Dissolved and dissolvable iron concentrations and ligand characteristics in samples taken during POLARSTERN expedition ARK-XXII/2 to the Arctic Ocean ...

• Main Authors: Thuróczy, Charles-Edouard, Gerringa, Loes J A, Klunder, Maarten B, Laan, Patrick, Le Guitton, M, de Baar, Hein J W
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 2011
• Subjects: International Polar Year 2007-2008 IPY; amundsen basin; Arctic Ocean; International Polar Year; IPY; makarov basin; Nansen Basin
• Online Access: https://dx.doi.org/10.1594/pangaea.839199; https://doi.pangaea.de/10.1594/PANGAEA.839199

The speciation of iron was investigated in three shelf seas and three deep basins of the Arctic Ocean in 2007. The dissolved fraction (<0.2 µm) and a fraction < 1000 kDa were considered here. In addition, unfiltered samples were analyzed. Between 74 and 83% of dissolved iron was present in the fraction < 1000 kDa at all stations and depth, except at the chlorophyll maximum (42-64%). Distinct trends in iron concentrations and ligand characteristics were observed from the shelf seas toward the central deep basins, with a decrease of total dissolvable iron ([TDFe] > 3 nM on the shelves and [TDFe] < 2 nM in the Makarov Basin). A relative enrichment of particulate Fe toward the bottom was revealed at all stations, indicating Fe export toward the deep ocean. In deep waters, dissolved ligands became less saturated with Fe (increase of [Excess L]/[Fe]) from the Nansen Basin via the Amundsen Basin toward the Makarov Basin. This trend was explained by the reactivity of the ligands, higher (log alpha ... : Data extracted in the frame of a joint ICSTI/PANGAEA IPY effort, see http://doi.pangaea.de/10.1594/PANGAEA.150150 ...