Fingerprinting microbial assemblages from the oxic/anoxic chemocline of the Black Sea

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.