• Korean Journal of Ecology and Environment
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• v.43 no.3
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• pp.428-436
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• 2010

This study was to evaluate water quality characteristics and ecological health using a mulimetric fish model in Taehwa-River watershed during May~September 2009. The ecological health assessments were based on the Index of Biological Integrity (IBI) using fish community and the multimetric model of Qualitative Habitat Evaluation Index (QHEI). For the study, the models of IBI and QHEI were modified as 8 and 11 metric attributes, respectively. We also analyzed spatial patterns of chemical water quality over the period of 2000~2009, using the water chemistry dataset, obtained from the Ministry of Environment, Korea. Values of BOD and COD averaged $1.7\;mg\;L^{-1}$ (scope: $0.1{\sim}31.8\;mg\;L^{-1}$) and $3.6\;mg\;L^{-1}$ (scope: $0.4{\sim}33\;mg\;L^{-1}$), respectively during the study. Total nitrogen (TN) and total phosphorus (TP) averaged $2.8\;mg\;L^{-1}$ and $96.8\;{\mu}g\;L^{-1}$, respectively, indicating an eutrophic-hypertrophic state. Also, TN and TP showed longitudinal increases toward the downriver reach. In the watershed, QHEI values varied from 67.5 (fair condition) to 164.5 (good condition) by the criteria of US EPA (1993). There was a abruptly decreasing tendency from T9 site in the QHEI values. According to 1st and 2nd surveys of Taewha River, multimetric model values of IBI was averaged 26.1 (n=14) with "good" condition (B) and the spatial variation was evident. Our results suggest that the mainstream sites was getting worse health condition along the river gradient due to inputs of the point and non-point sources from the urban (Ulsan city). Overall, dataset of IBI, QHEI, and water chemistry indicated that the ecological river health showed a downriver decline and the pattern was closely associated with habitat degradations and chemical pollutions as the waters pass through the urban region.

• Journal of the Korean Society of Food Culture
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• v.5 no.2
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• pp.217-228
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• 1990

An ecological study of food and nutrition was conducted among 198 children, 6 to 12 years old, of the Songmyun elementary school and Samsong elementary school, located in remote villages of Chungchun-myun, Goisan-gun, Chung Buk Province between July 11 and 16, 1988. The results were summarized as follows. In regard to frequency of skipping breakfast, 3.3% of subjects skipped every morning; 15% often skipped; and the others never skipped. The most common reason for skipping a meal was lack of appetite. 6.6% of subjects often skipped an evening meal because of delayed meal preparation by a mother who returned home late. The survey found that 5.1% of subjects skipped a lunch at school. The reasons for skipping lunch were the mother’s being too busy to prepare a boxed lunch; a school bag too heavy to carry for a long distance to school; no adequate side-dishes for the boxed lunch. Growth patterns of those children having poor food habits, were reflected in lower figures in arm circumference and weight for height. The percentage of children having meals with their family on weekdays was 84.7% for breakfast; 85.6% for evening meal. About 7% of subjects had many dislikes and 74.1% had some dislikes in what they ate; 18.9% had good food preferences. There was a strong correlation between appetite or food preferences and anthropometric measurements or nutrient intake. Boiled rice was the predominant dietary staple, and principal sources of protein taken by subjects at home were soy beans and soy products. Regarding the boxed lunch prepared at home, most popular was one with only one kind of side-dish, including kimchee. 43.4% of the side-dishes were prepared with vegetables only. As for between meal snacks, milk and milk products, fruits and breads were popular among the subjects. The survey found that the children liked fruits, yogurt, corn, Chajang noodle; in contrast, lowest preference was for soup made with bones, curried meat with rice, and aromatic vegetables. The survey discovered a local dietary characteristics; 46.2% of the children customarily ate frog meat, an unconventional food.

• Journal of Ecology and Environment
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• v.43 no.2
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• pp.85-97
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• 2019

Background: Despite the increasing role of dry forests in climate change adaptation and mitigation, these versatile resources has got less attention in the national and regional planning, their potential to enhance the local and national economy has been overlooked, and their contribution to sustainable environmental management has not been recognized. Hence, the objective of this study was to assess the socioeconomic contribution of dry forests and forest products to climate change adaptation in the Liben Woreda, Southern Oromia region of Ethiopia. Methods: For this study, an integrated qualitative and quantitative approach was used. A total of 74 households from villages in the Bulbul, Boba, and Melka-Guba kebeles were randomly selected for the household survey. Results: Results showed that 75% of the respondents in the area indicated that climate change has become their major sources of vulnerability, where drought has been manifested in the form of crops failure and massive death of livestock particularly cattle species. The main income strategies of the study households include livestock, crop, forests such as gum and resins, firewood and charcoal and non-farm activities such as in the form of petty trade, wage and aid. The average total household income was ETB 11,209.7. Out of this, dry forest income constituted 15% of the total income. In addition to using dry forests as rangeland for livestock, the communities collect wood for construction, fodder, traditional medicine, and forest food both for subsistence and for sale. On the other hand, dry forest products could be considered as less vulnerable, rather resilient livelihood strategies to climate- and environment-related risks compared to livestock and crop production such as in the face of drought periods. More than 48.6% of the households argued that the income generated from dry forests increased substantially due to increment in the level of engagement of family members in forest based income activities. On the other hand, 35.8% of the households responded that livestock production, particularly camels and goats, have been making the livelihood strategies of the respondents more resilient indicating the shift made from grazers browsers to livestock. In general trends show that, the trends of livelihood dependency on dry forest were highly increasing indicating the importance of dry forest income in responsse to frequent droughts. Conclusions: Dry forest income has been becoming crucial livelihood staretgy in response to frequent droughts in the study area and hence, it is important to improve the management of dry forests for livelihood enhancement, while also securing their long-term ecological functions.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.2
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• pp.210-217
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• 2009

Pollen flow is one of the essential components in the ecological risk assessment of transgenic crops, because pollen can act as a vehicle to disseminate transferred alien genes. Pollen flow pattern of a cultivated rice variety and Living modified (LM) rice was studied at diurnal and distance changes under field. We measured airborne pollen density at the distances of -1, 0.5, 0, 1, 2, 3, 4, 5, 7, 9, 11 and 13 m from rice cultivation and recorded the direction and speed of wind using weather station in the conventional rice paddy field during the flowering period of rice. Diurnal changes in pollen density were observed as a peak between 10:00 to 13:00 hr. The density of airborne rice pollen geometrically decreased with the increase of distance from pollen sources. It is therefore necessary to carry out a detailed investigation of pollen flow of a particular species, where ecological risk assessment requires an accurate estimation of pollen flow including both distance and intensity of pollen dispersal. The rice pollen flow was significantly influenced by weather conditions, particularly by wind direction and speed. The precise determination of the local wind conditions at flowering time therefore appears to be of primary importance for setting up suitable isolation distance from transgenic rice in the field.

• Journal of Korean Society on Water Environment
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• v.28 no.4
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• pp.561-573
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• 2012

The object of this study was to analyze long-term water quality gradients during 1992-2008 at six sites of Geumho River and near-by two sites of Nakdong River and their influences on fish trophic guilds and tolerance guilds along with ecological health. Water quality including biological oxygen demand (BOD), chemical oxygen demand (COD), conductivity, total phosphorus (TP), total nitrogen (TN), and total suspended solids (TSS) varied largely depending on the sampling locations and seasons. Values of ambient BOD, COD, TP, and TN were greater in the downstream than in the upstream reach, and seasonal and interannual variabilities were also higher in the downstreams. This phenomenon was evident due to a dilution by the Asian monsoon rainfall during the monsoon. These outcomes indicate that point sources near the downstream are important for the chemical conditions, but also seasonal stream runoff was considered as an important factor regulating the chemical conditions. Conductivity decreased rapidly during the summer due to ionic dilution, and nutrients (N, P), BOD, COD had an inverse function of seasonal precipitation. Based on the water quality, we selected two sites (control site = $C_s$ vs. impacted site = $I_s$) for impact analysis of water chemistry on fish community and trophic/tolerant guilds. Fish guild analysis showed that species diversity was higher in the headwater stream ($C_s$) than the impacted downstream ($I_s$), and that the proportion of tolerant and omnivore species were greater in the impacted site of downstream. Comparisons of water quality between Geumho River and Nakdong River indicated that Geumho River was considered as a point source which degradated water quality to the Nakdong River. Overall, chemical water quality and fish guild analysis suggest that even if current chemical quality got better after 1996 due to continuous constructions of wastewater disposal plants near the downstreams, fish compositions of tolerant and omnivores were still dominated the community. Thus, biological restoration based on ecological health is required for the ecosystem conservation.

• Korean Journal of Environmental Biology
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• v.38 no.1
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• pp.189-196
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• 2020

Mosquitos serve as vectors for diseases, causing inconvenience as well as a threat to human life and health. Concern about mosquitos introducing and spreading new diseases has been intensifying. We observed a variety of mosquito habitats based on land cover classification from Korea's Ministry of Environment, and the mosquito species that could appear were classified according to the each habitat type. Finally, we suggested the best control methods for each type of habitat considering habitat characteristics and the ecological traits of mosquitos. Urban areas harbor various habitats for pests, contributing significantly to mosquito habitats. Control must be performed regarding larva and adults because various sources for habitats exist. Public mosquito control programs such as educational training, as well as information brochures can be effective in managing mosquito populations and public health. Agricultural areas show high densities of mosquito larva to lentic zones such as reservoirs, wetlands, paddy fields. So, biological control using natural predators may be effective in controlling mosquito populations. Forests are major habitats for Aedes albopctus, so physical controls should be deployed for residents living nearby, and excessive deforestation should be minimized. Other areas including aquatic ecosystems should be adopted regarding biological control using Bti (Bacillus thuringiensis var. israelensis) and chemical control for eradicating mosquitos. We classified habitats into four types of land cover patterns considering ecological traits and habitat preference, and suggest adequate control methods for each habitat type. Our suggestion can be used to positively contribute toward effective managing mosquito's density and reducing the damage to public health.

• Korean Journal of Ecology and Environment
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• v.55 no.4
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• pp.398-405
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• 2022

The research was based on long-term studies on the major physico-chemical and hydrological factors and zooplankton community dynamics in the Hwang River. We had 341 times survey and collected zooplankton samples in the Hwang River of mid-Nakdong River from 1995 to 2013. We identified 97 zooplankton species, including 77 rotifers, 16 cladocerans, and 4 copepods. The total zooplankton abundance and species diversity were shown distinctive temporal variation (ANOVA, p<0.001). Annual average of zooplankton population density was 58.4±3.2 ind L^-1 (n=341) and the lowest was 17.0±3.8 ind L^-1 (1996, n=20), while the highest was 151.5±32.3 ind L^-1 (2010, n=22). For zooplankton, small rotifer groups(e.g., Keratella sp., Brachionus sp., Trichotria sp.) dominated the study site for 19 years survey. Statistical analysis revealed that there were positive relationships with SiO₂ (p=0.002) and water level (p<0.001) for the high abundance of rotifer community. There were considerable variations both the total cladocerans population and the number of cladocerans' species concerning annual precipitation. Despite the appearance of various zooplankton in the Hwang River, the mean population density remained low. Due to the lateral structures in the Nakdong River, the downstream basin of the Hwang River is inevitably affected. The zooplankton community in our study site is considered to be mainly influenced by external factors that can stably increase and maintain the volume of the water body and internal factors that induce an increase in food sources through the inflow of nutrients into the water body.

• Korean Journal of Environment and Ecology
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• v.38 no.1
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• pp.48-54
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• 2024

This study conducted a survey from April 2021 to December 2022 to investigate habitat factors affecting bird diversity in the region between Cheonwangbong Peak and Aghwibong in Baekdudaegan protected area, South Korea. Since the region has a spatial scale of 736.4 km² and is an area where a wide variety of habitats are mixed, we selected 20 survey areas of 3 km x 3 km by analysis of habitat homogeneity. As a result of analyzing the relationship between habitat environment and bird diversity in the survey area, it was found that the diversity of bird communities was directly or indirectly related to the diversity of terrestrial insects, slope, average habitat area, mean size of patches, elevation, and forest type, and distance from agricultural land. The slope of habitat, forest type, and distance from agricultural land affect the occurrence of food sources directly and indirectly, and the average area of habitats and forest type is closely related to the structural diversity of habitats. Therefore, it is determined that the diversity of bird communities is affected by the amount of food generated within the habitat and the diversity of habitats. It is determined that the relationship between bird communities and habitat environments in this surveyed region can be basic ecological data for establishing forest management measures to promote the diversity of bird communities.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.1
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• pp.25-36
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• 2016

Heavy metals in the stream sediments around Shihwa Lake were studied not only to investigate the characteristics of spacio-temporal distribution but also to assess the pollution degree and ecological risk using various pollution indices. Among metals, Zn had the highest values (1,311 mg/kg) and Hg showed the lowest value (0.261 mg/kg). The order of mean concentrations (mg/kg) of metals was Zn>Cu>Pb>Cr>Ni>Co>As>Cd>Hg in stream sediments around Shihwa Lake. Metal concentrations showed different pollution pattern with industrial region, indicating that these metals originated from different sources and industrial region had higher metal concentration than rural/urban regions. The results of geoaccumulation index (Igeo) showed that the stream sediments were significantly polluted with Cd, Cu, Zn and Pb, indicating moderately to highly polluted by these metals. According to PLI consideration, industrial region was more seriously polluted by metals whereas an rural/urban region was not polluted. About 85% of sampling site for Cr, Ni, Cu, Zn and Pb from industrial regions were exceeded the PEL values. The mPELQ and SQI values derived from PEL of industrial region were classified as 'highly toxic' and 'very poor' and metal pollution level tend to be worse in wet season. This indicates that the industrial activities and stromwater runoff represents an important sources of heavy metals around Shihwa Lake.

• Microbiology and Biotechnology Letters
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• v.45 no.2
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• pp.124-132
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• 2017

Microbial secondary metabolites of marine organisms are regarded as major sources of structurally and biologically novel compounds with numerous potential uses. Sponge-microbe associations are among the most interesting sources for exploring bioactive compounds. In this study, the bacterial strain Microbulbifer sp. (127CP7-12) was isolated from the Asian marine sponge Hymeniacidon sinapium collected at an intertidal zone on the west coast of Korea. Cultured bacteria produced a violet pigment, and optimal culture conditions for violet pigment production were investigated. Maximum production of the violet pigment from the strain culture was observed under the conditions of $25^{\circ}C$, pH 6.0, and 3% NaCl. Acetone provided better extraction of the pigment from fermented broth compared with ethanol and methanol. The proposed structure of the major component in the extracted crude pigment was determined via high-performance liquid chromatography, nuclear magnetic resonance, mass spectrometry, and UV spectra analyses, which showed that the metabolite was the promising bioactive compound violacein. This study describes the examination of marine bioactive materials from microbe-engaged metabolites and the ecological implications of the sponge-microbe association in a changing ocean.