Distribution of archaea in a black smoker chimney structure

Archaeal community structures in microhabitats in a deep-sea hydrothermal v ent chimney structure were evaluated through the combined use of culture-in dependent molecular analyses and enrichment culture methods. A black smoker chimney was obtained from the PACMANUS site in the Manus Basin near Papua New Guinea, and subsamples were obtained from vertical and horizontal secti ons. The elemental composition of the chimney was analyzed in different sub samples by scanning electron microscopy and energy-dispersive X-ray spectro scopy, indicating that zinc and sulfur were major components while an incre ased amount of elemental oxygen in exterior materials represented the prese nce of oxidized materials on the outer surface of the chimney. Terminal res triction fragment length polymorphism analysis revealed that a shift in arc haeal ribotype structure occurred in the chimney structure. Through sequenc ing of ribosomal DNA (rDNA) clones from archaeal rDNA clone libraries, it w as demonstrated that the archaeal communities in the chimney structure cons isted for the most part of hyperthermophilic members and extreme halopbiles and that the distribution of such extremophiles in different microhabitats of the chimney varied. The results of the culture-dependent analysis suppo rted in part the view that changes in archaeal community structures in thes e microhabitats are associated with the geochemical and physical dynamics i n the black smoker chimney.