Biosignatures in chimney structures and sediment from the Loki’s Castle low-temperature hydrothermal vent field at the Arctic Mid-Ocean Ridge ...

We investigated microbial life preserved in a hydrothermally inactive silica–barite chimney in comparison with an active barite chimney and sediment from the Loki’s Castle low-temperature venting area at the Arctic Mid-Ocean Ridge (AMOR) using lipid biomarkers. Carbon and sulfur isotopes were used t...

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Bibliographic Details
Main Authors: Jaeschke, Andrea, Eickmann, Benjamin, Lang, Susan Q., Bernasconi, Stefano M., Strauss, Harald, Früh-Green, Gretchen L.
Format: Article in Journal/Newspaper
Language:English
Published: ETH Zurich 2014
Subjects:
Hydrothermal
Silica chimney
Barite
Biomarker
GDGT
GMGT
Multiple S isotopes
Arctic
The Chimney
Online Access:https://dx.doi.org/10.3929/ethz-b-000081431
http://hdl.handle.net/20.500.11850/81431
Description
Summary:We investigated microbial life preserved in a hydrothermally inactive silica–barite chimney in comparison with an active barite chimney and sediment from the Loki’s Castle low-temperature venting area at the Arctic Mid-Ocean Ridge (AMOR) using lipid biomarkers. Carbon and sulfur isotopes were used to constrain possible metabolic pathways. Multiple sulfur (δ34S, ∆33S) isotopes on barite over a cross section of the extinct chimney range between 21.1 and 22.5 ‰ in δ34S, and between 0.020 and 0.034 ‰ in Δ33S, indicating direct precipitation from seawater. Biomarker distributions within two discrete zones of this silica–barite chimney indicate a considerable difference in abundance and diversity of microorganisms from the chimney exterior to the interior. Lipids in the active and inactive chimney barite and sediment were dominated by a range of 13C-depleted unsaturated and branched fatty acids with δ13C values between −39.7 and −26.7 ‰, indicating the presence of sulfur-oxidizing and sulfate-reducing bacteria. ... : Extremophiles, 18 (3) ...

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