identifier: traitmech:000108 label: dissimilatory manganese reduction definition: An anaerobic respiratory metabolism in which an organism conserves energy by reducing Mn(IV) oxides to soluble Mn(II) as a terminal electron acceptor while oxidizing organic matter or hydrogen. definition_source: DOI:10.1128/mr.55.2.259-287.1991 trait_category: METABOLISM term_kind: CLASS mapping_status: REVIEWED parent_traits: - traitmech:000039 synonyms: - synonym_text: Mn(IV) reduction synonym_type: RELATED_SYNONYM source: DOI:10.1128/mr.55.2.259-287.1991 evidence: - reference: DOI:10.1128/mr.55.2.259-287.1991 notes: Lovley establishes dissimilatory Fe(III)/Mn(IV) reduction as energy-conserving anaerobic respiration on metal-oxide acceptors. - reference: PMID:7826009 notes: Nealson & Saffarini review iron and manganese in anaerobic respiration as terminal electron acceptors. canonical_examples: - taxon_id: NCBITaxon:70863 taxon_label: Shewanella oneidensis note: "Model dissimilatory metal reducer (strain MR-1 = Manganese Reducer 1); respires Mn(IV)/Fe(III) via extracellular electron transfer." reference: PMID:12368813 causal_graphs: - graph_id: dmr_mn_oxide_respiration title: Dissimilatory manganese reduction respires Mn(IV) to Mn(II) description: Evidence-backed causal sketch linking Mn(IV) oxide as terminal electron acceptor to soluble Mn(II) and anaerobic respiration. nodes: - node_id: dmr_trait label: dissimilatory manganese reduction node_type: TRAIT grounding: traitmech:000108 description: Anaerobic respiration on Mn(IV) oxide as terminal acceptor. - node_id: mn_iv_oxide label: Mn(IV) oxide node_type: CHEMICAL description: Insoluble Mn(IV) oxide used as terminal electron acceptor. - node_id: mn_ii label: manganese(2+) node_type: CHEMICAL description: Soluble Mn(II) released after reduction. grounding: CHEBI:29035 - node_id: organic_matter label: organic matter node_type: CHEMICAL description: Organic carbon electron donor oxidized during Mn(IV) respiration. - node_id: hydrogen label: dihydrogen node_type: CHEMICAL description: H2 used as electron donor for dissimilatory manganese reduction. grounding: CHEBI:18276 - node_id: anoxia label: anoxic conditions node_type: ENVIRONMENTAL_FACTOR description: Absence of oxygen permitting anaerobic Mn(IV) respiration. - node_id: methane_oxidation label: anaerobic methane oxidation node_type: BIOLOGICAL_PROCESS description: Anaerobic oxidation of methane (AOM) coupled to metal-oxide reduction. edges: - subject: mn_iv_oxide predicate: oxidized to object: mn_ii description: Mn(IV) oxide is reduced to soluble Mn(II). evidence: - reference: DOI:10.1128/mr.55.2.259-287.1991 notes: Lovley establishes Mn(IV) reduction coupled to organic-matter oxidation as energy-conserving anaerobic respiration. predicate_id: METPO:2007405 - subject: mn_iv_oxide predicate: enables object: dmr_trait description: Mn(IV) acts as terminal electron acceptor enabling DMR. evidence: - reference: PMID:7826009 notes: Nealson & Saffarini place Mn(IV) as a terminal electron acceptor in anaerobic respiration. predicate_id: RO:0002327 - subject: organic_matter predicate: is oxidized coupled to object: dmr_trait description: Oxidation of organic matter is coupled to Mn(IV) reduction. evidence: - reference: DOI:10.1128/mr.55.2.259-287.1991 notes: 'Lovley: oxidation of organic matter coupled to reduction of Fe(III) or Mn(IV); fatty acids and aromatics fully oxidized with Mn(IV) as sole acceptor.' - subject: hydrogen predicate: donates electrons to object: dmr_trait description: H2 serves as electron donor for dissimilatory manganese reduction. evidence: - reference: DOI:10.1128/mr.55.2.259-287.1991 notes: 'Lovley: organisms with Mn(IV) as sole electron acceptor can completely oxidize hydrogen.' predicate_id: METPO:2007403 - subject: anoxia predicate: enables object: dmr_trait description: Anoxic conditions enable anaerobic Mn(IV) respiration. evidence: - reference: DOI:10.1128/mr.55.2.259-287.1991 notes: Lovley frames Mn(IV) reduction as anaerobic respiration in aquatic sediments, soils, and groundwater under anaerobic conditions. predicate_id: RO:0002327 - subject: methane_oxidation predicate: is coupled to object: dmr_trait description: Anaerobic methane oxidation can be coupled to Mn reduction (Fe-Mn-AOM). evidence: - reference: DOI:10.5194/egusphere-2024-1829 notes: 'Sivan: AOM coupled with Fe-Mn reduction (Fe-Mn-AOM) is a globally important biogeochemical process with MnO2-coupled AOM reactions.' curation_history: - timestamp: '2026-06-08T00:00:00Z' curator: claude action: PROPOSED_FROM_RESEARCH changes: Proposed candidate METABOLISM trait (dissimilatory manganese reduction); round 2, parented to the existing dissimilatory metal reduction axis (traitmech:000039) alongside round-1 iron reduction. llm_assisted: true - timestamp: '2026-06-10T14:00:00Z' curator: claude action: CURATED_CAUSAL_GRAPH changes: Added evidence-backed causal graph (Mn(IV) → Mn(II) respiration) with RO/METPO predicate groundings; promoted PROPOSED to REVIEWED. llm_assisted: true - timestamp: '2026-06-14T06:55:38Z' curator: claude action: GROUND_CAUSAL_NODES changes: Grounded 1 causal-node grounding field(s) via mappings/node_grounding.tsv (CHEBI:29035×1). llm_assisted: true - timestamp: '2026-06-23T00:00:00Z' curator: claude action: ENRICH_CAUSAL_GRAPH changes: Added 4 evidence-backed generic edges (4 new nodes) from the deep-research report. llm_assisted: true - timestamp: '2026-06-24T17:21:12Z' curator: claude action: GROUND_CAUSAL_PREDICATES changes: Grounded 2 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv (METPO:2007403×1, RO:0002327×1). llm_assisted: true - timestamp: '2026-06-24T17:23:32Z' curator: claude action: GROUND_CAUSAL_NODES changes: Grounded 1 causal-node grounding field(s) via mappings/node_grounding.tsv (CHEBI:18276×1). llm_assisted: true