• Journal of Korean Society on Water Environment
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• v.28 no.4
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• pp.561-573
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• 2012

The object of this study was to analyze long-term water quality gradients during 1992-2008 at six sites of Geumho River and near-by two sites of Nakdong River and their influences on fish trophic guilds and tolerance guilds along with ecological health. Water quality including biological oxygen demand (BOD), chemical oxygen demand (COD), conductivity, total phosphorus (TP), total nitrogen (TN), and total suspended solids (TSS) varied largely depending on the sampling locations and seasons. Values of ambient BOD, COD, TP, and TN were greater in the downstream than in the upstream reach, and seasonal and interannual variabilities were also higher in the downstreams. This phenomenon was evident due to a dilution by the Asian monsoon rainfall during the monsoon. These outcomes indicate that point sources near the downstream are important for the chemical conditions, but also seasonal stream runoff was considered as an important factor regulating the chemical conditions. Conductivity decreased rapidly during the summer due to ionic dilution, and nutrients (N, P), BOD, COD had an inverse function of seasonal precipitation. Based on the water quality, we selected two sites (control site = $C_s$ vs. impacted site = $I_s$) for impact analysis of water chemistry on fish community and trophic/tolerant guilds. Fish guild analysis showed that species diversity was higher in the headwater stream ($C_s$) than the impacted downstream ($I_s$), and that the proportion of tolerant and omnivore species were greater in the impacted site of downstream. Comparisons of water quality between Geumho River and Nakdong River indicated that Geumho River was considered as a point source which degradated water quality to the Nakdong River. Overall, chemical water quality and fish guild analysis suggest that even if current chemical quality got better after 1996 due to continuous constructions of wastewater disposal plants near the downstreams, fish compositions of tolerant and omnivores were still dominated the community. Thus, biological restoration based on ecological health is required for the ecosystem conservation.

• Journal of The Korean Association For Science Education
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• v.30 no.4
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• pp.498-518
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• 2010

This study analyzed the characteristics of organization scheme and the levels of core concepts in science textbooks used in Korea, Singapore, and Taiwan, which have shown superior achievement according to the TIMSS 2007. Science textbooks in Korea clearly divide the fields of Energy, Matter, Biology, and Earth, presenting the fields in nearly equal proportion in each grade. In the case of Singapore, science textbooks take an integrated content approach, combining concepts from several fields under a single theme. Science textbooks in Taiwan present a single content field in each unit. Also, because each grade engages in a specific field intensively, there are many cases in which concepts related to a single field are studied in a single grade. In view of levels of core concepts, Singapore or Taiwan showed higher achievement than Korea in themes of 'Cell and their Functions', 'Ecosystems', and 'Human Health' under the TIMSS 2007 biology field. Singapore introduces core concepts for these themes in lower grades compared to Korea and presents them repeatedly in several grades. In Taiwan, there are many cases in which these core concepts are taught only once during the course of $3^{rd}$ to $8^{th}$ grade, but the explanations are presented at a level that is suitable to TIMSS 2007 assessment objectives. Considering the results of this analysis, there is a need to reconsider the division of content fields and methods of presenting core concepts in the science textbooks of Korea.

• Korean Chemical Engineering Research
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• v.50 no.6
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• pp.1056-1063
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• 2012

Recent rapidly growth in nanotechnolgies is promised novel benefits through the exploitation of their unique industrial and biomedical applications. With increasing utilization of nanomaterials in consumer products, the potential release of nanomaterials into the environment and their impacts on the ecosystem and human health have been the issues of concern. Nanomaterials that was exposed unintentionally in environment might be accumulated in various environmental media, and finally it will be influenced to human and ecosystems. Therefore, it is important to understand the fate and behavior of nanoparticles for understanding effects on environmental media (air, water, and soil phase). Therefore, in this work, we investigated the several cases for environmental exposure of nanomaterials and suggested the direction of further research. In workplace, exposure to air media is dominant, but finally waste and wastewater was moved to the water and soil phase. In addition, we found the existing sewage treatment plant was not suitable to remove completely nanomaterials in wastewater flow. To deeper study, environmental monitoring tool must be developed additionally and we suggested the several analyzing method for aged and pristine physicochemical properties of nanomaterials exposed into environmental media. This review for nanomaterials' exposure to environmental media will be helpful to investigate the environmental fate of nanomaterials and define the suitable treatment method for nano-waste.

• Korean Journal of Ecology and Environment
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• v.37 no.4 s.109
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• pp.462-468
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• 2004

Most of the surveys of periphyton carried out for environmental and ecosystem health assessment of streams have considered the impact made on their fixative substrates (stones, rocks, sand, silt, clay and other abiotic matters), but there has been virtually no research that considered moving substrates. This study attempted to make an analysis and assessment of the habitat environments of the microalgae attached to the skin surfaces of fish living in small streams, with a focus on their species composition and community structure. The dominant fish in the this survey were Zacco temmincki and Zacco platypus, which are usually found in the streams, and rivers, and they accounted for 62% and 19%, respectively, in relative abundance. Substrates of fish, a representative organism with the trait of moving a long distance, show a marked contrast with those of organisms fixed at a certain place. Characteristics of both the upstream and the downstream reach well reflected in the microalgae attached to the skin surface of fishes, of which diatoms took the major composition. The result of this observation is considered to be useful to provide basic data in assessment of stream health. Also it may be suggested as a biological tool for the assessment of aquatic environment in the future.

• Ecology and Resilient Infrastructure
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• v.6 no.4
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• pp.227-235
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• 2019

This study monitored Daecheong 1-bo, Daecheong-stream, which carried out the project in 2014, from 2015 to 2016. The technology applied to the stream was evaluated using Periphytic Algae to check contamination indicators and ecological health of the area with an integral river-bed protection using non-toxic materials. The water quality of the monitoring section was confirmed to be above the river environment standard (II), and it was confirmed that the Saproxenic taxa of the river bed protection were higher than the upper and downstream sections. The TDI, which is an index of attachment algae, was shown in the average 51.03 and 52.15 for the pilot project sections in 2015 and 2016, confirming that the index is of the "normal" grade. This is the other sections in the upstream and downstream sections showed higher than "bad", which is thought to have a positive effect on the habitat of the river ecosystem components, especially the microbial population in river bed protection.

• Microbiology and Biotechnology Letters
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• v.31 no.2
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• pp.95-102
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• 2003

Microalgae are a diverse group of photosynthetic organisms and abundant in every ecosystem in the biosphere. They are common in aqueous environments including marine, brackish and fresh waters and in some habitats that lack eukaryotic life such as some hot springs and highly alkaline lakes. Microalgal biotechnology that is focused on the microalgae-based production of a variety of useful materials such as pharmaceutical comfounds, health foods, natural pigments, and biofuels is considered as an important discipline with the development of biotechnology. In addition, the mass cultivation of microalgae can also contribute to improving the environmental quality by reducing the concentration of $CO_2$ which is one of major gases lead to global warming. Consequently, it seems that the microalgae can be used as an efficient, renewable, environmentally friendly source of high-value biomaterials such as chemicals, pigments, energy, etc. and the microalgal biotechnology will most likely represent a larger portion of modern biotechnology.

• Journal of Environmental Health Sciences
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• v.27 no.2
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• pp.108-118
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• 2001

This study was performed to investigate the bioconcentration of IBP, methidathion and piperophos. The BCFs(bioconcentration factor), depuration rate constants for three pesticides in zebrafish(Brachydanio rerio) were measured by OECD guideline 305. The concentration of test pesicides were one-hundredth and one-thousandth concentration of 96-hrs L $C_{50}$ in accordance with OECD guideline 305. The results obtained are summarized as follows: The average BCF values of IBP were 5.31(n=4) and 7.30(n=4) at one-hundredth and one-thousandth concentration of 96-hrs L $C_{50}$ . The average BCF values of methidathion were 8.72(n=4) and 11.25(n=4), the average BCF values of piperophos were 34.30(n=4) and 42.60(n=4). Depuration rate constants of IBP were 0.09( $h^{-1}$ ) and 0.08( $h^{-1}$ ), half-life of IBP were 7.70 and 8.66 at each tested concentration. The concentrations of IBP in zebrafish at low and high concentrations rapidly decreased after 12(0.243$\mu\textrm{g}$/g) and 12 hours(0.040$\mu\textrm{g}$/g). Depuration rate constants of methidathion were 0.40( $h^{-1}$ ), half-life of methidathion were 1.73 at one-hunderdth and of 96-hrs L $C_{50}$ , repectively. The concentrations of methidathion in zebrafish at high concentrations rapidly decreased after 6 hours(0.18 $\mu\textrm{g}$/g). Depuration rate constant of low concentration was no measured because methidathion in zebrafish was depurated in 6 hours. Depuration rate constants of piperophos sere 0.15( $h^{-1}$ ) and 0.44( $h^{-1}$ ), half-life of piperophos were 4.62 and 1.58 at each tested concentration. The concentrations of piperophos in zebrafish at los and high concentrations rapidly decreased after 12(0.26$\mu\textrm{g}$/g) and 6 hours(0.015 $\mu\textrm{g}$/g). It was suggested that high BCF of piperophos was due to high Kow(octanol-water partition coefficient). The possibility of bioconcenration was not likely to be high because of its $K_{DEP}$(depuration rate constant) in the evniroment. It was suggested that low BCF of methidathion showed lowest Kow as well as the most rapid $K_{DEP}$. Therefore, the possibility of bioconcentration was not occured in the enviroment. It was suggested that the BCF dtermined for IBP was lower than that of other pesticides due to high Sw(water solubility), show $K_{DEP}$. Therefore, IBP revealed little bioconcentration effect on in aquatic ecosystem.ystem.

• Ecology and Resilient Infrastructure
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• v.2 no.2
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• pp.108-117
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• 2015

This study was carried out to assess problems related to legislative regulations and guidelines concerning some biological assessment systems applied to stream corridor in Korea. We comparatively reviewed the law of stream corridors and the guidelines for master plan concerned, and the law of water quality and health assessment criteria for the aquatic ecosystem concerned. Stream environments were not managed effectively due to the absence of detail regulations and the criteria for stream assessment. A biological assessment system was not equivalently integrated within the management of water resources in process implementation of projects resulting from the dualistic management system for stream corridors in Korea. The current biological assessment system was reflected to mainly physical habitats or only oriented to some aquatic species correlated with water quality. This system was also recognized as part of environment impact assessment based on an intensive survey method of most biological taxa. Conclusively rapid and quantitative assessment techniques based on advanced organisms, such as vegetation, fish and birds, etc. should be urgently provided for considering as representative indicators of stream conditions in Korea.

• Korean Journal of Ecology and Environment
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• v.54 no.1
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• pp.12-23
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• 2021

As fish communities are sensitive to natural environmental changes as well as anthropogenic pressures, their composition and characteristics help us to assess the aquatic ecosystem health. The fish fauna and the length-weight relationship of Zacco platypus in the Seomjin River system were investigated from July 2018 to May 2019. The collected species during the survey period were 49 species belong to 14 families including 19 Korean endemic and two endangered species. According to Bray-Curtis similarities, 14 sites were divided into four groups based on the fish community composition; two groups(group A, B) and two uncategorized sites(group C, D). There were significant differences between groups A and B(analysis of similarities, R=0.722, p=0.002). A similarity percentage analysis revealed that Z. koreanus(8.55%), Micropterus salmoides(6.90%), and Lepomis macrochirus (4.90%) contributed to these differences of fish assemblages between group A and B. Group A showed higher relative abundances of exotic species such as M. salmoides and L. macrochirus, while Z. platypus and Z. koreanus which are the common species in Korea, were the most dominant species in group B. Based on the length-weight relationship of Z. platypus, b values were varied from 2.82 to 3.80, indicating that growth patterns of the species were spatially different. This study could be served as baseline data for understanding fish fauna, assessing habitat characteristics based on the fauna, and identifying health conditions of Z. platypus in the Seomjin River system.

• Journal of Platform Technology
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• v.11 no.4
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• pp.19-34
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• 2023

In order to identify the trends and insights of 'startups' in the global era, we conducted an in-depth trend analysis of the global startup ecosystem using Google Trends, a big data analysis platform. For the validity of the analysis, we verified the correlation between the keywords 'startup' and 'global' through BIGKinds. We also conducted a network analysis based on the data extracted using Google Trends to determine the frequency of searches for the keyword or term 'startup'. The results showed a strong positive linear relationship between the keywords, indicating a statistically significant correlation (correlation coefficient: +0.8906). When exploring global startup trends using Google Trends, we found a terribly similar linear pattern of increasing and decreasing interest in each country over time, as shown in Figure 4. In particular, startup interest was low in the range of 35 to 76 from mid-2020 due to the COVID-19 pandemic, but there was a noticeable upward trend in startup interest after March 2022. In addition, we found that the interest in startups in each country except South Korea is very similar, and the related topics are startup company, technology, investment, funding, and keyword search terms such as best startup, tech, business, invest, health, and fintech are highly correlated.