• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.28-30
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• 2005

Because of high population diversity in soil microbial communities, it is difficult to accurately assess the capability of biodegradation of toxicant by microbes in soil and sediment. Identifying biodegradative microorganisms is an important step in designing and analyzing soil bioremediation. To remove non-important noise information, it is necessary to selectively enrich genomes of biodegradative microorganisms fromnon-biodegradative populations. For this purpose, a stable isotope probing (SIP) technique was applied in selectively harvesting the genomes of biphenyl-utilizing bacteria from soil microbial communities. Since many biphenyl-using microorganisms are responsible for aerobic PCB degradation In soil and sediments, biphenyl-utilizing bacteria were chosen as the target organisms. In soil microcosms, 13C-biphenyl was added as a selective carbon source for biphenyl users, According to $13C-CO_2$ analysis by GC-MS, 13C-biphenyl mineralization was detected after a 7-day of incubation. The heavy portion of DNA(13C-DNA) was separated from the light portion of DNA (12C-DNA) using equilibrium density gradient ultracentrifuge. Bacterial community structure in the 13C-DNAsample was analyzed by t-RFLP (terminal restriction fragment length polymorphism) method. The t-RFLP result demonstates that the use of SIP efficiently and selectively enriched the genomes of biphenyl degrading bacteria from non-degradative microbes. Furthermore, the bacterial diversity of biphenyl degrading populations was small enough for environmental genomes tools (metagenomics and DNA microarrays) to be used to detect functional (biphenyl degradation) genes from soil microbial communities, which may provide a significant progress in assessing microbial capability of PCB bioremediation in soil and groundwater.

• Korean Journal of Microbiology
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• v.8 no.2
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• pp.53-64
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• 1970

In order to study ecology of microorganisms during Takju brewing, microflora changes were examined fromm the start to the sixth day of Takju fermentation in 24 hours intervals. Takju made from rice, flour and dried sweet potato in a liter volume open container at the laboratory and a sanple of Takju brewing factory were studied for their microflora and their changes during fermentationl together with a sample of Kokja. Results obtained were as follows ; 1. The followings were the identified microorganisms in Kokja. The molds ; Absidia spinosa, Aspergillus parasiticus. The yeasts ; Candida melinii, Candida Solani, Hansenula anomala. The bacteria ; Luctobacillus casei, Leuconostoc mesenteroides, Bacillus subtilis, Bacillus pumilus. 2. Torulopsis inconspicua, Lactobacillus casei, Leuconotoc mesenteroides, Bacillus subtilis, Bacillus pumilus were isolated from main mash of laboratory-made Takju samples. The yeast, Torupsis inconspicua which was not present in Kokja and, probably of a contaminant yeast, dominated the yeast flora of Takju mash of rice, flour and sweet potato of labotatory brewing. The laboratory brewing lost also always showed large population of lactic acid bacteria flora. 3. None of the wild yeasts which were present in Kokja appeared in Takju mashes. The Kokja appears to be of no use as the yeast source for Takju fermentation. Also the Kokja appears to be of not so effective amylolytic and proteolytic enzyme sources considering the microflora characteristics. Probably the major role of Kokja in Takju fermentation may be to contribute in taste formation. 4. Inoculation of Sacharomyces cerevisiae into the mash to the level of $10^7$ ml at the start of fermentation greatly changed the ecological aspects eliminating conditions of rather slow rising of natural contaminant yeast populaiton and fermentation which might give rise to prosperity of lactic acid and Bacillus bacteria that would be avoidable. 5. Examination of microflora of the large factory scale Takju fermentation showed the quite similar pattern of microflora and their changes to that of the cultured yeast-inoculated laboratory batch Takju fermentation. The cultured yeast dominated as the only predominant microflora, and the lactic acid bacteria flora were completely suppressed and aerobic bacteria, greatly. Probably this may be the regular microflora pattern of normal Takju fermentation. The role of lactic acid bacteria and aerobic bacteria in Takju fermentation may not be clear yet from this experiment alone.

• Korean Journal of Ecology and Environment
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• v.46 no.1
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• pp.1-9
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• 2013

Algal blooms in potable water supplies are becoming an increasingly prevalent and serious water quality problem around the world. In addition to precipitating taste and odor problems, blooms damage the environment, and some classes like cyanobacteria (blue-green algae) release toxins that can threaten human health, even causing death. There is a recognized need in the water industry for models that can accurately forecast in real-time algal bloom events for planning and mitigation purposes. In this study, using data for an interconnected system of rivers and reservoirs operated by a New Jersey water utility, various ANN models, including both discrete prediction and classification models, were developed and tested for forecasting counts of three different algal classes for one-week and two-weeks ahead periods. Predictor model inputs included physical, meteorological, chemical, and biological variables, and two different temporal schemes for processing inputs relative to the prediction event were used. Despite relatively limited historical data, the discrete prediction ANN models generally performed well during validation, achieving relatively high correlation coefficients, and often predicting the formation and dissipation of high algae count periods. The ANN classification models also performed well, with average classification percentages averaging 94 percent accuracy. Despite relatively limited data events, this study demonstrates that with adequate data collection, both in terms of the number of historical events and availability of important predictor variables, ANNs can provide accurate real-time forecasts of algal population counts, as well as foster increased understanding of important cause and effect relationships, which can be used to both improve monitoring programs and forecasting efforts.

• International Journal of Human Ecology
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• v.12 no.2
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• pp.13-24
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• 2011

This study compared actual weight with perceived weight, described the prevalence of unhealthy weight control behavior, determined the differences in psychological and personal variables between participants that reported unhealthy weight control behavior and those who did not, and examined the relationship of eating habits to unhealthy weight control behavior for Korean adolescents. The study population consisted of a nationally representative sample of middle and high school students who completed the Fifth Korea Youth Risk Behavior Web-based Survey (KYRBWS): Fifth in 2009. Among the 75,066 participants of KYRBWS, 35,473 (n = 18,851 girls and 16,622 boys) were eligible for a research focused on unhealthy weight control behavior. The results of this research were as follows: First, there were considerable discrepancies (45.1% of girls and 32.8% of boys) between the perceived weight and the actual weight. Second, overall, unhealthy weight control behavior was more prevalent in girls and fasting was the most commonly reported behavior. Third, participants that reported unhealthy weight control behavior scored significantly lower on scaled measures of happiness, health, academic achievement, and economic status; in addition, they scored higher on stress measures. Fourth, girls and boys shared common protective factors of having breakfast and vegetables more often, perceiving their weight as underweight rather than overweight, and having a correct weight conception. Protective factors unique to girls were having lunch and dinner more often. Girls and boys shared common risk factors of the consumption of soda, fast food, instant noodles, and snacks more often, while consumption of fruit more often was a risk factor only for girls. The improvement of protective factors and minimization of risk factors through Home Economics classes (and other classes relevant to health) may mitigate unhealthy weight control behavior of adolescents.

• Journal of Fisheries and Marine Sciences Education
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• v.19 no.2
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• pp.180-196
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• 2007

This study aims at analyzing the potential of leports-fishing for improving fishing household income. Leports-fishing is a composite concept which is combined with those of leisure, sports and fishing. Korean on-shore resources have also a composite characteristic. The properties of the east, west and south coastal waters are quite different in geography, biology and ecology. There is a array of leports-fishing development potentials of utilizing their characteristics. At present, angling forms a main activity of leports-fishing, but coastal seas would be an emerging space for the public. In order for them to be a ground of fun, enjoyment and festivals, it would be necessary to supply a wide range of activities and facilities including angling, scuba diving, fish barbecue, ecological experience, fishing experience, cruise, and so forth. As seen in the survey results, the participants have strong desire for fun and enjoyment through leports-fishing activities. The proportion of people participating in one or two times a year amounts to 40 percent. Most coastal places visited are close to medium/large cities and two-days leports-fishing/tourism accounts for some 77 percent. However, it turned out that conflicts between leports-fishing participants and fishermen are not serious. The results of expenditure function estimation appear that the elasticity of per capita income is very high with 1.2660 and that there are negative relationships between leports-fishing expenditure and transportation/food/lodging costs. Assuming the annual national economic growth rate of 4 percent, it is anticipated that Korean leports-fishing population will increase to 3.18 million in 2010 and 4.07 million in 2015. Korean leports-fishing market potential in 2015, which is calculated based on per capita expenditure on leports-fishing, appears to amount to 1,400 billion won~1,600 billion won. The contribution of such market potential to the fishing households is expected to be 62.3~74.2 percent(934.5 billion won~111.3 billion won).

• The Korean Journal of Ecology
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• v.21 no.5_1
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• pp.457.2-486
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• 1998

Ecological success of introduced species is frequently attributed to the reproductive characters of those species. We examined the relationship between both flowering season and plant size and reproductive characters in two introduced species of Taraxacum, e.g., T. officinale and T.laevigatum. Seventy six plants of T. officinale and 23 plants of T. laevigatum were randomly tagged from a population at the sungshin Women's University in April of 1997. The size and number of vegetative characters such as rosette diameter, leaf number, and the largest leaf length and width were measured for each plant at the onset of flowering. The infructescence was collected continually from each plant before seed dispersal from April to August of 1997. The number of infructescence per plant, and seed number and total seed weight per infructescence were measured. Mean individual seed weight per infructescence was also obtained. T. officinale possessed larger sized, but smaller number of, leaves than T. laevigatum, thereby resulting in no significant difference in total leaf area. There was a trend that vegetatively larger plants in both of these species produced reproductive characters larger in size or greater in number, except for seed number and total seed weight per infructescence in T. laevigatum. All reproductive characters examined in T. officinale decreased toward the end of flowering season. In T. laevigatum, infructescence number per plant also declined during a flowering season: however, mean seed number per infructescence increaed toward the end of flowering season with no significant seasonal change in the total seed weight per infructescence. T. officinale produced on average about twice as many seeds per plant as T. laevigatum during a growing season. These two Taraxacum species produced quite small seeds in size compared to the endemic species, exhibiting a far better dispersal ability of introduced species. These data demonstrate that most reproductive characters decline in size and number in both species during a long flowering period, but the two species appear to employ different strategies to achieve reproductive success in disturbed habitats.

• The Korean Journal of Ecology
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• v.3 no.1_2
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• pp.11-16
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• 1980

Growth analytical and primary productivity experiments of soybean populations were conducted with special references to the development of productive structures and environmental conditions of nitrogen levels $(N_1,\; control:\; N_2,\; 6.67gN/\textrm m^2:\; N_3,\;13.34\textrm {gN/m}^2)$. The maximum amounts in LAI for $N_1,\; N_2\; and\; N_3$ stand were 17.3, 19.0 and 18.5; in total standing grops, 1570, 1785 and 1704gDM/$\m^2$; in total net productions, 543, 648 and 636gDM/$\m^2$, respectively. The maximum CGR attanined were 208, 237 and 272 gDM$\m^2$/week, while the mean EU was 2.55, 2.92 and 2.84% N1, N2 and N3, respectively. The total nitrogen standing quantity attained 53.4, 71.8 and 59.8 gN/$\m^2$ at the maximum standing crop period. The net nitrogen absorption rates showed highly significant differences among nitrogen treatments, i.e., 1.34, 10.77 and 13.22 mg/g/day for $N_1,\; N_2\; and \;N_3$ stand, repsectively.

• Journal of Ecology and Environment
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• v.43 no.4
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• pp.427-437
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• 2019

Background: Climate change is believed to be continuously affecting ticks by influencing their habitat suitability. However, we attempted to model the climate change-induced impacts on future genus Rhipicephalus distribution considering the major environmental factors that would influence the tick. Therefore, 50 tick occuance points were taken to model the potential distribution using maximum entropy (MaxEnt) software and 19 climatic variables, taking into account the ability for future climatic change under representative concentration pathways (RCPs) 4.5 and 8.5, were used. Results: MaxEnt model performance was tested and found with the AUC value of 0.99 which indicates excellent goodness-of-fit and predictive accuracy. Current models predict increased temperatures, both in the mid and end terms together with possible changes of other climatic factors like precipitation which may lead to higher tick-borne disease risks associated with expansion of the range of the targeted tick distribution. Distribution maps were constructed for the current, 2050, and 2070 for the two greenhouse gas scenarios and the most dramatic scenario; RCP 8.5 produced the highest increase probable distribution range. Conclusions: The future potential distribution of the genus Rhipicephalus show potential expansion to the new areas due to the future climatic suitability increase. These results indicate that the genus population of the targeted tick could emerge in areas in which they are currently lacking; increased incidence of tick-borne diseases poses further risk which can affect cattle production and productivity, thereby affecting the livelihood of smallholding farmers. Therefore, it is recommended to implement climate change adaptation practices to minimize the impacts.

• Journal of the Korean GEO-environmental Society
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• v.18 no.7
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• pp.21-35
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• 2017

The 3S Basin is described as an important contributor in terms of many aspects in the Mekong River Basin in Southeast Asia. However, the 3S Basin has been suffering adverse consequences of changing discharge and sediment, which are derived from farming, deforestation, hydropower dam construction, climate change, and soil erosion. Consequently, a large population and ecology system that live along the 3S Basin are seriously affected. Accordingly, the calculating and simulating discharge and sediment become ever more urgent. There are many methods to simulate discharge and sediment. However, most of them are designed only during a single rainfall event and they require many kinds of data. Therefore, this study applied a Catchment-scale Soil Erosion model (C-SEM) to simulate discharge and sediment in the 3S Basin. The simulated results were judged with others references's data and the observed discharge of Strung Treng station, which is located in the mainstream and near the outlet of the 3S Basin. The results revealed that the 3S Basin distributes 31% of the Mekong River Basin's total discharge. In addition, the simulated sediment results at the 3S Basin's outlet also substantiated the importance of the 3S Basin to the Mekong River Basin. Furthermore, the results are also useful for the sustainable management practices in the 3S Basin, where the sediment data is unavailable.

• The Journal of Fisheries Business Administration
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• v.30 no.2
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• pp.55-77
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• 1999

As the population grows, the importance of the fishery industry continues to rise. It is therefore vital to support and promote sustainable fishery industry. However, the fishery production has been declining, mainly due to overdevelopment and depletion in fishery resources and stricter limits on development limits caused by growing concerns over the marine environment and ecology. Recently, international activities related to marine environmental and its ecosystems conservation, have been vigorously pursued. The United Nations Convention on The Law of The Sea has stipulated the protection and conservation of the marine environment, and the implementation of fishery resources development, made in harmony with the environment and fishery resources and based upon scientific findings and principles has become important. Accordingly, fishery industry must pay thorough attention to marine ecological and environmental problems and its international fisheries regime. Fisheries development can affect fishery resources, their environment and ecosystems. Adverse ecological effects resulting from fishery resources development practices in general include overdevelopment and incidental development of non target species, physical degradation of seabed habitants and degraduation of water quality. It has now become more important than ever to build up fishery resources development while achieving the conservation of biodiversity and the marine environment, as well as the restoration of destroyed ecosystems. To maintain fishery industry, it is necessary to develop bioeconomic fishery production system and industry policies for the ESSD(environmentally sound and sustainable development) given that maintenance of a favourable marine environment will ensure the fishery resources productivity. These bioeconomic system and policies are necessary to ensure the sustainability and viability of the fishery industry under ESSD fisheries concepts.