• 한국해안·해양공학회논문집
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• 제26권4호
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• pp.217-224
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• 2014

Cochlodinium polykrikoides 적조생물은 우리나라 연안에서 가장 빈번하게 적조를 유발하는 생물이다. 적조는 식물플랑크톤의 급격한 번식(algal bloom)으로 발생하기 때문에 적조를 유발하는 적조생물에 대한 최적의 성장조건 정보가 가용하다면 정확한 적조성장 모형 구성이 가능하며, 적조 발생예측에도 활용할 수 있다. 그러나 적조 성장에 영향을 미치는 인자가 빛, 수온, 염분, 영양염류 농도 등으로 다양하고, 적조성장을 제어하는 함수형태가 다양하기 때문에 실험조건의 최적 성장조건에 대한 연구 성과를 활용하여 적조 수치모형에서 활용할 수 있는 최적 성장모형을 구성한 연구는 매우 미흡한 수준이다. 본 연구에서는 우리나라의 대표적인 적조생물에 해당하는 Cochlodinium polykrikoides 적조생물의 최적 성장조건에 관한 연구 자료를 이용하여 다양한 함수형태에 따른 최적 매개변수 추정 및 오차비교 분석과정을 거쳐 적조 모형에서 바로 활용할 수 있는 최적 성장모형을 개발 제시하였다. 개발된 성장모형은 실험조건에서 추정된 최적 성장모형이기 때문에 현장자료를 이용한 모형의 보정 및 검정과정에서 본 연구결과로 제시된 최적 함수형태, 최적 매개변수 및 보정 매개변수의 범위 등을 기본 정보로 활용할 수 있으며, 실험조건과 현장조건의 차이 평가에도 활용할 수 있다.

• ALGAE
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• 제29권2호
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• pp.101-109
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• 2014

Small red algae, especially those previously referred to as 'primitive' are often overlooked, but can be quite abundant. These 'primitive' red algae are now placed in several classes distinct from the Florideophyceae, for example the Stylonematophyceae. A brownish-red filamentous alga was collected from a sandy tide pool at Cape Tribulation, Queensland, Australia. Cultured specimens were identified as Bangiopsis and conformed to the morphological characters of the genus (multicellular base, erect filaments branched or unbranched, uniseriate to multiseriate-tubular, single multilobed purple-red to red-brown plastid with central pyrenoid, vegetative cells released directly as spores). Molecular data of two plastid genes (rbcL, psbA) support placement of the Australian isolate and isolates from India in Bangiopsis. The genetic variation between these isolates and isolates from Puerto Rico previously attributed to B. subsimplex indicates that these should be considered as a separate species. As the type locality is in the Atlantic Ocean, French Guiana, and not far from Puerto Rico, and the Puerto Rican isolate has been used often in phylogenetic analyses, we propose that the Indian and Pacific Ocean isolates be designated a new species, B. franklynottii, to acknowledge Ott's many years of research on inconspicuous freshwater and marine red algae. Our research also highlights the lack of careful descriptions in many of the records of this genus and the lack of morphological characters to distinguish species. Especially within the morphologically simple red algae, morphological distinctness does not necessarily reflect evolutionary divergences.

• ALGAE
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• 제34권3호
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• pp.237-251
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• 2019

The dinoflagellate genus Alexandrium is known to often form harmful algal blooms causing human illness and large-scale mortality of marine organisms. Therefore, the population dynamics of Alexandrium species are of primary concern to scientists and aquaculture farmers. The growth rate of the Alexandrium species is the most important parameter in prediction models and nutrient conditions are critical parameters affecting the growth of phototrophic species. In Korean coastal waters, Alexandrium affine and Alexandrium fraterculus, of similar sizes, often form red-tide patches together. Thus, to understand bloom dynamics of A. affine and A. fraterculus, growth rates and nitrate uptake of each species as a function of nitrate ($NO_3$) concentration at $100{\mu}mol\;photons\;m^{-2}s^{-1}$ under 14-h light : 10-h dark and continuous light conditions were determined using a nutrient repletion method. With increasing $NO_3$ concentration, growth rates and $NO_3$ uptake of A. affine or A. fraterculus increased, but became saturated. Under light : dark conditions, the maximum growth rates of A. affine and A. fraterculus were 0.45 and $0.42d^{-1}$, respectively. However, under continuous light conditions, the maximum growth rate of A. affine slightly increased to $0.46d^{-1}$, but that of A. fraterculus largely decreased. Furthermore, the maximum nitrate uptake of A. affine and A. fraterculus under light : dark conditions were 12.9 and $30.1pM\;cell^{-1}d^{-1}$, respectively. The maximum nitrate uptake of A. affine under continuous light conditions was $16.4pM\;cell^{-1}d^{-1}$. Thus, A. affine and A. fraterculus have similar maximum growth rates at the given $NO_3$ concentration ranges, but they have different maximum nitrate uptake rates. A. affine may have a higher conversion rate of $NO_3$ to body nitrogen than A. fraterculus. Moreover, a longer exposure time to the light may confer an advantage to A. affine over A. fraterculus.

• Fisheries and Aquatic Sciences
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• 제1권2호
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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.

• 한국환경과학회지
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• 제11권3호
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• pp.215-225
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• 2002

In order to evaluate the relationship between geochemical characteristics and benthic facies of the sediments from the Oenaro Island where red tide proliferation is first observed every year including this year, surface and short multiple core sediment samples were analyzed in terms of geochemical and benthic facies variation. The contents of organic carbon, carbonate, and sulfide gas were relatively low. The variation in C/N ratios, which indicate nature of organic carbon, suggested that the organic carbon recorded in the study area is composed of mixtures of marine and terrigenous organic matters. The concentration of minor elements found at the surface and multiple core sediment samples were also low as well as the enrichment factors(Ef) for the seven heavy metals indicated that the sediment of this area is not polluted significantly. The macrobenthic faunal community comprised 61 species, and their mean density was 708 ind./m2. Polychaete worms were major taxa of this benthic community. A crustacean amphipod, Melita sp. was the most abundant species accounted for 20.7% of total abundance, and the small polychaetes such as Heteromastus filiformis, Paralacydonia poradoxa, Magelona japonica and Sigambra tentaculata were the next dominant species. The macrobenthos around the Oenaro Island were more diverse and abundant than that in Gamak Bay. The benthic communities in the study area sustained somewhat different species composition based on the cluster analysis and the MDS ordination. The benthic community health condition at three stations seemed to be unbalanced, and slightly polluted based on the biological index such as BPI and BC. There was no clear relationship between the geochemistry characteristic and the benthic faunal facies attributed by the micro-algal blooms in this coastal area.

• 한국어업기술학회:학술대회논문집
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• 한국어업기술학회 2001년도 추계 수산관련학회 공동학술대회발표요지집
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• pp.206-207
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• 2001

Cochlodinium polykrikoides is one of the most harmful red tide dinoflagellates and is highly toxic to fish. Red tides due to this dinoflagellate have been reported in Korea, Japan, and other countries, and frequently cause severe damage to fish farming. Recently study has suggested that C. polykrikoides generates reactive oxygen species (ROS) such as superoxide anion ($O_{2-}$) and hydrogen peroxide ($H_2O_2$), and the ROS-mediated ichthyotoxicity has been proposed. (omitted)

• 한국패류학회지
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• 제28권4호
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• pp.349-359
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• 2012

The purpose of this study is to compare the clearance rate (CR) and intake rate (IR) of juvenile purple clam, Saxidomus purpuratus when feeding on different unialgal diet of red tide dinoflagellates (RTDs), and to know what is the most important cell characteristic of RTDs to cause the differences in feeding parameters. Experiments were performed to measure the CR and IR of juvenile S. purpuratus as a function of algal concentration when food was either the standard food, Isochrysis galbana or one of 9 RTDs. Patterns of CR with increasing algal concentration were similar among different RTDs. The highest $C_{max}$ was observed when S. purpuratus was feeding on A. affine, while the lowest on C. polykrikoides. The patterns of IR with increasing algal concentration were also similar among different RTDs. However, there were great differences in the maximum value of IR ($I_{max}$) among different RTDs. The highest $I_{max}$ was observed when S. purpuratus was feeding on A. carterae, while the lowest on G. catenatum. Some RTDs similar in size showed different $C_{max}$. Other RTDs different in size showed similar $I_{max}$. Life form of each RTD affected significantly the $I_{max}$, which was higher for single-celled RTDs than chain-forming RTDs. There were no significant differences in feeding parameters between toxic and nontoxic RTDs. Moreover, a toxic dinoflagellate, A. carterae recorded the highest $I_{max}$ among RTDs. The most important characteristic of RTD as a factor affecting the feeding rate of S. purpuratus was life form, not size or toxicity of RTD species.

• 한국해양학회지:바다
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• 제5권1호
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• pp.37-46
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• 2000

1995년 이후 해마다 8월부터 10월까지 남해안에서 대규모로 발생되는 유해성 적조가 가장 먼저 발견되는 전남 고흥군 나로도 해역에서 적조원인생물을 포함한 식물플랑크톤의 포식자로써 적조역학(red tide dynamics)에 큰 영향을 줄 수 있는 종속영양성 와편모류(heterotraphic dinoflagellate; 이하 HTD)와 섬모류의 시공간적 분포를 연구하기 위하여, 1997년 6월 20일부터 9월 22일까지 모두 5차례에 걸쳐 3개의 정점, 5${\sim}$7개의 깊이에서 시료를 채집한 뒤 분석하였다. 연구기간 동안 총 17종의 HTD가 발견되었는데 그 중 Protoperidinium 속에 속하는 종이 11종으로 65% 정도를 차지하였다. 섬모류의 경우 종피류(tintinnid; 이하 TIN)가 총 15종 출현하였으며, 다수의 무피성 섬모류(naked ciliate; 이하 NC)가 출현하였다. 출현 종 수의 시간적 변화를 볼 때 HTD와 TIN모두 8월 1일과 21일 사이에 가장 많이 증가하였으나 최대 출현종 수는 Gyrodinium impudicum이 우점한 유해성 적조가발생한 직후인 8월 27일에 나타났는데 각각 13종과 10종이었다. 9월 22일에는 출현종 수가 급감하였다. 연구기간 중 나타난 HTD, TIN, NC의 최대 밀도는 각각 45, 39, 57 cells $ml^{-1}$었다. 한 시기에 채집한 모든 시료의 평균밀도(Average Density at All Station; 이하 ADAS)를 구한 결과 HTD의 ADAS는 출현종 수와 마찬가지로 8월 1일과 21일 사이에 가장 큰 폭으로 증가하다가 8월 27일에 약 6 cells $ml^{-1}$의 최대값에 도달하였으나, TIN의 ADAS는 8월 21일과 8월 27일 사이에 급증하여 최대값 7 cells $ml^{-1}$에 도달하였다. NC의 ADAS는 HTD나 TIN처럼 뚜렷한 시간적 변화를 나타내지 않았으나 8월 27일에 최대값 8 cells $ml^{-1}$을 나타냈다. 이러한 출현 종수와 평균밀도의 증가율을 볼 때 HTD의 경우 규조류의 변화 양상과 비슷하여 HTD가 규조류의 포식자일 가능성을 제시할 수 있는데, 특히 8월 27일의 경우 Protoperidinium 속의 수평, 수직적 분포는 규조류의 분포와 높은 상관관계를 가져 이들이 규조류의 주요 포식자임을 유추할 수 있다. 공간적 분포에 있어서 일반적으로 HTD와 섬모류 모두 내만에서 높은 값을 가졌으며 외만으로 갈수록 감소하였으므로, 본 연구는 HTD와 섬모류의 시공간적분포가 연안으로부터의 거리 및 먹이인 식물플랑크톤의 시공간적 분포와 밀접한 관계를 갖고 있음을 제시할 수 있고, 본 연구결과는 앞으로 주요 원생동물들의 적조원인생물을 포함한 우점 식물플랑크톤에 대한 포식실험의 기초자료로 이용되어 적조발생시와 발생 전후의 하부 먹이망을 완성하는데 기여될 것이다.

• ALGAE
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• 제22권2호
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• pp.95-106
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• 2007

Blooms of Chattonella species are normally during summer in inland seas with high nutrients from the land and inflowing water. These blooms cause mass fish kills worldwide. We isolated a Chattonella strain from the south coast of Korea and identified it as C. antiqua. It is known that the morphological changes of phytoplankton correspond to the diurnal vertical migrations that follow an intrinsic biological clock and a nutrient acquisition mechanism during the day and night. In electron micrographs, C. antiqua clearly showed a radial distribution of lipid bodies in subcellular regions and plastids composed in which thylakoid layers were perpendicular to the surface. A single pyrenoid was present in each plastid and it was found at the end of the plastid towards the center of the cell. Throughout the day, plastids of C. antiqua cells appeared as an expanded net-like recticulum. During the night, however, the plastids changed their shape and contracted toward the cell periphery. The electron density of pyrenoids was increased in cells harvested during the night.

• Fisheries and Aquatic Sciences
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• 제5권1호
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• pp.75-78
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• 2002

The effects of Coehlodinium polykrikoides on the gill of red sea bream, Pagrus major, were examined to clarify the ichthyotoxic mechanisms of this plankton species. The gill of fish exposed to dense blooms over 3,000 cells/mL for 24 h showed severe epithelial separation: a severe edema was found in the secondary lamellar epithelium and interlamellar regions of primary filament. In addition, lipid peroxidation of gill tissue in Coehlodinium-exposed fish was about 2.5 times higher than that of control. The composition of glycoproteins in the gill mucus of Coehlodinium-exposed fish was also changed. These results suggest that the loss of structural integrity of cell membranes in fish gill may be deeply involved in fish death by C. polykrikoides.