• Title, Summary, Keyword: Seawater

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Genetic Variation in Early Survival of Chum Salmon Families with Respect to Seawater Temperature

  • Choe Mi-Kyung;Yeo In-Kyu
    • Fisheries and aquatic sciences
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    • v.3 no.2
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    • pp.88-96
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    • 2000
  • The present study estimated the variation of early survival of chum salmon families with respect to temperature and size after transfer to seawater. Heritability for seawater tolerance of half-sib families was also estimated at 45 days after hatching. Gametes were collected from 6 male and 18 female chum salmon to make 18 paternal half-sib families. Seawater tests were carried out at 3, 7 and $12^{\circ}C$ of $32\%$ seawater and compared with freshwater. Survival was significantly affected by seawater temperature. The highest seawater tolerance was obtained in 45-day old chum salmon at $7^{\circ}C$ seawater and the lowest seawater tolerance was obtained at $3^{\circ}C$. Overall survivals in seawater tolerance at $32\%$ varied among families. There were significant variance in fry survival among females (P=0.0001), and among males (P=0.0001). The heritabilities of survival in seawater in chum salmon were estimated to be 0.32-0.34 for the sire components at 45 days after hatching in 1998.

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Quality of Tofu Prepared with Deep Seawater as Coagulant (해양심층수로 제조된 두부의 품질특성)

  • Kim, Gwang-Woo;Kim, Ga-Hyeon;Kim, Jeong-Sik;An, Hyo-Yeong;Hu, Gil-Won;Son, Jin-Ki;Kim, Ok-Seon;Cho, Soon-Yeong
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.41 no.2
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    • pp.77-83
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    • 2008
  • This study investigated the quality of tofu prepared by treating soybean milk with deep seawater as a coagulant. The quality and shelf-life of the tofu prepared using the deep seawater coagulant were determined and compared to those using $CaSO_4$, surface seawater, and intermediate seawater coagulant. The tofu made with the deep seawater coagulant was firmest. In addition, the deep seawater tofu product had more, smaller particles in the microscopic view, compared to the tofu made from surface and intermediate seawater coagulants. The deep seawater tofu product had the lowest viable cell counts and turbidity. In addition, the deep seawater tofu product had a longer extended shelf-life. From these results, deep seawater appears to improve the texture, taste, and shelf-life of tofu when used as a coagulant.

Effects of Permeability Change of Soil-Bentonite Mixture due to Seawater on Seawater Intrusion (해수로 인한 흙-벤토나이트 혼합물의 투수계수 변화가 해수유입에 미치는 영향)

  • Ahn, Tae-Bong
    • Journal of the Korean GEO-environmental Society
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    • v.2 no.1
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    • pp.81-89
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    • 2001
  • Soil-bentonite mixture is often used for barrier wall to prevent seawater intrusion. In this study, the effect of seawater on the permeability of soil-bentonite mixture is examined, and the effect of permeability change on the seawater intrusion is investigated. Seawater intrusion in coastal areas was modeled using a finite element method. Seawater intrusion in the seawater-contaminated zone was determined by considering the hydraulic conductivity changes using the residual flow procedure (RFP) in the simulation model. Steady state and unsteady state conditions with variations in ground water levels in an inland area were investigated. The interface between fresh water and seawater, found by the proposed method, was located lower at the seawater side and the level at the fresh water side is higher than those by conventional methods.

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Effects of Deep Seawater on the Growth of a Green Alga, Ulva sp.(Ulvophyceae, Chlorophyta)

  • Matsuyama, Kazuyo;Serisawa, Yukihiko;Nakashima, Toshimitsu
    • ALGAE
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    • v.18 no.2
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    • pp.129-134
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    • 2003
  • In order to examine the effects of deep seawater (mesopelagic water in the broad sense) on the growth of macroalgae, the growth and nutrient uptake (nitrate and phosphate) of Ulva sp. (Ulvophyceae, Chlorophyta) were investigated by cultivation in deep seawater (taken from 687 m depth at Yaizu, central Japan, in August 2001), surface seawater (taken from 24 m depth), and a combination of the two. Culture experiments were carried out in a continuous water supply system and an intermittent water supply system, in which aerated 500-mL flasks with 4 discs of Ulva sp. (cut sections of ca. 2 $cm_2$) were cultured at 20$^{\circ}C$ water temperature, 100 $\mu$mol photons $m^{-2}{\cdot}s^{-1}$ light intensity, and a 14:10 light:dark cycle. Nutrient uptake by Ulva sp. was high in all seawater media in both culture systems. The frond area, dry weight, chlorophyll a content, dry weight per unit area, and chlorophyll a content per unit area of Ulva sp. at the end of the experimental period were the highest in deep seawater and the lowest in surface seawater in both culture systems. These values, except for dry weight per unit area and chlorophyll a content per unit area, for each seawater media in the intermittent water supply system were higher than those in the continuous water supply system. We conclude that not only deep seawater as the culture medium but also the seawater supply system is important for effective cultivation of macroalgae.

The Research on Activation Plan for Seawater Desalination Plant Application in Korea (국내 해수담수화 플랜트 적용 활성화 방안 연구)

  • Sohn, Jinsik;Yang, Jeong-Seok;Park, Jinseo
    • Journal of Korean Society of Water and Wastewater
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    • v.23 no.2
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    • pp.251-255
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    • 2009
  • Foreign and domestic seawater desalination plant market investigation was performed to analyze the worldwide trend of seawater desalination plant market and to establish the activation plan for seawater desalination plant application. Water demand and seawater desalination related laws and regulations were investigated and analyzed for the activation plan. RO type and large scale plants are popular nowadays however there are only small plants in island region in Korea. There will be about $1 million\;m^3/day$ deficit in 2015 according to the water demand forecasting from Ministry of Environment and Ministry of Land, Transportation, and Maritime Affairs in Korea. Therefore, it is necessary to activate the domestic application of seawater desalination plant to secure stable water resources. To activate the domestic application of seawater desalination plant, first, we need to establish regulations, support system in the water service law for seawater desalination plant. Second, related Ministry should increase the support for the operation and management of seawater desalination plant and suggest the construction of seawater desalination plant for water resources security near seaside region.

Efficiency Tests of Seawater Exchange System for Enhancement of Seawater Quality (해수교환시스템의 수질향상 효율평가)

  • Jang, Chang-Hwan;Kim, Sang-Taek;Kim, Hyo-Seob;Kim, Kyu-Han;Song, Man-Soon
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.13 no.3
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    • pp.206-215
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    • 2010
  • The multi-outlets were installed on the existing seawater exchange breakwater in order to improve seawater exchange rate at Jumunjin harbor. Physical and numerical model system were fulfilled for 4 cases to evaluate seawater exchange system which is able to discharge water remotely. The seawater circulation pattern and seawater exchange rate in the harbor were compared and analyzed. Consequently, total seawater exchange rate for CASE 1 was calculated 48% due to the dead zones which hinder seawater circulation in the harbor. Otherwise, the seawater exchange rates of CASE 2, CASE 3, and CASE 4 with the installation of the system were enhanced 19%, 15% and 17%, respectively compare to CASE 1.

Effects of Deep Seawater and Salt on the Quality Characteristics of Breads (해양 심층수 및 염을 이용한 식빵의 품질 특성)

  • 김미림;정지숙;이명희;이기동
    • Korean Journal of Food Preservation
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    • v.10 no.3
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    • pp.326-332
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    • 2003
  • Deep seawater is pumped up about 200 m water depth, which has characteristics of rich nutrients, low temperature and cleanness. This study was performed to investigate the effect of deep seawater and deep seawater salt on the yeast growth of fermented bread. The rate of increase in volume of groups added with deep seawater and deep seawater salt was higher than that of groups added with distilled water. The pore pattern of groups added with deep seawater was more regular than that of groups added with distilled water. In sensory property, the bread added with distilled water and deep seawater salt has the highest score (6.56) in overall acceptability.

Assessment on the Seawater Attack Resistance of Antiwashout Underwater Concrete (수중불분리성 콘크리트의 해수침식에 대한저항성 평가)

  • 문한영;김성수;안태송;이승태;김종필
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.683-688
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    • 2001
  • In case of constructing the concrete structures under seawater environment, the concrete suffers from deterioration due to penetration of various ions such as chloride, sulfate and magnesium in seawater. Tn the present study, Immersion tests with artificial seawater were carried out to investigate the resistance to seawater attack of antiwashout underwater concrete. From the results of compressive strength, it was found that blended cement concrete due to mineral admixtures such as fly ash(FA) and ground granulated blast-furnace slag(SGC), were superior to ordinary portland cement concrete with respect to the resistance to seawater attack. Moreover, XRD analysis indicated that the formed reactants of ordinary portland cement paste by sulfate and magnesium ions led to the deterioration of concrete. As expected, however, the blended cements with FA or SGC have a good resistance to seawater attack. This paper would discuss the mechanism of seawater deterioration and benefical effects of antiwashout underwater concretes with mineral admixtures.

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Evaluation of Oil Pollutants Removal in Seawater as Pretreatment Process for Reverse Osmosis Desalination Process (역삼투식 해수담수화의 전처리공정으로서 유분 제거의 평가)

  • ;Okada Mitsumasa
    • Proceedings of KOSOMES biannual meeting
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    • pp.205-209
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    • 2003
  • The various pretreatment processes were evaluated for removal of oil pollutants with weathered oil contaminated seawater in a reverse osmosis desalination process. Weathered oil contaminated seawater was made by biodegradation and photooxidation with oil containing seawater. Coagulation, ultrafiltration, advanced oxidation processes and granular activated carbon filtration was used with pretreatment for dissolved organic carbon. Crude oil was removed but. weathered oil contaminated seawater was not removed by biodegradation and coagulation. DOC and E260 was removed with about 20 % and 40 % by membrane filter of cut off molecular weight 500. So, the most of dissolved organic carbon in weathered oil contaminated seawater was revealed that molecular weight was lower than 500. It is difficult to remove DOC in weathered oil contaminated seawater by advanced oxidation processes treatment, but, E260 was removed more high. However, DOC in weathered oil contaminated seawater was easily adsorbed to GAC. It is revealed that DOC was removed by adsorption.

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Characteristics of Foam Generation in Freshwater and Seawater (담수와 해수에서의 포말 생성 특성)

  • SHIN Jeong-Sik;KIM Byong-Jin;SUH Kuen-Hack
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.37 no.3
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    • pp.179-185
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    • 2004
  • The characteristics of foam generation were assessed for freshwater and seawater using a foam generator. Both in freshwater and seawater, the height of the foam layer increased with initial protein concentrations. The height of the foam layer also increased with pore size of the air distributor. The optimum superficial air velocities (SAV) in freshwater and seawater were 0.84 cm/sec and 0.6 cm/sec, respectively. The height of the foam layer was the highest in pH 3 in freshwater and in the region of pH 5-7 in seawater. The height of the foam layer increased with $NaHCO_3$ concentration in freshwater, and $NaHCO_3$ concentration had little effect in seawater. Removal efficiencies of total suspended solid (TSS) and turbidity decreased with an increase of initial protein concentrations in a batch foam separator both in freshwater and seawater.