Phylogenetic Diversity of the Archaeal Component in Microbial Mats on Coral-like Structures Associated with Methane Seeps in the Black Sea

With the use of molecular ecology methods, the archaeal component of microbial mats on coral-like structures associated with methane seeps occurring at a depth of about 200 m in the Black Sea was investigated without the isolation of pure cultures. Using archaea-specific 16S rDNA–targeted oligonucleotide primes, long fragments of genes were amplified, cloned, and sequenced and their phylogenetic analysis was carried out. It was shown that archaea in microbial mats on coral-like structures are represented by two dominant phylotypes that belong to the kingdoms Crenarchaeota and Euryarchaeota and are not specifically related to any described archaeal species. The possible role of the revealed archaea in the process of anaerobic methane oxidation is discussed.