Journal article

Genome-Resolved Metagenomics and Detailed Geochemical Speciation Analyses Yield New Insights into Microbial Mercury Cycling in Geothermal Springs

Caitlin M Gionfriddo, Matthew B Stott, Jean F Power, Jacob M Ogorek, David P Krabbenhoft, Ryan Wick, Kathryn Holt, Lin-Xing Chen, Brian C Thomas, Jillian F Banfield, John W Moreau

Applied and Environmental Microbiology | AMER SOC MICROBIOLOGY | Published : 2020

Abstract

Geothermal systems emit substantial amounts of aqueous, gaseous, and methylated mercury, but little is known about microbial influences on mercury speciation. Here, we report results from genome-resolved metagenomics and mercury speciation analysis of acidic warm springs in the Ngawha Geothermal Field (<55°C, pH <4.5), Northland Region, Aotearoa New Zealand. Our aim was to identify the microorganisms genetically equipped for mercury methylation, demethylation, or Hg(II) reduction to volatile Hg(0) in these springs. Dissolved total and methylated mercury concentrations in two adjacent springs with different mercury speciation ranked among the highest reported from natural sources (250 to 16,0..

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Funding Acknowledgements

Samples were collected with permission from landowners, mana whenua, and kaitiaki for a range geothermal features in the Ngawha Geothermal Field. We thank these groups for their support. We also thank Karen Houghton at GNS and Mike Tate, John DeWild, and Charlie Thompson at the USGS Mercury Lab for their analytical and logistical support.J.W.M. and C.M.G. were funded in part by an Early Career Researcher Award to J.W.M. from The University of Melbourne. J.F.P. and M.B.S. were funded by the geothermal science funding from GNS Science.