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Mercury SFA East Fork Poplar Creek Sediment Community

Community ID CommunityMech:000044
Ecological State PERTURBED
Environment Mercury-contaminated creek sediment
ENVO:00002007

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. 28 metagenome-assembled genomes (MAGs) were reconstructed from two sediment core sections (0-3 cm and 9-12 cm depth), with 27 representing novel prokaryotic species. 27 of 28 MAGs contained putative heavy metal resistance genes or ATPase efflux pump genes, reflecting strong selective pressure from chronic mercury contamination. 17 of 28 MAGs contained selenium assimilatory metabolism traits. The community includes both bacterial and archaeal members, with several lineages carrying hgcA/hgcB genes for mercury methylation, a process that converts inorganic mercury to the more bioavailable and toxic methylmercury. Methanogenic archaea in similar contaminated environments have been shown to methylate mercury at rates rivaling those of sulfate- and iron-reducing bacteria.

Taxonomy

Taxon Ontology ID Functional Roles Abundance
Proteobacteria NCBITaxon:1224 N/A
Acidobacteriota NCBITaxon:57723 N/A
Actinobacteriota NCBITaxon:201174 N/A
Gemmatimonadota NCBITaxon:142998 N/A
Eisenbacteria NCBITaxon:1930587 N/A
Myxococcota NCBITaxon:2818505 N/A
Thermoproteota NCBITaxon:2283796 N/A
Methanocella paludicola NCBITaxon:304371
CROSS_FEEDER
N/A
Methanocorpusculum bavaricum NCBITaxon:2188
CROSS_FEEDER
N/A
Methanofollis liminatans NCBITaxon:43625
CROSS_FEEDER
N/A
Methanosphaerula palustris NCBITaxon:521012
CROSS_FEEDER
N/A

Ecological Interactions

Ecological interaction network for Mercury SFA East Fork Poplar Creek Sediment Community Bipartite graph where circle nodes represent taxa and colored rectangles represent ecological interactions (cross-feeding, mutualism, syntrophy, competition, commensalism).
Taxon
Cross-feeding
Mutualism
Syntrophy
Competition
Commensalism

Mercury Methylation by hgcAB+ Organisms

COMMENSALISM

Metabolites: methylmercury (CHEBI:30785)

Biological Processes:

Evidence

  • PMID:29636434 - SUPPORT (IN_VITRO)
    "Methanogenesis has been linked to Hg methylation in several natural habitats where methylmercury production incurs risk to people and ecosystems "
  • PMID:29636434 - SUPPORT (IN_VITRO)
    "methylation rates vary inherently among hgcAB+ methanogens but that several species are capable of MeHg production at rates that rival those of the better-know Hg-methylating sulfate- and iron-reducing bacteria "

Heavy Metal Resistance

COMMENSALISM

Evidence

  • PMID:33927032 - SUPPORT (COMPUTATIONAL)
    "27 of the 28 MAGs contained either putative heavy metal resistance genes or ATPase efflux pump genes"

Selenium Assimilatory Metabolism

COMMENSALISM

Evidence

  • PMID:33927032 - SUPPORT (COMPUTATIONAL)
    "17 of the 28 MAGs contained traits for Se-assimilatory metabolism"

Associated Datasets

Dataset Type Repository Accession
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. 		METAGENOME NCBI_BIOPROJECT PRJNA670906

Environmental Factors

Factor Value Unit
Mercury Contamination elevated N/A
Sediment Depth 0-3 cm and 9-12 cm cm