Microbial Fe(III) Reduction as a Potential Iron Source from Holocene Sediments Beneath Larsen Ice Shelf
Recent recession of the Larsen Ice Shelf C has revealed microbial alterations of illite in marine sediments, a process typically thought to occur during low-grade metamorphism. In situ breakdown of illite provides a previously-unobserved pathway for the release of dissolved Fe2+ to porewaters, thus...
Published in: | Nature Communications |
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Main Authors: | , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | unknown |
Published: |
Digital Commons @ University of South Florida
2019
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Subjects: | |
Online Access: | https://digitalcommons.usf.edu/msc_facpub/2418 https://doi.org/10.1038/s41467-019-13741-x https://digitalcommons.usf.edu/context/msc_facpub/article/3466/viewcontent/s41467_019_13741_x.pdf https://digitalcommons.usf.edu/context/msc_facpub/article/3466/filename/0/type/additional/viewcontent/41467_2019_13741_MOESM2_ESM.pdf https://digitalcommons.usf.edu/context/msc_facpub/article/3466/filename/1/type/additional/viewcontent/41467_2019_13741_MOESM3_ESM.pdf https://digitalcommons.usf.edu/context/msc_facpub/article/3466/filename/2/type/additional/viewcontent/41467_2019_13741_MOESM4_ESM.xlsx |
Summary: | Recent recession of the Larsen Ice Shelf C has revealed microbial alterations of illite in marine sediments, a process typically thought to occur during low-grade metamorphism. In situ breakdown of illite provides a previously-unobserved pathway for the release of dissolved Fe2+ to porewaters, thus enhancing clay-rich Antarctic sub-ice shelf sediments as an important source of Fe to Fe-limited surface Southern Ocean waters during ice shelf retreat after the Last Glacial Maximum. When sediments are underneath the ice shelf, Fe2+ from microbial reductive dissolution of illite/Fe-oxides may be exported to the water column. However, the initiation of an oxygenated, bioturbated sediment under receding ice shelves may oxidize Fe within surface porewaters, decreasing dissolved Fe2+ export to the ocean. Thus, we identify another ice-sheet feedback intimately tied to iron biogeochemistry during climate transitions. Further constraints on the geographical extent of this process will impact our understanding of iron-carbon feedbacks during major deglaciations. |
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