Iron Distribution in the Subtropical North Atlantic: The Pivotal Role of Colloidal Iron
The low availability of the essential micronutrient iron (Fe) in the ocean impacts the efficiency of the biological carbon pump, and hence, it is vital to elucidate its sources, sinks, and internal cycling. We present size‐fractionated dissolved Fe (dFe, <0.2 μm) measurements from 130 surface sam...
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ftunivliverpool:oai:livrepository.liverpool.ac.uk:3062518 2023-05-15T17:31:21+02:00 Iron Distribution in the Subtropical North Atlantic: The Pivotal Role of Colloidal Iron Kunde, K Wyatt, NJ González‐Santana, D Tagliabue, A Mahaffey, C Lohan, MC 2019-12 text http://livrepository.liverpool.ac.uk/3062518/ https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019GB006326 http://livrepository.liverpool.ac.uk/3062518/1/2019GB006326.pdf en eng American Geophysical Union (AGU) http://livrepository.liverpool.ac.uk/3062518/1/2019GB006326.pdf Kunde, K, Wyatt, NJ, González‐Santana, D, Tagliabue, A orcid:0000-0002-3572-3634 , Mahaffey, C orcid:0000-0002-4215-7271 and Lohan, MC (2019) Iron Distribution in the Subtropical North Atlantic: The Pivotal Role of Colloidal Iron. Global Biogeochemical Cycles, 33 (12). pp. 1532-1547. Article NonPeerReviewed 2019 ftunivliverpool 2023-01-19T23:47:23Z The low availability of the essential micronutrient iron (Fe) in the ocean impacts the efficiency of the biological carbon pump, and hence, it is vital to elucidate its sources, sinks, and internal cycling. We present size‐fractionated dissolved Fe (dFe, <0.2 μm) measurements from 130 surface samples and 7 full‐depth profiles from the subtropical North Atlantic during summer 2017 and demonstrate the pivotal role of colloidal (cFe, 0.02 to 0.2 μm) over soluble (sFe, <0.02 μm) Fe in controlling the dFe distribution. In the surface (<5 m), a strong west‐to‐east decrease in dFe (1.53 to 0.26 nM) was driven by a dust gradient, which retained dFe predominantly as cFe (61% to 85% of dFe), while sFe remained largely constant at 0.19 ± 0.05 nM. In the euphotic zone, the attenuation of dFe resulted from the depletion of cFe (0% to 30% of dFe), with scavenging as an important driver. In the mesopelagic, cFe was released from sinking biogenic and lithogenic particles, creating a zone of elevated dFe (0.7 to 1.0 nM) between 400 to 1100 m depth. While the ocean interior, below the mesopelagic and above the seafloor boundary, exhibited a narrow range of cFe (40% to 60% of dFe), the abyssal cFe fraction varied in range from 26% to 76% due to interactions with seafloor sediments and a hydrothermal source with almost 100% cFe. Overall, our results produced an hourglass shape for the vertical cFe‐to‐dFe fraction and highlight the primary control of cFe on the dFe distribution. Article in Journal/Newspaper North Atlantic The University of Liverpool Repository |
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Open Polar |
collection |
The University of Liverpool Repository |
op_collection_id |
ftunivliverpool |
language |
English |
description |
The low availability of the essential micronutrient iron (Fe) in the ocean impacts the efficiency of the biological carbon pump, and hence, it is vital to elucidate its sources, sinks, and internal cycling. We present size‐fractionated dissolved Fe (dFe, <0.2 μm) measurements from 130 surface samples and 7 full‐depth profiles from the subtropical North Atlantic during summer 2017 and demonstrate the pivotal role of colloidal (cFe, 0.02 to 0.2 μm) over soluble (sFe, <0.02 μm) Fe in controlling the dFe distribution. In the surface (<5 m), a strong west‐to‐east decrease in dFe (1.53 to 0.26 nM) was driven by a dust gradient, which retained dFe predominantly as cFe (61% to 85% of dFe), while sFe remained largely constant at 0.19 ± 0.05 nM. In the euphotic zone, the attenuation of dFe resulted from the depletion of cFe (0% to 30% of dFe), with scavenging as an important driver. In the mesopelagic, cFe was released from sinking biogenic and lithogenic particles, creating a zone of elevated dFe (0.7 to 1.0 nM) between 400 to 1100 m depth. While the ocean interior, below the mesopelagic and above the seafloor boundary, exhibited a narrow range of cFe (40% to 60% of dFe), the abyssal cFe fraction varied in range from 26% to 76% due to interactions with seafloor sediments and a hydrothermal source with almost 100% cFe. Overall, our results produced an hourglass shape for the vertical cFe‐to‐dFe fraction and highlight the primary control of cFe on the dFe distribution. |
format |
Article in Journal/Newspaper |
author |
Kunde, K Wyatt, NJ González‐Santana, D Tagliabue, A Mahaffey, C Lohan, MC |
spellingShingle |
Kunde, K Wyatt, NJ González‐Santana, D Tagliabue, A Mahaffey, C Lohan, MC Iron Distribution in the Subtropical North Atlantic: The Pivotal Role of Colloidal Iron |
author_facet |
Kunde, K Wyatt, NJ González‐Santana, D Tagliabue, A Mahaffey, C Lohan, MC |
author_sort |
Kunde, K |
title |
Iron Distribution in the Subtropical North Atlantic: The Pivotal Role of Colloidal Iron |
title_short |
Iron Distribution in the Subtropical North Atlantic: The Pivotal Role of Colloidal Iron |
title_full |
Iron Distribution in the Subtropical North Atlantic: The Pivotal Role of Colloidal Iron |
title_fullStr |
Iron Distribution in the Subtropical North Atlantic: The Pivotal Role of Colloidal Iron |
title_full_unstemmed |
Iron Distribution in the Subtropical North Atlantic: The Pivotal Role of Colloidal Iron |
title_sort |
iron distribution in the subtropical north atlantic: the pivotal role of colloidal iron |
publisher |
American Geophysical Union (AGU) |
publishDate |
2019 |
url |
http://livrepository.liverpool.ac.uk/3062518/ https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019GB006326 http://livrepository.liverpool.ac.uk/3062518/1/2019GB006326.pdf |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
http://livrepository.liverpool.ac.uk/3062518/1/2019GB006326.pdf Kunde, K, Wyatt, NJ, González‐Santana, D, Tagliabue, A orcid:0000-0002-3572-3634 , Mahaffey, C orcid:0000-0002-4215-7271 and Lohan, MC (2019) Iron Distribution in the Subtropical North Atlantic: The Pivotal Role of Colloidal Iron. Global Biogeochemical Cycles, 33 (12). pp. 1532-1547. |
_version_ |
1766128861780639744 |