• Journal of Environmental Impact Assessment
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• v.3 no.2
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• pp.33-45
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• 1994

Water quality of Chongju and Daejeon Water Intake Tower Region, embayments in Daechong Reservoir was found to be worse than that of main lake after analysis of water which were sampled during April, July, October in 1993. Concentration of COD and SS at those two water intake tower sites were 2.8-5.6 mg/l and 2.2-3.2 mg/l, higher than that of main lake. T-N concentration of those two sites was 1.1-1.9 mg/l similar to that of main lake, and T-P concentration of those two sites was 0.14-0.18 mg/l, higher than that of main lake. This study used water quality model of embayment which can analyse pollutant loads from stream and surrounding land use, advection, decay, and diffusion transport between embayment and main lake. The model can predict water quality of embayment according to the change of pollutant load, water elevation of embayment, quantity of water intake in order to suggest water quality management. This study suggests embayment water quality management alternatives, 1) construction of waste water treatment facilities at embayment and main lake for the decrease of pollutant loading, 2) water intake at main lake less polluted or eutrophicated than embayment, and 3) outflow elevation selection for polluted hypolimnion water outflow during stratification.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.8 no.3
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• pp.225-236
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• 2003

In order to understand the relationship of depositional environment between fluvial and estuarine-embayment in Han River system, including depositional change in main Han River, more than 250 bottom sediment and 70 suspended sediment were analyzed with hydrologic data. Based on the previous data, the study area can be divided into two environment(fluvial and estuarine-embayment) by Singok underwater dam. The gravelly facies occurs in the South and North Han Rivers and sandy and silty facies occupies in the main Han River. Depositional environment of main Han River changed mainly because of limited sediment transport and hydrological condition. In the estuarine-embayment environment, coarse-grained sediments are dominant in tidal channel and of shore whereas fine and poorly sorted sediments are observed in coastal area. During moderate period, relationship between fluvial-estuarine-embayment system is discontinuou s because of flow restriction by artificial construction such as dam and underwater dam, so that each river system characterizes the individual environment. Fluvial and estuarine system is influenced by tide and, thus, transition zone of estuarine- embayment system moves landward. During flooding period, however, each river system is integrated as continuous depositional system by high discharge and, thus, transition zone of fluvial-estuarine-embayment system moves seaward. For further detailed systems about the lower Singok under-water dam, joint research of South-North Korea should be necessary.

• Journal of Environmental Impact Assessment
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• v.9 no.3
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• pp.215-228
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• 2000

This paper presents a novel method to predict a flushing rate in an embayment system, which can be utilized to assess an environmental impact caused by harbor construction. The method was successfully applied to the Ulsan-Onsan coastal area. The flushing rate was computed on the basis of water quality changes predicted by US Army Corps of Engineers' RMA-2/RMA-4 models. After calibration and verification to the measured tidal elevation and current velocity, the model was used to estimate the flushing rate in the proposed harbor. The water quality was simulated for 96 hours and the flushing rate was computed. The results indicated that the proposed harbor would significantly reduce the flushing rate in the Onsan harbor, especially at the small embayment area near the south breakwater. The flushing rate was evaluated for several alternatives, of which the tidal flow channel of 1,000 $m^2$ in the south pier appeared to be the best mitigation measure. This study proposes that the prediction of flushing rate would be a novel method to assess a water quality impact caused by harbor construction.

• Journal of the Korean association of regional geographers
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• v.17 no.6
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• pp.649-665
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• 2011

Estuary of River Nakdong(in south-eastern coast of Korean Peninsula) is the most representative site of delta in Korea. This study is to elucidate morpho-structural background associated with the embayment area and sedimentation processes, having allowed development of the delta. In this area, Great morphological trait of the embayment area had been formulated by differential erosion exploiting regional fracture system(NNE-SSW, NNW-SSE, E-W,...) of tectonic origin. For this reason, outline of the embayment basin shows quadrangular plan, and ridges and dissected valleys of neighbouring mountains draw frequently morphological lineament pattern. At the last glacial age when delta deposit had not yet filled the actual embayment basin of the Nakdong, mechanical weathering(frost shattering) and mass-movement processes had provided detritus materials composed of blocks, boulders on bottom the basin. With the postglacial transgression in the Holocene, the basin had been submerged, then began to be filled with fluvio-marine deposits from Kimhae-Yangsan area toward actual estuarine zone, so that Nakdong delta have been formed. Analysis and synthesis of from hundreds of boring data of the delta area reveal that progression of delta formation have been accompanied with the development of barrier islands. If the barrier islands had grown as forming a plural row, then their intervals have posteriorly filled with another fluvio-marine deposits. Besides, it shows that delta deposits are essentially alluvial. However, at the periphery of the delta, intervention of fine marine deposits is frequently found.

• Korean Journal of Microbiology
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• v.36 no.2
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• pp.125-129
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• 2000

The ecology of estuarine bacteria in terms of bactenal production and biomass was investigated in Naktong embayment. Intrusion of eutrophic freshwater was one of the major factors affecting on the ecosystem of Naktong embayment. Total bacterial number varied from $2.2{\times}10^5 cells/ml to 9.8{\times}10^5 $ cellslml, and the variation ranges of the bacterial biovolume and biomass were 0.023-0.201TEX>$\mu$$m^3$/cell and 0.010-0.140 TEX>$\mu$g-Clml, respectively, and there was a reciprocal relationship between bacterial number and biomass. Pool size of thymidine varied from 12.93 nM to 44.56 nM. The pool during summer was supposed to be composed of easily utilizable form than the typical one of winter, which suggests thal bacterial productivity measured in summer may be underestimated. Bactenal production varied from 0.12 TEX>$\mu$g-Cllh to 22.38 TEX>$\mu$g-Clllh, and the values were low in winter and increased from spring and reached the highest in summer. The variations of bacterial production showed high correlations with temperature, chlorophyll a, and bacterial biomass. These results suggested that the main source of organic matters which influence the bacterial production in Naktong embayment may be the photosynthetic excretory products of phytoplanktons.

• ALGAE
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• v.18 no.2
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• pp.169-176
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• 2003

Algal growth potential test (AGPT) bioassay were conducted to evaluate the stream and reservoir water in the Okchon Stream Watershed during May to September 2002. The water quality of the stream water was clean in the upstream, deteriorating toward the downstream. In particular, SRP and $NH_4$ significantly increased due to treated wastewater. The average AGPT value of the Okchon Stream watershed was 22.4 mg dw ${\cdot}l^{-1}$, with the range of 0- 195.7 mg dw ${\cdot}l^{-1}$. AGPT value was the highest immediately after inflow of treated wastewater, averaging 91.3 mg dw${\cdot}l^{-1}$. AGPT was highly correlated with SRP, $NH_4$ and TIN factors, with P having the greatest effect on the growth of algae. Among N components, $NH_4$ was preferred to $NO_3$ for the growth of algae. Likewise, AGPT was closely linked to meteological and hydrological effects and development of natural phytoplankton. In survey stations, mesotrophic, eutrophic and hypertrophic conditions accounted for 43%, 21% and 36%, respectively. On the other hand, hypertrophic condition focused on the downstream reaches. AGPT was useful in determining not only the limiting nutrients but also the water fertility for the growth of algae. Based on the AGPT results, the management of point sources for water pollution in treated wastewater was important in the protection of aquatic environment in the stream and embayment.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.09a
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• pp.422-423
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• 2005

• Korean Journal of Ecology and Environment
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• v.37 no.4 s.109
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• pp.455-461
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• 2004

Effects of the different strengths and intervals of the periodic outer water intrusions (kyuchos and bottom intrusions) on the dynamics of phytoplankton biomass in a small embayment were examined with a simple numerical model. Environmental conditions of Kitanada Bay in the Bungo Channel were applied to the model. As the interval of the intrusion became longer and the amplitude became smaller, phytoplankton biomass In the bay became higher. On the other hand, as the interval became shorter and the amplitude became larger, the growth rate of the phytoplankton became higher. It suggested that when the intrusion was weaker, water exchange of the bay decreased and the phytoplankton in the bay accumulated at a high density, When water exchange was improved by active intrusions, availability of light would become more efficient and the growth rate of the phytoplankton was enhanced.

• 한국해양학회지
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• v.29 no.4
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• pp.376-382
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• 1994

Seasonal distribution of zooplankton community in Inchon Dock, an artificially closed marine embayment has been studied. Samples were collected monthly during the period from December 1989 to December 1991 at four stations in the dock and compared with that at a single station in neighbouring waters of the Yellow Sea. Copepods dominated both in and outside of the dock all the year round, except in late autumn and early winter when protozoans outnumbered. dominant species were Oithona davisae, Acartia bifilosa, Paracalanus crassirostris, Noctiluca scintillas and Tintinnopsis tubulosa. A sharp decline in the abundance was observed in summer 1990 in the dock apparently due to oxygen deficiency (anoxic condition). Although no distinct deference in the abundance of zooplankton was observed between populations in and outside of the dock except in summer 1990, waters out of the dock showed to have a prosperity in species number throughout the year. Moreover, four species of copepods, Centropages abdominalis, Pseudodiaptomus marinus, Tortanus forcipatus and T. spinicaudatus occurred solely at the outside of the dock.

• Ocean and Polar Research
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• v.44 no.1
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• pp.83-97
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• 2022

The Amundsen Sea in West Antarctica is one of the most affected regions by climate change, but it is one of the least studied realms due to difficulties in access. Korea Polar Research Institute (KOPRI) launched a research project in the Amundsen Sea in 2010 using the icebreaker research vessel (IBRV) Araon and has been conducting various research initiatives. In this paper, previous researches derived from the Amundsen Sea Embayment by Korean researchers are introduced. Through previous studies, researchers have been able to interpret the environmental and biogeochemical changes according to the inflow Circumpolar Deep Water (CDW) and provide information for climate models. In particular, researches using radiocarbon isotopes (¹⁴C) were introduced to understand the physical and biogeochemical mechanisms of the carbon cycle in the Amundsen Sea. Opportunely, with the construction of a second icebreaker research vessel, the direction for systematic and long-term polar data acquisition can be presented.