Sulfur and nitrogen acidification pathways of dust aerosols over the eastern subtropical Atlantic will be studied to provide insight into these processes for iron solubility and biogeochemical and climate feedbacks. Size-segregated aerosols and rainwater will be collected during the Spanish RODA (English translation = Oceanic Eddies and Atmospheric Deposition in the Canary Current) cruise in the northeastern subtropical Atlantic Ocean, and major ion concentrations and isotopes of sulfate and nitrate will be analyzed. The global chemical transport model GEOS-CHEM will be used for quantitative interpretation of the measurements. Collaborative measurements of iron speciation in aerosol and ocean samples and phytoplankton abundance provide the opportunity to investigate the role of atmospheric acidification on the solubility of iron in dust aerosols and its potential effects on marine primary productivity. Constraints on atmospheric acidification mechanisms of dust will aid in understanding marine biogeochemical cycles and associated climate feedbacks. This project combines measurements of atmospheric chemistry with marine biological indicators involving groups from the U.S. and Spain, providing an opportunity to foster international collaboration. Broader impacts also include the training of one graduate student in geochemical analysis and chemical transport modeling in an interdisciplinary and international context, and support for a postdoctoral researcher.
