The importance of water mass transport and dissolved‐particle interactions on the aluminum cycle in the subtropical North Atlantic
The importance of water mass transport and dissolved‐particle interactions on the aluminum cycle in the subtropical North Atlantic
New dissolved aluminum (dAl) data from the 2017 GEOTRACES process study GApr08 along 22°N in the subtropical North Atlantic are presented. They show an east to west increase in dAl concentration in the surface waters. Simulation of these data with a 1D advection-dust deposition revealed that, (a) advection and dust dissolution are equally important dAl sources, (b) scavenging plays a minor role compared to advection in dAl removal, and (c) in addition to dust dissolution, another dAl source is required at the westernmost stations to fully explain our observations. We attribute this additional source to the dissolution of erosion products delivered to the western subtropical North Atlantic by the Lesser Antilles. For waters deeper than ∼200–300 m, an optimum multi-parameter analysis allowed to separate the component of the dAl signal derived from water mass transport from its biogeochemical component. This revealed, (a) a major role played by water mass transport, (b) a net dAl removal between 200 and 800 m, attributed to scavenging at the subtropical North Atlantic scale, and (c) internal dAl inputs between 800 m and the seafloor, attributed to reversible scavenging. While the dAl oceanic distribution is usually considered to be dominated by the atmospheric dust input and removal by particle scavenging, this study highlights the important role played by advection, and the need to explicitly take this into account in order to quantitatively reveal the impact of external sources and dissolved-particulate interactions on the Al cycle in the North Atlantic Ocean.
GEOTRACES, OMPA, dissolved aluminum, geochemical modeling, reversible scavenging, subtropical North Atlantic
Artigue, Lise
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Wyatt, Neil J.
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Lacan, François
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Mahaffey, Claire
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Lohan, Maeve C.
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8 May 2021
Artigue, Lise
8dfc3629-ad86-49de-a233-2ba6319d9c78
Wyatt, Neil J.
258d214b-9dae-4a5f-acc9-c0a55fb66efd
Lacan, François
5d9279cd-dd40-43c2-83c9-ce0704672a55
Mahaffey, Claire
6c868a01-2c9b-48b0-ae08-9ecf6b870032
Lohan, Maeve C.
6ca10597-2d0f-40e8-8e4f-7619dfac5088
Artigue, Lise, Wyatt, Neil J., Lacan, François, Mahaffey, Claire and Lohan, Maeve C.
(2021)
The importance of water mass transport and dissolved‐particle interactions on the aluminum cycle in the subtropical North Atlantic.
Global Biogeochemical Cycles, 35 (5), [e2020GB006569].
(doi:10.1029/2020GB006569).
Abstract
New dissolved aluminum (dAl) data from the 2017 GEOTRACES process study GApr08 along 22°N in the subtropical North Atlantic are presented. They show an east to west increase in dAl concentration in the surface waters. Simulation of these data with a 1D advection-dust deposition revealed that, (a) advection and dust dissolution are equally important dAl sources, (b) scavenging plays a minor role compared to advection in dAl removal, and (c) in addition to dust dissolution, another dAl source is required at the westernmost stations to fully explain our observations. We attribute this additional source to the dissolution of erosion products delivered to the western subtropical North Atlantic by the Lesser Antilles. For waters deeper than ∼200–300 m, an optimum multi-parameter analysis allowed to separate the component of the dAl signal derived from water mass transport from its biogeochemical component. This revealed, (a) a major role played by water mass transport, (b) a net dAl removal between 200 and 800 m, attributed to scavenging at the subtropical North Atlantic scale, and (c) internal dAl inputs between 800 m and the seafloor, attributed to reversible scavenging. While the dAl oceanic distribution is usually considered to be dominated by the atmospheric dust input and removal by particle scavenging, this study highlights the important role played by advection, and the need to explicitly take this into account in order to quantitatively reveal the impact of external sources and dissolved-particulate interactions on the Al cycle in the North Atlantic Ocean.
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Accepted/In Press date: 29 March 2021
e-pub ahead of print date: 8 May 2021
Published date: 8 May 2021
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Funding Information:
The authors thank K. Kunde and D. G. Santana for sampling alongside the Captain and crew of the RRS James Cook during GApr08. The authors thank J. Gaillardet for his help about the Lesser Antilles erosion and weathering. The authors thank J. K. Klar for the GA06 dAl data and for the helpful scientific discussion. The authors thank A. Carret for the help with MATLAB. The authors thank J. D. Milliman, R. Middag, and K. Kunde for the helpful scientific discussion. The authors thank the reviewers of this study, one anonymous, and J. Resing for constructive comments that helped improve the manuscript. The French Ministry of Higher Education, Research and Innovation (MESRI) funded through the University Toulouse III the Ph.D. fellowship of L. Artigue. The French National Centre for Scientific Research (CNRS) funded F. Lacan. NERC funded C. Mahaffey (NE/N001979/1) and M.C. Lohan (NE/N001125/1).
Funding Information:
The authors thank K. Kunde and D. G. Santana for sampling alongside the Captain and crew of the RRS James Cook during GApr08. The authors thank J. Gaillardet for his help about the Lesser Antilles erosion and weathering. The authors thank J. K. Klar for the GA06 dAl data and for the helpful scientific discussion. The authors thank A. Carret for the help with MATLAB. The authors thank J. D. Milliman, R. Middag, and K. Kunde for the helpful scientific discussion. The authors thank the reviewers of this study, one anonymous, and J. Resing for constructive comments that helped improve the manuscript. The French Ministry of Higher Education, Research and Innovation (MESRI) funded through the University Toulouse III the Ph.D. fellowship of L. Artigue. The French National Centre for Scientific Research (CNRS) funded F. Lacan. NERC funded C. Mahaffey (NE/N001979/1) and M.C. Lohan (NE/N001125/1).
Publisher Copyright:
© 2021. American Geophysical Union. All Rights Reserved.
Keywords:
GEOTRACES, OMPA, dissolved aluminum, geochemical modeling, reversible scavenging, subtropical North Atlantic
Identifiers
Local EPrints ID: 450680
URI: http://eprints.soton.ac.uk/id/eprint/450680
ISSN: 0886-6236
PURE UUID: 98202d24-94dc-47aa-a58e-d4b28e18345a
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Date deposited: 06 Aug 2021 16:30
Last modified: 17 Mar 2024 06:40
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Author:
Lise Artigue
Author:
François Lacan
Author:
Claire Mahaffey
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