Distribution of Dinoflagellate Cysts in Surface Sediments of Japanese Coastal Waters I. Omura Bay, Kyushu

A total of 167-596 cells･cm-3 (mean 348 cells･cm-3) of both living and empty dinoflagellate cysts was found in the surface sediments of Omura Bay, Kyushu, Japan. The dinoflagellate cyst assemblage of the bay predominantly comprised Polykrikos schwartzii, Pheopolykrikos hartmannii and Tuberculodinium vanampoae (=cyst of Pyrophacus seinii), followed by Spiniferites spp. (=cyst of Gonyaulax spp.), Operculodinium centrocarpum (=cyst of Protoceratium reticulatum) and Protoperidinium spp. Cysts of Po. schwartzii and Ph. hartmannii were found especially abundant in the southeastern part of the bay, whereas those of Py. seinii were common to abundant throughout the bay. The cyst assemblage in the surface sediments of Omura Bay was different from the plankton assemblage in composition and dominance ranking