Coccolithophores are important microorganism for the carbon and sulfur cycles. Coccolithophores bloom was found on 3 October 2007 in Suruga Bay. The seasonal appearance of coccolithophores and the relationship between nutrients are as follows.1. Coccolithophores generally increased in spring and showed the maximum in May. In spring they distributed more offshore surfaces than coastal area. The whole cell density decreased in summer and became the peak in October. 2. The dominant species was Emiliania huxleyi. 3. Increase of coccolithophores at the forehead of stratification appeared after the bloom of small diatoms. As for the nutrients, phosphate and silicate were less than the half of saturation constant of diatoms, while nitrate still remained, of which concentration sufficient for coccolithophores to increase.
