scholarly journals Clumped Isotopologue Fractionation by Microbial Cultures Performing the Anaerobic 10 Oxidation of Methane

Author(s):  
Shuhei Ono ◽  
Jeemin H. Rhim ◽  
Danielle S. Gruen ◽  
Heidi Taubner ◽  
Martin Kölling ◽  
...  

Methane is abundant in marine subsurface sediments, sourced from microbial or thermocatalytic products. The relative composition of its isotopologues (12CH4, 13CH4, 12CH3D and 13CH3D) is used to infer its sources and sinks. The anaerobic oxidation of methane (AOM) is an important methane sink reaction carried out by consortia of<br>anaerobic methanotrophic archaea (ANME) and partner bacteria in the presence of methane and sulfate. We investigated the methane isotopologue fractionations during<br>AOM in experiments with cultures of ANME-1 archaea and partner bacteria obtained from hydrothermally heated gas-rich sediments of the Guaymas Basin. During partial methane consumption in four sets of experiments, residual methane became enriched in 13CH4 and 12CH3D, following kinetic fractionations from 11.1 to 18.3 ‰ and from 117 to 180 ‰,respectively. Results from one set of experiments with D-depleted medium water (δD = – 200‰, whereas the control was –55‰) are inconclusive regarding the reversibility of AOM, which would lead to equilibrium as opposed to kinetic fractionations. The value of Δ13CH3D (the abundance of 13CH3D with respect to that expected from stochastic distribution) increased toward and beyond (up to 8.4‰) the value expected for isotopologue equilibrium (5.3‰ at 37 °C). The kinetic clumped isotopologue fractionation (difference between 13CH3D/12CH3D and 13CH4/12CH4 fractionations) of 4.8 to 12.8 ‰ is in contrast with our previous observation of little to no clumped isotopologue effect during aerobic methane oxidation. Our results demonstrate that AOM can contribute to near52<br>equilibrium Δ13CH3D values observed in marine sediments and 13CH3D systematics can be used to distinguish aerobic versus anaerobic methanotrophic processes in nature.

2020 ◽  
Author(s):  
Shuhei Ono ◽  
Jeemin H. Rhim ◽  
Danielle S. Gruen ◽  
Heidi Taubner ◽  
Martin Kölling ◽  
...  

Methane is abundant in marine subsurface sediments, sourced from microbial or thermocatalytic products. The relative composition of its isotopologues (<sup>12</sup>CH<sub>4</sub>, <sup>13</sup>CH<sub>4</sub>, <sup>12</sup>CH<sub>3</sub>D and <sup>13</sup>CH<sub>3</sub>D) is used to infer its sources and sinks. The anaerobic oxidation of methane (AOM) is an important methane sink reaction carried out by consortia of<br>anaerobic methanotrophic archaea (ANME) and partner bacteria in the presence of methane and sulfate. We investigated the methane isotopologue fractionations during<br>AOM in experiments with cultures of ANME-1 archaea and partner bacteria obtained from hydrothermally heated gas-rich sediments of the Guaymas Basin. During partial methane consumption in four sets of experiments, residual methane became enriched in <sup>13</sup>CH<sub>4</sub> and <sup>12</sup>CH<sub>3</sub>D, following kinetic fractionations from 11.1 to 18.3 ‰ and from 117 to 180 ‰,respectively. Results from one set of experiments with D-depleted medium water (δD = – 200‰, whereas the control was –55‰) are inconclusive regarding the reversibility of AOM, which would lead to equilibrium as opposed to kinetic fractionations. The value of Δ<sup>13</sup>CH<sub>3</sub>D (the abundance of <sup>13</sup>CH<sub>3</sub>D with respect to that expected from stochastic distribution) increased toward and beyond (up to 8.4‰) the value expected for isotopologue equilibrium (5.3‰ at 37 °C). The kinetic clumped isotopologue fractionation (difference between <sup>13</sup>CH<sub>3</sub>D/<sup>12</sup>CH<sub>3</sub>D and <sup>13</sup>CH<sub>4</sub>/<sup>12</sup>CH<sub>4</sub> fractionations) of 4.8 to 12.8 ‰ is in contrast with our previous observation of little to no clumped isotopologue effect during aerobic methane oxidation. Our results demonstrate that AOM can contribute to near<br>equilibrium Δ<sup>13</sup>CH<sub>3</sub>D values observed in marine sediments and <sup>13</sup>CH<sub>3</sub>D systematics can be used to distinguish aerobic versus anaerobic methanotrophic processes in nature.


2020 ◽  
Author(s):  
Shuhei Ono ◽  
Jeemin H. Rhim ◽  
Danielle S. Gruen ◽  
Heidi Taubner ◽  
Martin Kölling ◽  
...  

Methane is abundant in marine subsurface sediments, sourced from microbial or thermocatalytic products. The relative composition of its isotopologues (<sup>12</sup>CH<sub>4</sub>, <sup>13</sup>CH<sub>4</sub>, <sup>12</sup>CH<sub>3</sub>D and <sup>13</sup>CH<sub>3</sub>D) is used to infer its sources and sinks. The anaerobic oxidation of methane (AOM) is an important methane sink reaction carried out by consortia of<br>anaerobic methanotrophic archaea (ANME) and partner bacteria in the presence of methane and sulfate. We investigated the methane isotopologue fractionations during<br>AOM in experiments with cultures of ANME-1 archaea and partner bacteria obtained from hydrothermally heated gas-rich sediments of the Guaymas Basin. During partial methane consumption in four sets of experiments, residual methane became enriched in <sup>13</sup>CH<sub>4</sub> and <sup>12</sup>CH<sub>3</sub>D, following kinetic fractionations from 11.1 to 18.3 ‰ and from 117 to 180 ‰,respectively. Results from one set of experiments with D-depleted medium water (δD = – 200‰, whereas the control was –55‰) are inconclusive regarding the reversibility of AOM, which would lead to equilibrium as opposed to kinetic fractionations. The value of Δ<sup>13</sup>CH<sub>3</sub>D (the abundance of <sup>13</sup>CH<sub>3</sub>D with respect to that expected from stochastic distribution) increased toward and beyond (up to 8.4‰) the value expected for isotopologue equilibrium (5.3‰ at 37 °C). The kinetic clumped isotopologue fractionation (difference between <sup>13</sup>CH<sub>3</sub>D/<sup>12</sup>CH<sub>3</sub>D and <sup>13</sup>CH<sub>4</sub>/<sup>12</sup>CH<sub>4</sub> fractionations) of 4.8 to 12.8 ‰ is in contrast with our previous observation of little to no clumped isotopologue effect during aerobic methane oxidation. Our results demonstrate that AOM can contribute to near<br>equilibrium Δ<sup>13</sup>CH<sub>3</sub>D values observed in marine sediments and <sup>13</sup>CH<sub>3</sub>D systematics can be used to distinguish aerobic versus anaerobic methanotrophic processes in nature.


2018 ◽  
Vol 84 (11) ◽  
Author(s):  
Shawn E. McGlynn ◽  
Grayson L. Chadwick ◽  
Ariel O'Neill ◽  
Mason Mackey ◽  
Andrea Thor ◽  
...  

ABSTRACTPhylogenetically diverse environmental ANME archaea and sulfate-reducing bacteria cooperatively catalyze the anaerobic oxidation of methane oxidation (AOM) in multicelled consortia within methane seep environments. To better understand these cells and their symbiotic associations, we applied a suite of electron microscopy approaches, including correlative fluorescencein situhybridization-electron microscopy (FISH-EM), transmission electron microscopy (TEM), and serial block face scanning electron microscopy (SBEM) three-dimensional (3D) reconstructions. FISH-EM of methane seep-derived consortia revealed phylogenetic variability in terms of cell morphology, ultrastructure, and storage granules. Representatives of the ANME-2b clade, but not other ANME-2 groups, contained polyphosphate-like granules, while some bacteria associated with ANME-2a/2c contained two distinct phases of iron mineral chains resembling magnetosomes. 3D segmentation of two ANME-2 consortium types revealed cellular volumes of ANME and their symbiotic partners that were larger than previous estimates based on light microscopy. Polyphosphate-like granule-containing ANME (tentatively termed ANME-2b) were larger than both ANME with no granules and partner bacteria. This cell type was observed with up to 4 granules per cell, and the volume of the cell was larger in proportion to the number of granules inside it, but the percentage of the cell occupied by these granules did not vary with granule number. These results illuminate distinctions between ANME-2 archaeal lineages and partnering bacterial populations that are apparently unified in their ability to perform anaerobic methane oxidation.IMPORTANCEMethane oxidation in anaerobic environments can be accomplished by a number of archaeal groups, some of which live in syntrophic relationships with bacteria in structured consortia. Little is known of the distinguishing characteristics of these groups. Here, we applied imaging approaches to better understand the properties of these cells. We found unexpected morphological, structural, and volume variability of these uncultured groups by correlating fluorescence labeling of cells with electron microscopy observables.


2012 ◽  
Vol 9 (10) ◽  
pp. 3891-3899 ◽  
Author(s):  
A. Bannert ◽  
C. Bogen ◽  
J. Esperschütz ◽  
A. Koubová ◽  
F. Buegger ◽  
...  

Abstract. While the importance of anaerobic methane oxidation has been reported for marine ecosystems, the role of this process in soils is still questionable. Grasslands used as pastures for cattle overwintering show an increase in anaerobic soil micro-sites caused by animal treading and excrement deposition. Therefore, anaerobic potential methane oxidation activity of severely impacted soil from a cattle winter pasture was investigated in an incubation experiment under anaerobic conditions using 13C-labelled methane. We were able to detect a high microbial activity utilizing CH4 as nutrient source shown by the respiration of 13CO2. Measurements of possible terminal electron acceptors for anaerobic oxidation of methane were carried out. Soil sulfate concentrations were too low to explain the oxidation of the amount of methane added, but enough nitrate and iron(III) were detected. However, only nitrate was consumed during the experiment. 13C-PLFA analyses clearly showed the utilization of CH4 as nutrient source mainly by organisms harbouring 16:1ω7 PLFAs. These lipids were also found as most 13C-enriched fatty acids by Raghoebarsing et al. (2006) after addition of 13CH4 to an enrichment culture coupling denitrification of nitrate to anaerobic oxidation of methane. This might be an indication for anaerobic oxidation of methane by relatives of "Candidatus Methylomirabilis oxyfera" in the investigated grassland soil under the conditions of the incubation experiment.


2011 ◽  
Vol 77 (13) ◽  
pp. 4429-4436 ◽  
Author(s):  
Jörg S. Deutzmann ◽  
Bernhard Schink

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.


2008 ◽  
Vol 72 (12) ◽  
pp. 2868-2879 ◽  
Author(s):  
Nina J. Knab ◽  
Barry A. Cragg ◽  
Christian Borowski ◽  
R. John Parkes ◽  
Richard Pancost ◽  
...  

2001 ◽  
Vol 67 (4) ◽  
pp. 1922-1934 ◽  
Author(s):  
V. J. Orphan ◽  
K.-U. Hinrichs ◽  
W. Ussler ◽  
C. K. Paull ◽  
L. T. Taylor ◽  
...  

ABSTRACT The oxidation of methane in anoxic marine sediments is thought to be mediated by a consortium of methane-consuming archaea and sulfate-reducing bacteria. In this study, we compared results of rRNA gene (rDNA) surveys and lipid analyses of archaea and bacteria associated with methane seep sediments from several different sites on the Californian continental margin. Two distinct archaeal lineages (ANME-1 and ANME-2), peripherally related to the orderMethanosarcinales, were consistently associated with methane seep marine sediments. The same sediments contained abundant13C-depleted archaeal lipids, indicating that one or both of these archaeal groups are members of anaerobic methane-oxidizing consortia. 13C-depleted lipids and the signature 16S rDNAs for these archaeal groups were absent in nearby control sediments. Concurrent surveys of bacterial rDNAs revealed a predominance of δ-proteobacteria, in particular, close relatives ofDesulfosarcina variabilis. Biomarker analyses of the same sediments showed bacterial fatty acids with strong 13C depletion that are likely products of these sulfate-reducing bacteria. Consistent with these observations, whole-cell fluorescent in situ hybridization revealed aggregations of ANME-2 archaea and sulfate-reducing Desulfosarcina andDesulfococcus species. Additionally, the presence of abundant 13C-depleted ether lipids, presumed to be of bacterial origin but unrelated to ether lipids of members of the orderDesulfosarcinales, suggests the participation of additional bacterial groups in the methane-oxidizing process. Although theDesulfosarcinales and ANME-2 consortia appear to participate in the anaerobic oxidation of methane in marine sediments, our data suggest that other bacteria and archaea are also involved in methane oxidation in these environments.


2012 ◽  
Vol 9 (4) ◽  
pp. 4919-4945
Author(s):  
A. Bannert ◽  
C. Bogen ◽  
J. Esperschütz ◽  
A. Koubová ◽  
F. Buegger ◽  
...  

Abstract. While the importance of anaerobic methane oxidation has been reported for marine ecosystems, the role of this process in soils is still questionable. Grasslands used as pastures for cattle-overwintering show an increase in anaerobic soil micro-sites caused by animal treading and excrement deposition. Therefore anaerobic potential methane oxidation activity of severely impacted soil from a cattle winter pasture was investigated in an incubation experiment under anaerobic conditions using 13C-labeled methane. We were able to detect a high microbial activity utilizing CH4 as nutrient source shown by the respiration of 13CO2. Measurements of possible terminal electron acceptors for anaerobic oxidation of methane were carried out. Soil sulfate concentrations were too low to explain the oxidation of the amount of methane added, but enough nitrate and iron(III) were detected. However, only nitrate was consumed during the experiment. 13C-PLFA analyses clearly showed the utilization of CH4 as nutrient source mainly by organisms harbouring 16:1ω7 PLFAs. These lipids were found in Gram-negative microorganisms and anaerobes. The fact that these lipids are also typical for type I methanotrophs, known as aerobic methane oxidizers, might indicate a link between aerobic and anaerobic methane oxidation.


2021 ◽  
Author(s):  
Hanni Vigderovich ◽  
Werner Eckert ◽  
Michal Elul ◽  
Maxim Rubin-Blum ◽  
Marcus Elvert ◽  
...  

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.


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