• ALGAE
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• 제38권1호
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• pp.57-70
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• 2023

The mortality rate of red-tide dinoflagellates owing to predation is a major parameter that affects their population dynamics. The dinoflagellates Ansanella granifera and Ansanella sp. occasionally cause red tides. To understand the interactions between common heterotrophic protists and A. granifera, we explored the feeding occurrence of nine heterotrophic protists on A. granifera and the growth and ingestion rates of the heterotrophic dinoflagellate Gyrodinium dominans on A. granifera as a function of prey concentration and those of Oxyrrhis marina at a single high prey concentration. The heterotrophic dinoflagellates Aduncodinium glandula, G. dominans, Gyrodinium moestrupii, Luciella masanensis, Oblea rotunda, O. marina, Polykrikos kofoidii, and Pfiesteria piscicida and the naked ciliate Strombidium sp. were able to feed on A. granifera. With increasing mean prey concentrations, the growth and ingestion rates of G. dominans feeding on A. granifera rapidly increased and became saturated or slowly increased. The maximum growth and ingestion rates of G. dominans on A. granifera were 0.305 d^-1 and 0.42 ng C predator^-1 d^-1 (3.8 cells predator^-1 d^-1), respectively. Furthermore, the growth and ingestion rates of O. marina on A. granifera at 1,700 ng C mL^-1 (15,454 cells mL^-1) were 0.037 d^-1 and 0.19 ng C predator^-1 d^-1 (1.7 cells predator^-1 d^-1), respectively. The growth and ingestion rates of G. dominans and O. marina feeding on A. granifera were almost the lowest among those on the dinoflagellate prey species. Therefore, G. dominans and O. marina may prefer A. granifera less than other dinoflagellate prey species. The low mortality rate of A. granifera may positively affect its bloom formation.

• 한국해양학회지:바다
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• 제7권4호
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• pp.221-225
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• 2002

한국 서해안의 곰소만에서 숙주-기생자 배양체 Prorocentrum minimum- Amoebophrya sp.를 분리하여 실험, 배양하는데 성공하였다. 본 연구는 이 숙주-기생체를 실험배양 하면서 광학 및 형광현미경 관찰을 토대로 규명된 적조생물 P minimum을 숙주로 하는 기생성 와편모류 Amoebophrya sp.의 생활사 단계를 보고한다. 이 기생성 와편모류에 의한 감염은 숙주 P minimum의 핵 내부에서 일어나고, 성장하여 결국은 세포질을 포함한 숙주 세포 공간의 대부분을 차지한다. 이 영양체의 세포 내의 성장이 완결되면 숙주의 각을 열고 세포 밖으로 나온다. 숙주 세포 밖의 자유유영 생활사 단계인 vermiform stage를 거쳐, 순간적으로 발산하여 수많은 dinospore를 형성하는 단계에 이른다. 우리나라 연안해역에서 춘·하계에 대규모 적조를 일으키는 원인 생물인 P. minimum과 이에 기생하는 본 Amoebophrya sp.의 숙주-기생배양체는 생물학적 적조제어기술 개발을 위한 중요한 생물재료의 하나이다.

• 한국어업기술학회:학술대회논문집
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• 한국어업기술학회 2000년도 추계수산관련학회 공동학술대회발표요지집
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• pp.141-142
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• 2000

To elucidate the ichthyotoxic mechanisms of a harmful dinoflagellate Cochlodinium polykrikoides, biochemical and hematological responses of fish exposed to blooms were investigated. Particularly, based on our finding that oxidative damages of gill were associated with fish mortality, dysfunction of ion-transporting enzymes and secretion of gill mucus of fish exposed to this bloom species were examined. (omitted)

• 한국수산과학회지
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• 제29권6호
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• pp.837-842
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• 1996

The resting cyst of Gymnodinium catenatum was found in the surface sediments collected from Chinhae Bay in October, 1991. This is the first record of the species in the Korean waters. The relative abundance was low with the maximum of $1.7\%$. The colonial motile form consisting of four cells was observed in 1992 from the excystment of the cyst collected from the Wonmun Bay in Chinhae Bay. No blooms caused by G. catenatum has been observed in Chinhae Bay during the survey.

• 한국수산과학회지
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• 제34권6호
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• pp.691-696
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• 2001

우리나라 연안에서 Cochlodinium polykrikoides 적조는 1982년 낙동강하구에서 최초로 발생하였으며, 1988년까지는 진해만과 그 부근해역에서 발생하였다. 그러나 1989년 이후부터는 진해만에서는 거의 발생하지 않고 충무, 거제, 남해, 여수 둥의 남해안의 중부해역에서 주로 발생하였고, 1995년부터는 동해연안까지 발생해역이 확대되었다. 그리고, 1998, 1999년도에는 서해연안에서도 이종에 의한 적조가 발생하였다. C. polykrikoides 적조 발생건수는 매년 증가하는 추세를 보였으며, 발생시기는 $7\~10$월로 특히 9월에 집중 발생하는 것으로 나타났다. 적조지속기간도 매년 증가하여 처근에는 한달 이상 지속되는 양상을 보이고 있으며, 적조밀도 역시 '91년까지는 최고 5,000cells $mL^{-1}$를 초과하지 않았으나, '99년도에는 43,000 cells $mL^{-1}$까지 나타나 매년 증가하는 추세를 보였다. 한편 C. polykrikoides적조는 '82년과 '84년에는 다양한 규조류 및 편모조류와 함께 발생하는 혼합적조로 출현하였으나, 이후에는 주로 단독적조로 출현함으로써 C. polykrikoides 적조가 혼합적조에서 단독적조로 발전해 갔음을 알 수 있었다. 이와 같이 C. polykrikoides 적조는 발생해역이 우리나라 전연 안으로 확대되고, 적조밀도가 높아지며, 발생기간이 $1\~2$개월로 장기간 지속하고 있는 양상을 나타내고 있으며 특히 양식산업이 성행하고 있는 충무, 남해도, 거제도, 여수 및 거문도 연안에서 $8\~9$월에 자주 적조를 형성하므로서 양식산업 발전에 큰 위협이 되고 있다.

• 환경생물
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• 제18권4호
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• pp.447-456
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• 2000

마산-진해만에서 1990년 1월부터 1997년 8월까지 Prorocentrum 개체군 (P. dentatum Stein, P. micans Ehrenberg, P. minimum (Pavillard) Schiller, P. triestinum Schiller) 변동을 monitoring하였다. Prorocentrum 개체군은 대부분 6-8월 해수 성층화가 일어나는 시기에 bloom을 일으켰고 수온은 24-28$^{\circ}C$, 염분도는 24-34$\textperthousand$ 범위였다. 마산-진해만에서 Prorocentrum 개체군은 외만에서 내만으로 갈수록 발생빈도와 발생량이 증가하였고, 수직적으로는 2.5m상층부에 집중되었다. 또한 마산-진해만에서 Prorocentrum개체군은 과거 80년대와 90년대 초반과 비교하여 출현 종수는 감소하였으나 세포밀도는 점차적인 고밀도의 양상을 띠었다. 그리고 Prorocentrum 개체군은 과거와 비교하여 저수온기인 겨울철에도 출현빈도가 빈번해짐을 관찰하였다. Prorocentrum속 조류 중에서 P. minimum의 bloom규모와 그 지속 기간이 가장 길었다.

• 한국환경과학회지
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• 제6권3호
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• pp.231-238
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• 1997

The community of phyloplankton and water quality were Investigated 5 times from October, 1994 to October, 1995 In the east area of Chinhae Bay. Seasonal changes of enoronmental parameters were shown general pattern and related to the red tide mechanism of phytoplankton community. Seasonal variations of dissolved oxygen concentrations were affected by the photosynthetic activity of phytoplankton community and the Increase of COD at the bottom water was occurred after the red tide. The standing stocks of phytoplankton In this study area ranged 202 - 1616 Cells . ml-1 and the bloom(red tide) was formed from April to July. The diatom species, Skeletonema costahm was a dominant species all the year round and the dinoflagellate species, Alexandrium tmuense and prorocentrum triestinum were red tide species Increased standing stocks in phytoplankton bloom.

• ALGAE
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• 제30권1호
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• pp.49-58
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• 2015

In September 2007, reports of respiratory irritation and fish kills were received by the Florida Fish and Wildlife Conservation Commission (FWC) from the Jacksonville, Florida area. Water samples collected in this area indicated a bloom of Karenia brevis, the dinoflagellate that produces brevetoxin, which can cause neurotoxic shellfish poisoning. For the next four months, K. brevis was found along approximately 400 km of coastal and Intracoastal waterways from Jacksonville to Jupiter Inlet. This event represents the longest and most extensive red tide the east coast of Florida has experienced and the first time Karenia species other than K. brevis have been reported in this area. This extensive red tide influenced commercial and recreational shellfish harvesting activities along Florida's east coast. Fourteen shellfish harvesting areas (SHAs) were monitored weekly during this event and 10 SHAs were closed for an average of 53 days due to this red tide. The length of SHA closure was dependent on the shellfish species present. Interagency cooperation in monitoring this K. brevis bloom was successful in mitigating any human health impacts. Kernel density estimation was used to create geographic extent maps to help extrapolate discreet sample data points into $5km^2$ radius values for better visualization of the bloom.

• ALGAE
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• 제31권4호
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• pp.373-378
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• 2016

Cochlodinium polykrikoides is a red-tide forming dinoflagellate that causes significant worldwide impacts on aquaculture industries and the marine ecosystem. There have been extensive studies on managing and preventing C. polykrikoides blooms, but it has been difficult to identify an effective method to control the bloom development. There is also limited genome information on the molecular mechanisms involved in its various ecophysiology and metabolism processes. Thus, comprehensive genome information is required to better understand harmful algal blooms caused by C. polykrikoides. We estimated the C. polykrikoides genome size using flow cytometry, with detection of the fluorescence of DNA stained with propidium iodide (PI). The nuclear genome size of C. polykrikoides was 100.97 Gb, as calculated by comparing its mean fluorescence intensity (MFI) to the MFI of Mus musculus, which is 2.8 Gb. The exceptionally large genome size of C. polykrikoides might indicate its complex physiological and metabolic characteristics. Our optimized protocol for estimating the nuclear genome size of a dinoflagellate using flow cytometry with PI can be applied in studies of other marine organisms.

• 한국환경과학회지
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• 제19권12호
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• pp.1385-1395
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• 2010

Harmful dinoflagellate Cochlodinium polykrikoides blooms have been frequently occurred in coastal areas of the East Sea since 1995. We compared the oceanic conditions in years 1995, 2001 and 2003 when the C. polykrikoides bloom was strong, and in years 1998 and 2004 when the C. polykrikoides bloom was not appeared. We studied temporal and spatial variation of upwelling and geostrophic currents on the western channel of Korean Strait, an entrance of the East Sea. The period and occurrence area of C. polykrikoides bloom was depended on variation of upwelling in summer. In the distributions of geostrophic current, southward current was dominant near the coast in August, 1998 and 2000. Whereas northward current was dominant near and off the coast in August, 1995 and 2003 which the C. polykrikoides bloom was strong. When compared dominant phytoplankton of the coastal areas in each year, Kuroshio indicator species Proboscia alata and Chaetoceros affine were dominant, respectively, in 2001 and 2003 at every stations. However, the dominant species was variable at each coastal area in 1998 and 2000. In 2003, the abundance of Sagitta elegans which is known as the cold water indicator was low, but the abundance of S. enflata, warm water indicator, was very high in Gangneung compared to Sokcho. It seemed that the distribution of S. elegans is restricted by strong warm water current. In conclusion, it was estimated that the distribution of C. polykrikoides bloom in the coastal area of the East Sea was closely related with the strength of East Korea Warm Current and upwelling.