The Influence of Natural, Anthropogenic, and Wildfire Sources on Iron and Zinc Aerosols Delivered to the North Pacific Ocean

Abstract Atmospheric deposition is an important source of iron (Fe) and perhaps zinc (Zn) to the oceans. We present total and water‐soluble aerosol Fe and Zn isotopic compositions, size‐fractionated aerosol Fe isotopic compositions, and aerosol enrichment factors from the North Pacific GEOTRACES GP1...

Full description

Saved in:
Bibliographic Details
Main Authors: Z. B. Bunnell, M. Sieber, D. S. Hamilton, C. M. Marsay, C. S. Buck, W. M. Landing, S. G. John, T. M. Conway
Format: Article
Language:English
Published: Wiley 2025-02-01
Series:Geophysical Research Letters
Subjects:
Online Access:https://doi.org/10.1029/2024GL113877
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1850036605622943744
author Z. B. Bunnell
M. Sieber
D. S. Hamilton
C. M. Marsay
C. S. Buck
W. M. Landing
S. G. John
T. M. Conway
author_facet Z. B. Bunnell
M. Sieber
D. S. Hamilton
C. M. Marsay
C. S. Buck
W. M. Landing
S. G. John
T. M. Conway
author_sort Z. B. Bunnell
collection DOAJ
description Abstract Atmospheric deposition is an important source of iron (Fe) and perhaps zinc (Zn) to the oceans. We present total and water‐soluble aerosol Fe and Zn isotopic compositions, size‐fractionated aerosol Fe isotopic compositions, and aerosol enrichment factors from the North Pacific GEOTRACES GP15 section (Alaska‐Tahiti) during the low dust season. We found distinct bulk aerosol provinces along this latitudinal transect: Asian aerosols (especially crustal dust) dominate at higher latitudes (52–32°N) while North American heavier‐than‐crustal wildfire aerosols dominate in Equatorial Pacific deployments (20°N to 20°S). Soluble aerosol Fe was isotopically lighter‐than‐crustal along the full transect, strongly indicative of a pervasive anthropogenic Fe contribution to the Pacific. Comparison to a global aerosol deposition model corroborates that an isotopically heavy endmember is required for wildfire Fe, attributed to pyroconvective entrainment of soil particles. For Zn, the entire GP15 section is dominated by non‐crustal anthropogenic sources, reflected by light isotopic compositions (bulk: −0.12 ± 0.08‰ and soluble: −0.17 ± 0.14‰).
format Article
id doaj-art-4c0553248ee343db80038d8d064a2a42
institution DOAJ
issn 0094-8276
1944-8007
language English
publishDate 2025-02-01
publisher Wiley
record_format Article
series Geophysical Research Letters
spelling doaj-art-4c0553248ee343db80038d8d064a2a422025-08-20T02:57:05ZengWileyGeophysical Research Letters0094-82761944-80072025-02-01523n/an/a10.1029/2024GL113877The Influence of Natural, Anthropogenic, and Wildfire Sources on Iron and Zinc Aerosols Delivered to the North Pacific OceanZ. B. Bunnell0M. Sieber1D. S. Hamilton2C. M. Marsay3C. S. Buck4W. M. Landing5S. G. John6T. M. Conway7College of Marine Sciences University of South Florida St Petersburg FL USACollege of Marine Sciences University of South Florida St Petersburg FL USADepartment of Marine, Earth, and Atmospheric Sciences North Carolina State University Raleigh NC USASkidaway Institute of Oceanography University of Georgia Savannah GA USASkidaway Institute of Oceanography University of Georgia Savannah GA USADepartment of Earth, Ocean, and Atmospheric Science Florida State University Saint Petersburg FL USADepartment of Earth Sciences University of California Los Angeles Los Angeles CA USACollege of Marine Sciences University of South Florida St Petersburg FL USAAbstract Atmospheric deposition is an important source of iron (Fe) and perhaps zinc (Zn) to the oceans. We present total and water‐soluble aerosol Fe and Zn isotopic compositions, size‐fractionated aerosol Fe isotopic compositions, and aerosol enrichment factors from the North Pacific GEOTRACES GP15 section (Alaska‐Tahiti) during the low dust season. We found distinct bulk aerosol provinces along this latitudinal transect: Asian aerosols (especially crustal dust) dominate at higher latitudes (52–32°N) while North American heavier‐than‐crustal wildfire aerosols dominate in Equatorial Pacific deployments (20°N to 20°S). Soluble aerosol Fe was isotopically lighter‐than‐crustal along the full transect, strongly indicative of a pervasive anthropogenic Fe contribution to the Pacific. Comparison to a global aerosol deposition model corroborates that an isotopically heavy endmember is required for wildfire Fe, attributed to pyroconvective entrainment of soil particles. For Zn, the entire GP15 section is dominated by non‐crustal anthropogenic sources, reflected by light isotopic compositions (bulk: −0.12 ± 0.08‰ and soluble: −0.17 ± 0.14‰).https://doi.org/10.1029/2024GL113877aerosolsirontrace metalsdustwildfiresGEOTRACES
spellingShingle Z. B. Bunnell
M. Sieber
D. S. Hamilton
C. M. Marsay
C. S. Buck
W. M. Landing
S. G. John
T. M. Conway
The Influence of Natural, Anthropogenic, and Wildfire Sources on Iron and Zinc Aerosols Delivered to the North Pacific Ocean
Geophysical Research Letters
aerosols
iron
trace metals
dust
wildfires
GEOTRACES
title The Influence of Natural, Anthropogenic, and Wildfire Sources on Iron and Zinc Aerosols Delivered to the North Pacific Ocean
title_full The Influence of Natural, Anthropogenic, and Wildfire Sources on Iron and Zinc Aerosols Delivered to the North Pacific Ocean
title_fullStr The Influence of Natural, Anthropogenic, and Wildfire Sources on Iron and Zinc Aerosols Delivered to the North Pacific Ocean
title_full_unstemmed The Influence of Natural, Anthropogenic, and Wildfire Sources on Iron and Zinc Aerosols Delivered to the North Pacific Ocean
title_short The Influence of Natural, Anthropogenic, and Wildfire Sources on Iron and Zinc Aerosols Delivered to the North Pacific Ocean
title_sort influence of natural anthropogenic and wildfire sources on iron and zinc aerosols delivered to the north pacific ocean
topic aerosols
iron
trace metals
dust
wildfires
GEOTRACES
url https://doi.org/10.1029/2024GL113877
work_keys_str_mv AT zbbunnell theinfluenceofnaturalanthropogenicandwildfiresourcesonironandzincaerosolsdeliveredtothenorthpacificocean
AT msieber theinfluenceofnaturalanthropogenicandwildfiresourcesonironandzincaerosolsdeliveredtothenorthpacificocean
AT dshamilton theinfluenceofnaturalanthropogenicandwildfiresourcesonironandzincaerosolsdeliveredtothenorthpacificocean
AT cmmarsay theinfluenceofnaturalanthropogenicandwildfiresourcesonironandzincaerosolsdeliveredtothenorthpacificocean
AT csbuck theinfluenceofnaturalanthropogenicandwildfiresourcesonironandzincaerosolsdeliveredtothenorthpacificocean
AT wmlanding theinfluenceofnaturalanthropogenicandwildfiresourcesonironandzincaerosolsdeliveredtothenorthpacificocean
AT sgjohn theinfluenceofnaturalanthropogenicandwildfiresourcesonironandzincaerosolsdeliveredtothenorthpacificocean
AT tmconway theinfluenceofnaturalanthropogenicandwildfiresourcesonironandzincaerosolsdeliveredtothenorthpacificocean
AT zbbunnell influenceofnaturalanthropogenicandwildfiresourcesonironandzincaerosolsdeliveredtothenorthpacificocean
AT msieber influenceofnaturalanthropogenicandwildfiresourcesonironandzincaerosolsdeliveredtothenorthpacificocean
AT dshamilton influenceofnaturalanthropogenicandwildfiresourcesonironandzincaerosolsdeliveredtothenorthpacificocean
AT cmmarsay influenceofnaturalanthropogenicandwildfiresourcesonironandzincaerosolsdeliveredtothenorthpacificocean
AT csbuck influenceofnaturalanthropogenicandwildfiresourcesonironandzincaerosolsdeliveredtothenorthpacificocean
AT wmlanding influenceofnaturalanthropogenicandwildfiresourcesonironandzincaerosolsdeliveredtothenorthpacificocean
AT sgjohn influenceofnaturalanthropogenicandwildfiresourcesonironandzincaerosolsdeliveredtothenorthpacificocean
AT tmconway influenceofnaturalanthropogenicandwildfiresourcesonironandzincaerosolsdeliveredtothenorthpacificocean