Microbial diversity of Loki's Castle black smokers at the Arctic Mid‐ Ocean Ridge

• Published in: Geobiology
• Main Authors: Jaeschke, A., Jørgensen, S. L., Bernasconi, S. M., Pedersen, R. B., Thorseth, I. H., Früh‐Green, G. L.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2012
• Subjects: Arctic; The Chimney
• Online Access: http://dx.doi.org/10.1111/gbi.12009; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fgbi.12009; https://onlinelibrary.wiley.com/doi/pdf/10.1111/gbi.12009

Abstract Hydrothermal vent systems harbor rich microbial communities ranging from aerobic mesophiles to anaerobic hyperthermophiles. Among these, members of the archaeal domain are prevalent in microbial communities in the most extreme environments, partly because of their temperature‐resistant and robust membrane lipids. In this study, we use geochemical and molecular microbiological methods to investigate the microbial diversity in black smoker chimneys from the newly discovered L oki's C astle hydrothermal vent field on the A rctic M id‐ O cean R idge ( AMOR ) with vent fluid temperatures of 310–320 °C and pH of 5.5. Archaeal glycerol dialkyl glycerol tetraether lipids ( GDGT s) and H ‐shaped GDGT s with 0–4 cyclopentane moieties were dominant in all sulfide samples and are most likely derived from both (hyper)thermophilic E uryarchaeota and C renarchaeota . Crenarchaeol has been detected in low abundances in samples derived from the chimney exterior indicating the presence of T haumarchaeota at lower ambient temperatures. Aquificales and members of the E psilonproteobacteria were the dominant bacterial groups detected. Our observations based on the analysis of 16S rRNA genes and biomarker lipid analysis provide insight into microbial communities thriving within the porous sulfide structures of active and inactive deep‐sea hydrothermal vents. Microbial cycling of sulfur, hydrogen, and methane by archaea in the chimney interior and bacteria in the chimney exterior may be the prevailing biogeochemical processes in this system.