sites. In addition, HSP70 sequences of C. gigas and M. galloprovincialis showed high similarity with that of another marine species. According to our results, there were differences in internal responses following environmental stress in aquaculture farms, with respect to HSP70 gene expression. The results suggest that the HSP70 gene is a useful molecular indicator for monitoring stress responses in Bivalvia species in the field.