• Journal of Ecology and Environment
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• v.36 no.4
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• pp.273-291
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• 2013

Dinoflagellate species composition has changed around Jeju Island as well as in Korean waters due to global warming and climate changes. An investigation was conducted to monitor changes in planktonic dinoflagellates around Jeju Island from June 2006 to September 2009. A total of 86 species belonging to 14 families and 15 genera were identified, of which 34 species were newly recorded in Korean waters. Among the newly recorded species, >20 were confirmed as tropical species. Thus, the occurrence of such tropical dinoflagellates could be an indicator to monitor of environmental changes including global warming around Jeju Island and in Korean waters.

• Journal of Ecology and Environment
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• v.38 no.4
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• pp.599-609
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• 2015

A total of 19 species of three genera Dinophysis, Histioneis, and Parahistioneis of the family Dinophysaceae are reported here from samples obtained using a 20-µm mesh net from June 2006 to December 2014 around Jeju Island including the East China Sea, and 16 of these species are new to Korean waters. A checklist of the three genera of dinoflagellates reported from coastal and oceanic Korean waters is presented. Short descriptions and synonyms are given for each species. The dinoflagellates of the family Dinophysaceae belong to mostly marine species, and include many tropical and/or subtropical species. Recently, the composition of dinoflagellate species has changed around Jeju Island as well as in Korean waters due to global warming and climate change. Tropical and subtropical dinoflagellates occur frequently in the coastal waters of Jeju Island, which reflects the ecosystem shift around the sea adjacent to Jeju Island from a temperate to a subtropical / tropical region.

• ALGAE
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• v.36 no.2
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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.

• Animal cells and systems
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• v.15 no.4
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• pp.315-324
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• 2011

The actiniarian sea anemone, Entacmaea quadricolor, and the scleractinian coral, Alveopora japonica, host symbiotic dinoflagellates belonging to the genus Symbiodinium (Freudenthal). We studied the host-symbiont specificity of these two anthozoan hosts in the northwestern Pacific Ocean. Symbionts within the two hosts were identified using partial large subunit (LSU) ribosomal DNA (rDNA) and complete internal transcribed spacers (ITS) 1 rDNA regions. The host, E. quadricolor, was identified using the partial LSU rDNA molecular marker. Genetic analysis showed that E. quadricolor only harbors dinoflagellates belonging to subclade C1/3 of the genus Symbiodinium. Moreover, no genetic variation was detected among the symbionts of E. quadricolor within the study region (Korea and Japan), even though the two distant sites were separated by more than 1000 km, at collection depths of 1 m in shallow and 13-16 m in deep water. Whilst scleractinian corals host multiple Symbiodinium clades in tropical waters, A. japonica, sampled over a wide geographical range (800 km) within the study region, only hosts Symbiodinium sp. clade F3. The high specificity of endosymbionts in E. quadricolor and A. japonica within the northwestern Pacific Ocean could be accounted for because symbiotic dinoflagellates within the host anemones appear to be acquired maternally, and the Kuroshio Current might affect the marine biota of the northwestern Pacific. However, the consistency of the symbiotic relationships between these two anthozoan hosts and their endosymbionts could change after climate change, so this symbiotic specificity should be monitored.

• Korean Journal of Environmental Biology
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• v.30 no.4
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• pp.355-361
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• 2012

Genus of Gambierdiscus, Ostrepsis, Prorocentrum, Coolia and Amphidinium are epiphytic ciguatoxin-producing armored dinoflagellate, often attached on macroalgae. These organisms are the primary causative agent of ciguatera fish poisoning which occurs in tropical and subtropical regions. However, regardless of the fact that population of epiphytic dinoflagellates have expanded to such temperate areas from sub-trophic and trophic areas, monitoring of the epiphytic dinoflagellates was greatly lacked in coastal water of Korean Peninsula. This study was performed in the Korean Peninsula in November, 2011. Cell densities of Gambierdiscus spp. on macroalgae ranged from zero to 10 cells $g^{-1}$ and the maximum density was recorded at St.18 (Pohang guryongpo). The abundance of Ostreopsis spp. was highest on macro-algaes Chondrus ocellatus, Lomentaria catenata and Plocamium telfairiae (140 cells $g^{-1}$). The maximum abundance of Prorocentrum, Coolia and Amphidinium were 52, 3 and 1 cells $g^{-1}$, respectively. Of these, Prorocentrum lima was observed at most stations of East Sea. Therefore, our results suggest that the epiphytic armored dinoflagellates may have adapted to Korean coastal water of temperate areas (i.e., East Sea) and those abundances may be related to the macroalgal species.

• Ocean and Polar Research
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• v.35 no.4
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• pp.415-425
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• 2013

In order to understand phytoplankton and bacterial distribution in tropical coral reef ecosystems in relation to the mangrove community, their biomass and activities were measured in the sea waters of the Chuuk and the Kosrae lagoons located in Micronesia. Chlorophyll a and bacterial abundance showed maximal values in the seawater near the mangrove forests, and then steeply decreased as the distance increased from the mangrove forests, indicating that environmental conditions for these microorganisms changed greatly in lagoon waters. Together with chlorophyll a, abundance of Synechococcus and phototrophic picoeukaryotes and a variety of indicator pigments for dinoflagellates, diatoms, green algae and cryptophytes also showed similar spatial distribution patterns, suggesting that phytoplankton assemblages respond to the environmental gradient by changing community compositions. In addition, primary production and bacterial production were also highest in the bay surrounded by mangrove forest and lowest outside of the lagoon. These results suggest that mangrove waters play an important role in energy production and nutrient cycling in tropical coasts, undoubtedly receiving large inputs of organic matter from shore vegetation such as mangroves. However, the steep decrease of biomass and production of phytoplankton and heterotrophic bacteria within a short distance from the bay to the level of oligotrophic waters indicates that the effect of mangrove waters does not extend far away.

• Journal of Food Hygiene and Safety
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• v.10 no.2
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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

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.2
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• pp.143-150
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• 1984

A field survey and experiment on aquaculture in Costa Rica including Nicoya Gulf was carried out for a month, December $2{\sim}28$, 1981. 1) Air temperature was $27{\sim}32^{\circ}C$, water temperature, $28{\sim}29.5^{\circ}C$ and salinity, $20{\sim}28.5\%$ both in the surface and 5 m layer on December 22, 1981. 2) Dissolved oxygen plentiful, $7.3{\sim}9.95\;ml/l$. 3) Mean precipitation for the past ten years in Nicoya Gulf area was $1298.6{\sim}2196.3$ mm near Puntarenas area and rainy days a year was 137.7, Most rainfalls was concentrated from May to November, the rainy season. 4) Precipitation in main oyster farms near Chungmu, Korea was 1836.0mm a year and it was similar to that of Costa Rica. 5) Diatoms were 16 species belonged to 13 genera and dinoflagellates, 3 species belonged to 2 genera. Standing crops was $639{\sim}130,211\;cells/l$ and dominant species were Chaeteocros curvisetus, Chaetoceros decipiens, Nitzschia serata. Thalassiothrix mediterranca, a tropical esturary species, was found. 6) Nicoya Gulf has the good environmental factors in the water temperature, salinity, dissolved oxygen and planktons, and it is desirable to experiment and culture the oyster (Crassostrea rhrizophorae).

• Korean Journal of Environmental Biology
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• v.35 no.3
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• pp.361-372
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• 2017

This study described the spatial distribution of dinoflagellate cyst assemblages in the Ulsan Coastal Waters (UCW). Surface sediment samples from 15 stations revealed the occurrence of 33 species involving the Groups Protoperidinioid (51.5%), Gonyaulacoid (30.4%), Calciodineloid (9.1%), Gymnodinioid (3.0%), Diplopsallid (3.0%) and Tuberculodinioid (3.0%). The recorded cyst abundance in the UCW recorded was low ($260{\sim}1,680cysts\;g-dry^{-1}$) compared to Korean coastal waters. The abundance of heterotrophic cysts is higher in the Ulsan harbour and northwestern parts of UCW with eutrophic areas, however autotrophic species are more prevalent in the southern parts with open sea environments. The dinoflagellate cyst assemblages in the UCW were characterized by the dominance of Gonyaulax scrippsae, Protoperidinium sp. (Brigantedinium sp.), and Gonyaulax spinifera complex. The advent of the toxic dinoflagellate, Pyrodinium bahamense var. bahamense was recorded for the first time in the East-south sea of Korea. Therefore, as a result of ongoing monitoring and management for new toxic dinoflegallates from tropical or subtropical regions, analysis of dinoflagellate cyst assemblages in the UCW has been deemed necessary.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.4
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• pp.310-321
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• 2016

This study describes the spatial distribution of dinoflagellate cyst assemblages from the fishing ports along Jeju Island. Surface sediment samples from 22 stations revealed the occurrence of 29 species involving the Groups Protoperidinioid (44.8%), Gonyaulacoid (31.0%), Calciodineloid (10.3%), Gymnodinioid (6.9%), Diplosalid (3.5%) and Tuberculodinioid (3.5%). The cyst abundance recorded here is very low ($13{\sim}220cysts\;g-dry^{-1}$) as compared to Korean coastal regions. The abundance of heterothophic cysts increased in several fishing pots with fine sediments and anthropogenic tidal pools. And cyst abundance was well correlated with the grain-size composition of surface sediments. The dinoflagellate cyst assemblages in Jeju fishing ports were characterized by the dominant species, cyst of Gymnodinium sp., cyst of Pyrodinium bahamense and cyst of Scrippsiella trochoidea in 2012, Protoperidinium sp. (Brigantedinium sp.), cyst of Scrippsiella sp./trochoidea and cyst of Gymnodinium sp. in 2014, and Protoperidinium sp. (Echinidinium sp. and Brigantedinium sp.) in 2016. The advent of the toxic dinoflagellate, Pyrodinium bahamense were recorded for the first time in Jeju coastal waters. As a results, we are determined should be to monitoring and management measures for new toxic dinoflegallates from tropical or subtropical reigions and anthropogenic tidal pools by industrial activities.