• Ocean and Polar Research
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• 제34권1호
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• pp.65-71
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• 2012

Gambierdiscus toxicus, Adachi et. Fukuyo, is a benthic ciguatoxin-producing armored dinoflagellate, often attached to macroalgae. This organism is the primary causative agent of ciguatera fish poisoning which occurs in tropical and subtropical regions. However, regardless of the fact that the population of Gambierdiscus spp. has expanded to such temperate areas from sub-trophic and trophic areas, monitoring of G. toxicus has been lacking in the Korean coastal waters of temperate areas. This study was performed at the uninhabited Baekdo Islands off the southern coast of Korea and at Seopsom Island in the vicinity of Seogwipo, Jeju Province during April and May, 2011. Cell densities of Gambierdiscus spp. on macroalgae at Baekdo and Jeju Island ranged from zero to 56.4 cells $g^{-1}$. Maximum density was recorded on the brown alga Cladophora japonica at St. 3 of Jeju Island. In particular, the cell densities of Gambierdiscus spp. were influenced by the substrate characteristics of macroalgae. In the future, the continuous monitoring of toxic benthic dinoflagellate is necessary to predict and prevent ciguatera poisoning in Korean coastal waters.

• ALGAE
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• 제26권4호
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• pp.317-325
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• 2011

Five benthic species of the genus Gambierdiscus (Dinophyceae) were observed for the first time in the coastal waters of Pakistan, Northern Indian Ocean. The morphology of the epiphytic, ciguatera-related toxic species G. toxicus, G. belizeanus, G. polynesiensis, G. australes and G. cf. yasumotoi are presented here, described by the Kofoid system of thecal plates Po, 3', 7", 6c, 8s, 5"', 1p, 2"" with differences in cell shape, cell size, plates, pores around the apical pore plate by using light and scanning electron microscopy. The occurrence of these potentially toxic dinoflagellate species in Pakistani coastal areas of Manora Channel and Balochistan during high temperatures of 28-$32^{\circ}C$ is cause of concern for human health impacts from ciguatera fish poisoning.

• Ocean and Polar Research
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• 제43권3호
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• pp.99-111
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• 2021

Occurrence of epiphytic dinoflagellates (EPDs) in coastal waters off Jeju was first reported in 2011 based on 45 substrate samples from 24 macroalgal species. When re-analyzing, the extreme heterogeneous distribution of whole and genus-specific EPDs was reconfirmed across the sampling stations and substrate macroalgal species, as well as even across substrate samples of the same species. Abundance maximum of an EPD genus (cells g-wwt^-1) at a fixed surface-to-volume ratio (SA/V ratio) of the macroalgal species increased as the SA/V ratio increased up to 500 (cm² cm^-3). However, the abundance maximum of Ostreopsis further increased even in the MG2 (morphological group 2) macroalgae with the SA/V ratios over 500. The number of substrate macroalgal species on the plane of the MG and sampling station was more or less evenly scattered than the average EPD abundance, which was primarily driven by Gambierdiscus and Ostreopsis. Of the total EPD abundance of the five stations, 90.6% were represented by the two most common and abundant genera, Gambierdiscus and Ostreopsis, each accounting for 41.6% and 49.0%. Spatially, 95.9% of the total EPD abundance was found in St. 4 and St. 5, of which St. 4 with higher water temperature had more Ostreopsis spp. (31.8%), and St. 5 with higher salinity had more Gambierdiscus spp. (27.3%). Thus, the environmental transition to favorable T-S condition to MG2, the thin filamentous macroalgal group with very high SA/V ratios, is thus likely to support further success in EPD genera led by Ostreopsis in the coastal waters of Jeju.

• ALGAE
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• 제36권2호
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• pp.91-109
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• 2021

The occurrence of benthic dinoflagellates, many of which are known to be toxic, is a critical concern for scientists, government officers, and people in the aquaculture, dining, and tourism industries. The interest in these dinoflagellates in countries with temperate climate is increasing because tropical or subtropical species introduced into temperate waters by currents are able to survive the winter season in the new environment owing to global warming. Recently, several species from the benthic dinoflagellate genera Amphidinium, Coolia, Ostreopsis, Gambierdiscus, and Prorocentrum have been reported in the waters of the South and East Sea of Korea. The advent of the benthic dinoflagellates in Korean waters is especially important because raw or slightly cooked seaweeds, which may harbor these benthic dinoflagellates, as well as raw fish, which can be potentially intoxicated by phytotoxins produced by some of these benthic dinoflagellates, are part of the daily Korean diet. The recent increase in temperature of Korean coastal waters has allowed for the expansion of benthic dinoflagellate species into these regions. In the present study, we reviewed the species, distribution, and toxicity of the benthic dinoflagellates that have been reported in Korean waters. We also provided an insight into the ecological and socio-economic importance of the occurrence of benthic dinoflagellates in Korean waters.

• 환경생물
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• 제30권4호
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• pp.355-361
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• 2012

우리나라 전국연안에서 해조류에 부착한 저서성 부착 맹독와편모조류의 분포특성을 파악하기 위해서 2011년 11월 25일에서 30일 사이 조사하였다. 해조류에 부착하는 맹독와편모조류 Gambierdiscus spp.는 전국 27개 정점 중 5개 정점[St. 6 (전남고흥군), St. 9 (경남남해군), St. 18 (경북 포항시 구룡포), St. 20 (경북 영덕), St. 26 (강원도 양양)]에서 출현하였다. Ostreopsis spp.는 3개 정점의 해조류[St. 11 (잎꼬시래기, 붉은까막살, 애기풀가사리), St. 18 (진두발, 마디잘록이, 참곱슬이), St. 21 (붉은까막살, 마디잘록이, 큰잎모자반)]에서 출현하였으며, 그중, 정점 18에서는 극히 높은 개체수(140 cells $g^{-1}$)가 관찰되었다. Prorocentrum lima는 서해와 남해안에서는 거의 출현하지 않았으나, 동해해역 대부분의 정점에서 높은 밀도로 출현하였다. Coolia spp.는 서해와 남해안에서는 전혀 출현하지 않았으나, 동해해역 일부 정점에서 극히 낮은 밀도로 출현하였다. 결과적으로 아열대성 저서 와편모조류는 우리나라 대부분의 연안해역 (동해를 중심으로)에 정착하고 있다는 것을 확인 할 수 있었고, 그들의 개체수 밀도는 해조류의 기질과 관련이 있을 것이다.

• 한국식품위생안전성학회지
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• 제10권2호
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• pp.73-79
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• 1995

Incidents of seafood and massive fish kills have been rapidly increasing in both frequency and geographical distribution and the socioeconomic impacts brought by those incidents. However, the biological origins of those marine toxins have not been well clarified. Most of the marine organisms investigated are filter-feeder, which accumulate toxins from their food and/or their symbiotic microalgae. We have examined the action on rabbit platelets of marine toxins isolated from cultured dinoflagellates and sponge collected at Okinawa. Maitotoxin (MTX) is a water-soluble toxin isolated from the cultured dinoflagellate Gambierdiscus toxicus which causes a seafood poisoning in tropical regions. Zooxanthellatoxin A (ZT-A) was isolated from exteracts of cultured symbiotic dinoflagellate Symbiodinium sp. (socalled zooxanthella) from flatworms of the genus Amphiscolops collected at Okinawan marine sponge Theonella sp. MTX caused a disaggregation and a dissolution of large aggregates. ZT-A caused a dissolution of small aggregates followed by a increment of light tranmission. TZ-A caused an initial and transient shape change followed by a sustained aggregation and a increment of large aggregates. In conclusion, marine toxins exert unique patterns on the light trasmission and the size of aggregates in rabbit platelets by their concentrations and kinds