• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.13 no.4
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• pp.333-341
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• 2008

Three embankments are located in the Chunggye Bay, each named as Changpo, Bokkil and Kuil and environmental changes are expected due to freshwater input. To investigate this phenomenon, three sample sites in front of each embankment gate were selected in Nov. 2006(autumn), Feb. 2007(winter), May. 2007(spring) and Aug. 2007(summer). At every point of embankment spot, large cells(micro-size, >$20\;{\mu}m$) of phytoplankton were turned out to be a major cause of algal bloom in Feb. 2007 and nano-size($2-20\;{\mu}m$) phytoplankton became dominant during rainy season. In rainy season, each point of embankment showed low salinity and transparency with higher ammonium and phosphorus concentrations than dry season. However, the number of phytoplankton has decreased and it is expected that freshwater influx has more influence on high turbidity and radical decrease of salinity than nutrient. According to the results of this study, therefore, nutrient could have more influence on growth of phytoplankton in dry season, but high turbidity and radical changes of salinity have more influence in rainy season.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.9 no.2
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• pp.23-32
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• 2006

Total suspended solids (TSS), five-day biochemical oxygen demand ($BOD_5$), total nitrogen (T-N), and total phosphorous (T-P) concentrations around and under a floating island were examined from October 2002 to September 2003. The island was installed in July 2002 on the surface of an agricultural irrigation reservoir located in the southern part of the Korean Peninsula. It was composed of six polyethylene panels. Each panel was 2 m (length) ${\times}$ 1 m (width) ${\times}$ 0.02 m (thick) and had about thirty-two holes each with a diameter of eight centimeters, through which plant roots grew down into the water. Coconut fibers of nine-centimeters in height were placed on the panel, which sustained plants rhizomes and roots. Both the fibers and the panel were raped with polyethylene wire mashes. About thirty irises (Iris pseudoacorus) were planted into the fibers of each panel. The concentrations of TSS, $BOD_5$, T-N and T-P below the island during the iris-growing season averaged 9.70, 2.59, 3.61 and 0.14 mg/L, respectively and those around it averaged 9.99, 2.83, 4.07 and 0.16 mg/L, respectively. The average concentrations of TSS, $BOD_5$, T-N and T-P below it during the iris non-growing season were 8.68, 2.37, 3.25 and 0.14 mg/L, respectively and those near it were 8.76, 2.43, 3.34 and 0.15 mg/L, respectively. At a significance level of ${\alpha}$=0.05, $BOD_5$, T-N and T-P concentrations under the island during the iris-growing season were significantly low when compared with those around it except TSS. No differences in TSS, $BOD_5$, T-N and T-P concentrations between around and near it were found at a significance level of ${\alpha}$=0.05 during the iris non-growing season. The removal of $BOD_5$, T-N, and T-P during the growing season were significantly high when compared with those during the non-growing season. TSS abatement of the floating island was very low during both the growing and non-growing seasons. The island's reductions of $BOD_5$, T-N and T-P were good during the growing season, especially T-N and T-P, which have been considered as primary pollutant sources causing the water quality degradation of reservoirs. The removal of T-N and T-P was primarily attributed to the absorption of nitrogen and phosphorous by the irises during the growing season.

• Journal of The Korean Society of Grassland and Forage Science
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• v.34 no.2
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• pp.125-128
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• 2014

The objective of this study is to investigate the changes in levels of odorous compounds in pig slurry during different seasons. Slurry from pens of finishing pigs was sampled every 4-wk and concentration of odorous compounds was analyzed. There was no difference in the range of phenols level (123 to 156 ppm) during spring (April to May), summer (July to August) and fall (October to November). The concentration of indoles was higher (P<0.05) during spring (14.3 ppm) than summer and fall (5.4~7.6 ppm). Level of BCFA ranging from 727 to 1,194 ppm was not different at any season. Among SCFA, there was no difference in propionic acid during any season but levels of acetic acid and butyric acid were highest (P<0.05) during spring season. Concentration of odorous compounds in pig slurry was highest during spring season. Interestingly, it tended to be lower during summer season compare to fall. This result might be due to relatively lower ventilation rate in order to maintain a constant temperature during spring season. Further study will be necessary to determine the relationship between the concentration of odorous compounds and ventilation system.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.233-233
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• 2015

Vu Gia - Thu Bon basin is located in central Vietnam between Truong Son mountain range on the border with Lao in the west and the East Sea in the east. The basin occupies about 10,350 km2 or roughly 90% of the Quang Nam Province and includes Da Nang, a very large city with about 876,000 inhabitants. Total annual rainfall ranges from about 2,000 mm in central and downstream areas to more than 4,000 mm in southern mountainous areas. Rainfall during the monsoon season accounts for 65 to 80% of total annual rainfall. The highest amount of rainfall occurs in October and November which accounts for 40 to 50% of the annual rainfall. Rainfall in the dry season represents about 20 to 35% of the total annual rainfall. The low rainfall season usually occurs from February to April, accounting for only 3 to 5% of the total annual rainfall. The mean annual flow volume in the basin is $19.1{\times}109m 3$. Similar to the distribution of rainfall, annual flows are distinguished by two distinct seasons (the flood season and the low-flow season). The flood season commonly starts in the mid-September and ends in early January. Flows during the flood season account for 62 to 69% of the total annual water volume, while flows in the dry season comprise 22 to 38% of total annual run-off. The water volume gauged in November, the highest flow month, accounts for 26 to 31% of the total annual run-off while the driest period is April with flows of 2 to 3% of the total annual run-off. There are some hydropower projects in the Vu Gia - Thu Bon basin as the cascade of Song Bung 2, Song Bung 4, and Song Bung 5, the A Vuong project currently under construction, the Dak Mi 1 and Dak Mi 4 projects on the Khai tributary, and the Song Con project on the Con River. Both the Khai tributary and the Song Con join the Bung River downstream of SB5, although the Dak Mi 4 project involves an inter-basin diversion to Thu Bon. Much attention has recently been focused on the effects that climate variability and human activities have had on runoff. In this study, data from the Vu Gia - Thu Bon River Basin in the central of Viet Nam were analyzed to investigate changes in annual runoff during the period of 1977-2010. The nonparametric Mann-Kendall test and the Mann-Kendall-Sneyers test were used to identify trend and step change point in the annual runoff. It was found that the basin had a significant increasing trend in annual runoff. The hydrologic sensitivity analysis method was employed to evaluate the effects of climate variability and human activities on mean annual runoff for the human-induced period based on precipitation and potential evapotranspiration. This study quantitatively distinguishes the effects between climate variability and human activities on runoff, which can do duty for a reference for regional water resources assessment and management.

• Journal of Environmental Science International
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• v.12 no.7
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• pp.697-704
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• 2003

Through data analysis using the meteorological data during 40 years(1961∼2000) for 2 stations(Daegu and Chupungnyong), we studied the present condition and long-term trends in urban climatic environments of Daegu. It was found that there was about 1.5$^{\circ}C$ rise in annual mean temperature of Daegu from 1961 to 2000. On the other hand, that of Chupungnyung was not more than 0.4$^{\circ}C$ for the same period. The regional disparity in temperature changes has been caused by the difference of urban effects on climate between two regions. In particular, the urban warming appears more significant in winter season. There was about 3$^{\circ}C$ rise in annual mean daily minimum temperature of winter season(Dec.∼Feb.) in Daegu. As the result, the number of winter days continuously decreased from 115 days(1961) to 75 days(2000). The long-term trends of relative humidity were also studied to exame the effects of urbanization on climate in Daegu. It was found that there was about 7% decrease in relative humidity of Daegu during past 40 years(1961∼2000). On the other side, the decrease of Chupungnyung was not more than 2% for the same period. The long-term trends of the other climatic factors(fog days, tropical night days, etc) were also studied in this study.

• The Korean Journal of Ecology
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• v.17 no.4
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• pp.463-469
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• 1994

For better understanding of population dynamics of Symplocarpus renifolius, some aspects of seed production were studied in natural populations for 3 years. The rate of reproducing plants (RP) was 8.06% among the whole studied. The RPs were 0.0% in leaf size class under 500cm2 per individual, and 3.6% in 500~1,000cm2, and 44.3% in over 3,000cm2. The resource allocated to sexual organ was 11.6% of total biomass at the end of growing season, and that to belowground was about 80% regradless of presence or absence of sexual organ. In the previous and the next years of seed production, the energy allocated to sexual organ didn't affect the changes of leaf size, year by year. After flowing season. Especially, a large number of sex organ were degraded in April, a period of pollination and fertilization. The number of seeds per individual was degraded in April, a period of pollination and fertilization. The number of seeds per individual was 13~22 and didn't relate to leaf size. But the weight per seed increased along leaf size per individual. Therefore, in S.renifolius population, large individual produced large seeds rather than many seeds.

• 한국해양학회지
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• v.12 no.1
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• pp.13-32
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• 1977

In order to determine the distributional ecology, and to investigate factors influencing these features, the diatom communities in plankton at depths of one, twenty-five, fifty, and seventy five meters in the area were studied and measured over a fifteen month of period. Measurements of environmental factors including temperature and salinity and algal nutrients such as phosphate, silicate, nitrate, and ammonia were also made at the same depths and locations. The results indicate that the size of diatom communities and the species population changes were heavily dependent upon to season and location parameters as well as nutrient concentrations and hydrographic factors. Major factors influencing population distributions varied with principal species responsible for dominant species and species sucession. Two distinct distributional patterns in total diatom crop were observed in the study area. Maximum standing crop observed during spring and/or summer were related to the concentration of nutrients available at the onset of the spring bloom on a large scale. On a small scale, however, the distributions of total diatom standing crops were significantly correlated with both season/location factors and with hydrographic parameters as well. Vertical stratification of diatoms was observed only in the presence of the thermocline in the water column. Within the study area there was some seasonal consistancy in the composition of the species groups. However, some species association in these environments may vary with the change of season.

• Korean Journal of Environment and Ecology
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• v.15 no.2
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• pp.99-102
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• 2001

본 연구는 번식기와 비번식기에 있어서 까치의 행동변화를 파악하기 위해 강원도 춘천시 동면 감정리에 위치한 강원도 산림개발연구원 시험림 및 부근지역에서 2000년 3월부터 2001년 2월까지의 기간동안 실시되었다. 조사지 내 전체 면척은 5.6$\textrm{km}^2$였으며, 전체 지역에서 까치의 둥지는 모두 49개가 발견되었다. 이중 2000년 봄철의 번식기동안에는 24개의 둥지에서 까치가 번식을 한 것으로 나타났다. 까치의 번식밀도는 4.3쌍/$\textrm{km}^2$였으며, 둥지의 평균거리는 평균 357.5m 인 것으로 나타났다. 까치에 부착한 전파발신기에서 발신되는 전파를 추적하여 번식기와 비번식기에 둥지로부터 이동한 거리는 큰 차이를 보였다.(t-test, t= 2.98, P<0.01). 번식기에는 평균 133.5m의 거리를 둥지로부터 이동하였으며, 최대 184m 이동한 것으로 나타났다. 그 결과 세력권의 크기는 약 5.6ha인 것으로 추정되었다. 또한 비번식이에 있어서는 둥지로부터의 이동거리 평균 384.2m 였으며, 최대 457m 까지 이동하였다. 6월에서 8월 까지는 보통 2~3개체 정도가 무리를 형성하였고, 12월에 가장 많은 12개체 정도가 하나의 무리를 이루었다. 번식기에 암컷과 수컷을 행동은 매우 다른 것으로 나타났으나(t=2.89, P<0.05)비번식기에는 큰 차이가 없었다(t=1.03, P>0.05).

• Korean Journal of Microbiology
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• v.24 no.2
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• pp.184-193
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• 1986

Interrelation between environmental influences on soil microorganisms and it's effect on disease development in ginseng (Panax ginseng C.A. Meyer) field were studied to obtain a preventive measures against the root rot of ginseng caused by soil-borne pathogens in soil in three major Korean ginseng producing areas such as Kumsan, Goesan and Poonggi. Populations of actinomycetes were relatively high in fall season from September to November. Their numbers were highly populated in healthy plot in field than replanted disease field of ginseng, whereas ratio of Trichoderma spp to actinomycetes increased in healthy plot of field indicating the higher numbers of Trichoderma spp pressented in healthy plot field. The numbers of propagules of Trichoderma spp generally increased in early summer through early fall season. Their numbers were also highly populated in the healthy plot of fields. The contents of organic matter and phosphate in healthy plot of field were somewhat high, and phophate/organic matter ratio and Mg content were high in diseased replanted field. All of the soil samples showed a weak acidic pH from 4.5 to 4.7. Soilmoisture content was increased during winter season and it did not show any significant changes curing the growing period, showing 24.6% in healthy plot in field and 19.5% in deseased plot in field respectively. Soil temperature was highest in July and August and lowest in January and February.

• Journal of Integrative Natural Science
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• v.6 no.2
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• pp.118-123
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• 2013

Korea, which is located in the middle-latitude area of the northern hemisphere, has four seasons. These seasons can be classified based on their months, mean temperatures, biology and natural phenomena. In this study, climatic changes were identified by biotic and temperature seasons, changing trends were compared by season, and the appropriateness of the biotic phenomena for the biotic season classification was examined. The data for this study included the mean temperatures, and biology phenomenon observation dates, which had been observed for 38 years from the ASOSs in seven Gwangju and Jeonnam regions. Limitations were found in the classification of the temperature and biotic seasons. Especially in the case of the biotic season based on a single life, the points of the first sighting and the initial sound fluctuated so much that the accuracy of the results was not guaranteed. Therefore, the life species had to be selected subject to detailed verification and accurate specifications, and to be applied to the meteorological phenomena. In addition, there were lives in the standard biology that could no longer be observed because of environmental pollution and climatic change, which indicates the need to protect the existing standard biology.