• 한국물환경학회지
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• 제34권6호
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• pp.661-668
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• 2018

Geosmin is volatile metabolites produced by a range of filamentous cyanobacteria which causes taste and odor problems in drinking water. Molecular ecological methods which target biosynthetic genes (geoA) are widely adopted to detect geosmin-producing cyanobacteria. The aim of this study was to investigate the potential production capability of 8 strains isolated from the Nakdong River. Ultimately, a suggestion for a genetical monitoring tool for the identification of geosmin producers in domestic waters was to be made. Geosmin was detected using solid phase microextraction gas chromatography mass spectrometry (SPME GC-MS) in two strains of Dolichospermum plactonicum (DGUC006, DGUC012) that were cultured for 28 day. The highest concentrations during the experiment period was $17,535ngL^{-1}$ and $14,311ngL^{-1}$ respectively. Additionally, geoA genes were amplified using two primers (geo78F/971R and geo78F/982R) from strains shown to produce geosmin, while amplification products were not detected in any of non-producing strains. PCR product (766 bp) was slightly shorter than the expected size for geosmin producers. According to the BLAST analysis, amplified genes were at nucleotide level with Anabaena ucrainica (HQ404996, HQ404997), Dolichospermum planctonicum (KM13400) and Dolichospermum ucrainicum (MF996872) between 99 ~ 100 %. Both strains were thus confirmed as potential geosmin-producing species. We concluded that the molecular method of analysis was a useful tool for monitoring potential cyanobacterial producers of geosmin.

• Journal of Ecology and Environment
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• 제42권1호
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• pp.43-49
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• 2018

Iris laevigata is geographically restricted and legally protected in Korea. In this study, a mesocosm study was conducted to examine the effects of environmental conditions such as water levels and soil nutrient conditions on the growth and survival of I. laevigata seedlings. Complete submergence lowered the total number of leaves, biomass, and survival rates. A rise in soil nutrients increased overall seedling growth and increased tiller numbers via the promotion of asexual reproduction. Also, we found that the lowest measured values of seedlings are associated with the most stressful condition due to the interaction of low soil nutrients and high water levels. I. laevigata seedlings, however, are distributed in low-nutrient habitats such as floating mat, even though they do not grow well under these conditions. This study suggests that I. laevigata does not prefer low-nutrient condition but choose another benefit such as low competition. Also, the water level must be lower than the seedling height for effective growth and management of I. laevigata.

• 수산해양교육연구
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• 제27권4호
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• pp.1021-1030
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• 2015

For the water quality improvement in the ocean outfall area of sewage treatment plant, this study tried to control the water quality of outfall area using the biofilter method through seaweeds, a way of ecological engineering treatment that is applicable in the marine ecosystem. Therefore, this research made an attempt the main factors necessary for creating seaweed bed to improve water quality in the outfall area of sewage treatment plant, and the results are as follows. In the case of making the seaweed bed in the ocean outfall area of sewage treatment plant, Habitat Suitability Index of Ecklonia cava per all survey points, considered physical and physico-chemical factors in 5~10 meters below sea level, was 50~93% (average 80%), so this seaweed, Ecklonia cava, was suitable for making the seaweed bed.

• Journal of Ecology and Environment
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• 제37권1호
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• pp.13-19
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• 2014

The effect of different turnover time of water on the decomposition of emergent macrophyte litter (Zizania latifolia Griseb.) was investigated using a microcosm experiment. Microcosm treatment represented different turnover time of water; 1, 2, 4 and 8 weeks. The litterbags from each treatment were retrieved every 2 weeks until the 8th week and the water simultaneously sampled with the litterbag. The dry weight and the content of major cations in the litter, and the content of available N, P, and major cations in the water were analyzed. Dry weight loss after 8 weeks indicated the lower decay rates under the condition of short turnover time of water. Major cations from the litter and the water showed that the leached amounts of K and Mg from the litter were highest in the 2nd week and dramatically decreased from the 4th week. The dynamics of available nitrogen and phosphorus in the water showed that as the water turnover time was getting longer, the amounts of available nitrogen and phosphorus remained higher. These results suggest that wetlands with longer turnover time of water could maintain the increased nitrogen and phosphorus and no outflow of the nutrients could cause eutrophication problem.

• 한국지구과학회지
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• 제42권3호
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• pp.264-277
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• 2021

본 연구의 목적은 최근 발생한 태풍들의 이동속도와 관련하여 대기 중 총가강수량의 변화를 분석하는 것이다. 이 연구를 위해 미국기상위성연구소 및 기상청 천리안위성 2A호(GEO-KOMPSAT-2A)의 총가강수량 및 주야간 RGB 합성영상 자료뿐만 아니라 기상청의 기온, 강수량 및 풍속 등의 지상 관측 자료가 사용되었다. 기상청에서 제공하는 태풍 위치 및 이동속도를 활용하여, 2020년 태풍 바비, 마이삭, 하이선과 2019년 태풍 타파, 그리고 2018년 태풍 콩레이의 이동속도를 위도별 태풍 평균속도 통계자료와 비교하였다. 그 결과, 타파와 콩레이는 태풍의 위도별 평균속도와 유사하게 나타났으나 바비와 마이삭은 위도 약 25°N-30°N 구간에서 이동속도가 크게 감소하여 나타났다. 이는 대기 중의 수증기 띠가 전선의 형태로 바비와 마이삭 두 태풍의 전방에 위치하여 이들 태풍의 이동에 방해를 주었기 때문이었다. 즉 이동하는 태풍의 전방에 하층제트로 인해 발생한 수증기 띠가 전선을 형성할 경우, 이 전선과 태풍 사이에 위치하는 고기압 역은 더욱 발달하면서 열대야와 함께 블로킹 효과로 작용하여 태풍의 이동속도가 느리게 나타났다. 결과적으로 대기 중의 수증기가 많았던 바비와 마이삭의 경우, 1차로 하층제트를 따라 수증기 띠가 전선을 형성함으로 인한 집중호우가, 2차로 전선과 태풍 사이에 고기압 역의 하강기류로 인한 열대야 현상이, 그리고 3차로 태풍 자체의 육지 상륙에 의한 강풍과 폭우가 연달아 발생하였다.

• 한국물환경학회지
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• 제27권5호
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• pp.617-624
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• 2011

In order to confirm the creation of the OH radical which influences to RNO bleaching processes, it experimented using laboratory reactor of dielectric barrier discharge plasma (DBDP). The experiments performed in about 4 kind process variables (diameter of ground electrode, diameter of discharge electrode, diameter of quartz tube and effect of air flow rate) which influence to process. In order to examine optimum conditions of design factors as shown in Box-Behnken experiment design, ANOVA analysis was conducted against four factors. The actual RNO removal at optimized conditions under real design constraints were obtained, confirming Box-Behnken results. Optimized conditions under real design constraints were obtained for the highest desirability at 1, 1 mm diameter of ground and discharge electrode, 6 mm diameter of quartz tube and 5.05 L/min air flow rate, respectively.

• 대한가정학회지
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• 제41권3호
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• pp.93-111
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• 2003

This study aimed to examine the water consumption of urban households according to pro-environmental attitude for environmental protection. In contrast to preview studies, this study purposed to include various related independent variables, motive to environmental behavior, in special, in the model, and suggest informative data for research, education and strategies related to environmental protection. The data were from 665 housewives living in five urban areas. For the analysis of data, frequencies, means, percentages, GLM analysis, DMR test and Chi-square test were used. The main results of this study were as follows; 1. The respondents held high pro-environmental attitude that pro-environmental behaviors are important to protect environment. The pro-environmental attitude among the respondents were statistically different from the independent variables : spouse's occupation, living area, help of housekeeper, knowledge about environmental protection, convenience to check water consumption, and perception of voluntary conservative behavior among neighborhood 2. There were great difference on water consumption among respondents. The significant independent variables to have effects on water consumption were different between water consumption per person and higher/lower average water consumption. The relationships of pro-environmental attitude and motive to pro-environmental behavior with two water consumption as dependent variables were unique. Also, living areas and knowledge about environment protection were consistently important to explain the difference of water consumption.

• Journal of the Korean Data and Information Science Society
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• 제14권1호
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• pp.23-35
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• 2003

This paper provides the checklist of statistical methods in the water environmental research of Han and Nakdong river basins in South Korea. There are many errors pointed out in adopting statistical methods for the researches, as an example, basic statistical assumptions are missed for t-tests or regression analyses. Some new ideas are proposed for better researches of the river basins in Korea.

• 수산해양교육연구
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• 제12권2호
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• pp.164-175
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• 2000

Port facilities and marine structures used in marine environment were encountered to corrosion damages because of the influence of Cl-. Generally, to protect these accidents, anti-corrosion paint and epoxy coating have been used. But they were still remained erosion-corrosion damage like impingement erosion, cavitation erosion and deposit attack. It is necessary to develope the new composite lining material in order to protective those corrosion damages. In this paper, polyester glass flake, vinylester glass flake lining and epoxy coating for SS400 were investigated by the electrochemical polarization test and the impingement-cavitation erosion test for corrosion behaviour under the sea water. The main results obtained are as follows ; 1) Epoxy coating appear potentiodynamic polarization behaviour, but polyester glass flake and vinylester glass flake lining do not appear potentiodynamic polarization behaviour. 2) Open circuit potential of polyester glass flake lining is more noble than that of epoxy coating and corrosion current density of polyester glass flake lining is less drained than that of epoxy coating in sea water. 3) Open circuit potential of vinylester glass flake lining is more noble than that of polyester glass flake lining and corrosion current density of vinylester glass flake lining is less drained than that of polyester glass flake lining in the sea water.

• 반도체디스플레이기술학회지
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• 제14권3호
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• pp.37-43
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• 2015

In this paper, a new background subtraction algorithm for video based fence monitoring surveillance systems is proposed. We adopt the sampling based background subtraction technique and focus on the two main issues: handling highly dynamic environment and handling the flickering nature of pulse based IR (infrared) lamp. Natural scenes from fence monitoring system are usually composed of several dynamic entities such as swaying trees, moving water, waves and rain. To deal with such dynamic backgrounds, we utilize the confidence factor for each background value of the input image. For the flickering IR lamp, the original sampling based technique is extended to handle double background models. Experimental results revealed that our method works well in real fence monitoring surveillance systems.