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| Conway, T. M.; John, S. G.; Lacan, F.. |
| Intercomparison of trace metal data is a key aspect of the International GEOTRACES program, allowing data from multiple laboratories and countries to be combined to produce high-resolution datasets for the oceans. The use of crossover stations by the GEOTRACES program provides the opportunity both for comparison of analytical techniques and assessment of temporal variability in the cycling of trace metals such as iron (Fe). Here, we present the first comparison of dissolved Fe stable isotope ratio (δ56Fe; relative to IRMM-014) profiles in the oceans, from re-occupations of three locations in the Atlantic Ocean; (1) the Bermuda Atlantic Time Series Station (31.75°N 64.17°W) during the U.S. GEOTRACES IC1 cruise (June 2008) and the U.S. GEOTRACES GA03 cruise... |
| Tipo: Text |
Palavras-chave: Trace metals; GEOTRACES; Biogeochemistry; Intercomparison. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00332/44330/43932.pdf |
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| Labatut, M.; Lacan, F.; Pradoux, C.; Chmeleff, J.; Radic, A.; Murray, J. W.; Poitrasson, F.; Johansen, A. M.; Thil, F.. |
| This work presents iron isotope data in the western equatorial Pacific. Marine aerosols and top core margin sediments display a slightly heavy Fe isotopic composition (Fe-56) of 0.330.11 (2SD) and 0.140.07, respectively. Samples reflecting the influence of Papua New Guinea runoff (Sepik River and Rabaul volcano water) are characterized by crustal values. In seawater, Fe is mainly supplied in the particulate form and is found with a Fe-56 between -0.49 and 0.34 +/- 0.07 parts per thousand. The particulate Fe seems to be brought mainly by runoff and transported across continental shelves and slopes. Aerosols are suspected to enrich the surface Vitiaz Strait waters, while hydrothermal activity likely enriched New Ireland waters. Dissolved Fe isotopic ratios... |
| Tipo: Text |
Palavras-chave: Iron isotopes; Particles; Equatorial Pacific; Papua New Guinea; Seawater; GEOTRACES. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00290/40074/39162.pdf |
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| Arsouze, Thomas; Treguier, Anne-marie; Peronne, Simon; Dutay, J. -c.; Lacan, F.; Jeandel, C.. |
| Boundary Exchange (BE - exchange of elements between continental margins and the open ocean) has been emphasized as a key process in the oceanic cycle of neodymium (Nd) (Lacan and Jeandel, 2005a). Here, we use a regional eddy-permitting resolution Ocean General Circulation Model (1/4A degrees) of the North Atlantic basin to simulate the distribution of the Nd isotopic composition, considering BE as the only source. Results show good agreement with the data, confirming previous results obtained using the same parameterization of the source in a coarse resolution global model (Arsouze et al., 2007), and therefore the major control played by the BE processes in the Nd cycle on the regional scale. We quantified the exchange rate of the BE, and found that the... |
| Tipo: Text |
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| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00013/12412/9201.pdf |
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| Lacan, F.; Radic, A.; Jeandel, C.; Poitrasson, F.; Sarthou, Geraldine; Pradoux, C.; Freydier, R.. |
| This work demonstrates for the first time the feasibility of the measurement of the isotopic composition of dissolved iron in seawater for a typical open ocean Fe concentration range (0.1-1 nM). It also presents the first data of this kind. Iron is preconcentrated using a Nitriloacetic Acid Superflow resin and purified using an AG1x4 anion exchange resin. The isotopic ratios are measured with a MC-ICPMS Neptune, coupled with a desolvator (Aridus II), using a Fe-57-Fe-58 double spike mass bias correction. Measurement precision (0.13%, 2SD) allows resolving small iron isotopic composition variations within the water column, in the Atlantic sector of the Southern Ocean (from delta Fe-57 = -0.19 to +0.32 parts per thousand). Isotopically light iron found in... |
| Tipo: Text |
Palavras-chave: MC ICP MS; Chelating resin; Southern ocean; Fractionation; Seawater; Earth; Separation; Accuracy; Pacific; FE(III). |
| Ano: 2008 |
URL: https://archimer.ifremer.fr/doc/00202/31374/29781.pdf |
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