| مستخلص: |
Soluble and total trace metals were measured in four size fractionated aerosol samples collected over the tropical eastern Atlantic Ocean. In samples that were dominated by Saharan dust, the size distributions of total iron, aluminum, titanium, manganese, cobalt, and thorium were very similar to one another and to the size distributions of soluble manganese, cobalt, and thorium. Finer particle sizes (< ~3 μm) showed enhanced soluble concentrations of iron, aluminum, and titanium, possibly as a result of interactions with acidic sulfate aerosol during atmospheric transport. The difference in fine particle solubility between these two groups of elements might be related to the hyperbolic increase in the fractional solubility of iron, and a number of other elements, during the atmospheric transport of Saharan dust, which is not observed for manganese and its associated elements. In comparison to elements whose solubility varies during atmospheric transport, the stability of thorium fractional solubility should reduce uncertainties in the use of dissolved concentrations of this element in seawater as a proxy for dust deposition, although this topic requires further work. Key Points: The solubility in fine fractions of Saharan dust aerosols is enhanced for Fe, Al, and Ti but not for Mn, Co, and ThFe, Al, and Ti solubility increases strongly during atmospheric transport of dust, while Mn, Co, and Th solubility does notThe stability of Th solubility during transport may make it a more suitable tracer for dust inputs to the ocean than Al or Ti [ABSTRACT FROM AUTHOR] |
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