• Korean Journal of Ichthyology
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• v.27 no.1
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• pp.21-25
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• 2015

We studied the effects of temperature and salinity on the egg development and larvae of sevenband grouper Epinephelus septemfasciatus under sea cage culturing condition. In regard to rearing environment, the water temperature is $21.5{\sim}23.5^{\circ}C$ (mean $22.0{\pm}0.05^{\circ}C$) and the salinity is 32.0~33.0 psu (mean $32.5{\pm}0.05psu$). The time of egg development was positively proportional to water temperature with 29 hrs, 27 hrs, 24 hrs, 17 hrs, 15 hrs after fertilization in $15^{\circ}C$, $20^{\circ}C$, $25^{\circ}C$, $30^{\circ}C$, $35^{\circ}C$ respectively. Each of the salinity hatching rate was 80% in the section of 15 psu, 81.8% in the section of 25 psu, 89.1% in the section of 30 psu, and 79.1% in the section of 35 psu. All things considered, the highest hatching rate appeared in the range of the section of 25~30 psu. Abnormalities of low salinity section, such as 15 psu (20.0%) and 20 psu (18.2%), was lower than the abnormalities of 35 psu that belongs to high salt section. The relation between the time of egg development (t:hour) and water temperature ($T:^{\circ}C$) was represented by the mathematical formulae. The mean biological minimum temperature was $5.4^{\circ}C$.

• Korean Journal of Microbiology
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• v.20 no.4
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• pp.195-200
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• 1982

Rhizobium japonicum was isolated from the nodule of soybean root grown at the reclaimed tidal land in Kang-Wha island. The effect of pH and salt concentration to the viability of the isolated strain were examined in relationship between microbial growth and accumulation of PHB. Optimal pH value for the good viability of the isolated strain was 7.0 and also, at 5.0 and 6.0 viability was favorable to large extent, but 9.0 was unfavorable. Examined the effect of salt concentration treated two times as of the salinity in the reclaimed tidal land, viability of the isolated strain showed about 30 to 40%. And also in treatment with NaCl(40g/l) whatever the pH value adopted, viability was mostly less than 10%. The amount of accumulated PHB was relatively high at low pH value(5-6) and at high salt concentrration, respectively.

• Journal of Ecology and Environment
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• v.38 no.4
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• pp.443-450
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• 2015

The east coast of the Korean Peninsula is susceptible to fires because of the low rainfall in winter and spring, and large forest fires have occurred in this area. Lack of fresh water to combat fires has hampered efforts to prevent widespread forest fires in this region. Seawater has not been used as a suppressant because of possible detrimental effects of salt. We investigated the mobility of saline water in the forest soil and their effect on the microbial activity. Using a fire-fighting helicopter, seawater was sprayed over three plots (50 × 100 m) located on the eastern slope of the Baekdu mountain range in South Korea in April, 2011. We sampled the soil in April 4, May 20, and August 5 to determine the amount of salt that remained in the soil. The electrical conductivity value of the soil decreased to <400 μS/cm over a 1-month period. Approximately, four months after the application of seawater, the electrical conductivity value and Na⁺ content in all treatment plots did not significantly differ to those of the control plot, and total microbial activity also recovered to that of the control. Our results indicate that the amount of rainfall, soil physical-chemical properties, and topological factors may be a critical factor determining the mobility of saline water in forest soil.

• Ocean and Polar Research
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• v.32 no.3
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• pp.321-329
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• 2010

Photosynthetic pigments, nutrients, and hydrographic variables were examined in order to elucidate the spatio-temporal variation of water column structure and its effect on phytoplankton community structure in the western channel of the Korea Strait in fall 2006 and spring 2007. High phytoplankton biomass in the spring was associated with high salinity, implying that nutrients were not supplied by coastal waters or the Yangtze-River Diluted water (YRDW) with low salinity. Expansion of the Korea Strait Bottom Cold Water (KSBCW) and a cold eddy observed during the spring season might enhance the nutrient supply from the subsurface layer to the euphotic zone. Chemotaxonomic examination showed that diatoms accounted for 60-70% of total biomass, followed by dinoflagellates. Nutrient supply by physical phenomena such as the expansion of the KSBCW and the occurrence of a cold eddy appears to be the controlling factors of phytoplankton community composition in the Korea Strait. Further study is needed to elucidate the mechanisms by which the KSBCW is expanded, and its role in phytoplankton dynamics.

• Korean Journal of Food Science and Technology
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• v.44 no.5
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• pp.545-552
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• 2012

To improve a low-salted yacon pickle, the change of quality characteristics during the storage of yacon pickles were investigated at $18^{\circ}C$ for 50 days using two-way ANOVA. One factor that was added was the leaf-mustard and pepper (A), the other was storage time (B). The leaf-mustard and pepper were added to increase the yacon pickle's taste, flavor, and properties. The sugar content, total acidity and salinity were significant for factor A and B. With the interaction effect of the two factors, yacon pickles increased as storage time increased. The L value was not significant for factor A but significant for factor B. The a and b values were significant for the two factors. All Hunter's color value had the interaction effect. The shearing force was not significant for each factor, and yacon pickles did not show a softening effect. In the results of the sensory evaluation, color, taste, and overall preference were significant for factor A and B, yet the flavor was only significant for factor B. The texture was not significant at all. In the overall preference, yacon pickles were higher at 30 and 40 days and also, had the interaction effect. Yacon pickles were not above the 3.0% of salinity.

• International Journal of Industrial Entomology and Biomaterials
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• v.33 no.2
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• pp.102-107
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• 2016

Stress may be defined as any modification of environmental parameters that leads to a response by biological organisms. Stresses that affect biolpgical structures may be nonthermal, such as ultraviolet radiation, pH, or salinity, or thermal. Temperture is one of the major stresses that all living organism face. The major effects of cold(low emperature) are decrease of membrane fluidity and the stabilization of secondary structures of RNA and DNA in the cells, which may effect the efficiency of translation, transcription, and DNA replication. In this study, we focus on discovering the genes that are expressed by the cold(low temperature) stress in the silkworm. In cold(low temperature) stress test, we found 100% survive from cold stress at $0^{\circ}C$ up to 12h and $-5^{\circ}C$ up to 2h, and then, survive rate was rapidly decrease in silkworm. Thereafter two whole genes have selected by SSH(Suppression subtractive hybridization). (GenBank accession : GQ149511, GQ338156)

• The Korean Journal of Malacology
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• v.28 no.1
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• pp.21-28
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• 2012

The combined effects of water temperature and salinity on the settlement rate and density (spats/$cm^2$) of Crassostrea gigas pediveliger larvae were studied under the hatchery conditions. Four water temperatures (20.0, 23.0, 26.0 and $29.0^{\circ}C$) were tested at three salinities (20.0, 30.0 and 40.0). The optimum water temperature by salinity conditions were $29.0^{\circ}C$ and 20.0, 30.0 which significantly (P < 0.05) the highest mean (${\pm}S.D$) larval settlement rate of $43.1{\pm}0.1%$, $42.1{\pm}0.1%$, respectively. But the combination of water temperatures and salinities for settlement density was not effected, but each factor as water temperature ($29.0^{\circ}C$), salinity (40.0) was shown significantly high and low settlement density, respectively (P < 0.05). The statistics result of settlement density frequency was appeared: mode ($1.2-2.3spats/cm^2$), Mean ($1.9-2.4spats/cm^2$), Range ($3.0-5.8spats/cm^2$) and the lowest variance was obtained 0.4 at water temperature $20.0^{\circ}C$ by salinity 30.0, but $29.0^{\circ}C$ by 20.0 was the highest (1.1). The best condition at this results for the larvae setting under the artificial seed collection of C. gigas was $29.0^{\circ}C$ and 20.0-30.0.

• The Korean Journal of Malacology
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• v.15 no.2
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• pp.71-79
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• 1999

To develop new products for aquaculture, which fishermen at South Sea can get high income, after bay scallop was transplanted from Sandong province in China from October 17, 1996 to March 18, 1997 at Duekrang Bay in Janghung gun and Kamak Bay in Y대녀 City on Chollanam province, Sumjin river estuary in Hadong gun and Gejae Bay in Keoje city on Kyongsangnam proince. Temperature was decreased from 20.5$^{\circ}C$ to 5.1$^{\circ}C$ in February and then it was increased to 12.0 in March. Ranges of salinity, DO and Chlorophyll-a were 22.40-34.70 psu, 5.24-9.77 mg/l and 1.27-22.28 $\mu\textrm{g}$/l, respectively, and low temperature, sudden changes of salinity and low concentration of chlorophyll-a influenced the growth of bay scallop. bay scallop in the rearing period showed the fastest growth from October 17 to November 18 through the every size rages, while it grew slowly or stopped growing from December 18 to March 18. Among 4 transplanted areas, young scallop at Duekrang Bay showed the fastest growth and then Kamak Bay, Gejae Bay, Sumjin estuary in order. The daily growth rate of young scallop in the middle size range (5.70%) was higher than those in large (2.07%) and small (5.49%) size range. The meat weight index showed the highest in December. Survival rates from October to December were high, not related to the size ranges, but survival rate of the small young scallop from January to March was higher than Those of the rest. As the Result, transplanted bay scallop at South Sea was shown to grow by the middle of December (around 1$0^{\circ}C$ temperature).

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.6
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• pp.415-422
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• 2009

Effect of soil salinity variation on the growth of barley, rye and oat was studied at the Hwaong, Iweon and Yeongsangang reclaimed lands in the western seaside of Korea. Soil salinity variation and soil EC were very high for crops to be killed or to be brought serious growth retardation during the growing season at the Iweon and Hwaong reclaimed lands, but fully low not to bring growth retardation at the Yeongsangang reclaimed land. Relation between soil salinity and crop growth and yield was well expressed as logarithmic function. Surface soil EC to reach at 50% of seed-emergence reduction was estimated $6.5dS\;m^{-1}$ for barley and $5.1dS\;m^{-1}$ for rye and oat by logarithmic function. In addition, surface soil EC to reach at 50% of grain yield reduction to the best growth in the experimental site was estimated $5.6dS\;m^{-1}$ for barley, $5.8dS\;m^{-1}$ for rye and $5.7dS\;m^{-1}$ for oat, while soil EC to reach at 50% of dry matter reduction was estimated $5.5dS\;m^{-1}$ for barley, $6.2dS\;m^{-1}$ for rye and $5.8dS\;m^{-1}$ for oat by logarithmic function. Grain yield of barley, rye and oat was 395, 164 and $325kg\;10a^{-1}$ in the Yeongsangang reclaimed lands naturally controlled below condition of $6dS\;m^{-1}$ of soil EC, but no harvest was obtained in the Hwaong and Iweon reclaimed land because of high salinity more than $15dS\;m^{-1}$ in maximum soil EC during growing period. Consequentially, it was concluded that soil salinity must be controlled below $6dS\;m^{-1}$ for good growth and high yield of winter barley, rye and oat in the reclaimed land in Korea.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.3
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• pp.199-204
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• 2014

We conducted a short-term incubation experiment in order to understand the effect of the salinity of reclaimed coastal soils on nitrogen mineralization of livestock manure compost (LMC). Two soils with the same soil texture but different EC levels were collected from the same field. These samples were treated with 0%, 1%, 2%, and 3% of LMC by weight basis and incubated at $25^{\circ}C$ to observe changes in inorganic N contents, pH, and dehydrogenase activity with respect to time. As a result, regardless of the soil EC level, as the LMC increased, the total content of the inorganic N ($NH_4{^+}+NO_3{^-}$) increased. Difference in the soil EC level did not affect N mineralization of LMC greatly. The soil EC had negligible effect on the dehydrgenase activity as with the case of inorganic nitrogen. The $NH_4{^+}$ contents remained very low throughout the experimental period starting from the first week of incubation. We believe this is due to the high pH level (pH 7.9 and pH 8.3) of the original soils leading to ammonia volatilization. On the other hand the $NO_3{^-}$ content maintained high level as the LMC treatment level increased and reached maximum at the third week. The pH of the soil during incubation period decreased as the $NO_3{^-}$ contents increased and increased slightly after three weeks. The rise of pH level is believed to be from the $NO_3{^-}$ absorption for immobilization by microbes. In conclusion, the high soil $EC_{1:5}$ level of $12dS\;m^{-1}$ conducted in this experiment did not affect the growth in terms of soil microbes involved in N mineralization of LMC.