• Korean Journal of Microbiology
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• v.51 no.2
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• pp.97-107
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• 2015

Wetlands constitute a transitional zone between terrestrial and aquatic ecosystems and have unique characteristics such as frequent inundation, inflow of nutrients from terrestrial ecosystems, presence of plants adapted to grow in water, and soil that is occasionally oxygen deficient due to saturation. These characteristics and the presence of vegetation determine physical and chemical properties that affect decomposition rates of organic matter (OM). Decomposition of OM is associated with activities of various extracellular enzymes (EE) produced by bacteria and fungi. Extracellular enzymes convert macromolecules to simple compounds such as labile organic carbon (C), nitrogen (N), phosphorus (P), and sulfur (S) that can be easily taken up by microbes and plants. Therefore, the enzymatic approach is helpful to understand the decomposition rates of OM and nutrient cycling in wetland soils. This paper reviews the physical and biogeochemical factors that regulate extracellular enzyme activities (EEa) in wetland soils, including those of ${\beta}$-glucosidase, ${\beta}$-N-acetylglucosaminidase, phosphatase, arylsulfatase, and phenol oxidase that decompose organic matter and release C, N, P, and S nutrients for microbial and plant growths. Effects of pH, water table, and particle size of OM on EEa were not significantly different among sites, whereas the influence of temperature on EEa varied depending on microbial acclimation to extreme temperatures. Addition of C, N, or P affected EEa differently depending on the nutrient state, C:N ratio, limiting factors, and types of enzymes of wetland soils. Substrate quality influenced EEa more significantly than did other factors. Also, drainage of wetland and increased temperature due to global climate change can stimulate phenol oxidase activity, and anthropogenic N deposition can enhance the hydrolytic EEa; these effects increase OM decomposition rates and emissions of $CO_2$ and $CH_4$ from wetland systems. The researches on the relationship between microbial structures and EE functions, and environmental factors controlling EEa can be helpful to manipulate wetland ecosystems for treating pollutants and to monitor wetland ecosystem services.

• Applied Biological Chemistry
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• v.14 no.1
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• pp.9-18
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• 1971

In order to obtain basic information on the production of single cell protein from petroleum, more than 400 yeast strains were isolated from various soil samples in Korea utilizing petroleum hydrocarbon as the sole carbon source. A yeast strain showing the highest cell yield among the isolated strains was selected and identified. The optimal culture condition was searched in the flasks shaken throughout the procedure. And the growing characteristics for the selected yeast strain and chemical analysis of the yeast cell component were carried out. The results obtained were as follows: 1. The selected yeast strain was identified as Candida curvata and we named it Candida curvata-SNU 70. 2. The composition of the medium proposed for the present yeast strain is: Light Gas Oil 30ml, Urea 400mg, Ammonium sulfate 100mg, Potasium phosphate (monobasic) 670mg, Sodium phosphate (dibasic) 330mg, Magnesium sulfate 500mg, Calcium carbonate 3g, Yeast extract 50mg, Tween 20 0.05ml, Tap water 1,000ml. 3. Other culture conditions employed for the yeast were pH 5.5-7.0, temp. $30^{\circ}C$ under an affluent aerobic state. 4. Addition of light gas oil in portions to the culture media as the growth proceeded was more effective, especially in the cultivation on the higher oil concentration media. 5. Studies on the propagation of the yeast cells in the light gas oil medium revealed that the yeast has the lag phase lasted 16 hours and the logarithmic growth phase covered 16 to 28 hours. The specific growth rate was about $0.22\;hr^{-1}$ and doubling time was 3.2 hrs. during the logarithmic growth phase. 6. Under the cultural condition employed, the cell yield against the amount of light gas oil (wt%) was 16.1% and the protein content of the dried yeast cells was 48.4%.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.63 no.2
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• pp.140-148
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• 2018

As the global warming causing desertification increase, there is growing concern about damage of crops. It was to investigate how the treatment with hydrogen peroxide before leaf development affects the growth and yield of sorghum for minimizing a damage of crops to drought. The germination experiment was conducted at alternating temperature of $25^{\circ}C/20^{\circ}C$(12 hr/12 hr) under water stress condition of 0 ~ -0.20 MPa adjusted with PEG solution containing 0 and 10 mM $H_2O_2$. In order to know the effect of foliar application of hydrogen peroxide on the growth of sorghum, 10 mM hydrogen peroxide was treated to leaves at 3-leaf stage of sorghum growing in greenhouse conditions. Seed germination rate was increased by 20% in hydrogen peroxide treatment as compared to the Control. under water stress conditions (-0.15 ~ -0.20 MPa). The length of seedlings was also on the rise by the hydrogen peroxide treatment. In the greenhouse pot experiment, the morphological characteristics (plant height, stem diameter, leaf length, and leaf number) and physiological characteristics (chlorophyll content, chlorophyll fluorescence (Fv/Fm), stomatal conductance) were higher in the plants treated with hydrogen peroxide under the drought stress condition than those of plants of $H_2O$ treatment. Experiment conducted with the soil moisture gradient system showed that the foliar application of hydrogen peroxide increased photosynthetic ability of sorghum plant with respect to SPAD value and stomatal conductance and rooting capacity (root weight and root length) under drought condition. Generally, hydrogen peroxide treatment in sorghum increased the tolerance to drought stress and maintained better growth due to ameliorating oxidative stress.

• Economic and Environmental Geology
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• v.50 no.5
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• pp.341-352
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• 2017

Along with Cs-137 (half-life: 30.17 years), Sr-90 (half-life: 28.8 years) is one of the most important environmental monitoring radioactive elements. Rapid and easy monitoring method for Sr-90 using Laser-Induced Breakdown Spectroscopy (LIBS) has been studied. Strontium belongs to a bivalent alkaline earth metal such as calcium and has similar electron arrangement and size. Due to these similar chemical properties, it can easily enter into the human body through the food chain via water, soil, and crops when leaked into the environment. In addition, it is immersed into the bone at the case of human influx and causes the toxicity for a long time (biological half-life: about 50 years). It is a very reductive and related with the specific reaction that makes wet analysis difficult. In particular, radioactive strontium should be monitored by nuclear power plants but it is very difficult to be analysed from high-cost problems as well as low accuracy of analysis due to complicated analysis procedures, expensive analysis equipment, and a pretreatment process of using massive chemicals. Therefore, we introduce the Laser-Induced Breakdown Spectroscopy (LIBS) analysis method that analyzes the elements in the sample using the inherent spectrum by generating plasma on the sample using pulse energy, and it can be analyzed in a few seconds without preprocessing. A variety of analytical plates for samples were developed to improve the analytical sensitivity by optimizing the laser, wavelength, and time resolution. This can be effectively applied to real-time monitoring of radioactive wastewater discharged from a nuclear power plant, and furthermore, it can be applied as an emergency monitoring means such as possible future accidents at a nuclear power plants.

• Journal of Bio-Environment Control
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• v.6 no.2
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• pp.110-116
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• 1997

This experiment was conducted to investigate the effects of root zone warming on fruit yield of oriental melon (Cucumis melo L. var. Makuwa) in winter season. Root zone was warmed by hot water flowing through pipe set at 35cm depth from the ridge. Treatments of minimum soil temperature at 20cm depth were 17, 21, $25^{\circ}C$ and non-warming from Jan. 18 to Apr. 18. The results are summarized as follows. 1. The blooming of female flower was faster 1 days in 17$^{\circ}C$ plot, 6 days in 21$^{\circ}C$ plot, and 7 days in $25^{\circ}C$ plot than in control plot and the days from blooming to harvesting were shorter 5 days in 17$^{\circ}C$ plot, 11 days in 21$^{\circ}C$ plot, and 12 days in $25^{\circ}C$ plot than in control plot. 2. Mean fruit weight was the highest in 21$^{\circ}C$ plot, followed $25^{\circ}C$, 17$^{\circ}C$ and control plots, respectively, and flesh thickness was the highest in $25^{\circ}C$ plot, followed by 21, 17$^{\circ}C$ and control plots, respectively. 3. Early and middle-phase yield was the highest in $25^{\circ}C$ plot, followed by 21$^{\circ}C$, 17$^{\circ}C$ and control plots but late yield was the highest in 17$^{\circ}C$ plot, followed by control, 21, and $25^{\circ}C$ plots. Total yield per 10a was higher 33% in 17$^{\circ}C$ plot, 49% in 21$^{\circ}C$ plot, and 37a in $25^{\circ}C$ plots than in control plot, harvested 1, 490kg per 10a. 4. Total yield was highest in 21$^{\circ}C$ plot, followed by $25^{\circ}C$, 17$^{\circ}C$, and control plots. Malformed and fermented fruit rates were the highest in control, followed by 17, 25, and 21$^{\circ}C$ plots and marketable fruit rate was 21, 25, 17$^{\circ}C$, and control plot in order.

• Korean Journal of Agricultural Science
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• v.7 no.2
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• pp.131-144
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• 1980

The Linear Regression Model to extend the monthly runoff data in the short-recorded river was proposed by the author in 1979. Here in this study generalization precedure is made to apply that model to any given river basin and to any given station. Lengthier monthly runoff data generated by this generalized model would be useful for water resources assessment and waterworks planning. The results are as follows. 1. This Linear Regression Model which is a transformed water-balance equation attempts to represent the physical properties of the parameters and the time and space varient system in catchment response lumpedly, qualitatively and deductively through the regression coefficients as component grey box, whereas deterministic model deals the foregoings distributedly, quantitatively and inductively through all the integrated processes in the catchment response. This Linear Regression Model would be termed "Statistically deterministic model". 2. Linear regression equations are obtained at four hydrostation in Geum-river basin. Significance test of equations is carried out according to the statistical criterion and shows "Highly" It is recognized th at the regression coefficients of each parameter vary regularly with catchment area increase. Those are: The larger the catchment area, the bigger the loss of precipitation due to interception and detention storage in crease. The larger the catchment area, the bigger the release of baseflow due to catchment slope decrease and storage capacity increase. The larger the catchment area, the bigger the loss of evapotranspiration due to more naked coverage and soil properties. These facts coincide well with hydrological commonsenses. 3. Generalized diagram of regression coefficients is made to follow those commonsenses. By this diagram, Linear Regression Model would be set up for a given river basin and for a given station (Fig.10).

• Journal of Bio-Environment Control
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• v.24 no.2
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• pp.85-92
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• 2015

This study examined the settlement of a 1-2W type greenhouse using a timber pile, which was recently established on Gyehwa-do reclaimed land, in order to obtain base data for the construction of a greenhouse on reclaimed land. The results of this study are as follows. foundation and timber pile increased over time, irrespective of the interior and exterior of the upon investigation of the ground, it was confirmed that there was no soft rock stratum (bedrock), and that a sedimentary stratum existed under the fill deposit, which is estimated to have been reclaimed during the site renovation. It was also found that a weathered zone was located under the fill deposit and sedimentary stratum, and that the soil texture of the entire ground floor consisted of clay mixed with sand, silty clay, and granite gneiss, in that order, regardless of boreholes. In addition, the underground water level was 0.3m below ground, regardless of boreholes. Despite a slight difference, the settlement of the greenhouse or measurement sites (channels). With regard to the pillar inside the greenhouse, except in the case of CH-2, the data at a site located on the side wall of the greenhouse (wind barrier side) indicated vibrations of relatively larger amplitude. Moreover, the settlement showed a significant increase during a certain period, which was subsequently somewhat reversed. Based on these phenomena, it was verified that the settlement range of each site in the interior and exterior of the greenhouse was between 1.0 and 7.5mm at this time, except in the case of CH-1. The results of the regression analysis indicated good correlation, with the coefficient of determination by site ranging between 0.6362 and 0.9340. Furthermore, the coefficient of determination ranged between 0.6046 and 0.8822 on the exterior of the greenhouse, which is lower than inside the greenhouse, but still indicates significant correlation.

• Korean Journal of Environment and Ecology
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• v.26 no.4
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• pp.537-549
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• 2012

The purpose of this study was to provide data for the basic research to found the effective conservation and management plan for the Hamyangsangrim designated as Natural Monument No. 154 and surround areas by analyzing the ecological characteristics such as landuse and actual vegetation, plant community structure, soil chemical property and also to identify the tendency of the ecosystem changes through comparison with past studies. According to analysis the results, the landuse and actual vegetation of survey site was classified as 8 types which were forest, artificial greenspace, plaza and open-space, bare ground and the pavement, water bodies, facilities, agricultural land and etc.. It was also categorized as 38 types according to detailed characteristic. 15 kinds of forest vegetation community types comprising silva were classified among them. The changes of actual vegetation showed little variation that the Quercus serrata-Carpinus tschonoskii forest was the most widely distributed in 2003(forest area ratio is 48.3%) and 2010(forest area ratio is 48.1%), whereas, the Quercus serrata forest declined a more dramatic from 11.6% to 23.2%. The Quercus serrata-Carpinus tschonoskii forest increased sharply(11.6% ${\rightarrow}$ 23.2%) and also the Quercus serrata-Zelkova serrata forest increased steadily(2.2% ${\rightarrow}$ 7.9%). The agricultural land around forest was transformed into artificial green zone. Moreover, water bodies, bare ground and the pavement of areas have increased. In addition, the urbanized area has decreased because the damaged areas inside forest have been restored to the woodlands. According to the result of typical 6 types vegetation communities change, the middle layer trees grew up to the canopy layer trees and was formed the canopy layer structure. The middle layer trees expanded their forces widely. Also new species appeared. And the shrub individuals also more dramatically increased due to the growth of shrubs. The force of Quercus serrata declined as well. However the force of Carpinus tschonoskii and Zelkova serrata expanded and increased in the forest. It must be the result of the ecological vegetation succession and environmentally soundly health recovery by influence of the projects of forest surrounding environment improvement and limitation of access to forest have managed and maintained since 2003. Those sorts of changes seems to be going to develop continuously. In the future Carpinus tschonoskii and Zelkova serrata will not be only codominant in the canopy layer but also Carpinus Tschonoskii, Zelkova serrata, Meliosma myriantha, Sapium japonicum. Styrax obassia and Acer pseudo-sieboldianum will be codominant in the middle layer. As a result, the forest's codominance species are going to be changed such like that.

• Journal of the Korean association of regional geographers
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• v.3 no.1
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• pp.63-80
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• 1997

This study attempts to establish the criteria of site selection for establishing solid waste disposal facility, to determine optimal solid waste disposal sites with the criteria, and to examine the suitability of the selected sites. The Multi-Criteria Evaluation(MCE) module in Idrisi is used to determine optimal sites for solid waste disposal. The MCE combines the information from several criteria in interval and/or ratio scale to form a single index of evaluation without leveling down the data scale into ordinal scale. The summary of this study is as follows: First, the considerable criteria are selected through reviewing the literature and the availability of data: namely, percent of slope, fault lines, bedrock characteristics, major residential areas, reservoirs of water supply, rivers, inundated area, roads, and tourist resorts. Second, the criteria maps of nine factors have been developed. Each factor map is standardized and multiplies by its weight, and then the results are summed. After all of the factors have been incorporated, the resulting suitability map is multiplied by each of the constraint in turn to "zero out" unsuitable area. The unsuitable areas are discovered in urban district and its adjacencies, and mountain region as well as river, roads, resort area and their adjacency districts. Third, the potential sites for establishing waste disposal facilities are twenty five districts in Youngyang-gun. Five districts are located in Subi-myun Sinam-ri, nine districts in Chunggi-myun Haehwa-ri and Moojin-ri, and eleven districts in Sukbo-myun Posan-ri. The first highest score of suitability for waste disposal sites is shown at number eleven district in Chunggi-myun Moojin-ri and the second highest one is discovered at number twenty one district in Sukbo-myun Posan-ri that is followed by number nine district in Chunggi-myun Haehwa-ri, number seventeen and twenty three in Sukbo-myun Posan-ri, and number two in Subi-myun Sinam-ri. The first lowest score is found in number six district in Chunggi-myun Haehwa-ri, and the second lowest one is number five district in Subi-myun Sinam-ri. Finally, the Geographic Information System (GIS) helps to select optimal sites with more objectively and to minimize conflict in the determination of waste disposal sites. It is important to present several potential sites with objective criteria for establishing waste disposal facilities and to discover characteristics of each potential site as a result of that final sites of waste disposal are determined through considering thought of residents. This study has a limitation of criteria as a result of the restriction of availability of data such as underground water, soil texture and mineralogy, and thought of residents. To improve selection of optimal sites for a waste disposal facility, more wide rage of spatial and non-spatial data base should be constructed.

• Applied Biological Chemistry
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• v.16 no.1
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• pp.1-11
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• 1973

In order to obtain the basic informations on the production of single cell protein from ethanol, 145 yeast strains utilizing ethanol as a sole carbon source were isolated from 32 soil samples in Korea. A yeast strain showing the highest cell yield among the isolated strains was selected and identified. The optimum culture condition, utilization of other carbon sources and the cultural characteristics for the selected yeast, and the chemical analysis of the yeast cell composition, and utilization of ethanol by the selected yeast were investigated. All the culture was carried out in the shaking flasks. The results obtained were as follows: 1. The selected yeast strain was identified as Debaryomyces nicotianae-SNU 72. 2. The optimum composition of the medium for the selected yeast is : Ethanol 40 ml, Urea 0.5 g, Potassium phosphate (dibasic) 0.5 g, Ammoium phosphate (monobasic) 0.15 g, Magnesium sulfate 0.05 g, Calcium chloride 0.01g, Yeast extract 0.005 g, Tap water 1000 ml. 3. The optimum pH was 5.0-5.5, the optimum temperature $30-33^{\circ}C$ and the aerobic state was unimportant. 4. Utilization of methanol, n-propanol, iso-propanol, n-butanol, iso-butanol, tert-amyl alcohol and acetic acid by the selected yeast was very weak. So substitution of the subtrate was thought to be impossible. 5. Studies on the propagation of the yeast cells showed that the lag phase of the yeast cells lasted 16 hours, and the logarithmic growth phase extended 16 to 28 hours. The specific growth rate was about $0.19\;hr^{-1}$ and the doubling time was 3.6 hours during the logarithmic growth phase. 6. As the result of the chemical analysis of the dry yeast cells, the content rate of the crude protein was 55.19 %, the content of others was similar to the average content of the yeast component. 7. After 34 hours cultivation, under the optimum culture condition investigated, the dry cell yield against the amount of the added ethanol was 53.4 % (W/V%), the dry cell yield against the amount of the utilized ethanol was 73.6 % (W/V%), the evaporation rate of ethanol was about 19.1 %.