• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.2
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• pp.186-194
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• 2020

In this study, spectral analysis was conducted to identify environmental factors af ecting short-term changes in water temperature in the East, West and South coasts of Korea. The data used in the spectrum analysis is the 2016 summer water temperature, air temperature, tide level and wind data provided by Korea Hydrographic & Oceanographic Agency. In power spectrum results, peaks of water temperature and tide level were observed at same periods in West Sea (Incheon, Pyeungteak, Gunsan and Mokpo) and South Sea (Wando, Goheung, Yeosu, Tongyeong and Masan) where mean tidal range was more than 100 cm. On the other hand, periodicity of water temperature did not appear in East Sea and Busan where the mean tidal range was small. Coherence analysis showed that water temperature was highly correlated with tide in West Sea and three stations(Wando, Goheung and Tongyeong) of South Sea. Especially, correlation between water temperature and tide level in Wando and Tongyeong presented 0.96 at semi-diurnal period. Water temperature in Yeosu seems to have influenced by tide and inflow of fresh water. In Masan, water temperature is influenced by south wind, tide and inflow of fresh water. In East Sea, influence of tide on water temperature is small due to current and small tidal range. As a result of comparing the time series graph, stations where the correlation between water temperature and tide is high show that relatively cold water was inputted at flood tide and flow out at ebb tide. short-term variation of water temperature was affected by tide, but long-term variation over a month was affected by air temperature.

• Journal of Ecology and Environment
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• v.32 no.2
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• pp.123-127
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• 2009

Weight loss and nutrient dynamics of Quercus mongolica leaf litter during decomposition were investigated from December 2005 through August 2008 in Mt. Worak National Park as a part of National Long-Term Ecological Research Program in Korea. The decay constant (k) of Q. mongolica litter was 0.26. After 33 months decomposition, remaining weight of Q. mongolica litter was 49.3$\pm$4.4%. Initial C/N and C/P ratios of Q. mongolica litter were 43.3 and 2,032, respectively. C/N ratio in decomposing litter decreased rapidly from the beginning to nine months decomposition, and then showed more or less constant. C/P ratio increased to 2,407 after three months decomposition, and then decreased steadily thereafter. N and P concentration increased significantly during decomposition. N immobilization occurred from the beginning through 18 months decomposition, and mineralization occurred afterwards in decomposing litter. P immobilized significantly from fifteen months during decomposition. K concentration decreased rapidly from the beginning to six months decomposition. However it showed an increasing pattern during later stage of decomposition. Remaining K decreased rapidly during early stage of decomposition. There was no net K immobilization. Ca concentration increased from the beginning to twelve months decomposition, and then decreased rapidly till twenty one months elapsed. However, it increased again thereafter. Ca mineralization occurred from fifteen months. Mg concentration increased during decomposition. There was no Mg immobilization during litter decomposition. After 33 months decomposition, remaining N, P, K, Ca and Mg in Q. mongolica litter were 79.2, 110.9, 36.2, 52.7 and 74.4%, respectively.

• Journal of Ecology and Environment
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• v.30 no.1
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• pp.17-21
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• 2007

The organic carbon (OC) distribution of Pinus densiflora forest in Songgye valley at Mt. Worak National Park were studied as a part of the National Long-Term Ecological Research in Korea. In order to investigate the OC distribution, OC in plant biomass, litterfall, litter layer on forest floor, and soil were estimated. The density of P. densiflora forest was 1,300 trees/ha, average DBH was $15.2{\pm}6.17\;cm$ and average tree height was $10.7{\pm}2.56\;m$. The shrub layer was dominated by shrubby Quercus variabilis, Fraxinus sieboldiana and lndigofera kirilowii with low frequency, and herb layer was dominated by Pteridium aquilinum and Miscanthus sinensis. Total amount of OC stored in this pine forest was 142.78 ton C/ha. Organic carbon stored in soil and plant biomass accounted for 59.2% and 37.8%, respectively. Amount of OC distributed in trees, shrubs, herbs and litter layer in this pine forest was 51.79, 2.03, 0.12 and 4.29 ton C/ha, respectively. Amount of OC returned to forest floor via litterfall was $1.50\;ton\;C\;ha^{-1}\;yr^{-1}$. Soil organic carbon (SOC) decreased along the soil depth. Total amount of SOC within 50cm soil depth was $84.55\;ton\;C\;ha^{-1}\;50\;cm-depth^{-1}$.

• Journal of the Korean Geographical Society
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• v.47 no.6
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• pp.836-852
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• 2012

Based on a long-term ethnographic study, this paper examines how the propositions and practices for desertification management in Inner Mongolia, China have changed over time. Desertification as an ecological issue cannot simply be treated as a something "natural" or "social," while it is an outcome of the construction made by both human and non-human agents. My research has found that the propositions for desertification management have been involved in the process of defining desertification, particularly by selecting different actors related to the ecological process in this region. Ultimately, the crisis in the inner Mongolia has always been constructed by the ways in which the selected actors and their relationships are differently defined. My study also reveals that although the proposed preventive measures, including afforestation, area protection, and pasturing prohibition, have tried to reconcile the conflicts of interest among the different actors, they have always been faced with certain limitations and failed in dryland management. In this historical context of crisis construction, by introducing a new non-human agent, "the chicken," the project of grassland chicken farming has eventually appeared to be an innovative strategy that can overcome the earlier limitations and coordinate the interests of Mongolian pastoralists who have suffered from economic difficulty.

• Journal of Ecology and Environment
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• v.29 no.5
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• pp.439-443
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• 2006

Soil properties of Quercus variabilis forest on Youngha valley at Mt. Worak National Park were studied as a part of Korea National Long-Term Ecological Research. Soil sampling was carried out along the 50 cm soil depth with 10cm intervals at every quarter from May 2005 through July 2006. Fresh soil was used for $NH_4{^+}-N,\;NO_3{^-}-N$, and soil water content determination. Remaining soils were air dried in the shade, and then used for determination of soil pH, T-N, T-P and exchangeable cation. Average soil organic matter in top soil was $8.5{\pm}1.2%$ and decreased with soil depth. Bulk density of top soil was $0.82{\pm}0.07g/cm^3 $and increased with soil depth. Soil organic matter and bulk density showed a negative linear correlation ($R^2=0.8464$). Soil pH in top soil and subsoil was similar. T-N, $NH_4{^+}-N,\;NO_3{^-}-N$ and T-P in top soil were $1.9{\pm}0.5mg/g,\;7.3{\pm}1.0mg/kg,\;2.0{\pm}0.4mg/kg\;and\;0.2{\pm}0.05mg/g$, respectively. $K^+,\;Ca^{2+}\;and\;Mg^{2+}$ in top soil were $84.6{\pm}24.4,\;408.8{\pm}137.8\;and\;93.4{\pm}23.0mg/kg$, respectively. They decreased with soil depth. Amounts of organic matter, T-N, $NH_4{^+}-N,\;NO_3{^-}-N$, T-P, $K^+,\;Ca^{2+}\;and\;Mg^{2+}$ in 50 cm soil depth were 250.9, 3.45, 0.025, 0.003, 0.639, 0.181, 0.845 and 0.302 ton $ha^{-1}\;50cm-depth^{-1}$, respectively.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.1
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• pp.33-44
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• 2019

Due to the recent climate change realization (timing, rainfall pattern changes), the flow regime is changing according to the watershed. The long-term change of flow regime is causing a significant change in structure and function of aquatic ecosystems. However, there is no analysis from the viewpoint of the aquatic ecosystem including flow rate alteration and ecological characteristics as well as the climate change connection in Korea yet. Therefore, We quantitatively assessed the impact of present-future flow regime alteration due to climate change on the Pseudopungtungia nigra habitat in the Mankyung river and floodplain area. As a result, it was confirmed that extreme hydrological conditions such as flood and drought are intensified in the future than the present. Especially, the changes of flow regime characteristics were clarified by comparing and analyzing the magnitude, frequency, duration, rate of change, and by linking flow regime characteristics with physical habitat analysis, it could be suggested that climate change would significantly increase the risk of future ecological changes.

• Journal of Plant Biotechnology
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• v.4 no.3
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• pp.103-107
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• 2002

The Good Agriculture Practice (GAP) program, being established in China, is an optimal way for the sustainable utilization of the medicinal plant and animal resources. Most frequently used Chinese materia medica will be mainly produced from the GAP bases in the future. To assure the successful operation of GAP program, standard operating procedure (SOP) should be implemented for specific plants or animals. Both GAP and SOP include the requirements in many aspects from the ecological environment of cultivation place, germplasm and varieties, seedling and transplant, fertilization, irrigation, and field care, to harvest and process, package, transport and storage. As a complex system, GAP demands strong commitment from the pharmaceutical industry, local administrative involvement, long term R&D support, and years of time of development before a satisfactory result can be achieved.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.1
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• pp.77-83
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• 1999

Molecular biological techniques that recently developed, have made it possible to realize some of new attempts in the research field of rumen microbiology. Those are 1) cloning of genes from rumen microorganisms mainly in E. coli, 2) transformation of rumen bacteria and 3) ecological analysis with nonculturing methods. Most of the cloned genes are for polysaccharidase enzymes such as endoglucanase, xylanase, amylase, chitinase and others, and the cloning rendered gene structural analyses by sequencing and also characterization of the translated products through easier purification. Electrotransformation of Butyrivibrio fibrisolvens and Prevotella ruminicola have been made toward the direction for obtaining more fibrolytic, acid-tolerant, depoisoning or essential amino acids-producing rumen bacterium. These primarily required stable and efficient gene transfer systems. Some vectors, constructed from native plasmids of rumen bacteria, are now available for successful gene introduction and expression in those rumen bacterial species. Probing and PCR-based methodologies have also been developed for detecting specific bacterial species and even strains. These are much due to accumulation of rRNA gene sequences of rumen microbes in databases. Although optimized analytical conditions are essential to reliable and reproducible estimation of the targeted microbes, the methods permit long term storage of frozen samples, providing us ease in analytical work as compared with a traditional method based on culturing. Moreover, the methods seem to be promissing for obtaining taxonomic and evolutionary information on all the rumen microbes, whether they are culturable or not.

• Journal of Environmental Impact Assessment
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• v.18 no.6
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• pp.393-399
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• 2009

The water of rivers and lakes are affecting by point and nonpoint source pollutions. The point source pollution can be controlled by establishing the treatment plants. However, nonpoint source pollution by various human activities is not easy to be controlled because it is difficult to determine the exits of the water flow and have many exit points. Due to contribution of nonpoint source pollution, the achievement ratio of water quality in rivers and lakes is not high. TMDL is the outstanding water quality control policy because all of the pollutant loadings from the watershed area are counting on the input loads. Our aqua-ecosystem has self-purification process by biological, physical and ecological processes. The self-purification process can remove the pollutant load from background concentrations. Usually forest area is main source of background concentrations. In Korea, about 70% of the national boundary area consists of mountains. This study is conducting as part of long-term monitoring to determine the Event Mean Concentration during a storm. The monitoring was performed on a broad-leaved tree area.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.3
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• pp.747-756
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• 2015

Brown alga Undaria peterseniana has been interested in the commercial scale aquaculture for warm water species development in southern coastal area of Korea. However, this species was classified an endangered species caused by a decrease in habitat and natural population. In this study, inhabit characteristics of U. peterseniana was investigated in their natural habitat of Ulleung Island, Korea. The U. peterseniana population was occurred dense patches at 20~30m depth. Total length of the alga reached 1.0~2.0m and the largest width ranged 10.0~35.0cm during the study. In 2013, habitats of this species increased two sites compared with the previous year and their distribution extended to low depth (10m) of coastal area. In long-term data, seawater temperature revealed a continuous increment by strong going north of East Korea Warm Current or Ulleung Warm Eddy turning around the coast of Ulleung Island. It suggested that habitat extension of U. peterseniana may be caused by suitable settlement condition and increase of warm water around the coastal area. Current studies of this species may be continuously required in the possibility of fisheries resources as aquaculture species and index species of increment of water temperature at the fixed monitoring site in East Sea. This is the first study to research ecological feature U. peterseniana population at the natural habitat of Ulleung Island.