• ALGAE
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• v.32 no.3
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• pp.189-197
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• 2017

To quantify the abundance of the harmful dinoflagellate Cochlodinium polykrikoides in natural seawaters, we developed the innovative procedure using a droplet digital PCR (ddPCR) with C. polykrikoides-specific primers targeting the internal transcription sequence (ITS). The abundance of C. polykrikoides was estimated by the specific copy number of target ITS DNA segments per cell in cultures and natural water samples. The copy number per C. polykrikoides cell as acquired by ddPCR was $157{\pm}16$, which was evaluated against known cell numbers through a simplified protocol preparing DNAs. The abundances of C. polykrikoides in the waters of different locations estimated by ddPCR agreed with the number of cells visually counted under a microscope. This protocol was used to measure the abundance of C. polykrikoides close to and further off the southern coast of Korea in August of 2016 and 2017. The practical application showed that this method can reduce time for analysis and increase accuracy.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.640-641
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• 2003

Abnormal oceanic conditions associated with the passage of typhoons are examined using hydrographic and satellite data 1990-2002. During the passage period of typhoons in the Korean waters, an abrupt decrease of sea surface temperature(SST) in range of 5 to 8 $^{\circ}$ was observed. The areas of SST decrease were an order of 100-200km, and the low SST lasted about 15-25 days after passage of typhoon. After passage of typhoon, the water temperatures in the surface mixed layer of 30m show negative anomalies for quite a long period. In addition, stratification parameters were substantially decreased and chlorophyll a density was rapidly increased.

• Journal of the korean society of oceanography
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• v.34 no.4
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• pp.220-230
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• 1999

Four tidal flats, covering two dissipative type beaches and two other tidal mud flats, around Yonaiong-Yongyu Islands, Inchon, Korea were studied in May 1991 to analyze the spatial distribution patterns of benthic communities on macrotidal flats. From the statistical test on spatial patterns of species number, density, and biomass, significant trends were found in species number and biomass. Although quantitative analysis was not performed, the interpretation showed that the variations were ruled out by environmental gradients such as sediment grain size and tidal elevation. The eight communities revealed in this study are as follows: Moerella-Mactra(Group 1), llyoplax-Glycera -Magelona japonica-Magelona sp.-Pe riserrula ( Group 2), Amphiura-Nephtys californiensis-Bullacta-Eohaustorius (Group 3), Leonnates-Heteromastus-Pretankyra-Nephtys polybranchia (Group4), Nephtys chemulpoensis-Macrophthalmus (Group 5), Ceratonereis-Scopimera (Group 6), Haustorioides-Urothoe (Group 7) and Cycladicama-Armandia-Minuspio community (Group 8). Some of these communities were classified into substratum-specific (Group 1 to 3) and tidal elevation-specific communities (Group 4). It was difficult to identify the predominant governing agent in Groups 5,6,7 and 8 because of their presence at extreme types of sediment and at uppermost elevations. Mixed effects seemed to act upon the latter four communities (Group 5 to 8). Based on the number of samples, 60% of the target samples were influenced by substratum properties, 20% by tidal elevation effect and 20% by mixed effect of the two factors. From this, it was concluded that substratum properties serve as the most important factors on soft bottom inhabitants in the area studied.

• 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.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.3 no.4
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• pp.228-233
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• 1998

This study presents a close-range photogrammetry that is applicable to beach profile estimation using a non-metric camera. Based on the analysis of oblique video image in which the video camera was installed on a horizontal plane and the field of view was fixed, a new equation to analyze a photograph was developed considering the following aspects: (1) camera is allowed to be rotated about its optical axis and (2) a simple error model is adopted to correct lens distortion and other systematic errors associated with the non-metric camera, which improves accuracy of non-metric imageries. To test the modified technique, photographs of the beach were taken near the Donghae City in February, 1998. In addition, beach profiles were surveyed with conventional dumpy level and surveying staff. RMS error between the estimated and measured beach profiles is less than 10 cm in elevation.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.7 no.3
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• pp.201-202
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• 2002

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.7 no.3
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• pp.213-217
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• 2002

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.1 no.2
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• pp.85-86
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• 1996

• Journal of the korean society of oceanography
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• v.31 no.3
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• pp.150-154
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• 1996

• Journal of the Korean Society of Marine Environment & Safety
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• v.9 no.2
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• pp.59-64
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• 2003

The long­term trend and inter­relationship with depth of temperature and salinity in coastal waters of Korea are studied using coastal oceanographic observation and serial oceanographic data measured by National Fisheries Research and Development Institute. Temperature of coastal waters of Korea except south­western sea of Korea where cold water appears to increase in summer. In case of temperature offshore, surface temperature of East Sea increases, the reverse, for 50m and 100m decreases. Temperature in South Sea of Korea increases in whole depth and for the Yellow Sea, surface temperature increases, but for 50m decreases. In case of salinity offshore, surface salinity of East Sea decreases, but for 50m increases. Surface salinity in South Sea of Korea decreases, the reverse, form 50m and 100m increases. salinity in the Yellow Sea decrease in whole depth According to the result of inter­relationship analysis, for temperature relationship coefficients of 50m and 100m in the East Sea and South Sea of Korea is higher, however, for the Yellow sea the inter­relationship between 50m and 100m is lower. In case of salinity, the inter­relationship between surface and 50m, and for the South Sea of Korea, between 50m and 100m, and for the Yellow Sea, between surface and 50m is higher.