Zonal distribution of dissolved aluminium in the Mediterranean Sea
Rolison, J.M.; Middag, R.; Sterling, C.H.; Rijkenberg, M.J.A.; de Baar, H.J.W. (2015). Zonal distribution of dissolved aluminium in the Mediterranean Sea. Mar. Chem. 177: 87-100. dx.doi.org/10.1016/j.marchem.2015.05.001
In: Marine Chemistry. Elsevier: Amsterdam. ISSN 0304-4203; e-ISSN 1872-7581, more
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| Author keywords |
Dissolved aluminium; Aluminum; Atmospheric deposition; Trace metals; Sediment resuspension; Mediterranean Sea; GEOTRACES |
| Authors | | Top |
- Rolison, J.M.
- Middag, R.
- Sterling, C.H.
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- Rijkenberg, M.J.A., more
- de Baar, H.J.W., more
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| Abstract |
Dissolved aluminium (Al) is an important tracer of atmospheric dust input to the oceans. The GEOTRACES expeditionto the highly dust impacted Mediterranean Sea afforded the opportunity to study the distribution of dissolvedAl in the Mediterranean Sea in detail. Interestingly, the elevated concentration of dissolved Al observedin Mediterranean surface waters (up to 80 nmol kg-1) is strongly correlated with salinity, both showing an increasefrom west to east due to mixing of low Al, low salinity Atlantic surface waters with high Al, high salinityMediterranean surface and intermediate waters. At intermediate depths (100–1250 m), a strong correlation betweendissolved Al and silicic acid (Si) was observed. Vertical mixing between surface, intermediate and olduplifted deep water between depths of 0 and 1300m is primarily responsible for the long recognized Al:Si relationshipat intermediate depths. However, since the subsurfacewaters have a surfacewater origin, vertical transportof Al and Si is required to maintain the high concentrations of dissolved Al and Si in Mediterranean deepwaters relative to surface waters. The most likely vertical transport mechanism is suggested to be biogenic particleswhichwouldthus be ultimately responsible for the Al:Si relationship at intermediate depths. Elevated concentrationsof dissolved Al relative to Si were observed in some Mediterranean deep waters with sedimentresuspension during episodes of deep water formation as the most likely source of the additional dissolvedaluminium. |
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