Channel: Marine biology http://www.jto.ac.cn EN-US http://www.jto.ac.cn/EN/1009-5470/current.shtml http://www.jto.ac.cn 1009-5470 http://www.jto.ac.cn/EN/10.11978/2022002 Surface sediments were collected on the Dongshan Bay of Fujian Province China in November 2016. Dinoflagellate cysts were analyzed in the sediments with a particular focus on the distribution of toxic and harmful dinoflagellate cysts. The contents of biogenic elements were examined to reveal the relationships between cysts and biogenic elements. A total of 22 cyst taxa were identified, including 14 autotrophic and 8 heterotrophic taxa. Cysts of Protoperidinium dominated in the sediments. Shannon-Wiener diversity index (H') ranged from 1.70 to 2.38, and Pielou’s evenness index (J) ranged between 0.64 and 0.84. Cyst concentrations ranged from 70.6 to 136.4 cysts·g^-1, with an average of 107.2 cysts·g^-1. Cyst concentrations were lower in the Zhangjiang estuary and Bachimen area. The high percentages of cysts of heterotrophic dinoflagellates (averagely 75.5%) suggested the high primary productivity and eutrophication level on the Dongshan Bay. Notably, cysts of seven toxic and/or harmful algal bloom (HAB) species were identified in this study, including cysts of the paralytic shellfish toxin (PSP) producers Alexandrium ostenfeldii and A. catenella/tamarense, the yessotoxin (YTX) producers Gonyaulax spinifera, the potential azaspiracid (AZP) producer Azadinium sp., the ichthyotoxic species Polykrikos hartmannii, and the bloom species Barrufeta bravensis and Scrippsiella acuminata. Cysts of the HAB species generally occurred in small numbers, however, high numbers of cysts of G. spinifera in some stations need to be concerned.

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