• Environmental Analysis Health and Toxicology
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• v.18 no.4
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• pp.277-285
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• 2003

연안의 방조제 건설은 하천수와 바다물의 교환을 인위적으로 차단하고, 방조제 내부에는 호수를 형성하게 된다. 이렇게 형성된 인공호수의 수질은 호수로 유입되는 하천의 수질에 크게 영향을 받을 수 있으며, 인공호수의 수질이 악화되면 인근 해양생태계에 영향을 미칠 수 있다. 본 연구는 인공호수의 물이 바다로 방류될 때 해양생태계에 어떠한 영향을 미칠 것인지를 예측하고자 수행되었다. 방조제 건설로 이미 형성되어 있는 시화호, 아산호, 부사호와, 현재 건설중인 새만금 방조제로 인하여 형성될 호수의 유입 하천인 만경강에서 표층수를 채수하여 둥근성게(Strongylocentrotus nudus)의 정자와 수정란을 이용한 생물 검정을 실시하였다. 담수호의 수질을 해양생물을 이용하여 평가할 수 있도록 하기 위하여 시료의 염분을 조절하면서 실험을 실시하였다. 정자를 이용한 수정 실험 결과, 시화호에서는 수정률에 영향을 미치지 않았고, 아산호와 부사호에서는 약간의 영향이 있었으나 그 정도는 미약하였다. 반면, 만경강의 경우 수정률의 저해가 상당히 크게 나타났다. 수정란을 이용한 발생 실험 결과, 시화호, 아산호, 부사호에서는 약간의 영향이 나타난 반면, 만경강의 경우는 매우 큰 영향이 나타났다. 이들 실험 결과를 종합하면, 시화호, 아산호, 부사호의 수질은 대체로 양호하나, 만경강의 수질은 크게 우려되는 수준이었다. 따라서, 앞으로 건설될 새만금 호수와 인근 해양생태계를 보전하기 위해서는 만경강의 수질 개선을 위한 대책이 마련되어야 할 것이다.

• Journal of the Korean earth science society
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• v.28 no.5
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• pp.635-642
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• 2007

Using data from 132 telephone interviewees, we examined the role of affective-cognitive ambivalence in forming overall attitude and behavior toward toxic chemical and radioactive waste issues in Marion, Ohio in the U.S. In order to compare attitudinal preference, participants were divided into four A-C groups: action-group (Affective+/Cognitive+), detached-group (A-/C+), concerned-group (A+/C-), and inaction-group (A-/C-). Affective and cognitive components interacted, producing redundant influences on overall attitudes and judgments as frequently observed and postulated in previous attitude studies. The results showed that the action-group who were feeling unsafe and believed that environmental accidents had happened or are happening in Marion were less willing to move to the area than other three groups who were feeling safe and/or doubted reports of contamination and its relation with leukemia. Affective and cognitive components were found to have redundant influences on overall attitude. It was also observed that affective-cognitive ambivalence theory has a great potential for explaining the mechanism by which people form attitudes, especially when people have moderate or positive feelings (e.g. sympathy or eagerness for resources) toward the objects and/or when uncertainty is a major feature of environmental issue under consideration (e.g. global climate change).

• Journal of Microbiology
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• v.37 no.1
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• pp.10-13
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• 1999

The bacterial abundance, proportion of respiring bacteria, and bacterial community of southern Lake Baikal were analyzed at 1 m and 400m depths during winter. The total bacterial numbers were 5.1${\times}$105 cells ml-1 at 1 m and 2.5${\times}$105 cells ml-1 at 400 m depth, which are about half and quarter of the numbers of other lakes. The proportion of respiring bacteria was as low as 2.5% at 1 m and 1.4% at 400 m depth. Considering the amount of organic carbon which need to be degraded and low proportion of respiring bacteria, the bacteria could be assumed to have high activities. The EUB/DAPI ratios were 77 and 89% at 1 m and 400 m depths, respectively. Of the bacterial community, the other group was dominant at both depths, and gamma group of protebacteria followed next. But the beta group of proteobacteria and Cytophaga-Flavobacterium groups occupied very small proportions.

• Journal of Environmental Science International
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• v.16 no.6
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• pp.699-706
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• 2007

Many lakes or irrigative reservoirs in Korea are rapidly contaminated due to the ever increasing pollutants. Although lots of treatment processes have been recommended and practiced, economical and technical improvement is currently needed. In this study, contaminated irrigation reservoir was treated using the proposed process which is consisted of fine air bubbles, coagulation and flotation. Fine bubbles, approximate diameter of 3 to $10{\mu}m$, were generated using cavitation in the pressurized tank and polyaluminum chloride was used as coagulants. This fine bubbles, coagulation and flotation effectively controlled the low density algae, for example, Chlorophyll-a was removed more than 97 %. Removal efficiency of COD, SS, T-N and T-P were 80.7%, 94.3%, 64.1 % and 92.4%, respectively. Pollutants released from the sediments was removed more than 80% of organics and 60-70 % of nutrients. Consequently, fine bubbles coagulation and flotation process could be effectively used as an alternative treatment method for the purpose of control of lake water quality.

• KSBB Journal
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• v.31 no.1
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• pp.79-84
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• 2016

Biofuel has been considered as promising renewable energy to solve various problems that result from increasing usage of fossil fuels since the early 20th century. In terms of chemical and physical properties as fuel, biobutanol has more merits than bioethanol. It could replace gasoline for transportation and industrial demand is increasing significantly. Production of butanol can be achieved by chemical synthesis or by microbial fermentation. The water hyacinth, an aquatic macrophyte, originated from tropical South America but is currently distributed all over the world. Water hyacinth has excellent water purification capacity and it can be utilized as animal feed, organic fertilizer, and biomass feedstock. However, it can cause problems in the rivers and lakes due to its rapid growth and dense mats formation. In this study, the potential of water hyacinth was evaluated as a lignocellulosic biomass feedstock in biobutanol fermentation by using Clostridium beijerinckii. Water hyacinth was converted to water hyacinth hydrolysate medium through pretreatment and saccharification. It was found that productivity of water hyacinth hydrolysate medium on biobutanol production was comparable to general medium.

• The Korean Journal of Quaternary Research
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• v.23 no.1
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• pp.38-41
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• 2009

Results from the most recent decade of Mars' missions to Mars highlight a liquid water and water-ice sculpted landscape. Evidence includes layered sedimentary sequences with weathered outcrops, debris flows, fluvial valleys, alluvial fans, deltas, glacial and periglacial landscapes, and geochemical/mineralogical signatures of aqueous activity, including the formation of sulfates and clays, and the leaching and deposition of elements such as potassium, thorium,and iron. Such evidence indicates weathered zones and possible paleosols in stratigraphic sequences, transport of water and rock materials to sedimentary basins, and the possible formation of extensive transient lakes and possibly transient oceans on Mars. This new evidence is consistent with Viking-era geologic investigations that reported magmatic-driven flooding, ponding to form large water bodies in the northern plains, and transient (tens of thousand of years) hydrological cycles. It may even indicate aqueous activity at present. Both endogenic (magmatic driven) and exogenic (both impact cratering and changes in orbital parameters) have influenced paleohydrologic and environmental change on Mars. Abundance of water and dynamic activity would be decisively important for the possibility of past and present life on Mars.

• Journal of Environmental Impact Assessment
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• v.22 no.4
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• pp.329-343
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• 2013

According to previous studies, the increased air temperature can lead to change of thermal stratification structure of lakes and reservoirs. The changed thermal stratification may result in alteration of materials and energy flow. The objective of this study was to predict the effect of climate change on the water temperature and stratification structure of Daecheong Reservoir, located in Geum River basin of Korea, using a three-dimensional(3D) hydrodynamic model(ELCOM). A long-term(100 years) weather data set provided by the National Institute of Meteorological Research(NIMR) was used for forcing the 3D model. The model was applied to two different hydrological conditions, dry year(2001) and normal year(2004). It means that the effect of air temperature increase was only considered. Simulation results showed that the surface water temperature of the reservoir tend to increase in the future, and the establishment of thermal stratification can occur earlier and prolonged longer. As a result of heat flux analysis, the evaporative heat loss can increase in the future than now and before. However, the convective heat loss and net long wave radiation from water surface decreased due to increased air temperature.

• Journal of Microbiology and Biotechnology
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• v.21 no.7
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• pp.697-702
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• 2011

A strain of the cyanobacterium Arthrospira was isolated from Lake Chahannaoer in northern China and was characterized according to microscopic morphology, photosynthetic oxygen-evolving activity, growth rate, and nutritional profile. Compared with thermophilic Arthrospira species occurring naturally in tropical and subtropical lakes, this isolate is mesophilic and grows optimally at ${\sim}20^{\circ}C$. The total protein, fatty acid, phycocyanin, carotenoid, and chlorophyll a contents were 67.6, 6.1, 4.32, 0.29, and 0.76 grams per 100 grams of dry weight, respectively. The strain is rich in polyunsaturated fatty acids (PUFAs). An essential omega-3 fatty acid, docosahexaenoic acid (DHA), was detected, and ${\gamma}$-linolenic acid (GLA) and DHA accounted for 28.3% of the total fatty acid content. These features of this newly isolated strain make it potentially useful in commercial mass culture in local areas or as a biofuel feedstock. It is also an alternative resource for studying the metabolic PUFA pathways and mechanisms of cold stress tolerance in cyanobacteria.

• Animal Systematics, Evolution and Diversity
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• v.2 no.1
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• pp.49-62
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• 1986

A taxonomic study was carried out on the freshwater copepods of Order Calanoida from Korean during the period from May, 1983 to November, 1984. Materials consist of both specimens deposited at the Department of Biology, Kangreung National University and the specimens collected from various freshwater regions (excluding the subterranean waters) such as rivers, lakes, ponds, bogs, ricefields, etc. during this period. As a result of examining the specimens collected at the 26 localities in South Korea, 8 species of 3 families were identified, of which 4 species are newly known from Korea ; Sinocalanus sinensis (Poppe, 1889) ; Tropodiaptomus oryzanus Kiefer , 1937 ; Sinodiaptomus sarsi (Rylov, 1923) ; Neodiaptomus schemackeri(Poppe et Richard, 1892).

• ALGAE
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• v.21 no.2
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• pp.217-228
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• 2006

Seasonal compositions, standing crops and trophic status of phytoplankton were investigated at 13 sites of Suwon-si, Gyeonggi-do from June, 2004 to March, 2005. Total of 304 taxa were found, and classified as 4 phylums 4 classes 13 orders 36 families 93 genera 246 species 47 varieties 8 forms and 3 unidentified species by Engler’s classification system. Judged by standing crops of phytoplakton, algal blooming was observed at every sampling sites except Pajang reservoir, Hagwanggyo reservoir, Suwon-cheon and Woncheon-cheon throughtout the whole study periods. While Hagwanggyo reservoir appeared to be in mesotrophic or oligomesotrophic status, most of the remaining sampling sites in Suwon-si were in eutrophic status according to trophic status index. In this study, the most abundant taxa revealed in eutrophic status were Anabaena circinalis, Pandorina morum, Scenedesmus acuminatus, and S. quadricauda as previously reported as the most abundant taxa in eutrophic status. But Navicula cryptocephala and Cyclotella stelligera, reported as the abundant taxa of mesotrophic and oligomesotrophic status, respectively, occurred in eutrophic status in this study.