Through collaboration with Jordi Dachs (IIQAB-CSIC, Barcelona) and Antonio Tovar (IMEDEA-CSIC, Mallorca), we are involved with the Spanish campaign RODA (English translation of the acronym RODA = Oceanic Eddies and Atmospheric Deposition in the Canary Current).  The figure to the right shows cruise tracks from two cruises that will take place during August 2006 and February 2007.  Size segregated aerosol samples will be collected during these cruises.  In addition, aerosol samples will be collected over the course of one year in the Canary Islands. 

We will be measuring the oxygen isotopic composition of sulfate and nitrate aerosols collected during the RODA campaign.  Sulfate and nitrate that form on alkaline aerosols such as dust have a unique oxygen isotopic composition, which will allow us to quantify the acidification pathways of dust aerosols.  Acidification of dust has implications for atmospheric chemistry, climate, and marine biogeochemistry.  Complementary measurements by other groups participating in RODA include Fe speciation to determine the amount of soluble iron in the aerosols (important as a nutrient for marine phytoplankton), and phytoplankton speciation and abundance, among other studies.  These complementary measurements by other groups will allow us to study the impact of atmospheric acidification of dust aerosols on nutrient deposition and marine primary productivity.  We will be using the GEOS-CHEM model to help interpret our results.  The figure to the left shows PM2.5 dust concentrations in the model, and highlights the large Saharan dust source. 

Jordi Dachs, Institute for Chemical and Environmental Research, IIQAB-CSIC, Barcelona, Spain

Antonio Tovar, Mediterranean Institute for Advanced Studies, IMEDEA-CSIC, Mallorca, Spain

Duncan Fairlie, Harvard University and NASA Langley