• Fisheries and Aquatic Sciences
• /
• v.12 no.3
• /
• pp.209-218
• /
• 2009

We examined physiological and histological responses related to the survival, oxygen consumption, excretion, and O/N ratio of the ark shell, Scapharca subcrenata, as a result of salinity changes. The 20-day $LS_{50}$ (median lethal salinity) at $15^{\circ}C$ was 13.87 practical salinity units (psu; confidence limits 10.30-18.74 psu), whereas the 14-day $LS_{50}$ at $25^{\circ}C$ was 12.59 psu (confidence limits 8.03-18.16 psu). In conditions of decreasing salinity, the osmolarity of individuals acclimated within 5 h above 26.4 psu but required more than 60 h below 13.2 psu. Oxygen consumption and ammonia excretion rates varied irregularly as salinity decreased. The O/N ratio was 19 and 27 at water temperatures of $15^{\circ}C$ and $25^{\circ}C$, respectively, but decreased to 1-10 as salinity declined. The effects of decreasing salinity were observed in the histological changes to each organ of S. subcrenata. As salinity decreased, cilia fell off, the epithelial layer underwent necrosis and vacuolation, the connective tissue layers of the mantle and visceral mass were destroyed, and hemocytes increased in the gills. The results of this study could prove important in investigating causes of mass mortality and managing shellfish aquaculture farms.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.50 no.2
• /
• pp.207-218
• /
• 2017

Seawater with salinity of 32.5 psu or less is observed in the southern Japan/East Sea (JES) every autumn. It is confined to a surface layer 30-45 m in depth that expands to cover the entire JES in October. Two sources of "autumn low-salinity water" have been identified from historical hydrographic data in the western JES: East China Sea (ECS) water mixed with fresh water discharge from the Yangtze River (Changjiang) and seawater diluted with melted sea ice in the northern JES. Low-salinity water inflow from the ECS begins in June and reaches its peak in September. Low-salinity water from the northern JES expands southward along the coast, and its horizontal distribution varies among years. A rare observational study of the entire JES in October 1969 indicated that water with salinity less than 33.0 psu covered the southwestern JES; the lowest salinity water was found near the Ulleung Basin. In October 1995, the vertical distribution of salinity observed in a meridional section revealed that water with salinity of 33.6 psu or less was present in the area north of the subpolar front.

• Journal of the Korean Society of Food Culture
• /
• v.34 no.6
• /
• pp.761-770
• /
• 2019

Two experiments were conducted to determine how much sodium in food could be detected using a salinity meter. First, the salinity of mixed solutions of 0 to 6% sugar, 0 to 5% oil, and 0 to 6.4% MSG in a 1% NaCl solution was measured using a salinity meter and a Mohr titration method, and the results were compared with the calculated sodium expectations. As a result, the sodium contents of the sugar solutions and MSG solutions measured using a salinity meter were lower than the expected concentrations at 2% or more and 0.8% or more, respectively (p<0.05). The salinity of the 18 HMR products was measured in the same way, and the results were then compared with the sodium contents of the nutrition facts. The average sodium content of all products measured using the salinity meter and Mohr method was 1.12 times and 1.06 times the sodium content of the nutrition facts, respectively. On the other hand, the differences between the products were significant. The correlation coefficients between the nutrition facts and salinity meter, the nutrition facts and the Mohr method, and the salinity meter and Mohr method were 0.885, 0.920, and 0.950, respectively (p<0.01).

• Journal of Ocean Engineering and Technology
• /
• v.32 no.5
• /
• pp.361-366
• /
• 2018

The present study analyzed the variation factors in inducing a salinity change using the existing observation network in the section between the Nakdong River Estuary Barrage and Changnyeong-Haman Weir, and also examined the seasonal changes in precipitation, salinity, and discharge. Furthermore, this study analyzed the causes of a salinity increase by collecting observational data during a period when abnormal salinity occurred, and further investigated the salinity transfer time in a section of approximately 5.3 km from the Nakdong River Estuary Barrage to Nakdong River Bridge to understand the behavioral characteristics of the salinity moving upstream. The study results would make it possible to control the increase in salinity and block salt water from moving upstream by understanding the salinity variation characteristics according to the discharge amount. This will provide stability in collecting water from various residential, agricultural, and industrial sources through water intake facilities scattered near the Nakdong River Estuary Barrage.

• The Korean Journal of Ecology
• /
• v.20 no.5
• /
• pp.367-373
• /
• 1997

The effects of salinity on the growth and production of rice were studied at Seosan reclaimed land from July to October, 1995. The plant height, the number of living aleaves, dead leaves and total leaves, the number of the grains and the dry weight of the grains per individual, and the dry weight of above the ground in $25cm{\times}25cm$ quadrat were investigated on 5 plots whers were different salinity. The plant height, the number of living leaves and total leaves and the number of grains and the dry weight of grains per individual, and the dry weight of above the ground decreased as the salinity of water increase and the number of dead leaves of rice increased as the salinity of water decrease. The effect of salinity on the reproductive production is severer than the vegetative production. Because of the salinity, the growth and the production of the rice at Seosan reclaimed land are worse than the normal rice field.

• Journal of fish pathology
• /
• v.15 no.3
• /
• pp.111-115
• /
• 2002

The scuticocilliate, Uronema marinum is a histophagous ciliate and the causative agent of 'scuticociliatosis'in cultured olive flounder Paralichthys olivaceus. In the present study, in vitro efficacy of hydrogen peroxide, formalin and copper sulfate on the scuticocilliate at low salinity was investigated. Each chemical showed synergistic parasiticidal effects with low salinity (salinity in 5 ppt) compared to each chemical alone (salinity in 33 ppt). At low salinity (5‰), ciliates were killed completely within 1.5h by exposure to 50ppm formalin (37% formaldehyde), at 100ppm hydrogen peroxide (30% solution) and at 100ppm copper sulfate (20% solution). The formalin was the most effective chemical against the parasites at low salinity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.07a
• /
• pp.74-77
• /
• 2001

In order to investigate the effect of salinity level on tracking characteristics of polymer insulators for distribution power systems, tracking tests were performed by tracking wheel tester under different salt concentration. In this study, 6 kinds of polymer insulators were tested under 2200 ${\mu}\textrm{s}$/cm and 4000${\mu}\textrm{s}$/cm salinity. The salinity level has a significant effect on the tracking characteristics. Namely, most polymer insulators showed the good tracking resistance in case of low salinity level. But, in case of high salinity level some polymer insulators showed the excessive erosion and tracking. These phenomena may come from the different aging mechanism. It can be concluded that too high salinity level is not desirable in aging test of polymer insulators.

• 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.

• Plant Resources
• /
• v.7 no.3
• /
• pp.226-232
• /
• 2004

This study was carried out to investigate seed germination and seedling of cabbage and sugar beet in four treatments of salinity including 0 (control), 0.5, 1.0 and 1.5％ NaCl. The results showed that different treatments of salinity had considerable effects on the germination and root and shoot length of cabbage and sugar beet. Percent of germination in both species showed significant decrease with increasing salinity up to 1.5％ NaCl. This decrease was more evident in cabbage when compared to sugar beet. The required time for germination increased with high levels of salinity. The seedling growth of both species were inhibited by all salinity levels. Particularly at 1.0 and 1.5％ NaCl, no measurable length was observed in cabbage and sugar beet. At 0.5％ NaCl root growth of both plant species was more affected as compared to shoot growth by salinity.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.53 no.4
• /
• pp.499-505
• /
• 2020

We investigated growth, survival and stress response depending on salinity changes in hybrid grouper (Epinephelus fuscoguttatus ♀×E. polyphekadion ♂, BCG) juvenile. Experiment I (Exp I), the hybrids were stocked at 32 psu and reared for 30 days under decreasing salinity at a rate of 5-7 psu per day (25, 20, 15, 10, 5 psu). Experiment II (Exp II), the salinity was decreased from 32 psu to 5 psu during a period of 24, 48 and 72 h. Experiment III (Exp III), acclimatized BCGs were exposed from 5 psu to decreasing salinity at 0, 1, 2, 3, 4 psu. In the Exp I, 90% survival only in the 5 psu. Growth were 5 and 32 psu had significantly low growth than other treatment. In the Exp II 100% survived by the end of the experiment. The plasma cortisol level was highest in the treatment the salinity rapidly dropped, but all the treatment recovered quickly after 24 h of salinity reduction. In the Exp III, the lower the salinity, the faster the mortality occurred in salinity below 5 psu. It is therefore concluded that the BCGs are highly tolerant of low salinity and the salinity tolerance threshold is 5 psu.