The University of Southampton
University of Southampton Institutional Repository

The role of prokaryotes in subsurface weathering of hydrothermal sediments: a combined geochemical and microbiological investigation

Severmann, S., Mills, R.A., Palmer, M.R., Telling, J.P., Cragg, B. and Parkes, R.J. (2006) The role of prokaryotes in subsurface weathering of hydrothermal sediments: a combined geochemical and microbiological investigation Geochimica et Cosmochimica Acta, 70, (7), pp. 1677-1694. (doi:10.1016/j.gca.2005.12.008).

Record type: Article

Abstract

A detailed geochemical and microbiological study of a ~2 m sediment core from the inactive Alvin mounds within the TAG hydrothermal field was conducted to examine, for the first time, the role of prokaryotes in subsurface weathering of hydrothermal sediments. Results show that there has been substantial post depositional remobilisation of metal species and diagenetic overprinting of the original high-temperature hydrothermal minerals, and aspects have involved prokaryotic processes. Prokaryotic enumeration demonstrates the presence of a population smaller than the average for deep sea sediments, probably due to the low organic carbon content, but not inhibited by (and hence adapted to) the metal rich environment. There was a small but significant increase in population size associated with the active redox boundary in an upper metal sulphide layer (50-70 cm) around which active metal remobilisation was concentrated (Cu, Au, Cd, Ag, U, Zn and Zn). Hence, subsurface prokaryotes were potentially obtaining energy from metal metabolism in this near surface zone. Close association of numbers of culturable Mn and Fe reducing prokaryotes with subsurface Fe2+ and Mn2+ pore water profiles suggested active prokaryotic metal reduction at depth in core CD102/43 (to ~175 cm). In addition, a prokaryotic mechanism, which is associated with bacterial sulphate reduction, is invoked to explain the U enrichment on pyrite surfaces and Zn and Pb remobilisation in the upper sediment. Although prokaryotic populations are present throughout this metalliferous sediment, thermodynamic calculations indicated that the inferred low pH of pore waters and the suboxic/anoxic conditions limits the potential energy available from Fe(II) oxidation, which may restrict prokaryotic chemolithotrophic biomass. This suggests that intense prokaryotic Fe oxidation and weathering of seafloor massive sulphide deposits may be restricted to the upper portion of the deposit that is influenced by near neutral pH and oxic seawater unless there is significant subsurface fluid flow.

PDF Severmann_et_al_(2006)_Role_of_microorganism_in_subsurface_weathering_of_hydrothermal_sediments.pdf - Other
Restricted to Registered users only
Download (896kB)

More information

Published date: 2006
Keywords: hydrothermal sediments, pore fluid, trace metal, Fe oxidisers

Identifiers

Local EPrints ID: 35412
URI: http://eprints.soton.ac.uk/id/eprint/35412
ISSN: 0016-7037
PURE UUID: 0be742f5-ed3c-4afb-8d4d-6199abe363cc
ORCID for R.A. Mills: ORCID iD orcid.org/0000-0002-9811-246X

Catalogue record

Date deposited: 15 May 2006
Last modified: 17 Jul 2017 15:47

Export record

Altmetrics

Contributors

Author: S. Severmann
Author: R.A. Mills ORCID iD
Author: M.R. Palmer
Author: J.P. Telling
Author: B. Cragg
Author: R.J. Parkes

University divisions

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×