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Ngawha Geothermal Acidic Springs Mercury Cycling Community

Community ID CommunityMech:000243
Ecological State STABLE
Environment acidic geothermal warm spring
ENVO:00000051

An acidic warm spring microbial community from the Ngawha Geothermal Field (Northland Region, Aotearoa New Zealand) characterized by genome-resolved metagenomics and mercury speciation analysis. Two adjacent springs differ in mercury speciation, with dissolved total and methylated mercury concentrations among the highest reported from natural sources (250 to 16,000 ng/L total; 0.5 to 13.9 ng/L methylmercury). Sediment total mercury ranges from 1,274 to 7,000 ug/g. Despite ultrahigh mercury levels, the geothermal microbiome is unexpectedly diverse and dominated by acidophilic and mesophilic sulfur- and iron-cycling bacteria, mercury- and arsenic- resistant bacteria, and thermophilic and acidophilic archaea. A conceptual model integrates community structure and metagenomic potential with abiotic and biotic controls on Hg methylation, demethylation, and reduction to volatile Hg(0).

Taxonomy

Taxon Ontology ID Functional Roles Abundance
acidophilic sulfur- and iron-cycling bacteria NCBITaxon:2
PRIMARY_DEGRADER
DOMINANT
  • PMID:32414793 - SUPPORT (IN_VIVO)
    "acidophilic and mesophilic sulfur- and iron-cycling bacteria"
mercury- and arsenic-resistant bacteria NCBITaxon:2
PRIMARY_DEGRADER
N/A
  • PMID:32414793 - SUPPORT (IN_VIVO)
    "mercury- and arsenic-resistant bacteria"
thermophilic and acidophilic archaea NCBITaxon:2157
PRIMARY_DEGRADER
N/A
  • PMID:32414793 - SUPPORT (IN_VIVO)
    "thermophilic and acidophilic archaea"

Ecological Interactions

Ecological interaction network for Ngawha Geothermal Acidic Springs Mercury Cycling 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
Niche partitioning
Colonization facilitation
Strain competition
Predation

Mercury Methylation, Demethylation, and Reduction

CROSS_FEEDING

Metabolites: mercury(2+) (CHEBI:16793), methylmercury (CHEBI:25196)

Biological Processes:

Evidence

  • PMID:32414793 - SUPPORT (IN_VIVO)
    "microorganisms genetically equipped for mercury methylation, demethylation, or Hg(II) reduction to volatile Hg(0)"

Diverse Community Despite Ultrahigh Hg

NICHE_PARTITIONING

Evidence

  • PMID:32414793 - SUPPORT (IN_VIVO)
    "In the context of such ultrahigh mercury levels, the geothermal microbiome was unexpectedly diverse"

External Resources

Name Repository Resource ID
Primary publication for the Ngawha Hg-cycling community
PubMed record for the Gionfriddo et al. 2020 Appl Environ Microbiol paper. 		OTHER PMID:32414793
  • PMID:32414793 - SUPPORT (IN_VIVO)
    "Genome-Resolved Metagenomics and Detailed Geochemical Speciation Analyses Yield New Insights into Microbial Mercury Cycling in Geothermal Springs"
DOI landing page
DOI link to the Applied and Environmental Microbiology paper. 		OTHER doi:10.1128/AEM.00176-20

Environmental Factors

Factor Value Unit
Mercury concentration ultrahigh dissolved and solid Hg N/A
  • PMID:32414793 - SUPPORT (IN_VIVO)
    "among the highest reported from natural sources (250 to 16,000 ng liter-1 and 0.5 to 13.9 ng liter-1, respectively)"
Spring chemistry pH <4.5, temperature <55 C N/A
  • PMID:32414793 - SUPPORT (IN_VIVO)
    "acidic warm springs in the Ngawha Geothermal Field"