Dissolved Iron Speciation in the Eastern Tropical South Pacific: Results from the U.S. GEOTRACES Section Cruise

Abstract:

The organic complexation of dissolved iron was determined in full water column depth profiles collected along the U.S. GEOTRACES zonal section cruise in the Eastern Tropical South Pacific in November and December 2013. These profiles depict the evolution of iron-binding ligand characteristics from the productive Peruvian coast to the oligotrophic South Pacific, and including profiles through a pronounced oxygen minimum zone inshore and a large hydrothermal plume over the East Pacific Rise. The concentrations and conditional stability constants of iron-binding ligands, and the resulting overall complexation capacity for iron in the water column, will be presented. These results will be compared with previous studies conducted in the Eastern Pacific and contrasted with results from the U.S. GEOTRACES North Atlantic section completed in 2011.