• Journal of the korean society of oceanography
• /
• v.31 no.1
• /
• pp.1-6
• /
• 1996

Salinity ecotypes in Ulva pertusa Kjellman were examined for the growth responses of the three isolates taken from different salinity regimes. All isolates showed a broad salinity tolerance, but growth patterns were correlated with the salinity regime of their original habitat. The germlings from Anin exhibited optimum growth at the native salinity of 32%. The germlings from Yongyon which had hypersaline habitats were tolerable to high salinity, i.e. growth rates peaked at 40%, whereas those from Samgando which had low salinities achieved maximum growth rate at 24\%. The germlings of inter-isolate cross demonstrated intermediate growth response between that of their respective parents. Our data also clearly indicated intraspecific differences among the three isolates, which was interpreted as development of different physiological ecotypes. We conclude that U. pertusa may consist of several ecotypes, each of which has some capacity for physiological adaptation to salinity variations.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.12 no.4
• /
• pp.235-247
• /
• 2009

In order to elucidate the cause of Cochlodinium polykrikoides blooms in the Korea southern coastal water, we investigated observational data of water temperatures and salinities in summer and winter, obtained from the stoppage of ship by NFRDI (National Fisheries Research and Development Institute) as well as composite images by NOAA from 1995 to 2008. Cochlodinium polykrikoides blooms occurred when water temperature was approximately $25.0{\sim}26.0^{\circ}C$ and salinity was 31.00 psu on average in Narodo neighboring seas. Different thermohaline fronts were observed between the Korea southern coastal water and the open sea water in summer and winter, respectively. That is, in winter four fronts were observed between the Korea southern coastal water with low temperature and low salinity, intermediate water originated from Tsushima Warm Current, Tsushima Warm Current with high temperature and high salinity, and the China coastal water with low temperature and low salinity. In contrast, in summer two fronts were observed between the Korea southern coastal water with low temperature and high salinity, Tsushima Warm Current with high temperature and low salinity, and the China coastal water with high temperature and high salinity. These thermohaline fronts also proved to be formed by two water masses with a different physical property, in terms of T-S diagrams. Consequently, we noticed that C. polykrikoides blooms occurring in Narodo neighboring seas in summer had a close relationship with thermohaline fronts observed between the Korea southern coastal water and Tsushima Warm Current.

• Journal of fish pathology
• /
• v.33 no.2
• /
• pp.145-151
• /
• 2020

The whiteleg shrimp Litopenaeus vannamei can survive in a wide range of salinity (1-40 psu). However, such variation, particularly at low salinity (1-5 psu), can affect various physiological changes such as survival rates, non-specific immunity and disease resistance. In this study, growth, non-specific immunity and disease resistance were measured following simultaneous oral feeding and addition of probiotic microbes into culture water for 73 day period. The salinity of the culture water was maintained at 3 psu by periodical salt additions. The result shows that survival rate increased significantly (5.6 vs. 15.4%) after 73 day rearing. Significant increases were identified in reactive oxygen species (ROS) production and phenol oxidase (PO) activity. However, superoxide dismutase (SOD) activity was not influenced. When the shrimp was artificially challenged with Vibrio alginolyticus, slight mortality reduction was observed in the probiotics-treated group (100 vs. 79%). In conclusion, the production of cultured whiteleg shrimp at low salinity might be increased by probiotics survivable at low salinity levels.

• Journal of Marine Life Science
• /
• v.7 no.2
• /
• pp.213-220
• /
• 2022

This study was conducted to investigate the effect of environmental factors such as water temperature and rearing density on the survival and growth of Litopenaeus vannamei under low salinity conditions. Overall, in the higher water temperature, the higher survival rate comes out and in the lower rearing density, the higher the survival rate does. In a study on feed efficiency, weight gain (WG) increased significantly as water temperature increased, and weight gain according to rearing density significantly decreased as rearing density increased. The growth rate of L. vannamei was faster when the water temperature was higher (water temperature 31℃) under low salinity conditions. In addition, in the evaluation of the growth rate according to the rearing density, it was confirmed that the growth rate was accelerated at a low rearinging density. It is believed that the results of this study will be usefully applied to the determination of the optimal rearinging density and breeding water temperature of L. vannamei in low salinity condition.

• Journal of Marine Life Science
• /
• v.2 no.2
• /
• pp.70-74
• /
• 2017

Interleukin-1 (IL-1) is one of the proinflammatory cytokines, after IL-1 binds to IL-1RI, IL-1RacP (interleukin-1 receptor accessory protein) joins with IL-1/IL-1RI to form a complex, and leading to cell activation. IL-1RAcP is involved in immune response, stress and apoptosis. The purpose of this study was to investigate the gene expression of IL-1RAcP in red seabream (Pagrus major) exposure to low water temperature (8℃, 33 psu) and low salinity (20℃, 10 psu). Results showed that, the expression of IL-1RAcP was significantly increased in the experiment groups, such as low water temperature (8℃, 33 psu), and low salinity (20℃, 10 psu). These results suggest that IL-1RAcP was played roles in biomarker gene on the environmental stress such as low water temperature and low salinity.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.65 no.1
• /
• pp.73-81
• /
• 2023

To understand salinity status of fresh water and paddy soils and the susceptibility of rice to salinity stress of Gunnae reclaimed tidelands, salinity monitoring was conducted in rainy and dry seasons. For fresh water, a high salinity was observed at the sampling location near the sluice gate and decreased with distance from the gate. This spatial pattern of fresh water salinity indicates the necessity of spatial distribution of salinity in the assessment of salinity status of fresh water. Interestingly, there was significant correlation between rainfall amount and salinity, implying that salinity of fresh water varies with rainfall and thus it may be possible to predict salinity of water using rainfall. Soil salinity also higher near the gate, reflecting the influence of high saline water. In addition, the groundwater salinity also high to threat rice growth. Though soil salinity status indicated low possibility of sodium injury, there was changes in soil salinity status during the course of rice growth, suggesting that more intensive monitoring of soil salinity may be necessary for soil salinity assessment. Our study suggests the necessity of intensive salinity monitoring to understand the spatio-temporal variations of salinity of water and soil of reclaimed tideland areas.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.16 no.2
• /
• pp.138-142
• /
• 2013

As an early warning system to reduce the damage of aquacultured mollusks due to low salinity water, we investigated the possibility of a biomonitoring system measuring the shell valve movement (SVM) of Pacific oyster (Crassostrea gigas) by using the Hall element sensor. In high salinity water of 27 psu, SVMs of Pacific oyster showed spikes which mean a relatively fast closing condition after opened condition of average 10-15 mm, and then the SVM showed back to opening condition slower than closing speed. In water salinity of 20-27 psu, the SVMs were similar to that of 27 psu. However, below 17 psu, it showed abnormal valve movements such as spending more time for shell closure. In 10 psu, we could not detected SVMs due to closed condition during experiment periods. Thus, if we quickly detect abnormal environmental variations like low salinity using bio-monitoring of SVM, it may be contribute to increased productivity by dramatically reducing damages in aquaculture.

• Korean Journal of Community Nutrition
• /
• v.25 no.1
• /
• pp.13-20
• /
• 2020

Objectives: This study examined the salinity of soups provided at childcare centers by measuring the salinity for three years and providing basic data for sodium reduction. Methods: The soup salinity was measured using a Bluetooth salinity meter from January 2015 to December 2017 at 80 childcare foodservice establishments enrolled in the Suseong Center for Children's Foodservice Management in Daegu. Results: An analysis of the soup salinity each year showed that the salinity decreased significantly from 0.48% in 2015 to 0.41% in 2017, particularly in clear soups and soybean soups compared to other soups (P < 0.05). The salinity and sodium content in seafood soups (0.45% and 179.1 mg/100 g, respectively) were highest, followed by soybean soups (0.44%, 175.2 mg/100 g), with perilla seed soups containing the lowest (0.42%, 167.2 mg/100 g) (P < 0.05). The salinity was significantly higher in institutional foodservice establishments than small foodservice establishments (P < 0.001). The salinity and sodium content were the highest in foodservice establishments with a small number of measurements, and the salinity was the lowest in foodservice establishments with salinity measurements performed an average of 151 times each year (three times a week) or more (P < 0.05). The soup salinity was low in the order of winter, spring, summer, and autumn, and the salinity decreased significantly year by year in all seasons. (P < 0.05). Conclusions: The soup salinity was significantly lower in foodservice establishments where the salinity was measured more than three times a week, indicating that continuous salinity management is effective.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.43 no.4
• /
• pp.234-238
• /
• 1998

To select new germplasm for salinity tolerance from new plant type (NPT) breeding lines, the sixty F$_4$ lines selected from the crosses between Korean cultivars and IRRI's NPT lines were evaluated for salinity tolerance at the seedling stage with salinized culture solution (EC=12 dS/m) in the controlled conditions. Two NTP lines derived from a cross between 'Ilmibyeo' and 'IR66152-AC5-1', 'HR15258-7-1' and 'HR15258-27-1', were found to have good tolerance. The salinity tolerance of the lines was compared to their parents and the sensitive ('IR29') and tolerant ('Pokkali') checks in three salinity levels, no salinity (control) and an EC of 12 and 16 dS/m. Visual salinity score, shoot Na+ and Na-K ratio in two NPT lines was significantly low compared with the parents and IR29. Indicating that salinity tolerance of the lines might be derived from a transgressive segregation. The relative water content of the lines was higher than Pokkali, and the dry weight of shoot and root was proportionally decreased to salinity score and salinizing concentration. The visual salinity scores were significantly correlated with shoot Na concentration, Na-K ratio, relative water content, and reduction of dry weight (P<0.01). Their tolerance was attributed to root and shoot characteristics that led to high shoot water content, thus diluting the toxic effect of salts.

• The Korean Journal of Community Living Science
• /
• v.23 no.1
• /
• pp.79-88
• /
• 2012

To evaluate the possibility of low-salinity of traditional fermented food, we investigated quality characteristic of low-salted Yacon Jangachi using soybean sauce with sugar or vinegar for 50 days. Sugar content, titration acidity, and salinity of all Yacon Jangachi was increased as storage time increased. All of the Yacon Jangachi had less than 3.0% salinity. Especially, the salinity of the Yacon Jangachi with sugar and vinegar was the lowest during storage time. The L value was decreased as storage time increased but the results of the a and b values were reversed. Cutting force was not significant among samples and storage periods. In the results of sensory evaluation, preference of all samples were increased as storage time increased. The preference of color was not significant among samples from 30 days but the taste was reversed. The preference of flavor was significant between samples in 40 days, texture was not significant during storage time. Overall preference was not significant after 30 days, which suggested that Yacon Jangachi using soybean sauce retains overall preference in steady level from 30 days. Yacon Jangachi using soybean sauce showed the highest preference when produced with sugar and vinegar.