• Journal of Korean Society on Water Environment
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• v.30 no.5
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• pp.503-511
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• 2014

The temporal and spatial analyses of total nitrogen (TN) fractionation were conducted in order to understand 1) total nitrogen components in streams and 2) their patterns in rainy and dry seasons. The result showed that the concentration of nitrogen components in stream water was lower in non-urban area and getting higher in urban area. Dissolved total nitrogen (DTN) was 95~97.7% of total nitrogen in streams, and the proportion of dissolved organic nitrogen (DON) and ammonia nitrogen ($NH_3-N$) was higher with increasing urban area. The concentration of total nitrogen and nitrate nitrogen ($NO_3-N$) were highest in winter among four seasons. The result was showed that concentration of $NH_3-N$ was same variation as concentrations of TN and $NO_3-N$ in urban-rural complex and urban areas, except rural areas. During rainy season, concentrations of particulate organic nitrogen (PON) and $NH_3-N$ increased in rural areas and decreased in both urban-rural complex and urban areas. Correlation between total nitrogen components and land uses was positively correlated with site > paddy, and negatively correlated with forest. The variation of total nitrogen concentration was determined by $NO_3-N$ in non-urban areas, by $NO_3-N$ and $NH_3-N$ in urban-rural complex and by $NH_3-N$ in the urban areas.

• Journal of Korean Society on Water Environment
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• v.33 no.1
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• pp.70-77
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• 2017

Total Pollution Load Control (TPLC) is a system for managing the discharge load assigned by satisfying the Target Water Quality (TWQ) in Standard Flow Conditions (SFC). TWQ for a between Metropolitan Cities/Dos Specified (Cites/Dos TWQ) is very important to be the basis of each Unit Watershed TWQ. The purpose of this study was to establish a rational and scientific 'Calculation Metohd of Cites/Dos TWQ'. A methodology for the 3rd phase 'Cites/Dos TWQ' was proposed in this study based on review of the past phase (1rd and 2rd) 'Cites/Dos TWQ' in nakdong river. And utilized water quality model to estimate 3rd phase 'Cites/Dos TWQ' The allocation method of individual discharge sources are important for estimating 'Cites/Dos TWQ' In this case, the key point of the method of calculating the total allowable individual sources is the balance of the equity and the efficiency between individual sources of reduced pollutants. Thus, water quality shall be determined with regard to the current emission levels, the reduction capacity and the technical possibilities of individual sources. We estimate 3rd phase 'Cites/Dos TWQ' according to the 'Calculation Method of Cites/Dos TWQ'.

• Korean Journal of Organic Agriculture
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• v.21 no.2
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• pp.265-270
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• 2013

Cooking oil and yolk mixture (COY) was applied to control the powdery mildew of sweet persimmon at the research field of Gyeongsangnam-do Agricultural Research and Extension Services from 2010 to 2011. COY was sprayed three times with 10 days interval on foliar parts of sweet persimmon and the disease development was monitored after 5 days of final spray. Diseased leaf area rate was 13.4% and the control efficacy of COY against powdery mildew was 80.5%. Disease rate was 68.6% on negative control. Using scanning electron microscope (SEM), the morphological changes of the powdery mildew fungus on the leaf surface were observed. On COY-treated leaves, fungal mycellia were morphologically characterized by a loss in cell volume, shriveling, plasma membrane rupture, and subsequent loss of intracellular contents. It may due to the destruction of fungal cell wall or membrane structure.

• 한국해양학회지
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• v.28 no.2
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• pp.114-120
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• 1993

Numerical method of nonlinear regression was introduced to characterize grain-size distribution more effectively than using the traditional textural parameters. This technique proved critical particularly to multimodal size distributions, as exemplified by samples from Cheju strait continental shelf. Grain-size analysis of samples collected from the Cheju Strait continental shelf reveals that 86% of the grain-size distributions are multimodal. As multimodal grain-size distribution deviates from the statistical (log) normal distribution, the grain-size parameters traditionally used in sediment studies do not describe the distribution efficiently. Therefore, the use of grain-size curves into elementary normal component curves was used. Means and standard deviations of 387 decomposed normal components were decided by a decomposition method (nonlinear least square regression) from 167 size curves of the Cheju Strait sediments. The mean values of decomposed normal components show peaks at 1-3 phi and 8-9 phi size classes. The plot of mean values of the coarse fraction normal components on the map shows a characteristic and complex areal distribution. On the basis of the areal distribution of the mean values of the components and that of isopach of total Plenipotence sediment, the areal distribution of layers composing a transgressive sand of Late Plenipotence age were revealed.

• 한국해양학회지
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• v.25 no.4
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• pp.189-204
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• 1990

In the KODOS (Korea Deep Ocean Study)-89 area, western part of clarion-Clipperton fracture zones in the northeastern equatorial Pacific, magnate nodules and sediments were sampled during the 'Farnella' cruise in Oct., 1989. Bulk chemical and mineralogical analyses have been made on a suit of ferromanganese nodules and sediments to study the origin and distribution pattern of the nodules. The nodules are classified into three groups based on their origin: diagenetic nodules with high Mn/Fe ratio, Cu, Ni, Zn, Mg, todorokite contents and rough surface texture; hydrogenetic nodules with high Fe, Co, vernadite contents and smooth surface texture; and transitional nodules with intermediate characters between diagenetic and hydrogenetic nodules. Study area is divided into four zones according to the origin and abundance of nodules: far north area where nodules are hydrogenetic and intermediate in abundance; north area where nodules are diagenetic and low in abundance; south area where nodules are diagenetic and intermediate in abundance; seamount area where nodules are hydrogenetic and high in abundance. distribution pattern of manganese nodules in the KODOS-89 area seems to be controlled by latitudinal variation of productivity in water column and sea bottom morphology.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.1
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• pp.18-24
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• 1999

The satellite image acquired by RADARSAT SAR on August 15, 1996 reveals internal waves in north coastal waters of Cheju Island. It is indicated from the image data, the tidal elevation data, and the bottom topography data, the internal waves seem to be generated by interaction between shallow bottom and tidal currents travelling in the stratified water in the summer time during the tidal changeovers from ebb to flood. The internal waves generated in such condition show patterns of trains of solitons. Probable amplitude of observed solitons is calculated using estimation of the soliton wave length from SAR image data and K-dV equation. Detection of the internal waves is very significant not only to military strategist for underwater maneuvers such as operation of submarines, but also to physical and biological oceanographers. Temporal and spatial variation of the internal waves are needed to be measured by simultaneous in-situ field study together with SAR to examine the nature of these internal waves.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.2 no.1
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• pp.14-20
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• 1997

The southwestern continental shelf of the East Sea, Korea developed mud deposits as a belt in the inner shelf area from Pusan to Pohang. The general surface sediments consist of very poorly to poorly sorted muddy sediment. The differences of physical, geological and geomorphic conditions in the study area may control and produce distinctive foraminiferal populations. To establish a baseline of environment for the muddy sediments in the southwestern continental shelf of the East Sea, 17 stations were sampled and proved to contain 45 species of living benthic foraminifera. Analysis of the foraminiferal populations in cluster analysis recognized to five habitat zones. These habitat zones contain distinctive cooccurrences of the entire occurring species. Foraminiferal community composition appeared to be closely interrelated of water masses, depths, nutrients and sediment characters.

• Journal of Wetlands Research
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• v.18 no.3
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• pp.218-225
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• 2016

Various strategies and management plans have been established in order to conserve water quality as well as ecosystem, prevent deterioration of scenic area, and more importantly, retain drinking water securely. However, due to the introduction of numerous small-scale development projects on the waterside area outside protection area of source water and reparian area, river water quality and landscape are severely deteriorated. In this study, We analyzed the expected environmental impacts on the ecosystem, topograph, geology, landscape, water quality according to development type, and assigned different environmental points to each development type depend on environmental impacts, which is able to divide small-scale development project into three categories such as projects with rigorous review, projects with general review and projects with simple review. Finally, we suggested the appraisal basement is to avoid or minimize the expected environment impacts of the small-scale development projects in riparian areas so that make them sustainable development by reasonable restriction.

• Journal of Wetlands Research
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• v.13 no.2
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• pp.275-289
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• 2011

We investigated the hydrological and geomorphological characteristics of small irrigation ponds in civilian control zone of Paju city in Korea. Among 85 small irrigation ponds, water level of 52 ponds changed seasonally and that of 33 was constant. Water sources of 12 ponds were surface water, 29 surface water and ground water, and 44 ground water. 4 ponds locate in the edges of forests, 33 in flat-lands, and 48 in valleys. Water in 45 ponds was exchanged with paddy fields and 40 ponds were isolated from paddy fields. Endangered or endemic species were inhabited in 26 ponds, which have ground water as water source and constant water level. Based on these characteristics, we suggested 4 types of small irrigation ponds: spring, water exchanging, stagnant/spring, stagnant water. This classification system will help ecosystem managers to investigate ponds systematically and manage them based on pond type.

• Journal of Wetlands Research
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• v.14 no.2
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• pp.277-288
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• 2012

Estuary is unique habitat ground under substantial changes of water quality, river side, bed material, and micro topography. Construction of SinGok underwater weir with excessive dredging for downstream of weir has changed hydraulic conditions of Han River. This study investigates spatial changes of estuary and expansion process of vegetation on sandbar for JangHang estuary in Han River through analysis of physical and ecological characteristics. As a result of investigation, we found that area of sandbar in JangHang estuary is expanded six times compared between 1985 and 2006, and area of Phragmites australis is gradually decreased while area of Salix subfragilis Anderson. is increased. Also the analysis result of soil layer shows that the Jang-Hang wetlands are created by effect from river, and woody plants are settled from middle part of wetlands, then spread to upper and lower part of wetlands.