Biogeochemistry and microbial ecology of methane oxidation in anoxic environments: a review. Anton Leeuwenhoek Int J G 81: 271-282

Scripps Institution of Oceanography, University of California at San Diego, 92093-0202, USA.
Antonie van Leeuwenhoek (Impact Factor: 1.81). 09/2002; 81(1-4):271-82. DOI: 10.1023/A:1020587206351
Source: PubMed


Evidence supporting a key role for anaerobic methane oxidation in the global methane cycle is reviewed. Emphasis is on recent microbiological advances. The driving force for research on this process continues to be the fact that microbial communities intercept and consume methane from anoxic environments, methane that would otherwise enter the atmosphere. Anaerobic methane oxidation is biogeochemically important because methane is a potent greenhouse gas in the atmosphere and is abundant in anoxic environments. Geochemical evidence for this process has been observed in numerous marine sediments along the continental margins, in methane seeps and vents, around methane hydrate deposits, and in anoxic waters. The anaerobic oxidation of methane is performed by at least two phylogenetically distinct groups of archaea, the ANME-1 and ANME-2. These archaea are frequently observed as consortia with sulfate-reducing bacteria, and the metabolism of these consortia presumably involves a syntrophic association based on interspecies electron transfer. The archaeal member of a consortium apparently oxidizes methane and shuttles reduced compounds to the sulfate-reducing bacteria. Despite recent advances in understanding anaerobic methane oxidation, uncertainties still remain regarding the nature and necessity of the syntrophic association, the biochemical pathway of methane oxidation, and the interaction of the process with the local chemical and physical environment. This review will consider the microbial ecology and biogeochemistry of anaerobic methane oxidation with a special emphasis on the interactions between the responsible organisms and their environment.

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    • "This could explain the lack of sulfide inhibition in seep sediments that showed AOM activity under conditions where 10 – 15 mM sulfide was produced ( Nauhaus et al . , 2002 ; Valentine , 2002 ; Joye et al . , 2004 ) . "
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    ABSTRACT: Extensive geochemical data showed that significant methane oxidation activity exists in marine sediments. The organisms responsible for this activity are anaerobic methane-oxidizing archaea (ANME) that occur in consortia with sulfate-reducing bacteria. A distinct zonation of different clades of ANME (ANME-1, ANME-2a/b, and ANME-2c) exists in marine sediments, which could be related to the localized concentrations of methane, sulfate, and sulfide. In order to test this hypothesis we performed long-term incubation of marine sediments under defined conditions with methane as a headspace gas: low or high sulfate (±4 and ±21 mM, respectively) in combination with low or high sulfide (±0.1 and ±4 mM, respectively) concentrations. Control incubations were also performed, with only methane, high sulfate, or high sulfide. Methane oxidation was monitored and growth of subtypes ANME-1, ANME-2a/b, and ANME-2c assessed using qPCR analysis. A preliminary archaeal community analysis was performed to gain insight into the ecological and taxonomic diversity. Almost all of the incubations with methane had methane oxidation activity, with the exception of the incubations with combined low sulfate and high sulfide concentrations. Sulfide inhibition occurred only with low sulfate concentrations, which could be due to the lower Gibbs free energy available as well as sulfide toxicity. ANME-2a/b appears to mainly grow in incubations which had high sulfate levels and methane oxidation activity, whereas ANME-1 did not show this distinction. ANME-2c only grew in incubations with only sulfate addition. These findings are consistent with previously published in situ profiling analysis of ANME subclusters in different marine sediments. Interestingly, since all ANME subtypes also grew in incubations with only methane or sulfate addition, ANME may also be able to perform anaerobic methane oxidation under substrate limited conditions or alternatively perform additional metabolic processes.
    Frontiers in Microbiology 10/2015; 6(p.988). DOI:10.3389/fmicb.2015.00988 · 3.99 Impact Factor
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    • "The co-existence of this group with the sulfur reducing thermophilic Archaeoglobales, Thermoccocales and Thermoplasmatales orders detected in this study is consistent with a frequently observed vent assemblage, as identified in Rainbow sediments (Reed et al., 2009; Roussel et al., 2011). Members in such assemblage that undergo anaerobic oxidation of methane " shuttle " the reduced compounds to the sulfate-reducing members (Valentine, 2002). The abundance of ANME-1 suggests that sulfate reduction reactions are probably being fuelled by methane, in the VC site. "
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    ABSTRACT: Deep-sea hydrothermal sediments are known to support remarkably diverse microbial consortia. Culture-independent sequence-based technologies have extensively been used to disclose the associated microbial diversity as most of the microorganisms inhabiting these ecosystems remain uncultured. Here we provide the first description of the microbial community diversity found on sediments from Menez Gwen vent system. We compared hydrothermally influenced sediments, retrieved from an active vent chimney at 812 m depth, with non-hydrothermally influenced sediments, from a 1400 m depth bathyal plain. Considering the enriched methane and sulfur composition of Menez Gwen vent fluids, and the sediment physicochemical properties in each sampled area, we hypothesized that the site-associated microbes would be different. To address this question, taxonomic profiles of bacterial, archaeal and micro-eukaryotic representatives were studied by rRNA gene tag pyrosequencing. Communities were shown to be significantly different and segregated by sediment geographical area. Specific mesophilic, thermophilic and hyperthermophilic archaeal (e.g., Archaeoglobus, ANME-1) and bacterial (e.g., Caldithrix, Thermodesulfobacteria) taxa were highly abundant near the vent chimney. In contrast, bathyal-associated members affiliated to more ubiquitous phylogroups from deep-ocean sediments (e.g., Thaumarchaeota MGI, Gamma- and Alphaproteobacteria). This study provides a broader picture of the biological diversity and microbial biogeography, and represents a preliminary approach to the microbial ecology associated with the deep-sea sediments from the Menez Gwen hydrothermal vent field.
    Marine Genomics 09/2015; DOI:10.1016/j.margen.2015.09.001 · 1.79 Impact Factor
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    • "Oceanic sulfate plays a key role in the biogeochemical cycles of S, C, O, and Fe (Canfield, 1998; Lyons and Gill, 2010; Halevy et al., 2012; Planavsky et al., 2012). For example, > 50 % of organic matter and methane in marine sediments is oxidized via processes linked to microbial sulfate reduction (MSR) (Jørgensen, 1982; Valentine, 2002). At a concentration of ∼ 29 mM in the modern ocean, sulfate is the second most abundant anion in seawater (Millero, 2005). "
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    ABSTRACT: Long-term secular variation in seawater sulfate concentrations ([SO42−]SW) is of interest owing to its relationship to the oxygenation history of Earth's surface environment. In this study, we develop two complementary approaches for quantification of sulfate concentrations in ancient seawater and test their application to late Neoproterozoic (635 Ma) to Recent marine units. The "rate method" is based on two measurable parameters of paleomarine systems: (1) the S-isotope fractionation associated with microbial sulfate reduction (MSR), as proxied by Δ34SCAS-PY, and (2) the maximum rate of change in seawater sulfate, as proxied by &partial; δ 34SCAS/∂ t(max). The "MSR-trend method" is based on the empirical relationship of Δ34SCAS-PY to aqueous sulfate concentrations in 81 modern depositional systems. For a given paleomarine system, the rate method yields an estimate of maximum possible [SO42−]SW (although results are dependent on assumptions regarding the pyrite burial flux, FPY), and the MSR-trend method yields an estimate of mean [SO42−]SW. An analysis of seawater sulfate concentrations since 635 Ma suggests that [SO42−]SW was low during the late Neoproterozoic (
    Biogeosciences 04/2015; 12(7):2131-2151. DOI:10.5194/bg-12-2131-2015 · 3.98 Impact Factor
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