Biomineralization induced by microbial Fe/As redox reaction in extreme environment: Formation of Pharmacosiderite in acido-thermal spring of Norris Geyser Basin, Yellowstone National Park
Abstract
Microbial metal redox reaction is ubiquitous geochemical reaction in natural environment, however it has not been fully studied in detail how it affects the mineral alteration and biomineralization. In the present study the sediment and hot-spring water collected from the acido-thermal spring (pH=3.5 and temperature=78℃) located at Norris Geyser Basin were incubated to elucidate the role of extremophile in Fe/As redox reaction and biomineralization. The sediment slurry were enriched with medium to enhance the microbial activity (enrichment condition) and compared with control (addition of glutaraldehyde) to differentiate the biotic and abiotic process in biomineralization. The incubation was performed to 12 months, and the reaction was stopped by freezing the samples.
Formation of new mineral phase, pharmacosiderite (KFe4(AsO4)3(OH)4·6-7H2O), identified in XRD profiles only for the enrichment condition, could be a consequence of microbial Fe- and As-redox reaction. Oxyanion of arsenic (As) is likely to be reduced abiotically to arsenate via As-S complex at low pH condition (~4.0) similar to that in the present study area (3.5). Nonetheless, concentration of arsenite increased only for the enriched condition in first 6-month of incubation, suggesting that oxidative phase of As was originated by microbial As oxidation. Indeed, the aroA gene (As-oxidase gene) of Sulfurihydrogenibium sp. detected in pyrosequencing analysis indicating the significant role of exxtremophiles in mineral alteration/formation process. This finding is important because unexpected biomineralization of pharmacosiderite was occurred in the acido-thermal condition. The mechanism and implications to the natural environments will be discussed.- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.V33D0211K
- Keywords:
-
- 4302 Geological;
- NATURAL HAZARDS;
- 7280 Volcano seismology;
- SEISMOLOGY;
- 8424 Hydrothermal systems;
- VOLCANOLOGY;
- 8488 Volcanic hazards and risks;
- VOLCANOLOGY