Resting cysts of potentially harmful dinoflagellates in Korean coastal area

Abstract

The frequency of harmful algal blooms (HABs) has been increasing dramatically since the 1980’s in Korean coastal waters, caused by the cyst-forming dinoflagellates. Although the distribution of dinoflagellate resting cysts has been widely investigated in Korean coastal areas, morphological characteristics of resting cysts of potentially harmful dinoflagellates are still unclear. Here we provide the descriptions of these potentially harmful dinoflagellates cysts in detail to help a better understanding of the morphological characteristics and biogeographic distribution of potentially harmful dinoflagellates. Sediment samples were collected from 51 stations in the southern coastal area, Korea. Viable resting cysts were isolated and induced to excysts, and identification was based on morphological characteristics and molecular phylogenetic positions of the germinated cells. 9 potentially harmful dinoflagellate species were identified: 7 potentially toxic species and 2 potentially bloom-forming species. The resting cysts of Gymnodinium aureolum, which has a smooth, thin wall and many pale lipid globules, were first observed from natural sediments. The presence of resting cysts of potentially harmful dinoflagellates suggests that further research deserves more attention and efforts in HAB monitoring and management.investigated in Korean coastal areas, morphological characteristics of resting cysts of potentially harmful dinoflagellates are still unclear. Here we provide the descriptions of these potentially harmful dinoflagellates cysts in detail to help a better understanding of the morphological characteristics and biogeographic distribution of potentially harmful dinoflagellates. Sediment samples were collected from 51 stations in the southern coastal area, Korea. Viable resting cysts were isolated and induced to excysts, and identification was based on morphological characteristics and molecular phylogenetic positions of the germinated cells. 9 potentially harmful dinoflagellate species were identified: 7 potentially toxic species and 2 potentially bloom-forming species. The resting cysts of Gymnodinium aureolum, which has a smooth, thin wall and many pale lipid globules, were first observed from natural sediments. The presence of resting cysts of potentially harmful dinoflagellates suggests that further research deserves more attention and efforts in HAB monitoring and management.