Chemistry and deposition of mineral aerosol over Southern oceanic area

Atmospheric supplies bringing trace metals are believed to have a significant impact on biogeochemical processes in HNLC oceanic areas. Time series of atmospheric deposition samples and aerosols were continuously collected in 2009-2010 on Kerguelen and Crozet Islands in the Southern Indian Ocean. We found very low levels of dust concentrations and high total dust deposition fluxes, which are in good agreement with atmospheric models but not with previous observations. Scavenging ratio calculation highlights that surface concentrations are not representative of the total dust column. This leads to the conclusion that deposition flux is difficult to derive from aerosol surface concentrations at remote ocean sites. Deposition fluxes were also presented for a suite of elements identified as coming either from sea-salt and crustal sources. Some of them (Pb, As, ...) have an anthropogenic contribution during the winter only. Al, Fe, Mn and Si deposition fluxes are similar for the both locations; we observed differences for the other non-sea-salt elements from a factor of two to a factor of five with a decreasing gradient from Crozet to Kerguelen Islands. Pb isotopic ratios highlight that aerosols on Kerguelen Islands come predominantly from South America; Crozet Island receives aerosols from South Africa. REE profiles could confirm this behavior. Finally, concentrations in rainwaters are very low and difficult to measure accurately because of possible contamination issues. Deduced solubilities are generally high.

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Source https://theses.hal.science/tel-00849747
Author Heimburger, Alexie
Maintainer CCSD
Last Updated May 10, 2026, 04:15 (UTC)
Created May 10, 2026, 04:15 (UTC)
Identifier tel-00849747
Language fr
Rights https://about.hal.science/hal-authorisation-v1/
contributor Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)) ; Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)
creator Heimburger, Alexie
date 2013-07-16T00:00:00
harvest_object_id f2f1352d-4f1a-410a-87ec-08c515d7b45a
harvest_source_id 3374d638-d20b-4672-ba96-a23232d55657
harvest_source_title test moissonnage SELUNE
metadata_modified 2025-08-12T00:00:00
set_spec type:THESE