Carbon Sink Potential of Sulfur-Oxidizing Bacteria in Groundwater at Petroleum-Contaminated Sites

Groundwater at petroleum-contaminated sites typically exhibits elevated dissolved inorganic carbon (DIC) levels due to hydrocarbon biodegradation; however, our prior field investigations revealed an enigmatic DIC depletion anomaly that starkly contradicts this global pattern and points to an unrecog...

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Main Authors: Pingping Cai, Zhuo Ning, Min Zhang
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Microorganisms
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Online Access:https://www.mdpi.com/2076-2607/13/7/1688
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author Pingping Cai
Zhuo Ning
Min Zhang
author_facet Pingping Cai
Zhuo Ning
Min Zhang
author_sort Pingping Cai
collection DOAJ
description Groundwater at petroleum-contaminated sites typically exhibits elevated dissolved inorganic carbon (DIC) levels due to hydrocarbon biodegradation; however, our prior field investigations revealed an enigmatic DIC depletion anomaly that starkly contradicts this global pattern and points to an unrecognized carbon sink. In a breakthrough demonstration, this study provides the first experimental confirmation that sulfur-oxidizing bacteria (SOB) drive substantial carbon sequestration via a coupled sulfur oxidation autotrophic assimilation process. Through integrated hydrochemical monitoring and 16S rRNA sequencing in an enrichment culture system, we captured the complete DIC transformation trajectory: heterotrophic acetate degradation initially increased DIC to 370 mg/L, but subsequent autotrophic assimilation by SOB dramatically reduced DIC to 270 mg/L, yielding a net consumption of 85 mg/L. The distinctive pH dynamics (initial alkalization followed by acidification) further corroborated microbial regulation of carbon cycling. Critically, <i>Pseudomonas stutzeri</i> and <i>P. alcaliphila</i> were identified as the dominant carbon-fixing agents. These findings definitively establish that chemolithoautotrophic SOB convert DIC into organic carbon through a “sulfur oxidation-carbon fixation” coupling mechanism, overturning the conventional paradigm of petroleum-contaminated sites as perpetual carbon sources. The study fundamentally redefines natural attenuation frameworks by introducing microbial carbon sink potential as an essential assessment metric for environmental sustainability.
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spelling doaj-art-e1e775e22c924befb4a8856e9bdc2b632025-08-20T02:47:19ZengMDPI AGMicroorganisms2076-26072025-07-01137168810.3390/microorganisms13071688Carbon Sink Potential of Sulfur-Oxidizing Bacteria in Groundwater at Petroleum-Contaminated SitesPingping Cai0Zhuo Ning1Min Zhang2School of Water Resources and Environment, Hebei GEO University, Shijiazhuang 050031, ChinaInstitute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, Shijiazhuang 050061, ChinaInstitute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, Shijiazhuang 050061, ChinaGroundwater at petroleum-contaminated sites typically exhibits elevated dissolved inorganic carbon (DIC) levels due to hydrocarbon biodegradation; however, our prior field investigations revealed an enigmatic DIC depletion anomaly that starkly contradicts this global pattern and points to an unrecognized carbon sink. In a breakthrough demonstration, this study provides the first experimental confirmation that sulfur-oxidizing bacteria (SOB) drive substantial carbon sequestration via a coupled sulfur oxidation autotrophic assimilation process. Through integrated hydrochemical monitoring and 16S rRNA sequencing in an enrichment culture system, we captured the complete DIC transformation trajectory: heterotrophic acetate degradation initially increased DIC to 370 mg/L, but subsequent autotrophic assimilation by SOB dramatically reduced DIC to 270 mg/L, yielding a net consumption of 85 mg/L. The distinctive pH dynamics (initial alkalization followed by acidification) further corroborated microbial regulation of carbon cycling. Critically, <i>Pseudomonas stutzeri</i> and <i>P. alcaliphila</i> were identified as the dominant carbon-fixing agents. These findings definitively establish that chemolithoautotrophic SOB convert DIC into organic carbon through a “sulfur oxidation-carbon fixation” coupling mechanism, overturning the conventional paradigm of petroleum-contaminated sites as perpetual carbon sources. The study fundamentally redefines natural attenuation frameworks by introducing microbial carbon sink potential as an essential assessment metric for environmental sustainability.https://www.mdpi.com/2076-2607/13/7/1688petroleum-contaminated aquiferscarbon sink effectsulfur-oxidizing bacteria
spellingShingle Pingping Cai
Zhuo Ning
Min Zhang
Carbon Sink Potential of Sulfur-Oxidizing Bacteria in Groundwater at Petroleum-Contaminated Sites
Microorganisms
petroleum-contaminated aquifers
carbon sink effect
sulfur-oxidizing bacteria
title Carbon Sink Potential of Sulfur-Oxidizing Bacteria in Groundwater at Petroleum-Contaminated Sites
title_full Carbon Sink Potential of Sulfur-Oxidizing Bacteria in Groundwater at Petroleum-Contaminated Sites
title_fullStr Carbon Sink Potential of Sulfur-Oxidizing Bacteria in Groundwater at Petroleum-Contaminated Sites
title_full_unstemmed Carbon Sink Potential of Sulfur-Oxidizing Bacteria in Groundwater at Petroleum-Contaminated Sites
title_short Carbon Sink Potential of Sulfur-Oxidizing Bacteria in Groundwater at Petroleum-Contaminated Sites
title_sort carbon sink potential of sulfur oxidizing bacteria in groundwater at petroleum contaminated sites
topic petroleum-contaminated aquifers
carbon sink effect
sulfur-oxidizing bacteria
url https://www.mdpi.com/2076-2607/13/7/1688
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AT zhuoning carbonsinkpotentialofsulfuroxidizingbacteriaingroundwateratpetroleumcontaminatedsites
AT minzhang carbonsinkpotentialofsulfuroxidizingbacteriaingroundwateratpetroleumcontaminatedsites