• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
• /
• 제4권1호
• /
• pp.59-69
• /
• 2000

The present study was undertaken in investigate the response to salinity and effect of plant growth regulators and proline under salinity stress on the germination and seedling growth of Vigna angularis. The protective effect of external Ca2+ on root elongation under saline conditions was also investigated. The seed germination of Vigna angularis decreased with an increase in salinity. The growth regulators GA3 was more effective than kinetin. At a higher salinity, low concentrations of kinetin and high concentrations of GA3 were more effective. The external application of proline and betaine improved germination under saline conditions. At a low salinity proline and betaine alleviated the salinity-induced inhibition of germination, yet at higher NaCl concentrations, proline and betaine were both ineffective. Exposure to salinity during germination was accompanied by an increase in the proline content, thereby suggesting that one compatible solute in the germinating seed would seem to be proline. The inhibition of germination by high NaCl concentrations was relatively more severe in scarified seeds than in intact seeds, indicating that the seed coat acts as a partial barrier to an Na2+ ameliorated the adverse effect of salinity stress.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2001년도 하계학술대회 논문집
• /
• 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.

• 한국물환경학회지
• /
• 제18권3호
• /
• pp.237-243
• /
• 2002

The effect of a salinity on the performance of a biological nutrient removal system was investigated using a model SBR(Sequencing Bach Reactor) system. The system was operated at a 12hr, 18hr, 24hr, and 36hr HRT with a salinity level of 20,000mg/L and compared with a system similarly operated with fresh water. The influent salinity level of 8,000 mg/L does not have a significant effect on BOD removal efficiency, there is a noticeable decrease in BOD removal rate from 10,000 mg Cl-/L. The Nitrogen could be removed from the saline wastewater with the same efficiency as for the fresh water because of low C/N ratio in anoxic period. The excess biological phosphorous removal is highly affected by the increase in the influent salinity. The efficiency is decreased from 96.6% to 43.4% when the influent salinity is increased from 0 to 20,000mg/L.

• 한국토양비료학회지
• /
• 제51권1호
• /
• pp.50-60
• /
• 2018

This study was to evaluate the effect of organic amendments incorporation on soil properties and plant growth under two different soil salinity levels and various cultivated crops at Saemangeum reclaimed tidal land for three years from 2012 to 2014. The soil texture of the experimental site was sandy loam. Four different crops, sesbania (Sesbania grandiflora), sorghum-sudangrass hybrid (Sorghum bicolor-Sorghum sudanense), rice (Oryza sativa L.) and barley (Hordeum vulgare) were cultivated at low (< $1dS\;m^{-1}$) and high (> $4dS\;m^{-1}$) soil salinity levels. The soil salinity was significantly lowered at the rice cultivation site compared to continuous upland crops cultivation site in high soil salinity level. But the soil salinity was increased as cultivating sesbania coutinuously in low soil salinity level. The soil organic matter content was increased with the incorporation of straw at the continuous site of rice and barley, and the average of soil organic matter was increased by $0.9g\;kg^{-1}$ per year which was effective in soil aggregate formation. The highest biomass yield plot was found in barley (high salinity level) and sesbania (low salinity level) cultivation site, respectively. Our research indicates that rice cultivation in paddy field with high salinity level was effective in lowering soil salinity and sesbania cultivation was useful to biomass production at upland with low salinity. In conclusion, soil salinity and organic matter content should be considered for multiple land use in newly reclaimed tidal land.

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

• 한국수산과학회지
• /
• 제53권4호
• /
• 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.

• 미생물학회지
• /
• 제29권5호
• /
• pp.339-343
• /
• 1991

Heterotrophic activity, total bacteria and salinity were determined seasonally in the estuary of Naktong River over half tidal cycle. Heterotrophic activity was determined by the uptake of [U- $^{14}$ C]glucose. Heterotrophic activity fluctuated with the tides and was decreased as salinity increased. Teh great activity occurred near low ebb tide at all seasons except summer. The main environmental factor affecting hetreotrophic activity was the salinity rather than water temperature in the estuary of Naktong River. In order to estimate the effect of salt, salt was added to estuarine water. Vmax for glucose of salt-added water was 17% and 77% of original estuarine water at station 1 and 2 respectively and slight increase was observed at station 3. Respiration rate and Kt+Sn for glucose of salt-added sample increased at all 3 stations. The increase of the Kt value implies the reduced affinity of bacterial population for glucose. The effects of salinity on the heterotrophic activity were more extensive in the upper region of estuary than at the mouth.

• 한국작물학회:학술대회논문집
• /
• 한국작물학회 2017년도 9th Asian Crop Science Association conference
• /
• pp.364-364
• /
• 2017

Saemangeum reclaimed land is a part of Saemangeum Development Project. Most of the persistent problems of Saemangeum reclaimed land remain to be related to soil salinity. Soil salinity is a major abiotic factor related to microbial community structure and also fungi have been reported to be more sensitive to salinity stress than bacteria. The aim of this study was conducted to investigate the effect of soil salinity levels on the microbial communities in Saemangeum reclaimed land using 454 pyrosequencing analysis. Soil samples was collected from 12 sites of in Saemangeum reclaimed land. For pyrosequencing, 27F/518R (bacteria) and ITS3/ITS4 (fungi) primers were used containing the Roche 454 pyrosequencing adaptor-key-linker (underlined) and unique barcodes (X). Pyrosequencing was performed by Chun's Lab (Seoul, Korea) using the standard shotgun sequencing reagents and a 454 GS FLX Titanium sequencing System (Roche, Inc.). In the soil samples, Proteobacteria (bacteria) and Ascomycota (fungi) shows the highest relative abundance in all the soil sample sites. Proteobacteria, Bacteroidetes, Plantomycetes, Gemmatimonadetes and Parcubacteria were shown to have significantly higher abundance in high salinity level soils than low salinity level soils, while Acidobacteria and Nitrospirae has significantly higher relative abundance in low salinity level soils. The abundance of fungal, Ascomycota has the highest relative abundance in soil samples, followed by Basidiomycota, Chlorophyta, Zygomycota and Chytridiomycota. Basidiomycota, Zygomycota, Glomeromycota and Cerozoa were show significantly higher relative abundance in low salinity level soils. The principal coordinate analysis (PCoA) and correlation analysis shown to salinity-related soil parameters such as ECe, Na+, SAR and EPS were affected to bacterial and fungal community structure. Proteobacteria, Bacteroidetes, Plantomycetes exhibited significantly positive correlation with soil salinity, while Acidobacteria exhibited significantly negative correlation. In the case of fungal community, Basidiomycota and Zygomycota were seen show significantly negative correlation with salinity related soil parameters. These results suggest that provide understanding effect of soil salinity on microbial community structure and correlation of microbial community with soil parameters in Saemangeum reclaimed land.

• 한국지구과학회지
• /
• 제26권7호
• /
• pp.714-724
• /
• 2005

The East Sea, a semi-enclosed marginal sea with shallow straits in the northwest Pacific, is marked by the nearly geographic isolation and the low sea surface salinity during the last glacial maximum (LGM). The East Sea might have the only connection to the open ocean through the Korea Strait with a sill depth of 130 m, allowing the paleo-Tsushima Water to enter the sea during the LGM. The low paleosalinity associated with abnormally light $\delta^{18}O$ values of planktonic foraminifera is interpreted to have resulted from river discharge and precipitation. Nevertheless, two LGM features in the East Sea are disputable. This study attempts to estimate volume transport of the paleo-Tsushima Water via the Korea Strait and further examines its effect on the low sea surface salinity (SSS) during the lowest sea level of the LGM. The East Sea was not completely isolated, but partially linked to the northern East China Sea through the Korea Strait during the LGM. The volume transport of the paleo-Tsushima Water during the LGM is calculated approximately$(0.5\~2.1)\times10^{12}m^3/yr$ on the basis of the selected seismic reflection profiles along with bathymetry and current data. The annual influx of the paleo-Tsushima Water is low, compared to the 100 m-thick surface water volume $(about\;79.75\times10^{12}m^3)$ in the East Sea. The paleo-Tsushima Water influx might have changed the surface water properties within a geologically short time, potentially decreasing sea surface salinity. However, the effect of volume transport on the low sea surface salinity essentially depends on freshwater amounts within the paleo-Tsushima Water and excessive evaporation during the glacial lowstands of sea level. Even though the paleo-Tsushima Water is assumed to have been entirely freshwater at that time period, it would annually reduce only about 1‰ of salinity in the surface water of the East Sea. Thus, the paleo-Tsushima Water influx itself might not be large enough to significantly reduce the paleosalinity of about 100 m-thick surface layer during the LGM. This further suggests contribution of additional river discharges from nearby fluvial systems (e.g. the Amur River) to freshen the surface water.

• 한국작물학회지
• /
• 제49권3호
• /
• pp.194-198
• /
• 2004

본 연구는 남서해안 간척지에서 토양 염농도(저염; 0.1%, 중염; 0.3∼0.4%)별로 쌀 품질 향상을 위한 적정 질소 시비량을 구명하기 위하여 시험한 결과를 요약하면 다음과 같다. 1.유추분화기의 초장은 질소 시비량이 많을수록 컸고, 토양염농도간에는 저염 토양에서 켰다. 2. 출수기는 저염 토양에서는 표준비인 N20kg/10a에 비해 N8-N16kg/10a까지는 같았으나 N24kg/10a에서는 1일 늦었고, 중염 토양에서는 N8-N16kg/10a 까지는 1일이 삘랐고 N24kg/10a에서는 같았으며, 토양 염농도간에는 저염 토양에서보다 중염 토양에서 4일 정도 늦었다. 3. 질소시비량이 많을수록 간장이 크고, 포장도복이 심했다. 4. 저염 토양에서 질소시비량이 많을수록 $\textrm{m}^2$ 당 립수는 많았으나 등숙비율이 낮아져 발 수량은 N12kg/10a이상에서는 유의차가 없었으며, N12kg/10a이하에서 현미의 완전미율이 높고 단백질 함량이 낮았다. 5.중염 토양에서는 질소시비량이 많을수록 $\textrm{m}^2$ 당 립수가 많고 등숙비율이 비슷하여 발 수량은 질소시비량이 많을수록 높았으나 N20kg/10a 이상에서는 유의차가 없었고, 현미의 완전미율과 단백질함량은 질소시비량간에 비슷하였다. 따라서 남서해안 간척지에서 쌀 수량 및 미질 등을 고려해 볼 때, 저염 토양에서는 N12kg/10a, 중염 토양에서는 N20kg/10a이 적당할 것으로 생각된다