Study on the diversity and germination of dinoflagellate cysts in the sediments of foreign ships in Shanghai Port

The dinoflagellate cysts present in the ballast water sediment of foreign ships in Shanghai Port have not been previously studied. Therefore, sediment samples were collected from the ballast water of 16 foreign ships in Shanghai Port, and the types of dinoflagellate cysts were identified and their abundance was calculated, with a specific focus on the analysis of toxic and harmful dinoflagellates. Moreover, simulations of temperature and salinity conditions throughout the year in the Shanghai port waters were conducted to carry out dinoflagellate cyst germination experiments, with analyze and compare the germinated dinoflagellate cysts under different conditions. Dinoflagellate cysts were found in 100 % of the ship sediment samples, including a total of 9 species of toxic and harmful dinoflagellate cysts. In the germination experiment, 15 °C was found to be the optimal temperature for the germination of dinoflagellate cysts in ballast water sediment, and high salinity is more favorable for cyst germination. •15°C is more suitable for the germination of dinoflagellate cysts in ballast water sediment.•Dinoflagellate cysts, including 9 toxic and harmful species, were found in 100% of the ballast water sediment.•Seawater is more conducive to the germination of dinoflagellate cysts than freshwater.