• Journal of the Korean Society for Marine Environment & Energy
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• v.14 no.3
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• pp.163-175
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• 2011

Though polycyclic aromatic hydrocarbon compounds (PAHs) in marine sediment has been produced by many colleges and institution in Korea, it is difficult to compare PAHs data in a study area with those in other areas due to the lack of confidence for the quality of data from the other organization. Therefore, we suggested the protocol for PAHs analysis in marine sediment through examining the method of PAHs analysis described in over twenty scientific papers and reports. When a known amount of 23 PAHs were spiked into a sediment and anlyzed following this new protocol, very good recoveries were obtained. In addition, for college and institution with their own method to analyze PAHs can keep producing PAHs data without exchanging to this new PAHs protocol, the method to get a full confidence through the QA/QC for the PAHs data produced by these organization is included to the protocol.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.6
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• pp.683-694
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• 2009

High-resolution (Chirp and Sparker system) seismic profiles were analyzed to investigate the sedimentary sequence and distribution pattern of the late Holocene deposits in Gyunggi Bay, the Yellow Sea. The bay is located in the western part of Korea, east of the Yellow Sea. The sedimentary sequence divided into three units bounded by erosional bounding surface: (1) acoustically parallel to subparallel reflectors with cross bedding structures (Unit 1); (2) confused inner reflectors and top of unit exposed partially at the seafloor (Unit 2); and (3) approximately parallel reflections and regressive to transgressive incision-fills (Unit 3). On the basis of seafloor morphology, surface bedforms, and subbotom acoustic characters, echo types in the study area were identified following the schemes of Chough et al. (2002); (1) flat seafloor with sharp bottom echoes (echo types 1-1, 1-2 and 1-3; transgressive sediment sheets or relict sands), (2) mounded seafloor with either smooth surface or superposed bedforms (echo types 2-1 and 2-2; tidal ridges), and (3) various-scale eroded seafloor (echo types 3-1 and 3-2; channels). Suspect features of acoustic turbid zones which is related to gas charged sediment are reported.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.5
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• pp.567-575
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• 2017

To understand the geochemical characteristics of Gomso Bay, which features extensive Manila clam, we measured various geochemical parameters, organic matter, and trace metals (Cu, Cd, Pb, Zn, Cr, Hg, As and Fe) of intertidal and subtidal surface sediments in 2011. The surface sediments consisted of sedimentary facies including gravel (0.21%), sand (61.1%), silt (32.1%), and clay (6.5%). The chemical oxygen demand (COD) and acid volatile sulfide (AVS) values in most areas were below sediment quality criteria (COD, $20mg/g{\cdot}dry$; AVS, $0.2mg/g{\cdot}dry$). Trace metals in the surface sediments were below pollution thresholds, except for As (morderately polluted). Sediment quality was evaluated using the trace metal pollution load index (PLI) and ecological risk index (ERI), which showed that sediments were generally not polluted and at low risk; however, values along the outer bay were higher. We expect these results will be valuable for sustainable aquaculture prodution and environmental management in Gomso Bay.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.6
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• pp.599-609
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• 2017

Desalination plants have been recently constructed in many parts of the world due to water scarcity caused by population growth, industrialization and climate change. Most seawater desalination plants are designed with a submarine pipeline for intake and discharge. Submarine pipelines are installed directly on the bottom of the water body if the bottom is sandy and flat. Intake is located on a low-energy shoreline with minimal exposure to beach erosion, heavy storms, typhoons, tsunamis, or strong underwater currents. Typically, HDPE (High Density Polyethylene) pipes are used in such a configuration. Submarine pipelines cause many problems when they are not properly designed; HDPE pipelines can be floated or exposed to strong currents and wind or tidal action. This study examines the optimal design method for the trench depth of pipeline, analysis of on-bottom stability and dilution of the concentrate based on the desalination plant conducted at the Pacific coast of Peru, Chilca. As a result of this study, the submarine pipeline should be trenched at least below 1.8 m. The same direction of pipeline with the main wind is a key factor to achieve economic stability. The concentrate should be discharged as much as high position to yield high dilution rate.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.5
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• pp.667-676
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• 1995

Settlement, recruitment, growth and production of Mactra venerifomis were investigated at Kunsan tidal flat located in the west coast of Korea from lune 1993 to May 1994. High density of planktonic larvae of M. veneriformis was observed between the mid and early July in 1993. The size of the newly settled larvae ranged from 250 to 350um in shell length with mean density of 601$inds.\cdot m^{-3}$. Recruitment of M. veneriformis larvae was occurred mainly in the mid June to mid July 1993. The larvae have no substratum preference during the larval settlement phase. Mortality of larval was affected by environment (substratum, exposure time, density of adult clams). After settlement they grew until November, and stopped growing in winter from December. The estimated turnover rate of M. veneriformis larvae was estimated as high as 4.91 and 4.94. Annual production of the 0-age group was estimated to be 2,900g $m^{-2}\;\cdot\;yr^{-l}$, which was relatively high compared with those of other age groups.

• ALGAE
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• v.27 no.3
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• pp.189-196
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• 2012

Twelve morphological characters and the biochemical composition of Undaria pinnatifida f. distans sporophytes growing on the rocky shores of Jindo and Wando and on cultivation ropes in Kijang were measured to determine whether each population could be characterized by morphological features and biochemical composition. The goal of this study was to compare phenotypic variations between populations as they relate to environmental conditions. The sporophytes of the Kijang population were two times longer and 19 times heavier than those at Jindo. Sporophylls of the Jindo U. pinnatifida population were significantly smaller in length, width, frill number, and weight than those at Wando and Kijang. Kijang Undaria plants showed the highest contents of total protein, crude fiber, total amino acids, the amount of essential amino acids, the proportion of total unsaturated fatty acids, and eicosapentaenoic acid. However, the Jindo population showed the greatest content of carbohydrates, lipids, and minerals (Zn and Ca) of the three U. pinnatifida populations. In particular, Zn content of Jindo plants was 30 times greater than that of Kijang plants. Thus, the proximate composition, mineral composition, amino acids, and fatty acids of Undaria pinnatifida plants were distinguishable among the three representative Undaria populations evaluated. These results suggest that morphological and biochemical differences of the three U. pinnatifida populations can be attributed to differences in environmental conditions of their habitats.

• 한국지구물리탐사학회:학술대회논문집
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• 2006.06a
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• pp.51-59
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• 2006

The surface wave data obtained in a tidal flat located in the sw coast of the Korean Peninsula were used to analyse the shear wave velocity structure of the area. First, the phase velocity dispersion curves were obtained by the tau-p stacking method and the group velocity dispersion curves by a wavelet transform method and the Multiple Filtering Technique by Dziewonski. The phase velocity dispersion curves exhibited bigger errors than the group velocity curves. The results showed that the wavelet transform method was more effective in separating the fundamental and the 1st higher mode group velocity curves than the Multiple Filtering Technique. Combined use of the fundamental and the 1st higher mode group velocity dispersion curves in the inversion for the shear wave velocity structure gave better spatial resolution compared when the fundamental mode group velocity was used alone. This study indicates that the group velocity dispersion curves can be used in the inversion of Rayleigh waves for the shear wave velocity structure, especially effectively with the higher mode group velocity curves together.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.3 no.3
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• pp.103-111
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• 1998

This paper reports the sediment geochemistry and its relation to the grain size distribution in Kyeonggi Bay, Korea. Sediment samples were collected from 90 stations during the cruise crossing the bay in December 1995. Variables investigated were the sediment grain size, organic carbon content, and concentrations of AI, Fe, Mn, V, Co, Ni, Cr, Zn and Cu in the sediment. We followed the change in these variables by comparing the data obtained from this region in 1981. Distribution pattern of sediment grain size was modified from that in 1981 in some places. Near the Shihwa Dike which was completed in 1994, sediment had got finer grained. Sediment facies changed from fine to mixed facies near Youngjong Island where the tidal flat has been reclaimed for airport construction. Contents of organic matter and metals in the sediment were mostly dependent upon the sediment grain size, but an exception was found in the harbor area. The sediment in the Incheon North Harbor showed higher accumulation of organic matter and metals such as Ni, Cr, Zn and Cu.

• Fisheries and Aquatic Sciences
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• v.10 no.2
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• pp.74-85
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• 2007

Pacific anchovy (Engraulis japonicus) eggs were collected during the spawning season (2000-2003) using a revised ring net in the coastal waters adjacent to the Geum River Estuary in the West Sea of Korea (Yellow Sea). Anchovy eggs were present from May to September, showing a peak in spawning from June to July when the water temperature and salinity were $17-27^{\circ}C$ and above 30.00 psu, respectively. During the main spawning season, no clear diel cycle (regarding the 24-h sampling period of dusk, night, dawn, and daytime) was detected in the vertical distribution of anchovy eggs near Eocheong Island (50-60m depth). Judging from the developmental stages of the collected eggs, it appeared that anchovies spawned mostly at night and that the eggs hatched at dusk and during the night. The density of anchovy eggs was high in the southwest-northeast direction in June, and spawners appeared to move offshore in July. Mean egg density was higher in June 2002 than in June 2003 when water temperatures and salinities were lower. This study on the spatiotemporal distribution of eggs will contribute to developing management plans for the Pacific anchovy in Korea.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.3
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• pp.259-266
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• 2011

To produce cupped oyster sprat consistently, we investigated the efficiency of nine settlement substrates using selective breeding of Pacific oyster Crassostrea gigas, with the goal of popularizing off-bottom culture on the west coast of Korea. We also compared the growth and survival of selectively bred sprat (diploid) with triploid sprat from an off-bottom culture system. Considering, the attachment rate and detachment efficiency, producing cupped oyster in a polypropylene gunny bag proved to be the most effective method. There were no differences in shell growth or total weight between the diploids from selective breeding and triploids from off-bottom culture for 5 months. However, the survival rate was 8 times higher in the diploids than the triploids. Transplanting sprat from selective breeding is one way to restore oyster farms and nurture off-bottom culture along the west coast.