Abstract. Dissolved Fe (DFe) samples from the GEOVIDE voyage (GEOTRACES GA01, May–June 2014) in the North Atlantic Ocean were analyzed using a
seaFAST-pico™ coupled to an Element XR sector field
inductively coupled plasma mass spectrometer (SF-ICP-MS) and provided interesting
insights into the Fe sources in this area. Overall, DFe concentrations ranged
from 0.09±0.01 to 7.8±0.5 nmol L−1.
Elevated DFe concentrations were observed above the Iberian, Greenland, and
Newfoundland margins likely due to riverine inputs from the Tagus River,
meteoric water inputs, and sedimentary inputs. Deep winter convection
occurring the previous winter provided iron-to-nitrate ratios sufficient to
sustain phytoplankton growth and lead to relatively elevated DFe
concentrations within subsurface waters of the Irminger Sea. Increasing DFe
concentrations along the flow path of the Labrador Sea Water were attributed
to sedimentary inputs from the Newfoundland Margin. Bottom waters from the
Irminger Sea displayed high DFe concentrations likely due to the dissolution
of Fe-rich particles in the Denmark Strait Overflow Water and the Polar
Intermediate Water. Finally, the nepheloid layers located in the different
basins and at the Iberian Margin were found to act as either a source or a
sink of DFe depending on the nature of particles, with organic particles
likely releasing DFe and Mn particle scavenging DFe.
Dissolved iron in the North Atlantic Ocean and Labrador Sea along the GEOVIDE section (GEOTRACES section GA01)
