• 한국토양비료학회지
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• 제47권5호
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• pp.313-318
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• 2014

The remote monitoring system of water salinity was assessed in Wando reclaimed land lake during a farming season in 2009. Increasing of water salinity in this lake used to bring about salt damage on rice plant occasionally. At the early stage of the rice growing period, rice growth was not damaged due to enough rainfall with more than 120 mm from the mid-May to the first ten days of June. Data collection using on-site water salinity measuring sensors every 2 hours and real-time transmission in system were carried out for the experiment. We compared the transmitted values from the sensor system with water sample values collected and analyzed by a local technical office. Salt concentrations measured by sensor in real-time monitoring system were available data. The regression equation between rainfall and water salinity was presented as (water salinity after rainfall) = $0.621{\times}$(water salinity before rainfall)${\times}exp(-0.0139{\times}rainfall)$, ($r^2=0.579$, p<0.01). It is suggested that the system is useful for stable farming in the area where farmer use water in reclaimed lakes as an irrigation source.

• Ocean and Polar Research
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• 제33권spc3호
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• pp.371-383
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• 2011

To investigate the physical characteristics and variations of oceanic parameters in the tropical central North Pacific, oceanographic surveys were carried out in summer of 2006 and 2007. The survey periods were classified by Oceanic Ni$\tilde{n}$o Index as a weak El Ni$\tilde{n}$o in 2006 and a medium La Ni$\tilde{n}$a in 2007. The survey instruments were used to acquire data on CTD (Conductivity Temperature and Depth), XBT (Expendable Bathythermograph), and TSG (Thermosalinograph). The dominant temporal variation of surface temperature was diurnal. The diurnal variation in 2007, when the La Ni$\tilde{n}$a weather pattern was in place, was stronger than that in 2006. Surface salinity in 2006 was affected by a northwestward branch of North Equatorial Current, which implies that the El Ni$\tilde{n}$o affects surface properties in the North Equatorial Current region. Two salinity minimum layers existed at stations east of Chuuk in both year's observations. The climatological vertical salinity section along $180^{\circ}E$ shows that the two salinity minimum layers exist in $2^{\circ}N{\sim}12^{\circ}N$ region, consistent with our observations. Analysis of isopycnal lines over the salinity section implies that the upper salinity minimum layer is from intrusion of the upper part of North Pacific Intermediate Water into the lower part of South Pacific Subtropical Surface Water and the lower salinity minimum layer is from Antarctic Intermediate Water.

• 한국수산과학회지
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• 제37권2호
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• pp.116-121
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• 2004

Physiological responses and tolerance limit of hybrid striped bass $(Morone\;Chrysops\;male{\times}\;M.\;saxatilis\;female),$ were investigated on salinity changes from 33 psu to 0 psu and from 0 to psu 33 psu in two separate trials, respectively. In the acute salinity decrease from sea water (33 psu) to fresh water (0 psu), plasma level of cortisol, glucose, total protein, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were not affected, however, $Na^+,\;Cl^-$ and osmolality significantly decreased. In the acute salinity increase from fresh water to sea water (33 psu), plasma cortisol level did not change. Glucose and total protein concentrations in plasma and hematocrit (Hct) decreased, whereas AST, ALT, $Na^+,\;Cl^-$ and osmolality increased. The hybrid striped bass can overcome the acute changes of salinity, from 0 psu to 33 psu or from 33 psu to 0 psu, But salinity decrease stressed the fish much more than salinity increase.

• Ocean and Polar Research
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• 제37권1호
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• pp.37-47
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• 2015

The effects of low salinity (fertilization success and larval survival) on the limpet Cellana grata were studied at early stages of development using the marine bioassay technique. It was shown that, under normal conditions for development from fertilization to the post veliger stage, the salinity must be not less than 20.0~35.0 psu. However, the fertilization rate and larval survival of C. grata was obviously reduced at 5.0 psu and 10.0 psu, respectively. Mass mortality was estimated to occur at <20.0 psu (48-h $EC_{50}=19.54psu$) and the survival rate of normal veliger larvae decreased with experimental time during exposure. No observed effective concentration (NOEC) and lowest observed effect concentration (LOEC) of post veliger were estimated at 30.0 psu and 25.0 psu, respectively, during 48-h exposure. The tolerance limits of the test species to salinity revealed various concentration ranges of salinity, which may reflect the physiology and ecology of the initial development stages of C. grata. These results demonstrate that reduced salinity is detrimental to the reproductive success and larval survival of C. grata, and if salinity is lowered by natural or anthropogenic sources during spawning, this would lead to decreased reproductive success and larval settlement.

• 환경생물
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• 제22권1호
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• pp.153-158
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• 2004

염분에 대한 두줄망둑의 내성범위를 파악하기 위한 일환으로 이들의 생존, 성장 및 산소소비에 미치는 염분의 영향을 40일간 사육실험을 통하여 검토하였다. 두줄망둑의 생존율은 염분 10.1$\textperthousand$ 이상에서 90%이상을 나타냈으나, 염분 3.4$\textperthousand$ 이하에서는 유의한 감소를 나타냈고, 담수에서는 40일째 32.5%의 생존율을 보였다. 체장과 체중의 증가 및 성장률은 13.4∼33.6%o의 염분 범위에서 유사한 경향을 나타냈으나, 염분 6.7$\textperthousand$ 이하에서 유의한 감소가 관찰되었다. 산소소비는 염분 10.1%o 이하에서 유의한 감소가 관찰되었고, 염분 10.1, 6.7 및 3.4$\textperthousand$ 에서는 가장 높은 산소소비를 나타낸 27.4$\textperthousand$ (6.67 ml $O_2g^{-1}$ dry weight)의 염분에 비해 각각 28.4, 30.9 및 37.4%가 감소하였고, 담수에서는 52.3%의 감소를 나타냈다. 이러한 결과는 두줄망둑이 낮은 염분에 노출되었을 때, 그들의 생존, 성장 및 산소소비율이 저하한다는 사실을 지적하고 있으며, 하구 수역과 같은 저염분 수역은 두줄망둑의 분포 및 개체수에 잠재적으로 영향을 미칠 수 있다는 것을 암시한다.

• Journal of the korean society of oceanography
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• 제33권4호
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• pp.146-156
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• 1998

Hydrographic data retrieved in the southwestern part of the East Sea in 1992-1993 were analyzed to investigate the probability of southward intrusion of the East Sea Intermediate Water (ESIW) into the Ulleung Basin. The ESIW showed the ranges of 1 to 4$^{\circ}$C in potential temperature, 33.80-34.06 psu in salinity, and 26.9-27.3 kg/m$^3$ in potential density (${\sigma}$$_{\theta}$). The mean depth occupied by the ESIW was 170 m, where the characteristic values of the above three were 2.64$^{\circ}$C , 34.02 psu, and 27.13 kg/m$^3$, respectively. One of the most prominent features of the ESIW was that its salinity changed not only seasonally but also interannually. It was low in summer and high in winter. The salinity within the isopycnal layer of 26.9-27.3 kg/m$^3$ was closely related with the potential vorticity (${\rho}$$_{\theta}^{-1}$ f ${\varrho}$${\rho}_{\theta}$/${\varrho}$z), being in direct proportion to the salinity. This implies that the low-salinity water was thicker than the high-salinity water. The flow path of the ESIW was investigated by tracking the low-salinity or the low-potential vorticity water and by referring to acceleration potential. Careful analysis of the flow path proves that the ESIW intrudes from the north between the Korean coast and Ulleung Island into the Ulleung Basin in summer. Existence of the high-potential vorticity water in the Ulleung Basin is associated with the interruption of the inflow of low-salinity water.

• 한국수산과학회지
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• 제50권1호
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• pp.25-31
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• 2017

The optimum temperature and salinity for long-distance transportation of rockfish Sebastes schlegeli were investigated by assessing hematological characteristics and hemocyte mortality. The possible effects of the interaction of temperature and salinity on these attributes were also investigated. No significant difference was found in hematocrit and hemoglobin among experimental conditions. Glucose levels were highest in fish exposed to salinities of 34 psu ($4^{\circ}C$), 18 psu ($4-6^{\circ}C$) and 10 psu ($4-8^{\circ}C$). Cortisol levels were elevated in the lowest temperature group ($4^{\circ}C$), but upper limits decreased with decreasing salinity. AST and ALT increased as temperature decreased at salinities lower than 26 psu. The ratio of living cells was 99.0-99.6% in all experimental groups. The percentage of necrotic cells was highest in fish exposed to salinities of 34 psu ($4^{\circ}C$), 18 psu ($6-8^{\circ}C$), and 10 psu ($4-8^{\circ}C$). The percentage of necrotic cells decreased significantly as temperature and salinity decreased, indicating that both salinity and the interaction of salinity and temperature affected cell necrosis.

• 한국수산과학회지
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• 제49권5호
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• pp.612-619
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• 2016

In this study, we crossbred Epinephelus akaara and E. lanceolatus to produce a hybrid grouper with faster growth and adaptation to domestic aquaculture environments. The plasma cortisol and glucose levels and osmoregulation (stress response indicators) of the hybrid grouper, E. akaara ♀ × E. lanceolatus ♂, were investigated under several salinity levels (32, 24, 16, and 8 psu). The body lengths and weights of E. akaara (8.2 ± 0.1 cm, 8.3 ± 0.4 g) and the hybrid (8.6 ± 0.1 cm, 10.0 ± 0.4 g) were similar at the start of the experiment, but were significantly different at the end of the experiment. Juveniles of both E. akaara and the hybrid showed greater weight gain, specific growth, and feed conversion rate (FCR) under low salinity of 16 psu. Under the 8 psu treatment, the juvenile E. akaara all died, while the hybrid juveniles survived. Plasma cortisol levels were not affected by lower salinity in both species. The above results indicate that the hybrid is more tolerant of low salinity than is E. akaara, although both species exhibited higher growth and FCR at 16 psu, lower than the salinity of natural seawater. Thus, juveniles of both E. akaara and the hybrid can be more effectively cultured in brackish areas or waters with salinity lower than that of seawater.

• Asian-Australasian Journal of Animal Sciences
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• 제27권6호
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• pp.825-831
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• 2014

The aim of this study was to determine the nutritive value of some legume species in salt-affected soils of South-East Anatolian region using chemical composition and in vitro gas production kinetics. In this study, Lotus corniculatus, Trifolium alexandrinum, Medicago sativa were sown and tested in four different locations. A 3 by 4 factorial design with 3 legume species and 4 salt levels (non salty electrical conductivity (EC)<4 dS/m; low salt: 4 dS/m>EC<8 dS/m, medium saline: 8 dS/m>EC<16 dS/m and high salt: 16 dS/m>EC) was used in the study. Results indicated that salinity and plants had no significant effect on ash and ether extract. Dry matter (DM), acid detergent fiber, digestible dry matter, dry matter intake (DMI) were affected by plant, salinity and plant${\times}$salinity interaction. On the other hand neutral detergent fiber, relative feed value (RFV), and DMI were affected by salinity and plant${\times}$salinity interaction. Mineral contents were affected by plant species, salinity and salinity${\times}$plants interactions. In vitro gas production, their kinetics and estimated parameters such as were not affected by salinity whereas the gas production up to 48 h, organic matter digestibility, metabolizable energy (ME), and net energy lactation ($NE_L$) were affected by plant and plant${\times}$salt interaction. Generally RFVs of all species ranged from 120 to 210 and were quite satisfactory in salty conditions. Current results show that the feed value of Medicago sativa is higher compared to Lotus corniculatus and Trifolium alexandrinum.

• Asian Journal of Atmospheric Environment
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• 제9권2호
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• pp.173-186
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• 2015

In Bangladesh, increases in the tropospheric ozone ($O_3$) concentration and in soil salinization may lead to crop damage. To clarify the effects of $O_3$ and/or soil salinity on Bangladeshi wheat cultivars, BAW1059 (salt-tolerant) and Shatabdi (salt-sensitive) were exposed to 70-day treatments with $O_3$ (charcoal-filtered air (CF), $1.0{\times}O_3$, and $1.5{\times}O_3$) and different levels of soil salinity (0, 4, and $8dS\;m^{-1}$). In both cultivars, the whole-plant dry mass and grain yield were significantly reduced by exposure to $O_3$. Increased soil salinity caused significant reductions in whole-plant growth and yield in Shatabdi, but the reductions were negligible in BAW1059. No significant interactions between $O_3$ and salinity were detected for growth, yield, and leaf gas exchange parameters in both cultivars. We concluded that the effects of $O_3$ are not ameliorated by soil salinity in two Bangladeshi wheat cultivars, regardless of their salinity tolerance.