Soluble trace metals in aerosols over the tropical south-east Pacificoffshore of Peru

[摘要] Bulk aerosol samples collected during cruise M91 of FS Meteor off the coast ofPeru in December 2012 were analysed for their soluble trace metal (Fe, Al,Mn, Ti, Zn, V, Ni, Cu, Co, Cd, Pb, Th) and major ion (includingNO₃⁻ and NH₄⁺) content. These data are among the firstrecorded for trace metals in this relatively poorly studied region of theglobal marine atmosphere. To the north of  ∼  13° S,the concentrations of several elements (Fe, Ti, Zn, V, Ni, Pb) appear to berelated to distance from the coast. At the south of the transect( ∼  15–16° S), elevated concentrations of Fe, Cu, Co,and Ni were observed, and we calculated dry deposition fluxes of soluble Cuapproximately an order of magnitude higher than a recent model-basedestimate of total Cu deposition to the region. The model did not takeaccount of emissions from the large smelting facilities in the south of Peruand northern Chile, and our results may indicate that these facilitiesconstitute an important source of trace metals to the region. Calculated drydeposition fluxes (3370–17800 and 16–107 nmol m⁻² d⁻¹ forinorganic nitrogen and soluble Fe respectively) indicated that atmosphericinput to the waters of the Peru upwelling system contains an excess of Feover N, with respect to phytoplankton requirements. This may be significantas primary production in these waters has been reported to be limited by Feavailability, but atmospheric deposition is unlikely to be the dominantsource of Fe to the system.

[学科分类] 地球化学与岩石