18S rRNA:fresh water
V9 region of the 18S rRNA gene were amplified using the primer sets which encode F1391/R1501 for eukaryotes, and the amplicons were sequenced using a 300-cycle MiSeq Reagent Kit v2 on a MiSeq platform with a 2 X 150 bp paired-end run in the presence of 25 % PhiX sequencing control DNA.