A sediment microbial community from East Fork Poplar Creek (EFPC) in Oak Ridge, Tennessee, contaminated with mercury from historical weapons production at the Y-12 National Security Complex. Twenty-eight metagenome-assembled genomes were reconstructed from two sediment core sections at 0-3 cm and 9-12 cm depth, and most encoded putative heavy-metal resistance or ATPase efflux functions.
Taxonomy
| Taxon | Ontology ID | Functional Roles | Abundance |
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| Proteobacteria — ontology label: Pseudomonadota | NCBITaxon:1224 · TaxonMech · TraitMech | N/A | |
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| Acidobacteriota | NCBITaxon:57723 · TaxonMech · TraitMech | N/A | |
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| Actinobacteriota — ontology label: Actinomycetota | NCBITaxon:201174 · TaxonMech · TraitMech | N/A | |
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| Gemmatimonadota | NCBITaxon:142182 · TaxonMech · TraitMech | N/A | |
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| Eisenbacteria — ontology label: Candidatus Eiseniibacteriota | NCBITaxon:1817801 · TaxonMech · TraitMech | N/A | |
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| Myxococcota | NCBITaxon:2818505 · TaxonMech · TraitMech | N/A | |
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| Thermoproteota | NCBITaxon:28889 · TaxonMech · TraitMech | 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.
Chronic Mercury Contamination and EFPC Community Context
Two depth sections of one EFPC sediment core yielded 28 MAGs from a chronically Hg-contaminated creek. The authors interpret the historical contamination as a selective context for the microbial community, drawing on prior EFPC work. This dataset is not a controlled Hg-selection experiment or an uncontaminated comparison. The seven canonical phylum-level entries are a subset of the sampled community, not seven isolates, all 28 MAGs or a complete functional roster.
Participating Taxa: Proteobacteria, Acidobacteriota, Actinobacteriota, Gemmatimonadota, Eisenbacteria, Myxococcota, Thermoproteota
Metabolites: mercury(2+) (CHEBI:16793 · MediaIngredientMech · CMMMech)
Biological Processes:
- response to metal ion (GO:0010038 · PathwayMech)
HYPOTHESIZED - chronic metal exposure could favor organisms carrying resistance or efflux functions. The 27/28 MAG annotation result is consistent with that interpretation, but no matched uncontaminated community or experimental Hg perturbation isolates selection of these genes.
Evidence
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PMID:33927032 - PARTIAL (COMPUTATIONAL)"The release of Hg into the EFPC ecosystem has selected for a unique microbial community that includes many Hg methylators"
EFPC Mercury Methylation Potential
The EFPC announcement describes a creek community that includes Hg methylators, citing prior EFPC research. This supports environmental methylation potential, not measured hgcAB carriage or methylmercury production by the 28 reconstructed MAGs or the seven canonical phylum entries. The separate methanogen culture study demonstrates positive methylation in eight of nine tested strains, but those cultures are not the sampled EFPC community. Exact carriers and methylation flux in these sediment samples remain unresolved.
Metabolites: methylmercury (CHEBI:49747 · MediaIngredientMech · CMMMech)
Biological Processes:
- mercury methylation (GO:0042192 · PathwayMech)
Evidence
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PMID:33927032 - PARTIAL (COMPUTATIONAL)"The release of Hg into the EFPC ecosystem has selected for a unique microbial community that includes many Hg methylators"
Putative Heavy Metal Resistance and Efflux Capacity
Annotation found putative heavy-metal resistance genes or ATPase efflux-pump genes in 27 of 28 EFPC MAGs; MAG124 was the exception. This is genomic capacity consistent with a contaminated habitat, not measured transcription, efflux, Hg-specific resistance, or a persistence advantage. The phylum-level participants identify a sampled subset, not uniform resistance of every organism in each phylum.
Participating Taxa: Proteobacteria, Acidobacteriota, Actinobacteriota, Gemmatimonadota, Eisenbacteria, Myxococcota, Thermoproteota
Metabolites: mercury(2+) (CHEBI:16793 · MediaIngredientMech · CMMMech)
Biological Processes:
- response to metal ion (GO:0010038 · PathwayMech)
Evidence
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PMID:33927032 - SUPPORT (COMPUTATIONAL)"27 of the 28 MAGs (all except MAG 124, a Saccharimonadales bacterium from the Pastescibacteria phylum) contained either putative heavy metal resistance genes or ATPase efflux pump genes"
Selenium Assimilatory Genomic Capacity
Se-assimilatory traits were annotated in 17 of 28 EFPC MAGs, including Eisenbacteria and Rokubacteria. This preserves the reported genomic finding, not measured selenium uptake, expression, flux or niche partitioning. The explicit Eisenbacteria participant is the corresponding canonical subset; Rokubacteria is named by the source but is not a separately grounded taxon in this record. Selenium assimilation is not established as a cause of Hg resistance or methylation.
Participating Taxa: Eisenbacteria
Metabolites: selenium atom (CHEBI:27568 · MediaIngredientMech · CMMMech)
Evidence
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PMID:33927032 - SUPPORT (COMPUTATIONAL)"17 of the 28 MAGs contained traits for Se-assimilatory metabolism"
Associated Datasets
| Dataset | Type | Repository | Accession |
|---|---|---|---|
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EFPC Sediment Metagenome
Shotgun metagenomic sequencing of two sediment core sections from East Fork Poplar Creek, yielding 28 metagenome-assembled genomes of novel prokaryotic species. |
METAGENOMICS | NCBI_BIOPROJECT | PRJNA670906 |
Knowledge gaps & discussions (1)
KNOWLEDGE_GAP OPEN Which EFPC organisms perform the predicted functions in the sampled sediments?
PMID:33927032 is a genome announcement, not a methylation or resistance assay. PMID:29636434 tested separate methanogen cultures: eight of nine exceeded matched fresh/spent-medium controls, the fused-hgcAB M. methylutens did not, and thiol/sulfide responses varied with growth and chemistry. Preserve those positive external results without assigning them to EFPC MAGs. Full primary main texts and the EFPC MAG table were read; supplements, raw genomes and original images were not audited. The selection-to-methylation arrow is removed; selection-to-resistance remains hypothetical. #1596 repairs the graph; non-graph imported methylation/sulfide claims and incomplete roster remain #1600. No new nodes or arrows.
Attaches to: ecological_interactions#Chronic Mercury Contamination and EFPC Community Context, ecological_interactions#EFPC Mercury Methylation Potential, ecological_interactions#Putative Heavy Metal Resistance and Efflux Capacity, ecological_interactions#Selenium Assimilatory Genomic Capacity
Environmental Factors
| Factor | Value | Unit |
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| Mercury Contamination | elevated | N/A |
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| Sediment Depth | 0-3 cm and 9-12 cm | cm |
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