• Title/Summary/Keyword: West-coast

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충남 고정리의 하계 해조상 (Summer Algal Flora of Gojeong-Ri, West Coast of Korea)

  • 유순애
    • Journal of Plant Biology
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    • 제22권4호
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    • pp.135-140
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    • 1979
  • The marine benthic algae of Gojeong-Ri was investigated in a floristic aspect. As a result, 34 species, 7 blue-green, 14 red, 6 brown and 7 green algae were identified as a summer flora from the area. Among them, Sirocoleum kurzii (blue-green alga), Ralfsia clavata (brown alga), Pseudulvella consociata and Cladophora speciosa (green algae) were known as new records to Korea.

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이원면 굴, Crassostrea gigas 양식어장의 월별 식물플랑크톤 종조성 및 수질환경 변화 (Monthly Variation of Phytoplankton Composition and Water quality in Cupped Oyster Crassostrea gigas Culture Area in Iwon, Korea)

  • 김수경;김병호;오은경;송기철;박승윤;한기연;임현정
    • 한국패류학회지
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    • 제30권3호
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    • pp.249-258
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    • 2014
  • Phytoplankton species composition and ecological index (diversity, evenness, richness and dominance) were analysed from April 2013 to March 2014 at 10 stations of cupped oyster, Crassostrea gigas culture area in Iwon coast, Korea. Seasonal and positional variation of phytoplankton standing crops, biomass, dominant species and water quality were distinctively different according to occasionally inflow of Iwon dam reservoired water. The composition of phytoplankton species were Bacillariophyceae 98, Dinophycease 22, Chlorophycease 13, Cyanophyceae 8, Silicofalgellate 4, Euglenophyceae 2, Cryptophyceae 1 species. The most dominant species was Bacillariophyceae as 64.0%. The highest biomass of phytoplankton recorded in September as $40,910{\times}10^3$ cell/L at the station 1, near from inland water inflow area. Ecological indices (diversity, richness, evenness, and dominance index), used for structural change of phytoplankton community and water quality (temperature, dissolved oxygen, salinity) showed difference of spatiotemporal property also.

Swell description for Bonga offshore Nigeria location

  • Olugbenga, Akinsanya Akinyemi;Gudmestad, Ove Tobias;Agbakwuru, Jasper
    • Ocean Systems Engineering
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    • 제7권4호
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    • pp.345-369
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    • 2017
  • The ocean environment offshore West Africa is considered to be mild. However, the generated swell from distant North and South Atlantic during austral winter and summer can reach high wave amplitudes with relatively low wave periods or low wave amplitudes with long wave periods, the later can be a crucial scenario to consider when the assessment of vessel resonance is of importance. Most offshore operations, which include offshore drilling, and installation in West Africa, are carried out from floating systems. The response of these systems and performance are governed by characteristics, such as amplitude and frequency of the wave and swell seas. It is therefore important to fully understand the sea conditions offshore Nigeria. This study covers the description of the swell sea offshore Nigeria using Bonga offshore wave measurements collected from the directional wave-rider (DWR), positioned at the Bonga site off the coast of Nigeria.

Sediment Toxicity Assessment in the Intertidal Flat Zone of the Middle West Coast of Korea

  • Hwang, G.S.;Dave, G.;Nilsson, E.;Kim, K.
    • 한국환경보건학회지
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    • 제30권4호
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    • pp.347-351
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    • 2004
  • A battery of sediment bioassays was performed for the sediments from the intertidal flat zone along the middle west coast of Korea to assess their potential toxicity. In the bioassays, three crustaceans, Daphnia magna, Nitocra spines, and Hyalella aztec a were exposed to $16\%$ sediments (wet weight) collected from 14 sites. Immobility($\%$) was checked as an endpoint after 24- and 48-h exposure of Daphnia magna and after 96-h exposure of Hyalella azteca and Nitocra spines. Among the three bioassays, the 48-h Daphnia bioassay showed the most distinct differential sensitivity in relation to sediment contamination, while the Nitocra and the Hyalella bioassays failed to show the differential sensitivity properly among the sites classified as polluted. Significantly different levels of immobility ($\%$) were obtained between the sites classified as chemical/nutrient polluted and the sites classified as non-polluted in the Daphnia bioassays, but not in the Nitocra bioassay and the Hyalella bioassay. Some differences of toxic response to the same sediments among bioassays were observed, suggesting that there may be a chemical specificity of response sensitivity to sediment toxicity, due to differences in bio-availability of sediment toxicants among test species.

Strong wind climatic zones in South Africa

  • Kruger, A.C.;Goliger, A.M.;Retief, J.V.;Sekele, S.
    • Wind and Structures
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    • 제13권1호
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    • pp.37-55
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    • 2010
  • In this paper South Africa is divided into strong wind climate zones, which indicate the main sources of annual maximum wind gusts. By the analysis of wind gust data of 94 weather stations, which had continuous climate time series of 10 years or longer, six sources, or strong-wind producing mechanisms, could be identified and zoned accordingly. The two primary causes of strong wind gusts are thunderstorm activity and extratropical low pressure systems, which are associated with the passage of cold fronts over the southern African subcontinent. Over the eastern and central interior of South Africa annual maximum wind gusts are usually caused by thunderstorm gust fronts during summer, while in the western and southern interior extratropical cyclones play the most dominant role. Along the coast and adjacent interior annual extreme gusts are usually caused by extratropical cyclones. Four secondary sources of strong winds are the ridging of the quasi-stationary Atlantic and Indian Ocean high pressure systems over the subcontinent, surface troughs to the west in the interior with strong ridging from the east, convergence from the interior towards isolated low pressure systems or deep coastal low pressure systems, and deep surface troughs on the West Coast.

실트질 모래지반의 응력경로를 이용한 액상화 분석 (Analysis of Liquefaction using Stress Path in Silty Sand Grounds)

  • 이송;김태훈;이민호
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2000년도 봄 학술발표회 논문집
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    • pp.239-246
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    • 2000
  • It has been generally much fine contents in West Coast of Korea. When cyclic shear stress causing liquefaction was estimated as using cyclic triaxial tests in these grounds, it didn't appear linear relations between deviator stress and confining stress where σ'₃ was more than 150 kpa. Namely, due to no normalization of cyclic shear stress ratio, the errors of this is increased. Therefore, more confining stress is increased, more increment of deviator stress is decreased. So, using linear relations between tanø'/sub d/ of dynamic internal friction angle and CSR where σ'₃ was less than 150 kpa, liquefaction of these grounds was evaluated. Also, as doing detail evaluation which had carried response analysis of earthquake, this appeared good results which was well compatible with empirical methods using N-value of SPT. It was thought that these result evaluated vulnerable liquefaction area more correct than existing methods. Also, characteristics of liquefaction in West Coast grounds was compared with clean sands, with analysis of behavior of pore pressure ratio and axial strain affected by fine contents, as cyclic loading was applied.

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