• ALGAE
• /
• 제27권1호
• /
• pp.63-70
• /
• 2012

Algae are sensitive to a wide range of pollutants, and are effective bioindicators in ecotoxicity assessments. Here, we evaluated the sub-lethal sensitivity of the marine dinoflagellate Cochlodinium polykrikoides upon exposure to copper (Cu), lead (Pb), bisphenol A (BPA), and Aroclor 1016 (polychlorinated biphenyl, PCB). Toxic effects were assessed by observations of the reduction in cell counts and chlorophyll a levels after exposure to each toxicant. C. polykrikoides displayed dose-dependent, sigmoidal responses when exposed to the tested chemicals. $EC_{50}$-72 h values for Cu, Pb, BPA, and PCB were 12.74, 46.70, 68.15, and $1.07mg\;L^{-1}$, respectively. PCB, which is an endocrine-disrupting chemical, was the most sensitive, proving its toxic effect on the dinoflagellate. This study provides baseline data on the toxic effects of commonly used heavy metals and endocrine-disrupting chemicals to a marine dinoflagellate.

• 한국수산과학회지
• /
• 제37권3호
• /
• pp.202-208
• /
• 2004

The spatio-temporal distribution of dinoflagellate resting cysts was investigated by palynological processing to understand the harmful algal bloom (HAB) potential in the sediment of the Saemangeun area in 2003. In total, thirty-two dinoflagellate species were identified, and their concentrations were in the range of $6-1,618\;cysts{\cdot}g^{-1}$ (dry weight). The concentrations of resting cysts were higher in the spring (26 species, $64-1,101\;cysts{\cdot}g^{-1})$ and summer (30 species, $81-1,618\;cysts{\cdot}g^{-1})$ than in the autumn (32 species, $6-1,150\;cysts{\cdot}g^{-1})$ and winter (24 species, $25-728\;cysts{\cdot}g^{-1}).$ The composition rate of the heterotrophic dinoflagellate species to the total, which is closely related to the eutrophication process, to ranged from 6 to $29\%$ in the study area. The most dominant species was toxic Alexandrium tamarense/catenella $(25\%)$ followed by Gonyaulax scrippsea $(9\%)$ and toxic Protoceratium reticulatum $(5\%).$ Given the high abundance of the toxigenic dinoflagellate species, the Saemangeun area is considered to have the great potential for HABs in the future.

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

• Fisheries and Aquatic Sciences
• /
• 제12권3호
• /
• pp.227-235
• /
• 2009

The marine toxic dinoflagellate Alexandrium catenella has been implicated in numerous paralytic shellfish poisoning (PSP) events in many countries. Due to difficulties in rapidly identifying A. catenella, field-based study of this species has been problematic. The present study developed a TaqMan format A. catenella-specific probe for real-time PCR assay (specific to Korean genotype) based on LSU rDNA sequence information for studying geographic and temporal distribution of the species in surface sediments and water columns of Jinhae Bay, Korea. The field survey from 2007 to 2008 revealed that A. catenella occurred in most seasons at low densities, mostly below 1 cell $mL^{-1}$, and was more abundant in spring (maximum cell density of 2 cells $mL^{-1}$) when shellfish exceed the quarantine toxin level for PSP toxins in Jinhae Bay.

• Journal of Ecology and Environment
• /
• 제36권4호
• /
• pp.347-370
• /
• 2013

A study on the presence of benthic dinoflagellates in the intertidal zone along the coasts of Jeju Island, Korea was conducted during 2011 and 2012. Identification and taxonomic observations were made of the benthic dinoflagellate samples using light and epifluorescence microscopy. Thirty-seven dinoflagellate taxa belong to five orders, nine families, 18 genera and 30 species, which are new records for Korean waters, were detected in this study. The detailed nomenclature, references, distribution, and illustrations are presented here. The commonly occurring genera were Amphidinium, Coolia, Ostreopsis, Prorocentrum, and Thecadinium. Among the recorded species, 26 were found only in sand sediment, seven in macroalgal samples, and four were found in both sand and macroalgal samples. Of the 37 species, nine were potentially toxic. These results suggest that diversified benthic dinoflagellates including several potentially toxic species occur in sand sediment and macroalgae in the intertidal zone along the coasts of Jeju Island. The morphological features of the identified species were more or less similar to observations made by previous studies in Korea and elsewhere. The presence of known toxic species may indicate a potential risk of toxicity in the marine ecosystem of Jeju Island. The present study can be helpful for further detailed taxonomic, toxicological, molecular phylogenetic studies and may help in the management and conservation of Jeju Island's marine ecosystem.

• 대한원격탐사학회지
• /
• 제38권5_3호
• /
• pp.979-989
• /
• 2022

본 연구는 유독 와편모조류 Alexandrium pacificum의 조기 감지 여부를 조사하기 위해 홀 소자 센서(Hall element sensor)를 활용하여 진주담치(Mytilus edulis)와 참굴(Crassostrea gigas)의 패각운동(shell valve movements, SVMs) 변화를 살펴보았다. 무독성 조류 Isochrysis galbana에 대한 SVMs는 M. edulis와 C. gigas에서 모두 증감이 관찰되지 않았다. 하지만 마비성 패독(paralytic shellfish poisoning, PSP)을 유발하는 A. pacificum에 노출됨에 따라 M. edulis와 C. gigas는 폭로 전후로 약 12시간 동안 평균 SVMs가 각각 1.25 times/hr에서 2.13 times/hr 그리고 2.23 times/hr에서 8.91 times/hr로 증가하였다. M. edulis는 A. pacificum에 노출되고 1시간 이내에 SVMs가 증가한 뒤 점차 감소한 추세를 보였지만, C. gigas는 노출 후 4시간까지도 높은 SVMs를 보여, C. gigas가 M. edulis보다 유독 와편모조류에 대한 민감성이 높은 것으로 보였다. 따라서 이러한 결과들은 유독 와편모조류 A. pacificum의 출현 시 조기 감지를 할 수 있는 생물모니터링 시스템 체계 구축에 기초자료로 활용될 수 있을 것으로 기대된다.

• 한국수산과학회지
• /
• 제40권2호
• /
• pp.95-101
• /
• 2007

We investigated the growth and phosphate uptake of a toxic dinoflagellate, Gymnodinium catenatum, isolated from Yeosuhae Bay, South Korea. A short-term phosphate uptake experiment revealed that its maximum uptake and the half-saturation constant were 1.39 pmol/cell/hr and $2.65{\mu}M$, respectively. In a semicontinuous culture, the maximum specific growth rate and minimum phosphorus cell quota of G. catenatum were 0.39/day and 1.27 pmol/cell, respectively. Thus, G. catenatum is a poor competitor in terms of inorganic nutrient use and is unlikely to form blooms in Yeosuhae Bay.

• ALGAE
• /
• 제26권4호
• /
• pp.317-325
• /
• 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.

• 한국동물학회:학술대회논문집
• /
• 한국동물학회 1998년도 한국생물과학협회 학술발표대회
• /
• pp.212.1-212
• /
• 1998

No Abstract, See Full Text

• Fisheries and Aquatic Sciences
• /
• 제3권1호
• /
• pp.26-32
• /
• 2000

Monospecific red tide by a toxic dinoflagellate belonging to the genus Alexandrium occurred at Chindong Bay in the southern coast of Korea and continued from April 6th to 15th in 1997. The ratio of its cell number to total phytoplankton cell number was much higher than $95\%$. This organism was identified as Alexandrium tamarense, although slight morphological differences were found comparing to the original and successive descriptions of the species. We found neither anterior nor posterior attachment pores in these cells of the bloom population. The occurrence of red tide caused by A. tamarense was first reported in Korea. Its plate formula is Po, Pc, 4', 6"c, 8s, 5"' and 2"". Thecal plates are thin with pore-like ornamentation. In those plates, the anterior part of the first apical plate (1') is narrower and its posterior end has sometimes a block-like accessory, but this variation was considered within the range of the morphological variability of this taxon. The cell density during the red tide exhibited a wide range of variation by the depth of water column, ranging from $2\times10^6$ cells$l^{-1}$ to $5\times10^6$ cells·$l^{-1}$. Water temperature varied from 11.8 to $12.3^{\circ}C$. Toxicity of A. tamarense during red tide was measured as $8.8\times10^5$. $MU\;\cdot\;cell^{-1}$ by mouse bioassay.