A circumpolar dust conveyor in the glacial Southern Ocean

The increased flux of soluble iron (Fe) to the Fe-deficient Southern Ocean by atmospheric dust is considered to have stimulated the net primary production and carbon export, thus promoting atmospheric CO(2) drawdown during glacial periods. Yet, little is known about the sources and transport pathway...

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Bibliographic Details
Published in:Nature Communications
Main Authors: Struve, Torben, Pahnke, Katharina, Lamy, Frank, Wengler, Marc, Böning, Philipp, Winckler, Gisela
Format: Text
Language:English
Published: Nature Publishing Group UK 2020
Subjects:
Article
Antarctic
Pacific
Southern Ocean
The Antarctic
Antarc*
Online Access:http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7652835/
http://www.ncbi.nlm.nih.gov/pubmed/33168803
https://doi.org/10.1038/s41467-020-18858-y
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Summary:The increased flux of soluble iron (Fe) to the Fe-deficient Southern Ocean by atmospheric dust is considered to have stimulated the net primary production and carbon export, thus promoting atmospheric CO(2) drawdown during glacial periods. Yet, little is known about the sources and transport pathways of Southern Hemisphere dust during the Last Glacial Maximum (LGM). Here we show that Central South America (~24‒32°S) contributed up to ~80% of the dust deposition in the South Pacific Subantarctic Zone via efficient circum-Antarctic dust transport during the LGM, whereas the Antarctic Zone was dominated by dust from Australia. This pattern is in contrast to the modern/Holocene pattern, when South Pacific dust fluxes are thought to be primarily supported by Australian sources. Our findings reveal that in the glacial Southern Ocean, Fe fertilization critically relies on the dynamic interaction of changes in dust-Fe sources in Central South America with the circumpolar westerly wind system.

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