Species composition of dinoflagellates cysts in ballast tank sediments of foreign ships berthed in Jiangyin Port
In order to explore the species composition and invasion risk of dinoflagellate resting cysts in the sediments of ballast tanks of foreign ships, we identified and analyzed the species of living dinoflagellate cysts in the sediments of five foreign ships ballast tanks in Jiangyin Port based on the morphological characteristics and molecular biology information of dormant cysts and germinating cells. A total of 29 species of dinoflagellate cysts (excluding three unkonwn species), belonging to
... yaulacoid group, Calcoidinellid group, Gymnodinioid group, Diplopsalid group and Protoperidinioid group, were recorded in ballast sediments. The density of living cysts ranged from 0.73 to 44.3 cysts/g DW. Cysts of toxic and harmful dinoflagellate Alexandrium tamarense species complex, Protoceratium reticulatum, and Gonyaulax spinifera were found in five ships. In addition, a variety of unrecorded dinoflagellate cyst types in Chinese coasts have been found, one of which was identified as Alexandrium insuetum. Germination and incubation experiments showed that it can proliferate in coastal waters of China. Therefore, Alexandrium insuetum has potential invasion risk and possibility of bloom in coastal China.