STUDY ON PLANKTONIC CHARACTERISTICS OF MARINE BENTHIC DINOFLAGELLATES

A study on the plaktonic characteristics of benthic dinoflagellates was carried out in a sandy beach of Yashima Bay, the Seto Inland Sea, Japan. The result showed that eight species of benthic dinoflagellates, namely Amphidinium carterae, A. klebsii, Amph. herdmanae, Gymnodinium sp 1, G. pyrenoidosum, Peridinium quinquecorne, Prorocentrum emarginatum and Pror. sp 1, were presented in the seawater samples, accounting for 11.6% of total dinoflagellate species number and 0 -51.3% of dinoflagellate cell density found in the water column during the sampling period. Comparing the distribution patterns of their cell density in sand with that in water column, it revealed that all of the species should be regarded as benthos rather than plankton, implying that their planktonic behavior was only a kind of pluralistic characteristics of behavior, resulted from the adaptation of there dynamic habitat during the long-term succession. Finally, the potential outbreak of red tide and its influence, caused by benthic dinoflagellates, in the near shore and inner bay waters was discussed.