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| Titel |
Dissolution of cobalt and zinc from natural and anthropogenic dusts in seawater |
| VerfasserIn |
C.-E. Thuróczy, M. Boye, R. Losno |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 7, no. 6 ; Nr. 7, no. 6 (2010-06-17), S.1927-1936 |
| Datensatznummer |
250004846
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| Publikation (Nr.) |
 copernicus.org/bg-7-1927-2010.pdf |
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| Zusammenfassung |
| Atmospheric dust inputs to the surface ocean are a major source of trace metals likely to be
bio-available for phytoplankton after their dissolution in seawater. Among them, cobalt (Co)
and zinc (Zn) are essential for phytoplankton growth and for the distribution of the major
groups such as coccolithophorids, cyanobacteria and diatoms. The solubility in seawater of
Co and Zn present in natural and anthropogenic dusts was studied using an open-flow reactor
with and without light irradiation. Those dusts can be transported in the atmosphere by the
wind before being deposited to the surface ocean. The analyses of cobalt and zinc were
conducted using voltammetric methods and the global elemental composition of dust was
determined by ICP-AES. This study highlighted the role of the dust origin in revealing the
solubility characteristics. Much higher dust solubility was found for zinc as compared to
cobalt; cobalt in anthropogenic particles was much more soluble (0.78%) in seawater after
2 h of dissolution than Co in natural particles (0.14%). Zinc showed opposite solubility,
higher in natural particles (16%) than in anthropogenic particles (5.2%). A natural
dust event to the surface ocean could account for up to 5% of the cobalt inventory and up
to 50% of the Zn inventory in the mixed layer in the Pacific Ocean whereas the cobalt and
zinc inventories in the mixed layer of the Atlantic Ocean might already include the effects
of natural dust inputs and the subsequent metal dissolution. Anthropogenic sources to the
surface ocean could be as important as the natural sources, but a better estimate of the
flux of anthropogenic aerosol to the surface ocean is needed to further estimate the
anthropogenic inputs. Variations in natural and anthropogenic inputs may induce large shifts
in the Co/Zn ratio in the surface ocean; hence it could impact the phytoplankton community
structure. |
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