1. A contemporary microbially maintained subglacial ferrous "ocean".
- Author
-
Mikucki JA, Pearson A, Johnston DT, Turchyn AV, Farquhar J, Schrag DP, Anbar AD, Priscu JC, and Lee PA
- Subjects
- Anaerobiosis, Antarctic Regions, Autotrophic Processes, Bacteria growth & development, Heterotrophic Processes, Metabolic Networks and Pathways, Molecular Sequence Data, Oxidation-Reduction, Oxidoreductases Acting on Sulfur Group Donors genetics, Oxidoreductases Acting on Sulfur Group Donors metabolism, Oxygen metabolism, Oxygen Isotopes analysis, Phylogeny, Seawater chemistry, Sulfates metabolism, Sulfites metabolism, Bacteria metabolism, Ecosystem, Ferric Compounds metabolism, Ferrous Compounds metabolism, Ice Cover, Seawater microbiology, Sulfur metabolism
- Abstract
An active microbial assemblage cycles sulfur in a sulfate-rich, ancient marine brine beneath Taylor Glacier, an outlet glacier of the East Antarctic Ice Sheet, with Fe(III) serving as the terminal electron acceptor. Isotopic measurements of sulfate, water, carbonate, and ferrous iron and functional gene analyses of adenosine 5'-phosphosulfate reductase imply that a microbial consortium facilitates a catalytic sulfur cycle. These metabolic pathways result from a limited organic carbon supply because of the absence of contemporary photosynthesis, yielding a subglacial ferrous brine that is anoxic but not sulfidic. Coupled biogeochemical processes below the glacier enable subglacial microbes to grow in extended isolation, demonstrating how analogous organic-starved systems, such as Neoproterozoic oceans, accumulated Fe(II) despite the presence of an active sulfur cycle.
- Published
- 2009
- Full Text
- View/download PDF