• Economic and Environmental Geology
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• v.42 no.6
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• pp.599-608
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• 2009

This study was conducted to examine chemical characteristics and correlations among seepage water, subsurface waters and inland groundwater in and around a coastal underground LPG cavern using factor and cluster analyses. The study area is located in western coast of Incheon metropolitan city and is about 8 km off the coast. The LPG cavern storing propane and butane was built beneath artificially reclaimed island. Mean bathymetry is 8.5 m and maximum sea level change is 10 m. Water sampling was conducted in May and August, 2006 from 22 sampling points. Correlation analysis showed strong correlations among $Fe^{2+}$ and $Mn^{2+}$ (r=0.83~0.99), and Na and Cl (r=0.70~0.97), which indicated reductive dissolution of iron and manganese bearing minerals and seawater ingression effect, respectively. According to factor analysis, Factors 1 (May) and I (August) showed high loadings for parameters representing seawater ingression into the cavern and effect of submarine groundwater discharge, respectively while Factors 2 and IV showed high loadings for those representing oxidation condition (DO and ORP). Factors 4 and II have large positive loadings for $Fe^{2+}$ and $Mn^{2+}$. The increase of $Fe^{2+}$ and $Mn^{2+}$ was related to decomposition of organic matter and subsequent their dissolution under reduced condition. Cluster analysis showed the resulting 6 groups for May and 5 groups for August, which mainly included groups of inland groundwater, cavern seepage water, sea water and subsurface water in the LPG storage cavern. Subsurface water (Group 2 and Group III) around the underground storage cavern showed high EC and major ions contents, which represents the seawater effect. Cavern seepage water (Group 5 and Group II) showed a reduced condition (low DO and negative ORP) and higher levels of $Fe^{2+}$ and $Mn^{2+}$.

• Korean Journal of Environmental Biology
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• v.32 no.4
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• pp.297-305
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• 2014

In order to understand the contribution of seaweed aquaculture to nutrients and carbon cycles in coastal environments, we measured the nutrients & carbon uptake rates of Porphyra yezoensis Ueda sampled at Nakdong-River Estuary using a chamber incubation method from November 2011 to April 2012. It was observed that the production rate of dissolved oxygen by P. yezoensis (n=30~40) was about $68.8{\pm}46.0{\mu}mol\;{g_{FW}}^{-1}h^{-1}$ and uptake rate of nitrate, phosphate and dissolved inorganic carbon (DIC) was found to be $2.5{\pm}1.8{\mu}mol\;{g_{FW}}^{-1}h^{-1}$, $0.18{\pm}0.11{\mu}mol\;{g_{FW}}^{-1}h^{-1}$ and $87.1{\pm}57.3{\mu}mol\;{g_{FW}}^{-1}h^{-1}$, respectively. There was a positive linear correlation existed between the production rate of dissolved oxygen and the consumption rates of nitrate, phosphate and DIC, respectively, suggesting that these factors may serve as good indicators of P. yezoensis photosynthesis. Further, there was a negative logarithmic relationship between fresh weight of thallus and uptake rates of nutrients and $CO_2$, which suggested that younger specimens (0.1~0.3 g) were much more efficient at nutrients and $CO_2$ uptake than old specimens. It means that the early culturing stage than harvesting season might have more possibilities to be developed chlorosis by high rates of nitrogen uptake. However, N & C demanding rates of Busan and Jeollabuk-do, calculated by monthly mass production and culturing area, were much higher than those of Jeollanam-do, the highest harvesting area in Korea. Chlorosis events at Jeollabuk-do recently might have developed by the reason that heavily culture in narrow area and insufficient nutrients in maximum yield season (Dec.~Jan.) due mostly to shortage of land discharge and weak water circulation. The annual DIC uptake by P. yezoensis in Nakdong-River Estuary was estimated about $5.6{\times}10^3\;CO_2$ ton, which was about 0.03% of annual carbon dioxide emission of Busan City. Taken together, we suggest more research would be helpful to gain deep insight to evaluate the roles of seaweed aquaculture to the coastal nutrients cycles and global carbon cycle.

• Journal of Wetlands Research
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• v.25 no.4
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• pp.335-344
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• 2023

Brachydiplax chalybea flavovittata, a climate-sensitive biological indicator species, was first observed and recorded at Jeju Island in Korea in 2010. Overwintering was recently confirmed in the Yeongsan River area. This study was aimed to predict the potential distribution patterns for the larvae of B. chalybea flavovittata and to understand its ecological characteristics as well as changes of population under global climate change circumstances. Data was collected both from the Global Biodiversity Information Facility (GBIF) and by field surveys from May 2019 to May 2023. We used for the distribution model among downloaded 19 variables from the WorldClim database. MaxEnt model was adopted for the prediction of potential and future distribution for B. chalybea flavovittata. Larval distribution ranged within a region delimited by northern latitude from Jeju-si, Jeju Special Self-Governing Province (33.318096°) to Yeoju-si, Gyeonggi-do (37.366734°) and eastern longitude from Jindo-gun, Jeollanam-do (126.054925°) to Yangsan-si, Gyeongsangnam-do (129.016472°). M type (permanent rivers, streams and creeks) wetlands were the most common habitat based on the Ramsar's wetland classification system, followed by Tp type (permanent freshwater marshes and pools) (45.8%) and F type (estuarine waters) (4.2%). MaxEnt model presented that potential distribution with high inhabiting probability included Ulsan and Daegu Metropolitan City in addition to the currently discovered habitats. Applying to the future scenarios by Intergovernmental Panel on Climate Change (IPCC), it was predicted that the possible distribution area would expand in the 2050s and 2090s, covering the southern and western coastal regions, the southern Daegu metropolitan area and the eastern coastal regions in the near future. This study suggests that B. chalybea flavovittata can be used as an effective indicator species for climate changes with a monitoring of their distribution ranges. Our findings will also help to provide basic information on the conservation and management of co-existing native species.

• Journal of the Economic Geographical Society of Korea
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• v.9 no.2
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• pp.149-166
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• 2006

The purpose of this study is to produce time-distance cartograms based on the various Korean transportation networks, and to analyze the spatial structure of time-distance accessibilities. For the purpose this study attempts to develop continuous area cartogram by utilizing Wolf's algorithm for creating contiguous cartogram in ArcGIS 9. The absolute physical space was transformed to the functional space indexed by time-distances along various transportation networks in Korea. We examined the differences in the time-distance accessibilities among transportation networks. This study makes a comparison between the spatial structure of time-distance accessibility of KTX network with them of existing railroad network, as well as with them of road network. In order to clarify the spatial structures of time-distance accessibilities, we restructured them on the time-distance circular diagrams and performing Multi-Dimensional Scaling analysis. Overall structure of time-distance accessibilities shows similar patterns: The time distances are shrinked a lot along the Seoul-Busan axis, while coastal parts, in particular the eastern part of the county, are shrinked relatively little via all transportation networks. The Road network affects significantly on the accessibilities of cities in Gangwon-do and Gyeonggi-do, while railway network affects on the accessibilities of cities in Jeolla-do and Gyeongsang-do in general. When we compared the time-distance accessibilities based on the 5 largest cities, Seoul appears as the most accessible city from/to all other cities in Korea. We can also find significant changes in the time-distance accessibility between KTX network and existing railroad network. Cities along the KTX network, in particular cities which has KTX stops, improved significantly in time-distance accessibilities.

• Journal of the Korean Geotechnical Society
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• v.15 no.4
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• pp.175-184
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• 1999

Several major land reclamation projects such as the Inchon International Airport construction, Songdo New City construction, LNG Tank and LPG storage construction are underway along the coastal line of Inchon in Korea. This study was carried out to investigate the feasible use of waste lime in the land reclamation projects. Waste lime (hydrated lime) used in this study is produced as a by-product in the manufacturing process of $Na_2CO_3$ from local chemical factory in Inchon. This study presents the characteristics of bearing capacity and settlement on the ground formed by layers of waste lime and dredged soil. From the laboratory and in-situ plate load test, the ultimate bearing capacity by in-situ test was 1.25~1.37 times higher than that of the theoretical ultimate bearing capacity. Based on the settlement analysis by Magset- II, the total settlement of layered ground steadly increased up to the ratio of waste lime depth 0.2 and therefore rapidly increased with the increase of waste lime depth. The results of the present study indicate that the ratio of waste lime depth for reclamation work is about 0.2.

• Journal of Life Science
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• v.23 no.9
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• pp.1088-1095
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• 2013

The swimming crab, Portunus trituberculatus, inhabits seafloor habitats containing sand or pebbles and is widely distributed throughout the world. The present study investigated genetic polymorphisms of 10 microsatellites in 281 samples of P. trituberculatus collected from four locations along the coastal water of the Korean side of the Yellow Sea (Yeonggwang, Taean, Sorea, and Yeonpyeong-do Island). The number of alleles per locus ranged from 50 to 129, with a mean of 69.5. The observed and expected hetrozygosity varied from 0.111 to 1.000 and from 0.609 to 0.979, respectively. The inbreeding coefficients (Fis) varied among the loci from -0.0207 to 0.8175. The genetic differentiation (Fst) was less than 0.05 (range 0.0020-0.0124). Therefore, the four groups of P. trituberculatus appeared to exhibit little genetic differentiation. The lack of differentiation was confirmed in a phylogenetic tree constructed by the unweighted pair group method with the arithmetic average (UPGMA). The hypervariation between the populations and the lack of genetic differentiation may reflect active gene flow among the Yellow Sea populations and the absence of geographical boundaries. The highly polymorphic microsatellite loci will be useful for molecular and phylogenetic studies, as well as stock management, of swimming crab, which is an important fishery resource.

• Journal of Digital Convergence
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• v.11 no.12
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• pp.615-620
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• 2013

This research is a data analysis result of a future gout treatment was carried out in order to take advantage of basic data by Planned Population Federation of Korea in 2012, classified by gender. Using SPSS 18.0 analysis, frequency analysis, chi-squared analysis and logistic regression analysis were conducted. As a result, there were exceptional number of male subjects that required hyperuricemia thorough complete examination, and in case of hypouricemia, it is notable to find much more female subjects (p<0.001). Subjects that required thorough complete examination per age group and hypouricemia were significantly higher in those above the age of 70 years(p<0.001). Conclusions that required hyperuricemia thorough complete examination were a bit higher in the city areas and hypouricemia was a bit higher in the county areas, hyperuricemia was a bit higher in ratio in inland areas and hypouricemia was a bit higher in ratio in the coastal areas. I believe that continuous observation of gout prevalence rate based on this research by year, age group, and gender, would be extremely useful in making decisions regarding the changing trend of gout prevalence rate. In addition, hyperuricemia increased in postmenopausal women, as well as research on the causes of hypouricemia study.

• Korean Journal of Environmental Biology
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• v.33 no.2
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• pp.240-247
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• 2015

This study was carried out to provide the preliminary data for study of zooplankton community structures and coastal pelagic ecosystem by understanding the seasonal change of zooplankton community depending on environmental factors at Dangdong bay in Tongyeong city. In this study, the environmental factors and the change of zooplankton community were analyzed for 2008 to 2011. In the results, a total of 80 species of zooplankton was sampled with a mean density of $1,599inds.m^{-3}$. The dominant species changed seasonally, and the most dominant species was Acartia steueri in winter and spring, Penilia avirostris in summer, and Evadne nordmanni in autumn. The Canonical Correspondence Analysis was conducted between the major dominant species and environmental factors. And for the environmental factors that effect the zooplankton community, the high correlation was observed with the water temperature, COD, DO and T-N, though there was slight difference among species. Therefore, more various research and environmental study are necessary to understand of planktonic ecosystem because the zooplankton community is affected by the interaction of both physical and biological factors.

• Journal of fish pathology
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• v.23 no.1
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• pp.123-129
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• 2010

The infestation status of anisakid type larvae was investigated in migrating chum salmon (Oncorhynchus keta), with different condition (captured area, sex, body portion) during 2006~2008. The mean infection number of anisakid larvae per individual female and male fish captured from Namdae river was $98{\pm}27$, $103{\pm}27$, respectively. The mean infection number of anisakid larvae per individual female and male fish captured from the coastal area of Yangyang was $63{\pm}18$ and $108{\pm}17$, respectively. The anisakid larvae were mainly found in abdominal muscles (85%) but only a little in the visceral portion. Two types of anisakid larvae (A. simplex, Contracaecum type) were identified but other anisakid larvae were not detected. To investigate the effect of storing temperature on the viability of anisakid larvae, the section of abdominal muscle were stored at different temperature (room temperature, $4^{\circ}C$, $-20^{\circ}C$, $-80^{\circ}C$). As a result, it was necessary to store at $-20^{\circ}C$ for more than 6 hrs to kill the larvae. The present results revealed that chum salmon caught in Korea are heavily infected with anisakid larvae, mainly in the abdominal muscle, and A. simplex was dominantly found in this study.

• Journal of Wetlands Research
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• v.13 no.3
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• pp.377-384
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• 2011

The objective of this research is to observe and to analyze how the precipitation change can affect urban area and coastal area to groundwater recharge. The variation in the precipitation data of the regional groundwater basin, which includes Busan Metropolitan City Suyeong Gu area, was to estimate the change in the groundwater recharge and to analyze the characteristic changes. Research result reflects that as the precipitation varied, there was some difference in the groundwater recharge. However, differences in the precipitation ratio and the groundwater recharge ratio were consistent. Variation in the precipitation had less impact on the groundwater recharge ratio, and the groundwater recharge ratio decreased as timeline increased. When the precipitation increased by 10 %, groundwater recharge changed by 2.23 %. Accordingly, when it decreased by 10 %, groundwater recharge changed by 2.20 %. When it increased by 20 %, groundwater recharge changed by 4.39 %, and when it decreased by 20 %, groundwater recharge changed by 4.36 %. Despite the dramatic changes in the precipitation, the changes in the groundwater recharge were minimal. From the research, we can observe that the precipitation change had a significant impact on the ratio, but it doesn't really affect the groundwater recharge. Therefore, in urban area, the changes in groundwater recharge don't conform to the changes in the precipitation, and the effect of direct runoff can increase the possible occurrence of urban flooding.