Surface seawater was collected at two sampling sites in Sendai Bay (C5: 141.083W, 37.976N; C12: 141.317W, 37.974N), Miyagi, Japan on October 7 and December 1 in 2013. Suspended particles were concentrated to 100 fold and divided into two subsamples: (1) mixied with DMSO(5%) and frozen to sore in liquid nitrogen, (2) kept non-frozen. Picophytoplankton cells were sorted by flow cytometry. The genomic DNA was extracted and amplified by whole genome amplification. Partial 18S rRNA gene of the eukaryotes was amplified and sequenced using GS junior.