Study On The Cysts Of Dinoflagellates In Bohai Bay

The distribution of the dinoflagellate cysts were investigated in the Bohai Bay.By analyzing the relationship with,environment,it can show that the changes of the environment.According to the characteristics of the cysts,a total of 6 categories 42 species of cysts were identified,including 15 species of Protoperidinioid,13 species of Gonyanlacoid,6 species of Gymnodinioid,3 species of Calcoidinellid,1 species of Tuberculodinioid,1 species of Diplopsalid and 3 undetermined species.The density of cysts varied in different survey areas.The average density of cysts was 220 cyst/g W in main waterways,anchorages and surrounding sea areas.And the average cyst density from May to August was 123 cyst/g W,153 cyst/g W,150 cyst/g W and 148 cyst/g W in the low-oxygen zone.The average cyst density was relatively low in the annual survey station,in which is only 10 cyst/g W.The cysts of three Yessotoxin(YTX)dinoflagellate species(Lingulodinium polyedra,Gonyaulax spinifera and Protoceratium reticulatum)and three paralytic shellfish poisoning(PSP)dinoflagellate cysts(Gymnodinium catenatum,Alexandrium tamarense,Alexandrium minutum/affine and Gymnodinium catenatum)were also found in this survey.The result help to understand the correlation between cysts and environment,date analysis uncover the cysts is mainly affected by environmental factors,while the phytoplankton is not significant.In addition,the dominant species of cysts Scrippsiella trochoidea was cultivating in the laboratory.The different environmental factors(vitamins,trace elements and CO2 concentration)would have effects on the growth of S.trochoidea.The limitation of trace elements can inhibit the growth of S.trochoidea,while the influence of vitamins is relatively small.The increase of CO2 concentration will have a limited effect on the vegetative cells of S.trochoidea.And the resting cysts formed in different environments.Through the culture experiment,we can understand the life history of S.trochoidea.Results of the present study can provide basic data support for exploring the mechanism of red tide.