• Journal of Korean Society of societal Security
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• v.2 no.1
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• pp.65-74
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• 2009

In this study, the air pollution management system based GIS has been developed to estimate the emission rate and air pollution modeling of air pollutants, effectively. This system is able to estimate emission rate of air pollutant and to analyze the emission characteristics with high spatial and temporal resolution. air pollution modeling. The air pollution management system was applied to Gwangyang Bay including large industry complex with a large number of emission sources. The air pollution management system was constructed using the spatial database of emission sources in Gwangyang Bay. It was found that the estimated emission rates of air pollutants is similar to the emission characteristics in Gwangyang Bay. Also, the spatial distribution of pollutants was similar to the location of emission sources. The predicted results of air pollution model was showed a good correlation coefficient (0.75) for TSP. The air pollution management system is expected to be effective tool (database system (GIS)) for the management and the control of air pollution.

• Journal of Environmental Science International
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• v.11 no.8
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• pp.793-800
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• 2002

Butyltin (BT) compounds were measured in seawater, sediment, sediment core, settling solids, and plankton from Gwangyang Bay in 2001, Tributyltin (TBT) was detected in seawater from 1 out of the 7 seawater sampling sites and in sediment from 18 out of the 35 sediment sampling sites. The highest concentration of TBT was found in the sediment from the site near Yeosu Harbor (53 ng Sn/g dry wt), acting as the point source for TBT The mean concentrations of TBT were in the order of plankton> settling solids> sediment. The degradation indexes ([DBT]+[MBT]/[TBT]) for the plankton were less than 1, indicating the possibility of recent inputs of TBT. The indexes for the sediment and settling solids ranged from 1.14 to 8.73. The composition of the BT compounds found in the settling solids was similar to that found in the sediment. The vertical profile of the total BT compounds in the sediment was characterized by an abrupt decline from the surface. However, no butyltin compounds appeared below a depth of 10 cm, corresponding to the 1980s. Accordingly, the current results demonstrated that the levels of all butyltin species in the environment of Gwangyang Bay were relatively lower than those in other polluted coastal areas. The vertical profile also suggested a fairly recent history for the down-core.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.19 no.1
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• pp.53-65
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• 2014

In order to estimate the effect of nutrients addition for phytoplankton growth and community compositons in spring and summer season, we investigated the abiotic and biotic factors of surface and bottom waters at 20 stations of inner and offshore areas in Gwangyang Bay, Korea. Nutrient additional experiments were also conducted to identify any additional nutrient effects on phytoplankton assemblage using the surface water for the assay. Bacillariophyceae occupied more than 90% of total phytoplankton assembleges. Of these, diatom Eucampia zodiacus and Skeletonema costatum-like species was mainly dominated in spring and summer, respectively. Here, we can offer the season why the two diatom population densities were maintained at high levels in both seasons. First, light transparency of spring season in the euphotic zone was greatly improved in the bay. This improvement is one of important factor as tigger of increase in E. zodiacus population. Second, low salinity and high nutrient sources supplied by Seomjin River discharge are a main cue for strong bottom-up effects on S. costatum-like species during the summer rainy season. Based on the algal bio-assays, although maximum growth rate of phytoplankton communities at inner bay (St.8) were similar to those of outer bay (St.20), half-saturation constant ($K_s$) for phosphate at outer bay was slightly lower than those of inner bay. This implied that adapted cells in low nutrient condition of outer bay may have enough grown even the low phosphate and they also have a competitive advantage against other algal species under low nutrient condition. In particular, efficiency of N (+) addition in summer season was higher compared to control and P added experiments. In the bay, silicon was not a major limiting factor for phytoplankton growth, whereas nitrogen (N) was considered as a limiting factor during spring and summer. Therefore, a sufficient silicate supply form water mixing Si recycled from diatom decomposition and river water is favorable form maintaining diatom ecosystems in Gwangyang Bay.

• Korean Journal of Environmental Biology
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• v.29 no.2
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• pp.81-91
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• 2011

To understand the spatio-temporal fluctuations and ecological characteristics of heterotrophic dinoflagellate $Noctiluca$ $scintillans$, we investigated their population densities and environmental factors during four seasons at 20 stations of Gwangyang Bay and at 23 stations of Jinhae Bay in 2010. $N.$ $scintillans$ was seasonally abundant during spring and summer, with temperature ranging 15 to $27^{\circ}C$ in the both bays, whereas the density reduced in fall and winter. The populations of $N.$ $scintillans$ at each station in both bays showed a significantly positive relationship with water temperature, indicating that relatively high water temperature within its optimum temperature stimulates the growth of $N.$ $scintillans$ population. In particular, low water temperature (<$4^{\circ}C$) and salinity (<12 psu) led to disappear of $N.$ $scintillans$ population, although they were observed at all season in both bays. Spatio-temporal variations of Chl.$a$ concentration was not significantly correlated with $N.$ $scintillans$ population densities. However, the $Noctiluca$ abundances were also high during spring and summer season when relatively high Chl.$a$ concentration was observed in both bays. This result suggests that standing crops of phytoplankton may be one of important contributing factors to enhance the abundance of $N.$ $scintillans$.

• Proceedings of KOSOMES biannual meeting
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• 2006.05a
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• pp.129-135
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• 2006

This study was performed to characterize the seasonal variation of water quality and sediment environment from May, 2004 to February, 2006 in 21 stations of Gwangyang bay. Gawngyang bay is located in the middle of south coast of Korea and semi-dosed with Yeosu peninsula, Gwangyang-city and Namhea-do. Water quality at the west coast of Myo-do were highly deteriorated than other stations. At summer season(July 2005), the concentration of the most analytical items were highly detected than other seasons and the lowest concentration was at the winter season(January 2005, February 2006). Especially, DIP and TP were highly detected around the coast of Yeosu industrial complex. N/P ratio were higher than 16 of Redfield ratio in the spring(May 2005) and winter(February 2006) at the surface layer. While at other seasons and most stations were lower than 16 of Redfield ratio. In the survey of sediment environment, ignition loss(IL), chemical oxygen demand(COD) and acid volatile sulfide(AVS) were in the range of $2.51\sim22.10%,\;2.65\sim48.41mg/g-dry\;and\;0.01\sim8.95mg/g-dry$, respectively. COD in surface sediment was highest at summer season AVS was highest at autumn. In sediment, the corelationship coefficients between COD and IL, COD and AVS were 0.65 and 0.44, respectively.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.3
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• pp.175-184
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• 2012

Changes of fish assemblage inhabiting around Dae Island in Gwangyang Bay, Korea were investigated using a small beam trawl monthly from March 2009 to February 2010. These data were compared with those obtained in previous studies(1990~1991 and 1995~1996) at our study sites. A total of 8,133 fish belonging to 74 species in 38 families were collected. Leiognathus nuchalis, Argyrosomus argentatus, Acentrogobius pellidebilis, Sillago japonica, Apogon lineatus, Thryssa hamiltoni, Repomucenus richardsonii, Pholis nebulosa, Pleuronichthys cornutus, Hexagrammos otakii, and Limanda yokohamae dominated, and these were responsible for 89.5% and 58.9% in the number of individuals and in biomass, respectively. These were primarily small species or early juveniles of larger species. Seasonal variation in both species composition and abundance was large: the peak number of fish species occurred in May and October 2009, whilst both number of individuals and biomass were the highest in May 2009. Fish numbers as well as biomass was lowest in January and February 2010. Seasonal changes in the abundance of fishes corresponded with temperature. Compared with the previous studies, the total number of individuals and biomass per unit area($m^2$) were higher, and the predominance of L. nuchalis occurred while abundances of Liparis tanakai were significant decreased. These results seemed to be change of species composition in fish assemblage which was due to variation of annual environmental characteristics in Gwangyang Bay.

• Korean Journal of Environmental Biology
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• v.31 no.4
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• pp.308-321
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• 2013

In order to understand the population dynamics of red tide dinoflagellate Noctiluca scintillans, we examined its hydrographical and bio-ecological characteristics at 19 to 20 stations of Gwangyang Bay during all four seasons from 2010 to 2012. During the 3-year period, N. scintillans was seasonally abundant during summer with water temperatures ranging from $15^{\circ}C$ to $22^{\circ}C$ and salinity ranging from 25 psu to 30 psu. On the other hand, N. scintillans population density significantly decreased in spring, fall and winter, although they were present even in lower temperatures (< $4^{\circ}C$). However, high water temperature (> $27^{\circ}C$) and low salinity (< 12 psu) led to the disappearance of N. scintillans population. Chl-a concentration in winter, spring and fall was positively correlated with N. scintillans population density, whereas the N. scintillans population was negatively correlated with Chl-a concentration in summer. This implies that densities of prey population such as diatoms are one of important contributing factor for maintaining abundance of N. scintillans in winter, spring and fall and for increasing abundance of N. scintillans in summer. During summer season, bio-accumulation of N. scintillans population by the wind from southwest is also considered to be a key factor in triggering the formation of large-scale blooms in Gwangyang Bay.

• Korean Journal of Ecology and Environment
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• v.55 no.3
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• pp.212-220
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• 2022

An estuary is a water ecosystem with a high abundance of the species diversity, due to a variety of complex physicochemical factors of the area where freshwater and ocean mixed. The identification of Corbicula species in the estuary environments is difficult because of various morphological characteristics. In this study, we provide taxonomic information on Corbicula species with taxonomic difficulties using morphological and genetic analysis. This study was conducted on clams from the Seomjin River-Gwangyang Bay, one of the major production area of marsh clam in Korea. As a result, we characterized Cytocrome C Oxidase subunit I (COI) sequences of the Corbicula. The 636 bp nucleotide sequences of COI have 98% homology among Corbicula species collected from 2 sites of Seomjin River-Gwangyang Bay. The phylogenetic analysis with 17 species of Corbicula indicated that most of the species collected from Seomjin River-Gwangyang Bay were brackish water clam (Corbicula japonica), and only one Asian clam (Corbicula fluminea). The evolutionary distance between C. japonica and C. fluminea was less than 0.003. Therefore, it was confirmed that C. japonica is phylogenetically closely related to C. fluminea. In 9 species of Cyrenidae, phylogenetic tree was classified into three lineages. These results will be used as an important data for an identification of clam species by providing genetic information for Corbicula species with a morphological diversity.

• Journal of the Korean Society for Marine Environment & Energy
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• v.8 no.4
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• pp.213-219
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• 2005

In this study, we try to Quantitatively assess the micropollutants in Gwangyang bay, Gamag bay and Yeoa bay, using simultaneous analytical method fir 310 chemicals. In the results, several dozen organic pollutants were detected in sampling sites, and the major chemicals detected were CH type chemicals, such as aliphatic and polycyclic compounds, and CHN(O) type chemicals, such as aromatic ammines and nitro compounds. The concentration of organic pollutants was higher in summer than in winter. However, there was no association of species of organic pollutants with season. The total concentration of pesticides at each sampling site was measured within the range of $ND{\sim}9.11{\mu}g/L$. Insecticides and fungicides of pesticide type were detected in Gwangyang bay and Gamag bay, while six kinds of endocrine disrupter were detected in southern coastal waters. From the results of this study, we should estimated that the insecticides, the fungicides, and a few of the endocrine disrupters are major pollutant factors in southern coastal waters.

• Journal of Ecology and Environment
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• v.35 no.2
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• pp.123-129
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• 2012

Salt marsh is an important transitional zone among terrestrial, riverine, and marine ecosystems and is a productive habitat that interacts extensively with adjacent landscape elements of estuarine and coastal ecosystems. Nowadays, in addition to various human activities, a variety of natural processes induce changes in salt marshes. This study aims to provide background information to restore disturbed salt marshes and to propose their ecological restoration using seed banks. The study area is a prepared area for the Gwangyang Container Port located in the southern Korea. This area was formed by accumulating mud soils dredged from the bottom of the forward sea. This land was created in a serial process of preparing the Gwangyang container port and the salt marsh was passively restored by seeds buried in mud soil dredged from seabed. As a result of stand ordination based on vegetation data collected from the land, stands were arranged according to tolerance to salinity in the order of $Suaeda$ $maritima$, $Salicornia$ $europaea$, and $Phragmites$ $communis$ communities on the Axis 1. Landscape structure of the projected area was analyzed as well. Edges of the projected area were divided from the marginal waterway by the dike. Four types of vegetation appeared on the dike: $Alnus$ $firma$ plantation, $Robinia$ $pseudoacacia$ plantation, $Lespedeza$ $cyrtobotrya$ plantation, and grassland. In the more internal areas, two types of vegetation sequences appeared: $Aster$ $tripolium$ community-$Suaeda$ $glauca$ community-$Salicornia$ $europaea$ community sequence and $Aster$ $tripolium$ community-$Suaeda$ $maritima$ community-$S.$ $europaea$ community sequence. Mixed community showed the highest species diversity (H' = 0.86) and $S.$ $europaea$ community showed the lowest (H' = 0.0). Evenness is the highest in Mixed community (J' = 2.26) and the lowest in $S.$ $maritime-S.$ $europaea$ community (J' = 0.0). Several plant communities were successfully established on the land created by mud soil dredged from the bottom of Gwangyang Bay. Moreover, community diversity in this area approached a similar level with those from other studies involving natural salt marshes. Therefore, restoration effect based on community diversity obtained in our study can be evaluated as a successful achievement. In this respect, although most salt marshes in Korea and other places worldwide have been destroyed or disturbed by excessive land use, feasibility of seed bank as a restoration tool is greatly expected.