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Lithogenic particle flux to the subantarctic Southern Ocean: a multi-tracer estimate using sediment trap samples

Citation

Traill, CD and Weis, J and Wynn-Edwards, C and Perron, MMG and Chase, Z and Bowie, AR, Lithogenic particle flux to the subantarctic Southern Ocean: a multi-tracer estimate using sediment trap samples, Global Biogeochemical Cycles, 36, (9) Article e2022GB007391. ISSN 0886-6236 (2022) [Refereed Article]


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Copyright Statement

© 2022. The Authors. This article is licensed under a Creative Commons Attribution 4.0 International (CC BY 4.0) License, (https://creativecommons.org/licenses/by/4.0/), which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

DOI: doi:10.1029/2022GB007391

Abstract

Mineral dust is a key source of essential micronutrients, particularly iron (Fe), for phytoplankton in the Southern Ocean. However, observations of dust deposition over the Southern Ocean are sparse, hindering assessments of its influence on marine biogeochemistry. We present a time series (2010-2019) of lithogenic particle flux estimates using sediment trap samples collected at 1,000 m depth at the subantarctic Southern Ocean Time Series (SOTS) site. Lithogenic flux was estimated using individual Fe, aluminium (Al), titanium, and thorium concentrations in sediment trap particles less than 1 mm in size. These tracers showed good agreement with one another, and their average was investigated as a proxy for mineral dust deposition. This multi-tracer average lithogenic flux exhibited strong seasonality, peaking in late spring and summer. No significant Fe enrichment was observed compared to the average upper continental crust, indicating that lithogenic material dominates particulate Fe flux at SOTS. Similar Fe:Al ratios in our samples compared to those reported in marine aerosols off southern Australia, coupled with particle trajectory analysis, suggested Australian dust constitutes the primary lithogenic source to SOTS sinking particles. Lead enrichment in our samples also highlighted an anthropogenic contribution to sinking particles, which might represent an additional aeolian source of more bio-available Fe to subantarctic waters. This study contributes a new long-term estimate of lithogenic particle fluxes and aeolian deposition over the subantarctic Southern Ocean. These estimates may enhance model representation of trace metal contribution to biogeochemical processes in the Southern Ocean.

Item Details

Item Type:Refereed Article
Keywords:dust deposition flux estimate, sinking marine particles, lithogenic tracers, subantarctic Southern Ocean, Southern Ocean Time Series (SOTS)
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Chemical oceanography
Objective Division:Environmental Management
Objective Group:Management of Antarctic and Southern Ocean environments
Objective Field:Antarctic and Southern Ocean oceanic processes
UTAS Author:Traill, CD (Mr Christopher Traill)
UTAS Author:Weis, J (Mr Jakob Weis)
UTAS Author:Wynn-Edwards, C (Dr Cathryn Wynn-Edwards)
UTAS Author:Perron, MMG (Miss Morgane Perron)
UTAS Author:Chase, Z (Professor Zanna Chase)
UTAS Author:Bowie, AR (Professor Andrew Bowie)
ID Code:153649
Year Published:2022
Deposited By:Directorate
Deposited On:2022-09-29
Last Modified:2022-11-28
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