Home ← Back to Communities Text Map Taxonomic UMAP Sequence Map Network Schema All Mech projects

ANME-SRB Marine Methane Seep Consortium

Community ID CommunityMech:000134
Ecological State STABLE
Environment marine sediment — ontology label: sediment
ENVO:00002007 · HabitatMech ↗

Natural marine methane-seep consortia in which anaerobic methanotrophic archaea (ANME) grow in syntrophic partnership with sulfate-reducing bacteria (SRB). These structured aggregates couple anaerobic oxidation of methane to sulfate reduction, limiting methane release from ocean sediments. The interaction is frequently organized as multicellular consortia containing ANME archaeal cells and bacterial sulfate reducers, with genomic evidence supporting direct interspecies electron transfer from ANME to the SRB partner.

Taxonomy

Taxon Ontology ID Functional Roles Abundance
anaerobic methanotrophic archaea — ontology label: Archaea NCBITaxon:2157 · TaxonMech · TraitMech
PRIMARY_DEGRADER
N/A
  • PMID:37747940 - SUPPORT (COMPUTATIONAL)
    "anaerobic methanotrophic archaea (ANME) in obligate syntrophic partnership"
  • PMID:34986141 - SUPPORT (COMPUTATIONAL)
    "none of which have been isolated in pure culture"
sulfate-reducing bacterial partners — ontology label: Desulfobacterales NCBITaxon:213118 · TaxonMech · TraitMech
SYNTROPHIC_PARTNER
N/A
  • PMID:34986141 - SUPPORT (COMPUTATIONAL)
    "syntrophic partnership between anaerobic methanotrophic (ANME) archaea and sulfate-reducing bacteria (SRB) "

Ecological Interactions

The graph shows only explicitly linked interaction participants. Community members without an asserted participant link are omitted; membership alone does not imply an interaction.

Ecological interaction network for ANME-SRB Marine Methane Seep Consortium Bipartite graph where circles represent taxa and non-circular symbols represent interactions, with distinct shapes and colours for syntrophy. Rare or untyped interactions share the Other symbol; exact curated types remain in the interaction details.
Taxon
Syntrophy
Other

Sulfate-Coupled Anaerobic Methane Oxidation

SYNTROPHY

ANME-SRB aggregates oxidize methane under anoxic conditions while sulfate is reduced by the bacterial partner. This syntrophy couples carbon and sulfur cycling in marine sediments and acts as an important methane sink at the seafloor.

Source Taxon: anaerobic methanotrophic archaea

Target Taxon: sulfate-reducing bacterial partners

Metabolites: methane (CHEBI:16183 · MediaIngredientMech · CMMMech), sulfate (CHEBI:16189 · MediaIngredientMech · CMMMech), carbon dioxide (CHEBI:16526 · MediaIngredientMech · CMMMech)

Evidence

  • PMID:37747940 - SUPPORT (COMPUTATIONAL)
    "Sulfate-coupled anaerobic oxidation of methane (AOM) is performed by multicellular consortia"
  • PMID:34986141 - SUPPORT (COMPUTATIONAL)
    "syntrophic partnership between anaerobic methanotrophic (ANME) archaea and sulfate-reducing bacteria (SRB) "

Direct Interspecies Electron Transfer

SYNTROPHY

Comparative genomics indicates that conserved protein complexes move electrons from ANME cells to the SRB outer membrane, providing a mechanistic basis for partner coupling in sulfate-reducing methane-oxidizing consortia. The hypothesized conduit involves electrically conductive pili and multiheme (S-layer-associated) cytochromes, proposed as the principal mechanism of sulfate-dependent AOM.

Source Taxon: anaerobic methanotrophic archaea

Target Taxon: sulfate-reducing bacterial partners

Biological Processes:

Downstream Effects:
→ Sulfate-Coupled Anaerobic Methane Oxidation

HYPOTHESIZED - transfer of methane-derived electrons from ANME to the SRB partner enables sulfate-coupled AOM. Comparative genomics and modeling support DIET, but the specific conductive-pili/multiheme-cytochrome conduit remains a proposed mechanism in these sources.

Evidence

  • PMID:37747940 - SUPPORT (COMPUTATIONAL)
    "direct interspecies electron transfer (DIET) from ANME to the SRB outer membrane"
  • PMID:33975943 - PARTIAL (COMPUTATIONAL)
    "multiheme cytochromes containing putative S-layer domains"

Sulfite Inhibition of ANME Methane Oxidation

Millimolar sulfite inhibited the ANME partner in methane-seep sediment microcosms and immediately decreased the rate of anaerobic oxidation of methane, indicating that sulfite is a suppressive sulfur perturbation on consortium AOM rather than a productive extracellular intermediate.

Target Taxon: anaerobic methanotrophic archaea

Participating Taxa: anaerobic methanotrophic archaea

Metabolites: sulfite (CHEBI:17359 · MediaIngredientMech · CMMMech)

Biological Processes:

Downstream Effects:
→ Sulfate-Coupled Anaerobic Methane Oxidation

Sulfite addition suppressed the ANME-driven methane oxidation that normally feeds sulfate-reducing bacterial partners.

Evidence

  • PMID:30559729 - SUPPORT (IN_VITRO)
    "sulfite at concentration of 1.0 mM was found to be inhibitory to ANME, leading to an immediate decrease in the rate of AOM "

Zero-Valent Sulfur Inhibition of ANME Methane Oxidation

Zero-valent sulfur supplied as polythionate or polysulfide inhibited methane oxidation by ANME-2a/2c in methane-seep sediment microcosms, arguing against zero-valent sulfur as a productive diffusible intermediate from ANME to the sulfate-reducing partner.

Target Taxon: anaerobic methanotrophic archaea

Participating Taxa: anaerobic methanotrophic archaea

Biological Processes:

Downstream Effects:
→ Sulfate-Coupled Anaerobic Methane Oxidation

Zero-valent sulfur compounds suppressed ANME-2a/2c methane oxidation in tests of the ANME/SRB syntrophy mechanism.

Evidence

  • PMID:30559729 - SUPPORT (IN_VITRO)
    "zero-valent sulfur amendments were inhibitory to ANME-2a/2c while growth in their syntrophic SRB partner was not observed "

Associated Datasets

Dataset Type Repository Accession
ANME comparative metagenomics resource
Comparative genomic analysis of ANME genomes reconstructed from environmental metagenomes and flow-sorted syntrophic consortia. 		METAGENOMICS OTHER PMID:34986141

Knowledge gaps & discussions (1)

KNOWLEDGE_GAP OPEN Which extracellular components conduct electrons between ANME and SRB in these aggregates?

PMID:37747940 identifies conserved candidate DIET complexes and PMID:33975943 models electron-transfer limitations. The latter explicitly describes the proposed conductive conduit as awaiting direct experimental confirmation. The inhibitory sulfur amendments in PMID:30559729 test alternative sulfur-transfer interpretations but do not identify the DIET conduit.

Attaches to: ecological_interactions#Direct Interspecies Electron Transfer, ecological_interactions#Sulfate-Coupled Anaerobic Methane Oxidation

Environmental Factors

Factor Value Unit
Methane-rich anoxic marine sediment Gas-hydrate-rich and methane-seep sediments N/A
  • PMID:34986141 - SUPPORT (COMPUTATIONAL)
    "Anaerobic oxidation of methane (AOM) coupled to sulfate reduction is a key microbiological process in ocean sediments "
Sulfate availability Sulfate as terminal electron acceptor N/A
  • PMID:34986141 - SUPPORT (COMPUTATIONAL)
    "anaerobic oxidation of methane coupled to sulfate reduction"
Sulfite inhibition of anaerobic methane oxidation Sulfite (1.0 mM) inhibitory to ANME N/A
  • PMID:30559729 - SUPPORT (IN_VITRO)
    "sulfite at concentration of 1.0 mM was found to be inhibitory to ANME, leading to an immediate decrease in the rate of AOM"
Zero-valent sulfur inhibition of anaerobic methane oxidation Polythionate/polysulfide (0.25-1.0 mM) inhibitory to ANME N/A
  • PMID:30559729 - SUPPORT (IN_VITRO)
    "zero-valent sulfur amendments were inhibitory to ANME-2a/2c while growth in their syntrophic SRB partner was not observed"

Growth Media

Anaerobic artificial seawater sediment/rock microcosm (methane seep AOM incubation)

Temperature variable by sample (4, 24, or 50 degrees C) °C
Atmosphere ANAEROBIC

Composition

Component Concentration Unit CHEBI
methane · MediaIngredientMech N/A N/A N/A
sulfate · MediaIngredientMech N/A N/A N/A
pyruvate · MediaIngredientMech N/A N/A N/A

Preparation notes: Samples were stored under an N2 atmosphere at 4°C prior to microcosm incubation. ANME-SRB consortia were incubated in (anaerobic) artificial seawater; sediment horizons received CH4 plus 250 μM L-Homopropargylglycine (HPG) at 4°C, and metabolic activity was confirmed by sulfide accumulation and BONCAT/HPG incorporation. Rock and push-core variants were incubated with CH4 (50°C), with pyruvate (24°C), or without added electron donor (24°C). Single active ANME:SRB aggregates were subsequently FACS-sorted for metagenomics.

Evidence

PMID:37747940

"was incubated in anaerobic artificial sea water without electron donor at 24°C"

PMID:37747940

"artificial sea water supplemented with pyruvate at 24°C"

PMID:37747940

"250 μM L-Homopropargylglycine (HPG) at 4°C"

PMID:37747940

"atmosphere at 4°C for sediment microcosm incubations"

PMID:37747940

"Push-core samples of seafloor sediment were collected from different locations on the Costa Rica margin"

Cross-Mech Suite Links

Explore related entities across the CultureBotAI X-Mech knowledge bases:

HabitatMech: marine sediment ↗ TaxonMech: anaerobic methanotrophic archaea ↗ TraitMech: anaerobic methanotrophic archaea ↗ TaxonMech: sulfate-reducing bacterial partners ↗ TraitMech: sulfate-reducing bacterial partners ↗ CultureMech Growth Media ↗ PathwayMech Pathways ↗