Respiratory quinones in Archaea: phylogenetic distribution and application as biomarkers in the marine environment.
Biomass samples from the Black Sea collected in 1988 were analyzed for SSU genes from Bacteria and Archaea after 10 years of storage at -80 degrees C. Both clonal libraries and direct fingerprinting by terminal restriction fragment length polymorphism (T-RFLP) analyses were used to assess the microbial community. Uniform and discrete depth distributions of different SSU phylotypes were observed. However, most recombinant clones were not restricted to a specific depth in the water column, and many of the major T-RFLP peaks remain uncharacterized. Of the clones obtained, an epsilon-Proteobacteria and a Pseudoalteromonas-like clone accounted for major peaks in the fingerprint, while deeply branching lineages of alpha- and gamma-Proteobacteria were associated with smaller peaks. Additionally, members were found among both the delta-Proteobacteria related to sulfate reducers and the Archaea related to phylotypes from the ANME groups that anaerobically oxidize methane.