Community Analysis of Dynamic Microbial Mat Communities from Actively Erupting Seamounts (Invited)

The actively erupting deep-sea volcanoes NW Rota-1 and W Mata have multiple diffuse low-temperature (Tmax= 20-30 degrees) vent sites which harbor dense populations of microbial mat communities driven by chemoautotrophy. These microbial mats were often composed of white filamentous bacteria growing in close proximity to focused hydrothermal flow. Eight microbial mats were sampled from discrete hydrothermal vents on NW Rota-1 and W Mata volcanoes in 2009. The microbial mat communities were analyzed with quantitative PCR (Q-PCR) and terminal-restriction fragment length polymorphism (T-RFLP) community fingerprinting. All of the sampled microbial mats were dominated by the class Epsilonproteobacteria. The microbial mat at Iceberg Vent contained 13.5% Archaea, while all other microbial mats contained less than 1% Archaea. Bacterial community fingerprints from NW Rota-1 and W Mata formed distinct clusters that were well separated from clusters formed by hydrothermal communities from Axial and Eifuku Seamounts that were also dominated by Epsilonproteobacteria. Iceberg vent communities from NW Rota-1 have transitioned from being dominated by Caminibacter phylotypes to Sulfuimonas group phylotypes since 2004. These data suggest that microbial communities found on actively erupting volcanoes are geographically distinct and provide a natural laboratory to study microbial colonization and community succession at hydrothermal systems.