Abstract:
The prokaryotic diversity associated with serpentinization-driven Manleluag Hyperalkaline (pH
11) Spring in Pangasinan, Philippines was investigated. DNA extracted directly from the sediment
samples was used to construct clone libraries based on bacterial and archaeal 16S rRNA gene
sequences. Phylogenetic analysis of 16S rRNA gene sequences from the clone library revealed
that the clones were grouped into Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria,
Cyanobacteria, Bacteroidetes, and Firmicutes. Analysis of the archaeal 16S rRNA clones revealed
the presence of sequences associated with members of Euryarchaeota and Thaumarchaeota. Most
of the sequences from Euryarchaeota were related to Methanobacteria and Methanomicrobia. Some
clones show little affiliation with known taxa and may represent novel sequences of organisms
adapted to the hyperalkaline conditions. The populations found suggest the type of metabolisms
that drive this specific environment, which include ammonia oxidation, and hydrogen-based and
methanogenic metabolisms. This study represents the first analysis of prokaryotic diversity from
community DNA of a hyperalkaline environment in the Philippines.
