• ALGAE
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• v.21 no.1
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• pp.83-90
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• 2006

Phytoplankton community in the coastal waters off the northeastern Korean Peninsula were characterized from May 2002 to August 2003. Taxonomic composition, abundance and biomass were determined at two water depths at 10 sample sites. A total of 153 phytoplankton species including 121 diatoms, 28 dinoflagellates, 7 green algae and 7 other species were identified. The mean abundance of phytoplankton varied from 15 to 430 cells mL–1 in the surface layer and from 11 to 545 cells mL–1 in the bottom layer, respectively. Phytoplankton was more abundant in coastal stations relative to those in more open ocean. The most dominant species were marine diatoms such as Thalassionema nitzschioides, Licmorphora abbreviata, Chaetoceros affinis and Chaetoceros socialis. In addition, a few limnotic diatoms including Fragilaria capucina v. rumpens, the green alga Scenedesmus dimorphus, some marine dinoflagellates and Cryptomonas sp. appeared as dominant species. Mean concentration of total chlorophyll-a varied from 0.22 to 7.87 μg chl-a L–1 and from 0.45 to 6.79 μg chl-a L–1 in the surface and bottom layers, respectively. The contribution of phytoplankton each size-fractionated varied highly with season. The contribution of microphytoplankton to total biomass of phytoplankton in the surface and bottom layer was high in February and August 2003, and that of nano-phytoplankton was high in May 2002 in both surface and bottom layers.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.3
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• pp.230-236
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• 1987

The correlation between tintinnid and dinoflagellate by means of seasonal variation of standing crops was investigated at two selected stations in Masan Bay, well-known as a red tide zone in southern coastal waters of Korea, during the period from January 1981 to December 1982. The most dominant dinoflagellates mainly belonged to $20-60\;{\mu}m$ of size class, and Gymnodinium and Prorocentrum were predominant from spring to summer season. Of tintinnid, Favella spp. were most dominant and associated with dinoflagellate blooms at the same season. Especially, Favella spp. were most positively correlated with $40-60\;{\mu}m$ size class of dinoflagellate, and also represented higher multiple corrleation with outer station (St.2), comprising relatively large species of Gymonodinium and Protogonyaulax, than with inner station (St. 1), dominated by Prorocentrum blooms. Thus, the interspecific food selection by size and morphology between tintinnid including Favella and dinoflagellate is recognized and it is considered to be an important factor influenecing on the prey-predator relationship in lower trophic level in the surveyed area.

• Journal of Life Science
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• v.13 no.5
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• pp.651-657
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• 2003

Randomly amplified polymorphic DNA (RAPD) analysis was used to study genetic relationships among C. polykrikoides, G. impudicum and G. catenatum, which possess similar morphological features. Four of 12 primers were selected and 59 amplification products ranged from 0.2 kb to 3.0 kb. The number of polymorphic products in C. polykrikoides, G. impudicum and G. catenatum was 16 (27.1%), 8 (13.5%), and 16 (27.1%), respectively, while 17 were monomorphic. Number of species-specific bounds was 26 (44.0%), 34 (57.6%), 26 (44.0%) in C. polykrikoides, G. impudicum and G. catenatum, respectively. The genetic similarity between C. polykrikoides and G. impudicum/G. catenatum was 0.83, whereas G. impudicum and G. catenatum was 0.78. Our results suggest that C. polykrikoides, G. impudicum and G. catenatum are extremely different on the basis of RAPD analysis, despite similarity based on their morphology. The RAPD technique appears to be efficient in detecting genetic variation in these dinoflagellates.

• 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.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.16 no.4
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• pp.238-245
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• 2011

Phytoplankton community composition was investigated in the Asan Bay (South) Korea. Water samples were collected monthly from five stations during January to December 2008. Phytoplankton blooms were observed in February and in August but the location of the bloom varied with the sampling time. A total of 134 phytoplankton species from seven classes (Bacillariophyceae, Chlorophyceae, Chrysophyceae, Cryptophyceae, Cyanophyceae, Dinophyceae, Euglenophyceae) were observed. Diatoms were dominant in all stations through-out the year except in summer when dinoflagellates were numerous and highly distributed within the outer bay rather than in the river mouth. Dominant and subdominant species were composed mostly of diatoms but were replaced by dinoflagellates in June and July. Results of ecological index showed that the diversity indices were increasing toward outer bay but the dominance indices showed a reverse trend.

• Ocean Science Journal
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• v.43 no.1
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• pp.49-59
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• 2008

To examine the population development of the dinoflagellates, Ceratium furca and Ceratium fusus, daily field monitoring was conducted between April and July 2003 in the temperate coastal water of Sagami Bay, Japan. During the study period, the concentrations of C. furca were always lower than those of C. fusus. A sharp increase in the densities of both species was recorded on 5 May showing the maximum cell concentrations (C. furca = $14,800\;cells\;L^{-1}$, C. fusus = $49,600\;cells\;L^{-1}$). In the 7 days prior to the May bloom of the Ceratium species (29 April to 1 May), the highest density of the heterotrophic dinoflagellate Noctiluca scintillans was observed. Additionally, a second bloom of C. fusus occurred on 22 July. Here, two causes of the significant increases in the Ceratium populations during the two blooming periods (first time; 1 to 8 May, second time; 15 to 22 July) are presented. First, an increase in the nutrients of the surface layer regenerated by the breakdown of blooms by N.scintillans could be considered as a major cause of the population increase of the two Ceratium species. Second, a decrease in salinity (to 27 psu) was correlated with the later bloom of C. fusus. These results suggest that the population development of the two Ceratium species requires nutrients regenerated after the reduction of the diatom population by N. scintillans and, for C. fusus, continuous low salinity conditions, compared to other environmental factors during the rainy season.

• Ocean and Polar Research
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• v.34 no.2
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• pp.111-123
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• 2012

To understand the phytoplankton community in the eastern part of the Yellow Sea (EYS), in the summer, field survey was conducted at 25 stations in June 2009, and water samples were analyzed using a epifluorescence microscopy, flow cytometry and HPLC method. The EYS could be divided into four areas by a cluster analysis, using phytoplankton group abundances: coastal mixing area, Anma-do area, transition water, and the central Yellow Sea. In the coastal mixing area, water column was well mixed vertically, and phytoplankton was dominated by diatoms, chrysophytes, dinoflagellates and nanoflagellates, showing high abundance ($>10^5\;cells\;l^{-1}$). In Anma-do coastal waters characterized by high dominance of dinoflagellates, high phytoplankton abundance and biomass separated from other coastal mixing area. The southeastern upwelling area was expanded from Jin-do to Heuksan-do, by a tidal mixing and coastal upwelling in the southern area of Manjae-do, and phytoplankton was dominated by benthic diatoms, nanoflagellates and Synechococcus group in this area. Phytoplankton abundance and biomass dominated by pico- and nanophytoplankton were low values in the transition waters and the central Yellow Sea. In the surface of the central Yellow Sea, high dominance of photosynthetic pigments, 19'-hexanoyloxyfucoxanthin and zeaxanthin implies that haptophytes and cyanobacteria could be the dominant group during the summer. These results indicate that the phytoplankton communities in the EYS were significantly affected by the formation of tidal front, thermal stratification, and coastal upwelling showing the differences of physical and chemical characteristics during the summer.

• Microbiology and Biotechnology Letters
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• v.18 no.1
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• pp.18-25
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• 1990

Paralytic Shellfish Poison (PSP) is mainly produced by marine dinoflagellates such as Protogonyaulax sp. and Pyrodinium sp.. The PSP was known to be accumulated in digestive gland of shellfish as result of feeding toxic dinoflagellates. PSP illness when occurs when one eats PSP intoxicated shellfish. Therefore PSP is becoming as serious problem in food hygiene and shellfish cultivation industry. The purpose of this study was to develop detoxification method for utilization of PSP intoxicated sea mussel and prevent from PSP illness. The PSP was extracted with 0.1 N HCl solution from the submitted sea mussel, then the toxicity was measured by mouse assay according to Official Methods of Analysis of the Association of Official Analytical Chemists. No detoxification effect was observed by adding extracted juice of garlic and ginger. When the sea mussel homogenate was heated at various temperatures, the PSP toxicity was not changed significantly at below $70^{\circ}C$ for 60 minutes but it was decreased as the heating temperature was increased. For example, when the sea mussel homogenate was heated at 100, $121^{\circ}C$ for 10 minutes, the toxicity was decreased about 67 and 90%, respectively. When the sea mussel containing 645 $\mu$g PSP per 100g of edible meat was processed according to general shellfish canning procedure, the toxicity was decreased as the level of PSP undetected by mouse assay.

• Fisheries and Aquatic Sciences
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• v.1 no.2
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• pp.283-292
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• 1998

The community dynamics and distribution of dinoflagellates and their cysts were monitored monthly from June 1996 to May 1997 at six stations in Masan-Chinhae Bay, one of the famous bays for red-tide occurrence in Korea. The dinoflagellate standing crops ranged from the minimum of 306 cells $ml^{-1}$ in February to the maximum of 37,959 cells $ml^{-1}$ in May. The species causing massive blooms were Prorocentrum micans Ehrenberg and Ceratium furca (Ehrenberg) Claparede & Lachmann in July, Gymnodinium sanguineum Hirasaka in October, Alexandrium tamarense (Lebour) Balech in April and Proroeentrum minimum (Pavillard) Schiller in May. Twenty-seven taxa of dinoflagellate cysts were isolated, including 20 identified species and 7 unidentified species. The mean cyst abundance ranged from the minimum of 556 cysts $cm^{-3}$ in June to the maximum of 5,727 cysts$cm^{-3}$ in February. The spatial pattern of cyst distribution showed the gradual increase in abundance from offshore to inshore stations. The cyst genera of Protoperidinium, Gymnodinium, Serippsiella, Gyrodinium and Alexandrium were abundant throughout the year. The vertical distribution of cysts showed the surface miximum at the 0-2cm layer and the sub-surface maximum at the 2-4cm layer. Total abundance of cysts showed the most significant relationships with water temperature, and some minor relationship with dissolved oxygen, salinity, pH, phosphate and total inorganic nitrogen of surface and bottom layer in the water column. The number of dinoflagellate species decreased, while the abundance of cysts increased 4.5 times as compared with the observation of 10 years prior to the present study at the same stations of Masan-Chinhae Bay.

• Journal of Environmental Science International
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• v.15 no.8
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• pp.727-735
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• 2006

In this study, the PHYTO-PAM-fluorometric method was used to evaluate the ETR$_{max}$ in terms of sensitivity to DIN/DIP against 14 microalgae: Prorocentrum micans, Heterocapsa triquetra, Gymnodinium impudicum, Cymnodinium catenatum, Amphidinium caterae, Chlorella vulgaris, Chroococcus minutus, Microcystis aeruginosa, Chlorella ellipsoidea, Nannochloris oculata, Oocystis lacustris, Chroomonas salina, Gloeocystis gigas, and Prymnessium parvum. We found that P. micans, H. triquetra, and A. caterae exposed to the maximum level of DIN/DIP were significantly smaller in the ETR$_{max}$ than that of the minimum and moderate mixture. Unlikely the ETR$_{max}$, the initial slope alpha was not significantly different at the level of 60 DIN/DIP. In G. catenatum, the moderate levels of 15 and 20 in DIN/DIP were found to be significantly different from the ETR$_{max}$ at Chl-Ch4. Gymnodinium impudicum had a higher value than that of the ETR$_{max}$ than that of dinoflagellates used in this study, ranging from 306.1 (Ch4, DIN/DIP: 10) to 520.1 (Ch4, DIN/DIP: 30). The ETR$_{max}$ value obtained from other microalgae was similar to C. impudicum at any of the ratios of DIN/DIP and channels. Consequently, the influence of offshore water current assures us of the suppression of photosynthesis and electron transport rate in dinoflagellates. Gymnodinium impudicum has not been researched in the area of red tides in Korea, but it will be enough to creat the massive algal blooms in the future because of higher potential photochemical availability.