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

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Main Authors: Thuróczy, Charles-Edouard, Gerringa, Loes J A, Klunder, Maarten B, Laan, Patrick, Le Guitton, M, de Baar, Hein J W
Format: Dataset Open Access
Language:en
Published: PANGAEA 2011
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author Thuróczy, Charles-Edouard
Gerringa, Loes J A
Klunder, Maarten B
Laan, Patrick
Le Guitton, M
de Baar, Hein J W
author_facet Thuróczy, Charles-Edouard
Gerringa, Loes J A
Klunder, Maarten B
Laan, Patrick
Le Guitton, M
de Baar, Hein J W
collection Datos científicos de ciencias marinas y ambientales
contents 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 > 13.5) in the Nansen and Amundsen basins than in the Makarov Basin (log alpha <13) where the sources of Fe and ligands were limited. The ligands became nearly saturated with depth in the Amundsen and Nansen Basins, favoring Fe removal in the deep ocean, whereas in the deep Makarov Basin, they became unsaturated with depth. Still here scavenging occurred. Although scavenging of Fe was attenuated by the presence of unsaturated organic ligands, their low reactivity in combination with a lack of sources of Fe in the Makarov Basin might be the reason of a net export of Fe to the sediment.
format Dataset Open Access
id pangaea_https___doi_org_10_1594_PANGAEA_839199
institution PANGAEA
language en
publishDate 2011
publisher PANGAEA
record_format pangaea
spellingShingle Dissolved and dissolvable iron concentrations and ligand characteristics in samples taken during POLARSTERN expedition ARK-XXII/2 to the Arctic Ocean
Thuróczy, Charles-Edouard
Gerringa, Loes J A
Klunder, Maarten B
Laan, Patrick
Le Guitton, M
de Baar, Hein J W
International Polar Year (2007-2008); IPY
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 > 13.5) in the Nansen and Amundsen basins than in the Makarov Basin (log alpha <13) where the sources of Fe and ligands were limited. The ligands became nearly saturated with depth in the Amundsen and Nansen Basins, favoring Fe removal in the deep ocean, whereas in the deep Makarov Basin, they became unsaturated with depth. Still here scavenging occurred. Although scavenging of Fe was attenuated by the presence of unsaturated organic ligands, their low reactivity in combination with a lack of sources of Fe in the Makarov Basin might be the reason of a net export of Fe to the sediment.
title Dissolved and dissolvable iron concentrations and ligand characteristics in samples taken during POLARSTERN expedition ARK-XXII/2 to the Arctic Ocean
topic International Polar Year (2007-2008); IPY
url https://doi.org/10.1594/PANGAEA.839199