The pH and pCO2 dependence of sulfate reduction in shallow-sea hydrothermal CO2 – venting sediments (Milos Island, Greece)

Bayraktarov, Elisa, Price, Roy E., Ferdelman, Tomothy G. and Finster, Kai (2013) The pH and pCO2 dependence of sulfate reduction in shallow-sea hydrothermal CO2 – venting sediments (Milos Island, Greece). Frontiers in Microbiology, 4 111.1-111.10. doi:10.3389/fmicb.2013.00111


Author Bayraktarov, Elisa
Price, Roy E.
Ferdelman, Tomothy G.
Finster, Kai
Title The pH and pCO2 dependence of sulfate reduction in shallow-sea hydrothermal CO2 – venting sediments (Milos Island, Greece)
Journal name Frontiers in Microbiology   Check publisher's open access policy
ISSN 1664-302X
Publication date 2013-05-08
Sub-type Article (original research)
DOI 10.3389/fmicb.2013.00111
Open Access Status DOI
Volume 4
Start page 111.1
End page 111.10
Total pages 10
Place of publication Lausanne, Switzerland
Publisher Frontiers Research Foundation
Language eng
Abstract Microbial sulfate reduction (SR) is a dominant process of organic matter mineralization in sulfate-rich anoxic environments at neutral pH. Recent studies have demonstrated SR in low pH environments, but investigations on the microbial activity at variable pH and CO2 partial pressure are still lacking. In this study, the effect of pH and pCO2 on microbial activity was investigated by incubation experiments with radioactive 35S targeting SR in sediments from the shallow-sea hydrothermal vent system of Milos, Greece, where pH is naturally decreased by CO2 release. Sediments differed in their physicochemical characteristics with distance from the main site of fluid discharge. Adjacent to the vent site (T ∼40-75°C, pH ∼5), maximal sulfate reduction rates (SRR) were observed between pH 5 and 6. SR in hydrothermally influenced sediments decreased at neutral pH. Sediments unaffected by hydrothermal venting (T ∼26°C, pH ∼8) expressed the highest SRR between pH 6 and 7. Further experiments investigating the effect of pCO2 on SR revealed a steep decrease in activity when the partial pressure increased from 2 to 3 bar. Findings suggest that sulfate reducing microbial communities associated with hydrothermal vent system are adapted to low pH and high CO2, while communities at control sites required a higher pH for optimal activity.
Keyword Sulfate Reduction
Sulfate reduction rate
Shallow-sea hydrothermal vents
pH effect
pCO2 effect
Microbial activity
Extreme environment
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ
Additional Notes http://journal.frontiersin.org/Journal/10.3389/fmicb.2013.00111/abstract

Document type: Journal Article
Sub-type: Article (original research)
Collection: Global Change Institute Publications
 
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Created: Mon, 15 Sep 2014, 15:49:18 EST by Elisa Bayraktarov on behalf of Global Change Institute