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    Biogeochemical probing of microbial communities in a basalt-hosted hot spring at Kverkfjöll volcano, Iceland

    Cousins, C.. and Fogel, M. and Bowden, R. and Crawford, Ian and Boyce, A. and Cockell, C. and Gunn, M. (2018) Biogeochemical probing of microbial communities in a basalt-hosted hot spring at Kverkfjöll volcano, Iceland. Geobiology 16 (5), pp. 507-521. ISSN 1472-4677.

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    Abstract

    We investigated bacterial and archaeal communities along an ice‐fed surficial hot spring at Kverkfjöll volcano—a partially ice‐covered basaltic volcano at Vatnajökull glacier, Iceland, using biomolecular (16S rRNA, apsA, mcrA, amoA, nifH genes) and stable isotope techniques. The hot spring environment is characterized by high temperatures and low dissolved oxygen concentrations at the source (68°C and <1 mg/L (±0.1%)) changing to lower temperatures and higher dissolved oxygen downstream (34.7°C and 5.9 mg/L), with sulfate the dominant anion (225 mg/L at the source). Sediments are comprised of detrital basalt, low‐temperature alteration phases and pyrite, with <0.4 wt. % total organic carbon (TOC). 16S rRNA gene profiles reveal that organisms affiliated with Hydrogenobaculum (54%–87% bacterial population) and Thermoproteales (35%–63% archaeal population) dominate the micro‐oxic hot spring source, while sulfur‐oxidizing archaea (Sulfolobales, 57%–82%), and putative sulfur‐oxidizing and heterotrophic bacterial groups dominate oxic downstream environments. The δ13Corg (‰ V‐PDB) values for sediment TOC and microbial biomass range from −9.4‰ at the spring's source decreasing to −12.6‰ downstream. A reverse effect isotope fractionation of ~3‰ between sediment sulfide (δ34S ~0‰) and dissolved water sulfate (δ34S +3.2‰), and δ18O values of ~ −5.3‰ suggest pyrite forms abiogenically from volcanic sulfide, followed by abiogenic and microbial oxidation. These environments represent an unexplored surficial geothermal environment analogous to transient volcanogenic habitats during putative “snowball Earth” scenarios and volcano–ice geothermal environments on Mars.

    Metadata

    Item Type: Article
    Additional Information: This is the peer reviewed version of the article, which has been published in final form at the link above. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.
    School: School of Science > Earth and Planetary Sciences
    Depositing User: Administrator
    Date Deposited: 07 Jun 2018 07:22
    Last Modified: 11 Feb 2021 11:44
    URI: https://eprints.bbk.ac.uk/id/eprint/22705

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