Artificial electron acceptors decouple archaeal methane oxidation from sulfate reduction

Science ◽  
2016 ◽  
Vol 351 (6274) ◽  
pp. 703-707 ◽  
Author(s):  
S. Scheller ◽  
H. Yu ◽  
G. L. Chadwick ◽  
S. E. McGlynn ◽  
V. J. Orphan
Keyword(s):  
Sulfate Reduction ◽  
Methane Oxidation ◽  
Electron Acceptors

scholarly journals Assessing the Effect of Humic Substances and Fe(III) as Potential Electron Acceptors for Anaerobic Methane Oxidation in a Marine Anoxic System

2020 ◽  
Vol 8 (9) ◽  
pp. 1288
Author(s):  
Sigrid van Grinsven ◽  
Jaap S. Sinninghe Damsté ◽  
Laura Villanueva
Keyword(s):  
Sulfate Reduction ◽  
Humic Substances ◽  
Methane Oxidation ◽  
Sea Water ◽  
Single Cells ◽  
Sodium Molybdate ◽  
Electron Acceptors ◽  
Anaerobic Methane Oxidation ◽  
Electron Shuttling ◽  
Incubation Experiments

Marine anaerobic methane oxidation (AOM) is generally assumed to be coupled to sulfate reduction, via a consortium of anaerobic methane-oxidizing archaea (ANME) and sulfate-reducing bacteria (SRB). ANME-1 are, however, often found as single cells, or only loosely aggregated with SRB, suggesting they perform a form of AOM independent of sulfate reduction. Oxidized metals and humic substances have been suggested as potential electron acceptors for ANME, but up to now, AOM linked to reduction of these compounds has only been shown for the ANME-2 and ANME-3 clades. Here, the effect of the electron acceptors anthraquinone-disulfonate (AQDS), a humic acids analog, and Fe3+ on anaerobic methane oxidation were assessed by incubation experiments with anoxic Black Sea water containing ANME-1b. Incubation experiments with 13C-methane and AQDS showed a stimulating effect of AQDS on methane oxidation. Fe3+ enhanced the ANME-1b abundance but did not substantially increase methane oxidation. Sodium molybdate, which was added as an inhibitor of sulfate reduction, surprisingly enhanced methane oxidation, possibly related to the dominant abundance of Sulfurospirillum in those incubations. The presented data suggest the potential involvement of ANME-1b in AQDS-enhanced anaerobic methane oxidation, possibly via electron shuttling to AQDS or via interaction with other members of the microbial community.

scholarly journals Trace methane oxidation and the methane dependency of sulfate reduction in anaerobic granular sludge

2010 ◽  
Vol 72 (2) ◽  
pp. 261-271 ◽  
Author(s):  
Roel J.W. Meulepas ◽  
Christian G. Jagersma ◽  
Yu Zhang ◽  
Michele Petrillo ◽  
Hengzhe Cai ◽  
...  
Keyword(s):  
Sulfate Reduction ◽  
Methane Oxidation ◽  
Granular Sludge ◽  
Anaerobic Granular Sludge

scholarly journals Contrasting Pathways for Anaerobic Methane Oxidation in Gulf of Mexico Cold Seep Sediments

mSystems ◽  
2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Adrien Vigneron ◽  
Eric B. Alsop ◽  
Perrine Cruaud ◽  
Gwenaelle Philibert ◽  
Benjamin King ◽  
...  
Keyword(s):  
Gene Expression ◽  
Electron Transfer ◽  
Gulf Of Mexico ◽  
Microbial Communities ◽  
Sulfate Reduction ◽  
Methane Oxidation ◽  
Sulfur Cycle ◽  
Anaerobic Methane Oxidation ◽  
Cold Seep ◽  
Biogenic Methane

ABSTRACTGulf of Mexico sediments harbor numerous hydrocarbon seeps associated with high sedimentation rates and thermal maturation of organic matter. These ecosystems host abundant and diverse microbial communities that directly or indirectly metabolize components of the emitted fluid. To investigate microbial function and activities in these ecosystems, metabolic potential (metagenomic) and gene expression (metatranscriptomic) analyses of two cold seep areas of the Gulf of Mexico were carried out. Seeps emitting biogenic methane harbored microbial communities dominated by archaeal anaerobic methane oxidizers of phylogenetic group 1 (ANME-1), whereas seeps producing fluids containing a complex mixture of thermogenic hydrocarbons were dominated by ANME-2 lineages. Metatranscriptome measurements in both communities indicated high levels of expression of genes for methane metabolism despite their distinct microbial communities and hydrocarbon composition. In contrast, the transcription level of sulfur cycle genes was quite different. In the thermogenic seep community, high levels of transcripts indicative of syntrophic anaerobic oxidation of methane (AOM) coupled to sulfate reduction were detected. This syntrophic partnership between the dominant ANME-2 and sulfate reducers potentially involves direct electron transfer through multiheme cytochromes. In the biogenic methane seep, genes from an ANME-1 lineage that are potentially involved in polysulfide reduction were highly expressed, suggesting a novel bacterium-independent anaerobic methane oxidation pathway coupled to polysulfide reduction. The observed divergence in AOM activities provides a new model for bacterium-independent AOM and emphasizes the variation that exists in AOM pathways between different ANME lineages.IMPORTANCECold seep sediments are complex and widespread marine ecosystems emitting large amounts of methane, a potent greenhouse gas, and other hydrocarbons. Within these sediments, microbial communities play crucial roles in production and degradation of hydrocarbons, modulating oil and gas emissions to seawater. Despite this ecological importance, our understanding of microbial functions and methane oxidation pathways in cold seep ecosystems is poor. Based on gene expression profiling of environmental seep sediment samples, the present work showed that (i) the composition of the emitted fluids shapes the microbial community in general and the anaerobic methanotroph community specifically and (ii) AOM by ANME-2 in this seep may be coupled to sulfate reduction byDeltaproteobacteriaby electron transfer through multiheme cytochromes, whereas AOM by ANME-1 lineages in this seep may involve a different, bacterium-independent pathway, coupling methane oxidation to elemental sulfur/polysulfide reduction.

scholarly journals Anaerobic Oxidation of Methane in Sediments of Lake Constance, an Oligotrophic Freshwater Lake

2011 ◽  
Vol 77 (13) ◽  
pp. 4429-4436 ◽  
Author(s):  
Jörg S. Deutzmann ◽  
Bernhard Schink
Keyword(s):  
Methane Oxidation ◽  
Electron Acceptors ◽  
Molecular Techniques ◽  
Freshwater Lake ◽  
Lake Constance ◽  
Anaerobic Oxidation Of Methane ◽  
Anaerobic Oxidation ◽  
Terminal Electron Acceptor ◽  
Oxidation Of Methane ◽  
Freshwater Habitats

ABSTRACTAnaerobic oxidation of methane (AOM) with sulfate as terminal electron acceptor has been reported for various environments, including freshwater habitats, and also, nitrate and nitrite were recently shown to act as electron acceptors for methane oxidation in eutrophic freshwater habitats. Radiotracer experiments with sediment material of Lake Constance, an oligotrophic freshwater lake, were performed to follow14CO2formation from14CH4in sediment incubations in the presence of different electron acceptors, namely, nitrate, nitrite, sulfate, or oxygen. Whereas14CO2formation without and with sulfate addition was negligible, addition of nitrate increased14CO2formation significantly, suggesting that AOM could be coupled to denitrification. Nonetheless, denitrification-dependent AOM rates remained at least 1 order of magnitude lower than rates of aerobic methane oxidation. Using molecular techniques, putative denitrifying methanotrophs belonging to the NC10 phylum were detected on the basis of thepmoAand 16S rRNA gene sequences. These findings show that sulfate-dependent AOM was insignificant in Lake constant sediments. However, AOM can also be coupled to denitrification in this oligotrophic freshwater habitat, providing first indications that this might be a widespread process that plays an important role in mitigating methane emissions.

Sulfate reduction, methanogenesis, and methane oxidation in the upper sediments of the Vistula and Curonian Lagoons, Baltic Sea

Microbiology ◽  
2013 ◽  
Vol 82 (2) ◽  
pp. 224-233 ◽  
Author(s):  
N. V. Pimenov ◽  
M. O. Ul’yanova ◽  
T. A. Kanapatskii ◽  
I. N. Mitskevich ◽  
I. I. Rusanov ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Sulfate Reduction ◽  
Methane Oxidation ◽  
Vistula And Curonian Lagoons

scholarly journals Modification of methane oxidation pathways during long-term incubations of methanic lake sediments

2021 ◽  
Author(s):  
Hanni Vigderovich ◽  
Werner Eckert ◽  
Michal Elul ◽  
Maxim Rubin-Blum ◽  
Marcus Elvert ◽  
...  
Keyword(s):  
Lake Sediments ◽  
Carbon Isotope ◽  
Iron Oxides ◽  
Methane Oxidation ◽  
Electron Acceptors ◽  
Anaerobic Oxidation Of Methane ◽  
Methanotrophic Bacteria ◽  
Oxidation Of Methane ◽  
Isotope Measurements

Abstract. Anaerobic oxidation of methane (AOM) is one of the major processes limiting the release of the greenhouse gas methane from natural environments. In Lake Kinneret sediments, iron-coupled AOM (Fe-AOM) was suggested to play a substantial role (10–15 % relative to methanogenesis) in the methanic zone (> 20 cm sediment depth), based on geochemical profiles and experiments on fresh sediments. Apparently, the oxidation of methane is mediated by a combination of mcr gene bearing archaea and aerobic bacterial methanotrophs. Here we aimed to investigate the survival of this complex microbial interplay under controlled conditions. We followed the AOM process during long-term (~18 months) anaerobic slurry experiments of these methanic sediments with two stages of incubations and additions of 13C-labeled methane, multiple electron acceptors and inhibitors. After these incubation stages carbon isotope measurements in the dissolved inorganic pool still showed considerable AOM (3–8 % relative to methanogenesis). Specific lipid carbon isotope measurements and metagenomic analyses indicate that after the prolonged incubation aerobic methanotrophic bacteria were no longer involved in the oxidation process, whereas mcr gene bearing archaea were most likely responsible for oxidizing the methane. Humic substances and iron oxides are likely electron acceptors to support this oxidation, whereas sulfate, manganese, nitrate, and nitrite did not support the AOM in these methanic sediments. Our results suggest in the natural lake sediments methanotrophic bacteria are responsible for part of the methane oxidation by the reduction of combined micro levels of oxygen and iron oxides in a cryptic cycle, while the rest of the methane is converted by reverse methanogenesis. After long-term incubation, the latter prevails without bacterial methanotropic activity and with a different iron reduction pathway.

scholarly journals Sources, trends, and fate of methane in shallow aquifers of Alberta, Canada

2020 ◽  
Author(s):  
Pauline Humez ◽  
Florian Osselin ◽  
Wolfram Kloppmann ◽  
Cynthia McClain ◽  
Michael Nightingale ◽  
...  
Keyword(s):  
Natural Gas ◽  
Sulfate Reduction ◽  
Methane Oxidation ◽  
Bacterial Sulfate Reduction ◽  
Monitoring Wells ◽  
Isotopic Compositions ◽  
Groundwater Samples ◽  
Groundwater Systems ◽  
Hydrogeochemical Parameters ◽  
Methane Concentrations

<p>Due to concerns regarding potential impacts of the development of natural gas from unconventional hydrocarbon resources on groundwater systems in North America and elsewhere, it has been crucial to improve methods of Environmental Baseline Assessment (EBA). Any subsequent deviations from the EBA could indicate migration of natural gas into the monitored groundwater systems. In collaboration with Alberta Environment and Parks, over 800 groundwater samples have been collected from dedicated monitoring wells since 2006 resulting in an extensive high-quality database of aqueous and gaseous geochemical and isotopic compositions. Because methane is the main component of natural gas, it had been the principal target of our groundwater studies. Our objectives were a) to assess the occurrence of methane in groundwater throughout the province of Alberta (Canada), b) to use isotope techniques to track the predominant sources of methane, c) to use a combination of chemical and multi-isotopic techniques and models to assess the fate of methane in groundwater, and d) to use probability for predicting the presence of methane in groundwater based on hydrogeochemical parameters in regions where no gas data exist.</p><p>Methane was found to be ubiquitous in groundwater samples throughout the province of Alberta with concentrations varying from 2.9 10<sup>-4</sup> to >2.4 mmol/l. The highest methane concentrations were found in Na-HCO<sub>3</sub> and Na-Cl water-types where the sulfate concentrations were <1 mmol/l. Analyses of the isotopic compositions of sulfate, dissolved inorganic carbon (DIC) and methane revealed that in some groundwater systems bacterial sulfate reduction occurred (δ<sup>34</sup>S<sub>SO4</sub> >+10‰ associated with lowest sulfate concentrations) and evidence for methane oxidation was also detected (highest δ<sup>13</sup>C<sub>CH4</sub> values > ‑55‰ associated with lowest methane concentrations). Moreover, some δ<sup>13</sup>C<sub>DIC</sub> values were as high as +13.8‰ associated with the highest methane concentrations. A geochemical and multi-isotope model using long-term monitoring data was developed and revealed two different sources of methane: 1) microbial methane resulting from in-situ methanogenesis within the aquifer for a subset of the samples; 2) migration of microbial methane into aquifers characterized by various redox conditions, followed by methane oxidation potentially coupled with bacterial sulfate reduction within sulfate-rich zones causing a pseudo-thermogenic carbon isotopic fingerprint for the remaining methane. So far, no evidence of unambiguously thermogenic methane in the groundwater samples collected from dedicated monitoring wells has been found. Efforts to assess the probability of regional occurrence of methane in groundwater systems in Alberta have then focused on a model for methane prediction model based on logistic regression (LR) for regions of Alberta where no gas data exist. Using basic hydrogeochemical parameters such as occurrence of electron donors, well depth and total dissolved solids of groundwater, the LR approach shows excellent performance metrics e.g. model sensitivity, specificity >80% regarding the prediction of methane occurrence in groundwater of Alberta.</p>

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