• Title/Summary/Keyword: Marine sand

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Pseudostomella Gastrotrichs (Macrodasyida, Thaumastodermatidae) from South Korea, with o Brief Review of the Genus

  • Lee, Ji-Min;Chang, Cheon-Young
    • Animal cells and systems
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    • v.6 no.3
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    • pp.207-213
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    • 2002
  • Two new marine gastrotrichs of the genus Pseudostomella, P. longifurca and P. koreana, are described from the shallow sublittoral sand bottoms of South Korea. Pseudostomella longifurca n. sp. is characterized by the cuticular armature with tetrancres, five dorsal papillae on the prebuccal apparatus, four dorsolateral adhesive tubes, and elongated pedicle. Pseudostomella koreana n. sp. is distinguished from its congeners by the small body, tetrancres, two pairs of dorsolateral adhesive tubes, and tube-shaped copulatory organ. A brief review of the genus is prepared, with the character comparison table for all congeners currently recognized, and a revised key to the species of Pseudostomella. This is the first record of the genus Pseudostomella from East Asia.

Water Mass Formation Variability in the Intermediate Layer of the East Sea

  • Min, Hong-Sik;Kim, Cheol-Ho
    • Ocean Science Journal
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    • v.41 no.4
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    • pp.255-260
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    • 2006
  • Long-term variability in the intermediate layer of the eastern Japan Basin has been investigated to understand the variability of water mass formation in the East Sea. The simultaneous decrease of temperature at shallower depths and oxygen increasing at deeper depths in the intermediate layer took place in the late 1960's sand the mid-1980's. Records of winter sea surface temperatures and air temperatures showed that there were cold winters that persisted for several years during those periods. Therefore, it was assumed that a large amount of newly-formed water was supplied to the intermediate layer during those cold winters. Close analysis suggests that the formation of the Upper Portion of Proper Water occurred in the late 1960's and the Central Water in the mid-1980's.

A Basic Study on the Development of Oily Sludge Treatment System by Ultrasonic Waves (초음파 오일 스러지 처리 시스템 개발을 위한 기초 연구)

  • 이은방
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.6 no.1
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    • pp.57-67
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    • 2000
  • All crude oil carries a little of water, sand, and mineral sediment molecules tightly bounded with hydrocarbons. The result is the gradual precipitation of these heavier elements into thick, granular petroleum by products known as crude oil sludge. The oily sludges in ship tanks and in storage facilities have to be treated efficiently in order to keep the security and the capacity of storage facilities, to protect a serious environmental pollution, and to retrieve lost resource. The oily sludge treatment system should be designed to satisfy requirements mentioned in safe work condition. As a basic study, in this paper, an oily sludge treatment system by ultrasonic waves was proposed. Then, the features of ultrasonic energy and recovery of sludge with ultrasonic waves are investigated by experiments. As results, we found that ultrasonic waves are a new energy to flow oil sludge environment-friendly in safe work condition. In addition, it was shown that ultrasonic energy is more efficient than thermal energy in treating oil sludge, and that the volume of wastes for disposal is reduced remarkably.

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Ecology of Sand Shrimp, Crangon affinis in the Nakdong River Estuary, Korea (낙동강 하구에 서식하는 자주새우(Crangon affinis)의 생태학적 연구)

  • HONG Sung Yun;OH Chul Woong
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.22 no.5
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    • pp.351-362
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    • 1989
  • Ecology of Crangon affinis was studied in the Nakdong River Estuary fron June 1988 to May 1989. The growth rate of female was similar to that of male. Size differences, however, were apparent between female and male. Sex ratio varies with season. The major spawning season was from June 1988 to May 1989 except for November 1988. The number of eggs of the largest ovigerous female (35.55mm TL) was over 4,000, while that of the smallest ovigerous female (15.05mm TL) more than 120. The mean number of eggs was 1778. The size of winter eggs is larger than that of the summer eggs. The mean percentage of egg loss from brooding to hatching was $29.06\%$. The rate of egg loss decreases with increasing age. Major component of food organisms includes mysids and polycheates.

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Deposition and Sedimentology of the Marine and Nonmarine Sedimentary Rocks of the Pyung-Ahn Group, Kangweondo, Korea (한국 고생대 후기의 평안층군 퇴적암(해성기원 및 육성기원)에 관한 퇴적작용과 퇴적환경 연구)

  • 박용안;최강원;김진호
    • The Korean Journal of Quaternary Research
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    • v.3 no.1
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    • pp.69-85
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    • 1989
  • The depositional environments of the Pyung-Ahn Group sedimentary rocks, Jeongseon-Kun, Kangweondo, Korea are investigated. The environments are understood to be characteristic transitional from a typical shallow marine to a typical continental environment. Such transitional conditions are also understood in various parts of Quaternary and modern environment on the earth. In particular, the absence of detrital feldspar sand grains in the Manhang and Keumcheon Formation Sandstone body is described firstly in Korea, and the fact and possible mechanism are discussed.

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Redescription of the Korean sandlance Hypoptychus dybowskii from Korea

  • Kwun, Hyuck Joon;Yim, Mi-Jin
    • Fisheries and Aquatic Sciences
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    • v.21 no.9
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    • pp.20.1-20.3
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    • 2018
  • Hypoptychus dybowskii, the Korean sandlance, is widespread in cold areas of the North Pacific. Although H. dybowskii has been considered to occur on the coast of Hamgyeongnam-do in Korea, the species is also distributed along the coast of Goseong-gun, Gangwon-do, south of Hamgyeongnam-do in the eastern part of the Korean Peninsula on the basis of newly collected specimens. In addition, many Koreans confuse H. dybowskii and Ammodytes japonicus (= A. personatus for Korean specimens) because the Korean common name or dialect of both species is "Yang-mi-ri", yet the two species differ in their external morphology. Hypoptychus dybowskii differs from A. japonicus in the location of the origin of the dorsal fin and the number of dorsal and anal fin rays.

Estimation of Geotechnical Characteristics at of the Marine Clay at Inchon International Airport Marine Clay Using Piezocone and Dilatometer Tests (CPTu와 DMT를 이용한 인천국제공항 해성점토의 공학적 특성연구)

  • 김종국;김영웅;최인걸;박영목
    • Journal of the Korean Geotechnical Society
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    • v.17 no.2
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    • pp.41-49
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    • 2001
  • 본 연구에서는 2단계 확정예정부지의 일부 원지반에서 수행된 CPTu(piezocone penetration test)와 DMT(dilatometer) 및 실내시험 결과를 바탕으로 흙의 분류, 비배수전단강도 그리고 압밀계수 등의 공학적 특성을 살펴보았다. CPTu와 DMT를 이용한 흙의 분류 결과, 점토층 사이에 얇게 산재한 샌드심(sand seam)층을 보다 정확하게 판정할 수 있었다. 삼축압축시험의 비배수 강도($S_{u}$ )를 기준으로 산정한 콘계수는 CPTu의 경우 $N_{k}$ =18.2를, DMT의 경우 Roque(1988)의 제안식을 이용한 $N_{c}$=6.35로 추정한 비배수전단강도가 비교적 일치하는 것으로 나타났다. 또한 CPTu와 DMT를 이용한 수평압밀계수는 비교적 근사한 것을 알 수 있었다. 그러나, 해성점토사이에 실트, 샌드심이 존재하는 실트질 지반에서의 수평압밀계수가 연직압밀계수보다 상당히 크며, 압밀계수비($C_{h(Oedo, CPTu, DMT)}$ /$C_{v Oedo}$ )는 4.3~10.2로 큰 차이를 보이고 있다.

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Turbulence of the Coastal Atmospheric Surface Layer and Structure of the Coastal Atmospheric Boundary Layer (해안 대기 표층의 난류와 해안 대기 경계층의 구조)

  • Kwon, Byung-Hyuk
    • Journal of Fisheries and Marine Sciences Education
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    • v.17 no.3
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    • pp.404-412
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    • 2005
  • The surface energy budget depends on many factors, such as the type of surface, the soil moisture and the vegetation canopy, the geographical location, daily, monthly and seasonal variations, and weather conditions. In the coastal region, the surface is not homogeneous at various scales for instance water, sand, mud, tall grass, and crops. The energy balance over the vegetation canopy was analyzed with the optical energy balance measuring system. The latent heat flux was more intensive than the sensible heat flux. The sensible heat flux was very small in summer due to the canopy effect and higher in spring and autumn. In summer the development of the atmospheric boundary depended on rather the vertical shear of wind than the sensible heat flux.

Seismic Stratigraphy and Depositional History of Late Quaternary Deposits on the Korea Strait Inner Shelf, Korea

  • Yoo, D.G.;Lee, H.Y.;Kim, S.P.;Kim, K.O.;Koo, N.H.;Kim, Y.G.
    • Journal of the Korean Geophysical Society
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    • v.5 no.4
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    • pp.271-281
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    • 2002
  • Interpretation of high-resolution seismic profiles collected from the inner shetf of the Korea Strait reveals that the shelf sequence in this area consists of three sedimentary units (I, II, and III in a descending order) formed after the last glacial maximum. Lower two units (II and III) represent the transgressive systems tract formed during the Holocene transgression, Unit III above the sequence boundary is interpreted to be the transgressive estuarine deposit, whereas Unit ll above the ravinement surface forms a thin transgressive sand which consists of the sediment produced through shoreface erosion and winnowing during the transgression. Unit I above the maximum flooding surface is the highstand systems tract consisting mainly of recent muds derived from the Nakdong River.

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