16S library of the picoplankton fraction from water collected at the Chubut River (Chubut Province, Argentina) close to Boca Toma place.
Prefiltered bucket-collected water was successively filtered through membrane filters of decreasing pore sizes (20, 10, 5 and 0.22 µm) to separate the different cell size fractions. The picoplankton was therefore immobilized onto the 0.22 µm membranes. The picoplankton DNA was extracted from the 0.22 µm filters and 16S sequences were amplified using universal primers 27F and 1492R and pyrosequenced with barcode-tagged 27F primer.