Dissolved iron in the North Atlantic Ocean and Labrador Sea along the GEOVIDE section (GEOTRACES section GA01)

• Published in: Biogeosciences
• Main Authors: Tonnard, M, Planquette, H, Bowie, AR, van der Merwe, P, Gallinari, M, de Gesincourt, FD, Germain, Y, Gourain, A, Benetti, M, Reverdin, G, Treguer, P, Boutorh, J, Cheize, M, Lacan, F, Barraqueta, J-LM, Pereira-Contreira, L, Shelley, R, Lherminier, P, Sarthou, G
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus GmbH 2020
• Subjects: Earth Sciences; Oceanography; Chemical oceanography; Newfoundland; Greenland; Irminger Sea; Denmark Strait; Labrador Sea; North Atlantic
• Online Access: https://doi.org/10.5194/bg-17-917-2020; http://ecite.utas.edu.au/137715

Dissolved Fe (DFe) samples from the GEOVIDE voyage (GEOTRACES GA01, MayJune2014) in the North Atlantic Ocean were analyzed using asea FAST -pico coupled to an Element XR sector fieldinductively coupled plasma mass spectrometer (SF-ICP-MS) and provided interestinginsights into the Fe sources in this area. Overall, DFe concentrations rangedfrom 0.090.01 to 7.80.5 nmol L −1 .Elevated DFe concentrations were observed above the Iberian, Greenland, andNewfoundland margins likely due to riverine inputs from the Tagus River,meteoric water inputs, and sedimentary inputs. Deep winter convectionoccurring the previous winter provided iron-to-nitrate ratios sufficient tosustain phytoplankton growth and lead to relatively elevated DFeconcentrations within subsurface waters of the Irminger Sea. Increasing DFeconcentrations along the flow path of the Labrador Sea Water were attributedto sedimentary inputs from the Newfoundland Margin. Bottom waters from theIrminger Sea displayed high DFe concentrations likely due to the dissolutionof Fe-rich particles in the Denmark Strait Overflow Water and the PolarIntermediate Water. Finally, the nepheloid layers located in the differentbasins and at the Iberian Margin were found to act as either a source or asink of DFe depending on the nature of particles, with organic particleslikely releasing DFe and Mn particle scavenging DFe.