A PRELIMINARY STUDY OF CALCAREOUS NANNOPLANKTON IN BOTTOM SEDIMENTS OF THE EAST CHINA SEA

Calcareous nannoplankton from surface sediments of the East China Sea was investigated for the first time.As revealed by the preliminary study,coccoliths are highly concentrated in sediments at the outer edge of the continental shelf and on the continental slope,being decreasing in number towarels deeper(bottom of the Ryukyu Trench)and shallower watef areas.The calcareous nannoplankton of the northern part of the East China Sea is dominated by wide-spred species such as Gephyrocapsa oceanico Kamptner and Emiliunia huxleyi(Lohmann)Hay and Mohler. The species diversity is rising southwards,with appearence of some warm-water species,as Helicopontosphueru kamptneri Hay and Mohler,Umbilicosphaera mirabilis Lohmann,Ceratolithus cristatus Kamptner,Rhabdosphner still fer Lohmann, Thoracosphaera sp.,Syrucosphaerd sp.and Bruarudosphaera bigelowi(Gran and Braarud)Deflandre etc.It is suggested,therefore,the main part of the East China Sea belongs to the North subtropic zone in the pacific biogeography zonation of nannoplankton,but its northernmost part——to the Boreal zone.