Physical weathering intensity controls bioavailable primary iron(II) silicate content in major global dust sources
Physical weathering intensity controls bioavailable primary iron(II) silicate content in major global dust sources
The speciation of iron (Fe) reaching the ocean, for instance in wind‐blown dust and coastal sediments, impacts its bioavailability to phytoplankton and its impact on atmospheric carbon dioxide (CO2) and climate. For dust reaching the Southern Ocean, primary Fe(II) silicates that are physically weathered from bedrock are highly bioavailable compared to more chemically weathered, Fe(III)‐rich species, suggesting that weathering in dust source regions impacts the bioavailable Fe supply. However, this phenomenon has not been studied in other important terrestrial Fe sources, where weathering regimes and source geology vary. Here, we use Fe X‐ray absorption spectroscopy on marine sediment cores to show that major global dust and sediment sources impacted by high physical weathering contain abundant primary minerals and thus are overlooked as a source of highly bioavailable Fe globally. Thus, it is important to consider the role of physical versus chemical weathering in Fe fertilization and biotic CO2 cycling.
10854-10864
Shoenfelt, Elizabeth M.
4651c23a-205e-45f1-8c59-aa0aeb2a676b
Winckler, Gisela
cff5621d-33ef-4562-b9dd-f6c4d863247c
Annett, Amber L.
de404d72-7e90-4dbd-884a-1df813808276
Hendry, Katharine R.
886d0da8-ae2d-4fa7-8e83-e850a6623392
Bostick, Benjamin C.
5826dfb0-f9ae-47c5-87a5-052d4e025539
16 October 2019
Shoenfelt, Elizabeth M.
4651c23a-205e-45f1-8c59-aa0aeb2a676b
Winckler, Gisela
cff5621d-33ef-4562-b9dd-f6c4d863247c
Annett, Amber L.
de404d72-7e90-4dbd-884a-1df813808276
Hendry, Katharine R.
886d0da8-ae2d-4fa7-8e83-e850a6623392
Bostick, Benjamin C.
5826dfb0-f9ae-47c5-87a5-052d4e025539
Shoenfelt, Elizabeth M., Winckler, Gisela, Annett, Amber L., Hendry, Katharine R. and Bostick, Benjamin C.
(2019)
Physical weathering intensity controls bioavailable primary iron(II) silicate content in major global dust sources.
Geophysical Research Letters, 46 (19), .
(doi:10.1029/2019GL084180).
Abstract
The speciation of iron (Fe) reaching the ocean, for instance in wind‐blown dust and coastal sediments, impacts its bioavailability to phytoplankton and its impact on atmospheric carbon dioxide (CO2) and climate. For dust reaching the Southern Ocean, primary Fe(II) silicates that are physically weathered from bedrock are highly bioavailable compared to more chemically weathered, Fe(III)‐rich species, suggesting that weathering in dust source regions impacts the bioavailable Fe supply. However, this phenomenon has not been studied in other important terrestrial Fe sources, where weathering regimes and source geology vary. Here, we use Fe X‐ray absorption spectroscopy on marine sediment cores to show that major global dust and sediment sources impacted by high physical weathering contain abundant primary minerals and thus are overlooked as a source of highly bioavailable Fe globally. Thus, it is important to consider the role of physical versus chemical weathering in Fe fertilization and biotic CO2 cycling.
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Accepted/In Press date: 3 September 2019
e-pub ahead of print date: 11 September 2019
Published date: 16 October 2019
Identifiers
Local EPrints ID: 435675
URI: http://eprints.soton.ac.uk/id/eprint/435675
ISSN: 0094-8276
PURE UUID: 63ca372f-6984-4af0-8224-ecb65cf3fa83
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Date deposited: 18 Nov 2019 17:30
Last modified: 17 Mar 2024 05:01
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Author:
Elizabeth M. Shoenfelt
Author:
Gisela Winckler
Author:
Katharine R. Hendry
Author:
Benjamin C. Bostick
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