• 한국해양학회지
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• v.30 no.4
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• pp.237-249
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• 1995

To understand the cross-sectional structures of temperature, salinity and current across the Korea Strait, field measurements were carried out for the period of May 2 to 20, 1994. Using the R/V Tam Yang, detailed CTD profiles and ADCP records were obtained and used to examine the mean and variability field on two time scales (15 days and 25 hours). A sharp coastal front in the middle of the Korea Strait exists across which two different water masses, i.e., warm and saline water in the eastern side and cold and less saline water in the western side are neighboring. We observed highly variable field of T and S apparently caused by the westward movement of warm and saline water mass. Short-term fluctuations of T and S in the middle layer are remarkable and their importance was analysed as the first Eigen mode accounting for more than 50% of total variances. The currents in th Korea Strait are strongly influenced by tidal currents with spring and neap variation whose maximum speed ranges 80-90 and 60-70 cm/s respectively near the central portion of the channel. Strong southward tidal current could even mask the Tsushima Current completely. Results of harmonic analysis show that the magnitudes of semidiurnal, diurnal and mean components of currents are comparable to each other at spring and neap tide conditions. The volume transport across the western channel of the Korea Strait were estimated to be 2.1 Sv at neap tide condition and 3.4 Sv at spring tide condition.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.16 no.3
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• pp.291-297
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• 1983

This paper describes the variations of the distribution of dissolved oxygen in the Japan Sea in summer during 1974-1977. In the Tsushima Current region of the Japan Sea the salinity maxima appears frequently in summer and the dissolved oxygen at the salinity maximum is less than that in the Japan Sea Proper Water. The Japan Sea is divided into three parts with respect to the type of vertical profiles of dissolved oxygen: The southern region of about $35^{\circ}N$ which has low dissolved oxygen similar to those in the Kuroshio region, the Japan Sea Proper Water region, and the area between about $36^{\circ}N$ and $40^{\circ}N$ which has high dissolved oxygen. The ranges of the dissolved oxygen and thermosteric anomaly(${\delta}_T$) at the salinity maximum are roughly between 4.9 and 6.5 m/l and between 210 and 240 cl/t respectively. The most frequent ranges of those values are between 5.5 and 5.7 ml/l and between 230 and 240 cl/t. The northern boundary of the Tsushima Current can be known by the characteristics of the distribuion of dissolved oxygen.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.4
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• pp.431-437
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• 2002

In order to understand the spatiotemporal variation of water quality, an investigation on variation characteristics of water quality was conducted at 13 stations in Yongil bay from 1990 to 1998. The salinity in summer was relatively lower than that in other seasons and it have increased from inner bay to outside of the bay gradually. However, nitrate concentration in summer was relatively higher than that in other seasons, and it was the highest, up to $65.40\%$, among dissolved inorganic nitrogens, Nitrate concentration indicates the possibility of affecting by freshwater discharges to Yongil bay. Correlation analysis showed that salinity had a significantly good correlation with nitrate. This result suggested that inflow of river had an influence on increase of nitrate. The result of Principal Component Analysis (PCA) indicated that nitrate was major factor to influence the water quality in Yongil Bay.

• KSBB Journal
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• v.16 no.4
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• pp.344-350
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• 2001

The effect of salinity stress of Brassica olearacea and Capsicum annuum were studied at various levels of salinity conditions(Na-gluconate, K-gluconate, NaCl, KCl). The effects of salinity stress were measured by seedling growth rates and secondary metabolites contents of the stressed plants. Each seedling studied on the response of different salinity stress. Seedling growth of Capsicum annuum was inhibited up to 200 mM salt tolerance and Brassica olearacea was inhibited up to 400 mM salt tolerance. The produced anthocyanin was separated to high value from 200 mM NaCl in case of Brassica olearana and 50 mM K-gluconate in case of Capsicum annuum. The BADH activity was very high in Brassica olearacea seedlings treated with 200 mM NaCl and in Capsicum annuum seedlings treated with 100 mM K-gluconate. The BADH activities were increased during the early culture days, it induced betaine synthesis. The salinity stress promoted BADH activiy, subsequently endogenous betaine contents were increased, and it seemed to be secure seedling from salinity stress. The salinity concentration of 200 mM was effective on the inhibition of seed germination and on the increase of proline accumulation in tissue. The inhibition of seedling growth and accumulation of secondary metabolites in seedling were caused osmotic hypersensitivity against salinity stress.

• Journal of Aquaculture
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• v.21 no.1
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• pp.41-46
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• 2008

The purpose of the study was to suggest the optimal lipid enrichment conditions used digestive enzyme activity of rotifer changing due to water temperature and salinity. The high population growth appeared at the experiment temperature more than 28 degrees highly on the culture temperature(maximum 32 degrees, 1,453 individual/mL). The fecundity was low at high temperature, and the egg ratio was high at low temperature. Population growth of 10 and 15 ppt appeared in most highly, but the fecundity and the egg ratio were high most significantly appeared in natural seawater(32 psu). The digestive enzyme activity by the culture environment mainly showed high activity in natural seawater(amylase exclusion, 15 psu). However, the TAP activity by the water temperature showed highly at the more high temperature, but the amylase and the lipase appeared at low temperature. We carried out the lipid enrichment at 20 degrees and 26 degrees in a condition of the natural seawater. Total protein, the total essential amino acids differed not significantly. The methionine content that was essential amino acids, a total lipid content, unsaturated index of fatty acids, DHA and the DHA/EPA ratio were high significantly each in $20^{\circ}C$ enrichment trial. Therefore, we could suggest the $20^{\circ}C$ and natural seawater for the optimal lipid enrichment condition in aquaculture, because methionine contents, several indexes by the lipid, TG-lipase activity, fecundity and egg ratio are high.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.177-177
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• 2020

새만금 간척지는 1989년 '새만금간척사업'이 발표된 이래 1991년에 방조제 공사를 시작으로 2006년 물막기 공사를 완료하였고, 2009년 이후 방조제를 완공하여 현재는 40,100ha의 간척지가 조성되었다. 하지만 간척지는 장기적으로 환경에 악영향을 미치며 특히 간척으로 인한 해안경관의 가치 상실, 생태계 파괴 및 교란에 따른 변화가 크기 때문에 이에 대한 대책이 필요하다. 적극적인 식생의 도입이 그 대책의 하나가 될 수 있는데 이는 자연적으로 식물천이를 유도하고 동물들을 유인하여 생태적으로 건강한 환경을 조성하는데 기여할 수 있다. 따라서 본 연구에서는 새만금간척지의 대표적인 수목생육 제한 요인으로 판단되는 염분, 배수 및 통기성에 대한 시험연구를 진행하고자 '09~'11까지 초기에 김제광활에서 2ha의 시험포를 운영하였고, '12부터는 군산옥구에서 2ha의 시험포를 운영하고 있다. 수목을 심을 포지를 구획하기 전에 토양의 염분값을 낮추기 위해서 군산옥구의 경우, 2ha의 시험포를 포함한 전체 묘목장 부지(100ha) 중에서 일부구간(38ha)을 '09 부터 자연강우 담수제염을 통해서 제염을 진행하였다. 이를 통해 초기 염분 값이 18ds/m~20ds/m에서 8ds/m~10ds/m로 낮아졌다. 이렇게 수목이 자랄 수 있는 정도의 제염이 이루어진 이후에는 배수 및 통기성 부분에 초점을 맞추어 포지를 구획하였다. 단지1의 경우, 사전제염작업을 하지 않고, 5M간격의 암거를 설치하였고, 단지2의 경우, 사전강우제염을 진행하고, 10M간격의 암거를 설치하였다. 단지3의 경우, 사전강우제염을 진행하고 그 위에 0.4M의 준설토를 성토하여 포지를 조성하고 일부구간에 5M, 10M암거를 설치하였다. 2년 간의 수목 생존률 및 생장 모니터링을 통해서 각 단지에서의 수목생장의 적합성의 정도를 간접적으로 판단할 수 있었다. 단지3이 암거설치 간격 및 설치유무에 관계없이 수목이 자라는데 가장 적합했다. 다음으로 단지2, 단지1 순으로 나타났다. 염분 값을 낮추기 위한 자연강우 담수제염의 경우에는 문제가 되지 않지만 배수 및 통기성 개선을 위한 암거설치의 경우는 새만금 전체 식재구역에 적용하기에는 경제성이 떨어지므로 배수 및 통기성을 위한 별도의 방안이 요구된다. 또한 각 단지에서의 수목 생장모니터링을 지속적으로 시행하여 보다 장기적인 측면에서의 식재기반 조성기법을 고려할 필요가 있다.

• Korean Journal of Environmental Biology
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• v.30 no.3
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• pp.272-279
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• 2012

This was the second study on the ecological characteristics of the epiphytes on seagrass leaf. The objective of this study was to understand the variation of epiphytes on seagrass leaf depending on the change of physico-chemical factors such as salinity, nutrients, and etc. This study showed the four results. 1) The eelgrass growth was influenced by water temperature, suggesting the positive correlation between eelgrass growth and water temperature. 2) The epiphytes growth on seagrass leaves did not show the correlation with water temperature, but negatively correlated with salinity. 3) The eelgrass growth decreased when the concentraion of nitrogen increased. 4) However, loads of epiphytes increased when the concentration of total nitogen (TN), nitrate ($NO_3^-$), and nitrite ($NO_2^-$) were high. This increase of epiphytes growth could be suggested in the cause-effect pathway of nutrient enrichment leading to seagrasses loss.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.05a
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• pp.59-64
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• 2005

Although experimental analysis for groundwater sample at wells located systematically are very effective to delineate seawater intrusion region at coastal area, this method is restricted in few wells and time. We have conducted electrical resistivity sounding at 30 points in the study areas to analyze the region of seawater intrusion and found the boundary between salt wedge and fresh water lens from the analysis results of geostatistical method using variogram for one-dimensional inversion results. The methodology adopted in this study would be useful for finding the seawater intrusion region and evaluating quantitatively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.4
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• pp.481-486
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• 1995

The salt stress at seedling stage of winter barley was examined in different concentrations of NaCl containing 1/2 Hoagland solution. Fresh weight of seedling at 30 days after seeding was highest at 25mM of NaCl concentration containing 1/2 Hoagland solution but if the NaCl concentration was more than 50mM it began to decrease seriously. Water content in plant was decreased according to increase of NaCl concentration in 1/2 Hoagland solution, so physiological mechanism of NaCl in barley was different from saline plant. Stoma number per cm$^2$ of first leaf was higher than that of control in case of stressed by NaCl but in that case the leaf length was decreased so the number of stoma per first leaf was slightly decreased. Chloroplast shape was not changed by 75mM of high NaCl contained 1/2 Hoagland solution but cell division at root growing point was inhibited by 75mM of NaCl. As the result of salt stress mitochondria was ruined in structure and irregular solid was found to be transfered from the cytoplasm to the cell wall in root growing point.

• Journal of the Korean Geosynthetics Society
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• v.15 no.4
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• pp.97-104
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• 2016

This paper performed consolidation tests on soft ground with and without artesian pressure conditions to find out characteristics of leaching effects using two types of one-dimensional column equipment(height : 1,100mm, outer diameter : 250mm). Artesian pressure of 5.5kPa was applied to the bottom of soft ground inside column equipment. Distribution of salinity and shear strength with soil depth were measured after the consolidation test. From the results, it was found that distribution of undrained shear strength and salt concentrations were similar at the top of clay ground irrespective of artesian pressure condition. However, at the bottom of clay ground, the values of undrained shear strength and salt concentration under artesian pressure were lower than those without artesian pressure. This result indicates that structure of soft soil with artesian pressure was weakened by salt leaching. Electronic resistance results showed that void ratio under artesian pressure condition was more reduced than that without artesian pressure condition.