Figure 3.

16S rRNA phylogenetic tree and species richness of aerobic methanotrophs. (A) Nucleotide phylogeny of the predicted 16S rRNA pyrotags generated from ATII-I (red), DD-I (orange) and KB-U/KB-L (green). Blue sequences represent 16S rRNA derived from marine environments. Red Sea brine pool OTUs based on 99% sequence identity were compared with SILVA 16S rRNA. The tree was generated using an 1891-bp alignment. The numbers of sequences collapsed in the selected node are indicated adjacent to the sample name. The trees were calculated using the maximum-likelihood approach with 100 bootstrap resampling. Bootstrap values ≥50% are depicted as open circles and those ≥70% with closed circles. The scale bar represents 10% estimated sequence divergence. (B) Species richness in the ATII-I, DD-I, KB-U and KB-L brine-seawater interface layers based on 16S rRNA pyrotag rarefaction curve analysis. Phylotypes were generated based on a distance threshold of 0.01.