Algae. 1997; 12(4): 269-276.

Harmful and Toxic Red Tide Algal Development and Toxins Production in Korean Coastal Waters

Chang-Hoon Kim, Jae-Beom Shin

Research Center for Ocean Industrial Development, Pukyong National University

To monitor the extensive outbreaks of harmful algal blooms and paralytic shellfish poisoning in Korean coastal waters, a monitoring program was undertaken concerning occurrences of harmful and toxic microalgae in Chinhae Bay since 1994. To clarify the toxin production of causative dinoflagellates Alexandrium species collected from different regions and Gymnodinium catenatum, 20 axenic clonal isolates were subjected to PSP toxin analysis by HPLC. In 1995, the most extensive and long lasting blooms by the dinoflagellates Ceratium furca and Cochlodinium polykrikoides, occurred in succession and spread into new areas throughout the southwestern to eastern coasts from September to October. Since then, the latter blooms occurred annually in the same season and caused serious fisheries damage. More recently, diatom Pseudonitzschia, known as domoic acid producer frequently forms red tides, and toxic dinoflagellates Alexandrium tamarense, Dinophysis spp. and Gymnodinium catenatum appear with high density in Chinhae Bay. In Chinhae Bay, Alexandrium motil cells appeared in January, and reached high concentration from march to May. Mussels became toxic in February and showed the highest level of toxicity in April to May. Alexandrium resting cysts were also found at every station surveyed, but the abundance was highly variablc in a concentration range of 200-2,000 cysts/cm super(3). Germinability of cysts collected from sediment samples changed dramaticall with annual rhythmic pattern by showing a higher frequency in the cold season and a lower one in summer season. Motile cells recurrent in the cold season could result from the germination of their cysts which have been controlled largely by an endogenous annual clock. Toxin profiles of Alexandrium strains, origination from different areas, contained C1/C2 and GTX1/GTX4 in large proportions, except for an isolate from Tadaepo, but the toxin compositions(mole %) were rather uniform within a geographical region. In G. catenatum, of which toxin production was first confirmed in Korean waters, toxin profiles including C1/C2, C3 and dcGTX3 as the major components were clearly distinguished from those of Alexandrium tamarense. Considering the extensive occurrence of harmful and toxic algal species with the same seasonality as a cyst germination, it is suggested that monitoring for the prediction of regional impacts should be undertaken based on the life cycle strategies and harmful consequences of causative organisms.

Keywords : Alexandrium species, Cochlodinium polykrikodes, endogenous annual clock, Gymnodinium catenatum, harmful algal blooms, HPLC-PSP toxin analysis, toxic microalgae