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Sediment cooling triggers germination and sulfate reduction by heat-resistant thermophilic spore-forming bacteria

Lookup NU author(s): Dr Angela SherryORCiD, Dr Ana Suarez Suarez, Professor Ian Head, Professor Casey Hubert



This is the authors' accepted manuscript of an article that has been published in its final definitive form by Wiley-Blackwell Publishing Ltd., 2020.

For re-use rights please refer to the publisher's terms and conditions.


Thermophilic endospores are widespread in cold marine sediments where the temperature is too low to support growth and activity of thermophiles in situ. These endospores are likely expelled from warm subsurface environments and subsequently dispersed by ocean currents. The endospore upper temperature limit for survival is 140°C, which can be tolerated in repeated short exposures, potentially enabling transit through hot crustal fluids. Longer‐term thermal tolerance of endospores, and how long they could persist in an environment hotter than their maximum growth temperature, is less understood. To test whether thermophilic endospores can survive prolonged exposure to high temperatures, sediments were incubated at 80–90°C for 6, 12 or 463 days. Sediments were then cooled by 10–40°C, mimicking the cooling in subsurface oil reservoirs subjected to seawater injection. Cooling the sediments induced sulfate reduction, coinciding with an enrichment of endospore‐forming Clostridia. Different Desulfofundulus, Desulfohalotomaculum, Desulfallas, Desulfotomaculum and Desulfofarcimen demonstrated different thermal tolerances, with some Desulfofundulusstrains surviving for >1 year at 80°C. In an oil reservoir context, heat‐resistant endospore‐forming sulfate‐reducing bacteria have a survival advantage if they are introduced to, or are resident in, an oil reservoir normally too hot for germination and growth, explaining observations of reservoir souring following cold seawater injection.

Publication metadata

Author(s): Bell E, Sherry A, Pilloni G, Suárez‐Suárez A, Cramm MA, Cueto G, Head IM, Hubert CRJ

Publication type: Article

Publication status: Published

Journal: Environmental Microbiology

Year: 2020

Volume: 22

Issue: 1

Pages: 456-465

Print publication date: 01/01/2020

Online publication date: 19/11/2019

Acceptance date: 15/11/2019

Date deposited: 21/01/2020

ISSN (print): 1462-2912

ISSN (electronic): 1462-2920

Publisher: Wiley-Blackwell Publishing Ltd.


DOI: 10.1111/1462-2920.14866

Notes: This is the pre-peer reviewed version of the following article: Bell, E., Sherry, A., Pilloni, G., Suárez‐Suárez, A., Cramm, M.A., Cueto, G., Head, I.M. and Hubert, C.R.J. (2020), Sediment cooling triggers germination and sulfate reduction by heat‐resistant thermophilic spore‐forming bacteria. Environ Microbiol, 22: 456-465. doi:10.1111/1462-2920.14866, which has been published in final form at doi:10.1111/1462-2920.14866. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.


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