A coastal sediment community in which long filamentous Desulfobulbaceae cable bacteria connect sulfide-rich deeper sediment to oxygen supplied near the sediment-water interface by an oxygenic photosynthetic biofilm. The system links sulfur oxidation, oxygen production, sulfide availability, and centimeter-scale long-distance electron transfer.
Taxonomy
| Taxon | Ontology ID | Functional Roles | Abundance |
|---|---|---|---|
| Desulfobulbaceae cable bacteria — ontology label: Desulfobulbaceae | NCBITaxon:213121 · TaxonMech · TraitMech |
CROSS_FEEDER
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N/A |
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| diatom-dominated photosynthetic biofilm — ontology label: Bacillariophyta | NCBITaxon:2836 · TaxonMech · TraitMech |
PRIMARY_PRODUCER
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N/A |
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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.
Photosynthesis Stimulates Cable-Bacteria Electron Harvesting
CROSS_FEEDINGPhotosynthetic oxygen supply from a diatom-dominated surface biofilm supports cable-bacteria sulfide oxidation. The light perturbation supports oxygen cross-feeding, but reciprocal benefit to the phototrophs is not established. Community-level scope uses the corrected phylum-level biofilm and family-level cable-bacteria roster, not species-resolved partners or an isolated two-member culture.
Metabolites: dioxygen (CHEBI:15379 · MediaIngredientMech · CMMMech)
Biological Processes:
- photosynthesis (GO:0015979 · PathwayMech)
Greater photosynthetic oxygen supply can provide the surface electron acceptor for cable-bacteria sulfide oxidation at depth. Light manipulation and microsensor responses support this coupling; the precise spatial redox-site model remains an interpretation.
Evidence
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PMID:25416774 - SUPPORT (IN_VITRO)"a greater oxygen supply can enable cable bacteria"
Electrogenic Sulfide Oxidation across Sediment Redox Zones
The source interprets microsensor and filament observations as cable-bacteria electron conduction coupling deep sulfide oxidation with oxygen reduction near the surface. Conduction along a filament is not separately classified as interorganism cross-feeding. Exact redox-site allocation, regulation and filament motility remain proposed mechanisms.
Metabolites: hydrogen sulfide (CHEBI:16136 · MediaIngredientMech · CMMMech), dioxygen (CHEBI:15379 · MediaIngredientMech · CMMMech)
Cable-bacteria electron conduction provides a mechanism for rapid coupling of altered surface oxygen availability to deep sulfide responses during light/dark perturbations. The observed rapid response supports coupling without uniquely resolving motility or biochemical regulation.
Evidence
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PMID:25416774 - SUPPORT (IN_VITRO)"harvesting electrons from free sulfide"
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PMID:25416774 - SUPPORT (IN_VITRO)"transferring these electrons along their longitudinal axes"
Rapid Redox Signal Transmission under Diel Illumination
Surface light/dark perturbations caused rapid, repeatable changes in sulfide at depth. Repeated cycles are not independent sediment-core replicates. The response supports electrical coupling, not a separate cross-feeding interaction; nonsignificant current-density contrasts and an inconsistent reported sulfide-depth significance claim are not treated as confirmed increases.
Metabolites: hydrogen sulfide (CHEBI:16136 · MediaIngredientMech · CMMMech), dioxygen (CHEBI:15379 · MediaIngredientMech · CMMMech)
Evidence
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PMID:25416774 - SUPPORT (IN_VITRO)"Changes in photosynthesis at the sediment surface had an immediate and repeatable effect on sulfide concentrations at depth"
Associated Datasets
| Dataset | Type | Repository | Accession |
|---|---|---|---|
|
Cable bacteria photosynthetic biofilm sediment article
Full-text article reporting sediment microsensor and biofilm-light perturbation evidence for rapid redox signal transmission by cable bacteria. |
PHENOTYPE | OTHER | PMID-25416774 |
Knowledge gaps & discussions (1)
KNOWLEDGE_GAP OPEN Which redox-site regulation or motility mechanisms explain the response, and do phototrophs benefit reciprocally?
Identity and chemical-grounding defects in #1267 are repaired, while species resolution and a defined two-member culture remain unsupported. Regulation, motility and reciprocal benefit remain unresolved. The existing bounds on replication and the inconsistent sulfide-depth significance claim remain; source access does not validate these mechanisms.
Attaches to: ecological_interactions#Photosynthesis Stimulates Cable-Bacteria Electron Harvesting, ecological_interactions#Electrogenic Sulfide Oxidation across Sediment Redox Zones, ecological_interactions#Rapid Redox Signal Transmission under Diel Illumination
Environmental Factors
| Factor | Value | Unit |
|---|---|---|
| diel light-dark cycle | Alternating light and dark periods | N/A |
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| sulfide-rich deeper sediment | Free sulfide in deeper sediment horizons | N/A |
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