TY - JOUR
T1 - The Organic Complexation of Dissolved Iron Along the U.S. GEOTRACES (GA03) North Atlantic Section
AU - Buck, Kristen N.
AU - Sohst, Bettina
AU - Sedwick, Peter N.
PY - 2015/6/1
Y1 - 2015/6/1
N2 - The organic complexation of dissolved iron was determined from full water column depth profile samples collected on the U.S. GEOTRACES North Atlantic Section cruises in 2010 and 2011 (GEOTRACES GA03). The concentrations of iron-binding ligands and their conditional stability constants were determined using competitive ligand exchange-adsorptive cathodic stripping voltammetry (CLE-ACSV) with salicylaldoxime as the added competitive ligand. Across the basin, iron-binding ligands were found in excess of dissolved iron concentrations in all samples except those with the highest dissolved iron in the Trans-Atlantic Geotraverse (TAG) hydrothermal vent plume, where dissolved iron concentrations exceeded ligand concentrations. Ligand results were categorized based on conditional stability constants into three ligand classes ( L 1 : log KFeLi,Fe′cond" role="presentation">>12; L 2 : log KFeL2,Fe′cond" role="presentation">=11–12; L 3 : log KFeL3,Fe′cond" role="presentation">=10–11). The stronger L 1 -type ligand class tracked closely with dissolved iron, with the strongest ligands (i.e., highest log KFeL1,Fe′cond" role="presentation">) found in the vicinity of the Trans-Atlantic Geotraverse (TAG) hydrothermal vent plume. All three ligand classes, including the stronger L 1 -type ligands, were observed through the water column. These measurements indicate that iron-binding ligands are indeed a ubiquitous feature of iron speciation in the North Atlantic.
AB - The organic complexation of dissolved iron was determined from full water column depth profile samples collected on the U.S. GEOTRACES North Atlantic Section cruises in 2010 and 2011 (GEOTRACES GA03). The concentrations of iron-binding ligands and their conditional stability constants were determined using competitive ligand exchange-adsorptive cathodic stripping voltammetry (CLE-ACSV) with salicylaldoxime as the added competitive ligand. Across the basin, iron-binding ligands were found in excess of dissolved iron concentrations in all samples except those with the highest dissolved iron in the Trans-Atlantic Geotraverse (TAG) hydrothermal vent plume, where dissolved iron concentrations exceeded ligand concentrations. Ligand results were categorized based on conditional stability constants into three ligand classes ( L 1 : log KFeLi,Fe′cond" role="presentation">>12; L 2 : log KFeL2,Fe′cond" role="presentation">=11–12; L 3 : log KFeL3,Fe′cond" role="presentation">=10–11). The stronger L 1 -type ligand class tracked closely with dissolved iron, with the strongest ligands (i.e., highest log KFeL1,Fe′cond" role="presentation">) found in the vicinity of the Trans-Atlantic Geotraverse (TAG) hydrothermal vent plume. All three ligand classes, including the stronger L 1 -type ligands, were observed through the water column. These measurements indicate that iron-binding ligands are indeed a ubiquitous feature of iron speciation in the North Atlantic.
KW - Iron
KW - Ligands
KW - Voltammetry
KW - Chemical speciation
KW - North Atlantic Ocean
UR - https://digitalcommons.usf.edu/msc_facpub/565
UR - https://doi.org/10.1016/j.dsr2.2014.11.016
U2 - 10.1016/j.dsr2.2014.11.016
DO - 10.1016/j.dsr2.2014.11.016
M3 - Article
VL - 116
JO - Deep Sea Research Part II: Topical Studies in Oceanography
JF - Deep Sea Research Part II: Topical Studies in Oceanography
ER -