Viable cold-tolerant iron-reducing microorganisms in geographically diverse subglacial environments

Subglacial environments are known to harbour metabolically diverse microbial communities. These microbial communities drive chemical weathering of underlying bedrock and influence the geochemistry of glacial meltwater. Despite its importance in weathering reactions, the microbial cycling of iron in...

Full description

Bibliographic Details
Published in:Biogeosciences
Main Authors: Nixon, Sophie L., Telling, Jon P., Wadham, Jemma L., Cockell, Charles S.
Format: Article in Journal/Newspaper
Language:English
Published: 2017
Subjects:
Online Access:https://hdl.handle.net/1983/6c118591-441f-4e2e-b070-5f2d5c32730c
https://research-information.bris.ac.uk/en/publications/6c118591-441f-4e2e-b070-5f2d5c32730c
https://doi.org/10.5194/bg-14-1445-2017
https://research-information.bris.ac.uk/ws/files/119649555/Full_text_PDF_final_published_version_.pdf
Description
Summary:Subglacial environments are known to harbour metabolically diverse microbial communities. These microbial communities drive chemical weathering of underlying bedrock and influence the geochemistry of glacial meltwater. Despite its importance in weathering reactions, the microbial cycling of iron in subglacial environments, in particular the role of microbial iron reduction, is poorly understood. In this study we address the prevalence of viable iron-reducing microorganisms in subglacial sediments from five geographically isolated glaciers. Iron-reducing enrichment cultures were established with sediment from beneath Engabreen (Norway), Finsterwalderbreen (Svalbard), Leverett and Russell glaciers (Greenland), and Lower Wright Glacier (Antarctica). Rates of iron reduction were higher at 4 °C compared with 15 °C in all but one duplicated second-generation enrichment culture, indicative of cold-tolerant and perhaps cold-adapted iron reducers. Analysis of bacterial 16S rRNA genes indicates Desulfosporosinus were the dominant iron-reducing microorganisms in low-temperature Engabreen, Finsterwalderbreen and Lower Wright Glacier enrichments, and Geobacter dominated in Russell and Leverett enrichments. Results from this study suggest microbial iron reduction is widespread in subglacial environments and may have important implications for global biogeochemical iron cycling and export to marine ecosystems.