Phylogenetic tree based on 16S rRNA sequences bacterial clones from Tirez water column and sediment from the rainy season. The tree topology was constructed with Mr. Bayes. Percentage of probability support in main nodes is indicated if ≥80%. The scale bar represents expected changes per site. Highlighted phylotypes in bold type are prefixed by Rw (rainy water), Rs (rainy sediment), Dw (dry water) and Ds (dry sediment) and followed by cb (clone bacteria) and ID number. The access number and the number of collapsed phylotypes assigned to OTU with ≥97% identity is indicated in parenthesis.