• Ocean and Polar Research
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• v.25 no.3
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• pp.303-314
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• 2003

The initiation of Cochlodinium polykrikoides blooming in the South Sea of Korea occurs in the sea near Naro-Do in late August. In this paper, the relationships of this annual occurrence with the environmental conditions are presented. In early summer, the winds in the sea near Naro-Do are southwesterly and the upwelling occurs in the near-shore area. The favorable winds to the upwelling are relaxed in August and the downwelling favorable northeasterly winds set in around late August. The change of wind direction causes the onshore transport of warm-and-fresh off-shore water into the sea near Naro-Do and a front between near-shore water and off·shore water is formed. Along the front, downwelling occurs and the environmental conditions for the diatom become unfavorable. When the typhoon and storm bring well-mixed East China Sea water into the sea near Naro-Do in September, the conditions for the dinoflagellates become unfavorable and blooming of C. polykrikoides disappears.

• ALGAE
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• v.32 no.3
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• pp.199-222
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• 2017

Occurrence of Cochlodinium polykrikoides red tides have resulted in considerable economic losses in the aquaculture industry in many countries, and thus predicting the process of C. polykrikoides red tides is a critical step toward minimizing those losses. Models predicting red tide dynamics define mortality due to predation as one of the most important parameters. To investigate the roles of heterotrophic protists in red tide dynamics in the South Sea of Korea, the abundances of heterotrophic dinoflagellates (HTDs), tintinnid ciliates (TCs), and naked ciliates (NCs) were measured over one- or two-week intervals from May to Nov 2014. In addition, the grazing impacts of dominant heterotrophic protists on each red tide species were estimated by combining field data on red tide species abundances and dominant heterotrophic protist grazers with data obtained from the literature concerning ingestion rates of the grazers on red tide species. The abundances of HTDs, TCs, and NCs over the course of this study were high during or after red tides, with maximum abundances of 82, 49, and $35cells\;mL^{-1}$, respectively. In general, the dominant heterotrophic protists differed when different species caused red tides. The HTDs Polykrikos spp. and NCs were abundant during or after C. polykrikoides red tides. The mean and maximum calculated grazing coefficients of Polykrikos spp. and NCs on populations of co-occurring C. polykrikoides were $1.63d^{-1}$ and $12.92d^{-1}$, respectively. Moreover, during or after red tides dominated by the phototrophic dinoflagellates Prorocentrum donghaiense, Ceratium furca, and Alexandrium fraterculus, which formed serial red tides prior to the occurrence of C. polykrikoides red tides, the HTDs Gyrodinium spp., Polykrikos spp., and Gyrodinium spp., respectively were abundant. The maximum calculated grazing coefficients attributable to dominant heterotrophic protists on co-occurring P. donghaiense, C. furca, and A. fraterculus were 13.12, 4.13, and $2.00d^{-1}$, respectively. Thus, heterotrophic protists may sometimes have considerable potential grazing impacts on populations of these four red tide species in the study area.

• Korean Journal of Environmental Biology
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• v.21 no.2
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• pp.132-141
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• 2003

We carried out a study on thermohaline structure and phytoplankton com munity in the East China Sea during early summer in 2005. As a result of marine environment and phytoplankton community, three characteristics of water type were identified. The former was characterized by the dominant species with diatoms, Chaetoceros lacinious, Ch. decipiens, Guninardia flaccida, Paralia sulcata, Pseudonitzschia pungens and Pseudosolenia calcar-avis in Chinese coastal waters, the secondary was done by lower water temperature, salinity and the dominant species with dinoflagellates, Prorocentrum donghaiense and Ceratium fusus, in over-all areas and the latter was done by the dominant species with coastal species of diatoms, Skeletonema costafum and Nitzschia longissima and silicoflagellate, Dictyocha speculum var. octopers in the transfer areas of Chinese continental coastal waters. Phytoplankton community in the surface layer identified a total of 66 species belonging to 36 genera. Dominant species was Prorocentrum donghaiense, Chaetoceros lacinious, Skeletonema costatum. Standing crops of phytoplankton in the surface layer flue tuated between $1.5 \times 10^4$cells $L^{-1}$ and $3.5\times 10^{5}$ cells $L^{-1}$. And the highest value appeared in the Changjiang estuaries with high dominance by diatoms and lowest one occurred in the southwestern area of Jeju Island with high dominance by dinoflagellates. Red tides with dinoflagellate, Prororcentrum donghaiense appeared in the frontal areas with mazimum cell density, $3.4\times 10^5$ cells $L^{-1}$. And outbreak environments was low water temperature under $20^{\circ}C$, and low salinity under 31.55 psu. The vertical distribution of red tide organisms went to about 30m depth from surface.

• Fisheries and Aquatic Sciences
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• v.26 no.2
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• pp.97-104
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• 2023

CD96 is a membrane-bound receptor discovered in humans in 1992 that is mainly present in natural killer cells and T cells derived from haematopoietic cells and performs immune functions. Based on the sequence of CD96 obtained from red seabream (Pagrus major), phylogenetic analysis with other species, infections of normal fish, Streptococcus iniae and red sea bream iridovirus (RSIV), and expression analysis was conducted using real-time polymerase chain reaction. Phylogenetic analysis showed the highest homology with Sparus aurata, and multiple sequence analysis confirmed the conservation of major domains between different fish species. Normal fish high expression results were confirmed in the head kidney, and spleen, which are the haematopoietic organs of the fish. High expression levels were confirmed in the gills, liver, spleen, and kidney on day three after RSIV infection. After S. iniae infection, high expression was confirmed in the gills and liver on day one, and high expression was confirmed in the spleen from 12 hours. These results show that PmCD96 functions as an immune gene in P. major and is considered a basic research case for CD96 in fish's hematopoietic organ immune system.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.37-37
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• 2003

Intraspecific hybrids have been proven to be a useful tool for increase growth rate in some freshwater fish species. However the effects of intraspecific hybrids in seawater fish species is little known. To assess whether intraspecific hybrids in red sea bream was associated with growth enhancement, growth performances of offspring from two inbred lines, selected Korean line (KORDI-F4) and cultured Japanese line (IPN) and two intraspecific hybrids lines (KORDI-F4♀×JPN♂ and JPN♀×KORDI-F4♂) of red sea bream were compared. There's no significant difference in body weight between offspring groups during seed production period (until 4 months old). At seven months old (after three months rearing trials on sea cages communally), the offspring from KORDI-F4 (41.0±11.1g) and JPN♀×KORDI-F4♂ (39.3±8.1g) showed significantly better performance in body weight than that of the offspring from KORDI-F4♀×JPN♂ (37.0±8.1g) and IPN (35.7±9.7g). At 15 months old, the offspring from JPN♀×KORDI-F4♂ showed best growth performances in body weight, weight gain, specific growth rate among four offspring groups. As the results, the intraspecific hybrids between cultured Japanese line and selected Korean line showed superior growth performances than their paternal and maternal inbred lines.

• Journal of Environmental Science International
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• v.16 no.7
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• pp.799-804
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• 2007

Oil spill caused severe effects on the marine fauna and flora due to direct contact of organisms with the oil and even in regions not directly affected by the spill. This study was conducted to understand the effects of the oil spill accidents and the use of dispersant on the red tide of Cochlodinium polykrikoides. Crude oil produced in Kuwait, bunker-C, kerosene and diesel oil, and a chemical dispersant produced in Korea, were added with a series of 10 ppb to 100 ppm in the f/2-Si medium at $20^{\circ}C$ under a photon flux from cool white fluorescent tubes of $100\;mol\;m^{-2}\;s^{-1}$ in a 14: 10 h L:D cycle for the culture of C. polykrikoides. In low concentrations of ${\leq}$ 1 ppm of examined oils no impact on the growth of C. polykrikoides was recorded, while in high concentration of ${\geq}$ 10 ppm, cell density was significantly decreased with the range of 10 to 80% in comparison with the control. The growth of C. polykrikoides after the addition of the dispersant and the mixtures combined with oils and a dispersant of ${\geq}$ 10 ppm appeared to decrease, whereas the growth of C. polykrikoides exposed to ${\leq}$ 100 ppb showed little serious impact. However, almost all the C. polykrikoides cells were died regardless of a dispersant and combined mixtures within a few days after the addition of high concentrations.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.1
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• pp.72-80
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• 1997

To elucidate food value and medicinal effect of sea cucumbers, sugar composition of those gly-coprotein and chondroitin sulfate was studied. The contents of sulfate esters in sea cucumbers were 1.21%(blue), 0.90%(red) and 1.19%(black). Predominant carbohydrates were identified as fucose, glucose, D-mannuronic acid and N-acetylglucosamine, and those amount was more than 80% to total carbo-hydrate, while the minor sugar composition was ribose, mannose, galactose, N-acetylgalactosamine and D-glucuronic acid. Also, the major carbohydrate moiety of glycoproteins of sea cucumbers was revealed as fucose, mannose, N-acetylglucosamine, glucose and ribose, and those amount was more than 86% to total carbohydrate. Galactose, N-acetylgalactosamine, D-glucuronic acid and mannuronic acid were minor carbohydrate moiety. The contents of sulfate esters in glycoproteins were 0.96% for blue sea cucumber, 1.15% for red sea cucumber and 1.13% for black sea cucumber, while those in chondroitin sulfates were 3.52%(blue), 3.60%(red) and 3.72%(black). The carbohydrate moiety of chondroitin sulfate was identified as N-acetylgalactosamine (73~ 87%), fucose (7~15%) and D-glucuronic acid(5~12%). As the base on the IR spectrum of strong absorption appeared in 1240$cm^{-1}$ / for stretching vibrations in S=0 group and weak absorptions in 850$cm^{-1}$ / and 820$cm^{-1}$ /for stretching vibrations in C-0-S group, chondroitin sulfates had sulfate group which was bound to $C_4$in fucose.

• Korean Journal of Remote Sensing
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• v.28 no.5
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• pp.531-548
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• 2012

To identify Cochlodinium polykrikoides red tide from non-red tide water (satellite high chlorophyll waters) in the South Sea of Korea (SSK), we improved a spectral classification method proposed by Son et al.(2011) for the world first Geostationary Ocean Color Imager (GOCI). C. polykrikoides blooms and non-red tide waters were classified based on four different criteria. The first step revealed that the radiance peaks of potential red tide water occurred at 555 and 680 nm (fluorescence peak). The second step separated optically different waters that were influenced by relatively low and high contributions of colored dissolved organic matter (CDOM) (including detritus) to chlorophyll. The third and fourth steps discriminated red tide water from non-red tide water based on the blue-to-green ratio, respectively. After applying the red tide classification, the spectral response of C. polykrikoides red tide water, which is influenced by pigment concentration as well as CDOM (detritus), showed different slopes for the blue and green bands (lower slope at blue bands and higher slope at green bands). The opposite result was found for non-red tide water. This modified spectral classification method for GOCI led to increase user accuracy for C. polykrikoides and non-red tide blooms and provided a more reliable and robust identification of red tides over a wide range of oceanic environments than was possible using chlorophyll a concentration, or proposed red tide detection algorithms. Maps of C. polykrikoides red tide in SSK outlined patches of red tide covering the area near Naro-do and Tongyeong during the end of July and early of August, 2012 and extending into from Wan-do and Geoje-do during the middle of August, 2012.

• KSBB Journal
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• v.31 no.4
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• pp.214-218
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• 2016

Serratia marcescens characterized by the ability to produce red pigments inhabits various ecological niches. A strain Serratia marcescens PYU was isolated from abalone (Haliotis discus) collected at the West Sea in Korea. The isolated strain was gram-negative, motile, rods like coccus, oxidase-negative, and catalase-positive; and formed red pigment. S. marcescens PYU was grown in the presence of 0~10% (w/v) NaCl, at pH 4~9, and at $10{\sim}40^{\circ}C$. The strain PYU produced red pigment, and the extracted pigment showed antibacterial activity against Streptococcus iniae and Lactococcus garviae which has been known as an important fish pathogens. Further studies are underway to elucidate the direct relationship between the red pigment and antibacterial activity.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.697-699
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• 2003

We present a simple algorithm for detection of red patches by remote sensing in coastal waters of Korea. The red tide patches can by identified by the relative intensity of red band signal with respect to the blue-green background signal, provided the radiometric signals only in the sea area are properly stretched. We tested our algorithm by Ocean COlor Monitor(OCM) data of Indian Satellite IRS-P4, which has been received from 2001 by National Fisheries Research and Development Institute of Korea. A comparison of our results with observation shows that the locations of red tides derived from remote sending imagery by our algorithm are in accordance with observations.