Distributions of dissolved and particulate iron in the sub-Antarctic and Polar Frontal Southern Ocean (Australian sector)
| Type | : | ACL |
|---|---|---|
| Nature | : | Production scientifique |
| Au bénéfice du Laboratoire | : | Oui |
| Statut de publication | : | Publié |
| Année de publication | : | 2011 |
| Auteurs (9) | : | LANNUZEL D BOWIE A,r REMENYI Tomas LAM Phoebe TOWNSEND Ashley IBISANMI Enitan BUTLER Edward WAGENER Thibault SCHOEMANN Veronique |
| Revue scientifique | : | Deep-sea Research Part II-Topical Studies In Oceanography |
| Volume | : | 58 |
| Fascicule | : | 21 |
| Pages | : | 2094-2112 |
| DOI | : | 10.1016/j.dsr2.2011.05.027 |
| URL | : | <go to isi>://wos:000295762400005 |
| Abstract | : | This paper presents iron (Fe) profiles in the upper 1000 m from nine short-term (transect) stations and three long-term (process) stations occupied in the Australian sector of the Southern Ocean during the SAZ-Sense expedition in austral summer (January-February) 2007. Strong vertical and horizontal gradients in Fe concentrations were observed between the 18 sampled profiles (i.e. 0.09-0.63 nmol/l dissolved Fe (dFe)). Average dFe concentrations in surface gggwaters in the northern Sub-Antarctic Zone (SAZ-N) West (station P1) were 0.27 +/- 0.04 nmol/l. This is lower in the SAZ-N East region (station P3 and around) where average dFe values in the mixed layer were 0.48 +/- 0.10 nmol/l. The Polar Front (PF) station (P2) exhibited the lowest average surface Fe values (i.e., 0.22 +/- 0.02 nmol/l). Iron concentrations in deep waters down to 1000 m were more uniform (0.25-0.37 nmol/l dFe), which is in accordance with values reported elsewhere in remote waters of the Southern Ocean, but lower than those observed in the North Atlantic and North Pacific basins. A strong decoupling was observed between dFe and nutrient cycles at all stations. Particulate Fe levels were generally very low for all SAZ stations ( <0.08-1.38 nmol/l), with higher values observed at stations collected near Tasmania and in the SAZ-N East region. The intrusion of subtropical waters, enriched with Fe from sediments or dust further north, is thought to mediate Fe input to the SAZ-N and STZ areas, while input from below would be the main source of Fe in the PF region. We applied the tracer Fe* (Fe*= [dFe] - R-Fe:p x [PO43-] where R-Fe:P is the algal uptake ratio) to estimate the degree to which the water masses were Fe limited. In this study, Fe* tended to be negative and decreased with increasing depths and latitude. Positive Fe* values. indicating Fe sufficiency, were observed in the (near-)surface waters collected in the SAZ-N East and near continental sources, where primary production was higher and ultimately limited by the lack of macro-nutrients, not Fe. Micro-organisms residing in the SAZ-N West and PF on the other hand experienced negative Fe*, indicating a strong co-limitation by low silicic acid concentration and Fe supply (and light in the case of PF). (C) 2011 Elsevier Ltd. All rights reserved. |
| Mots-clés | : | - |
| Commentaire | : | Times Cited: 25 Bowie, Andrew/C-8677-2013; Townsend, Ashley/J-7445-2014 Bowie, Andrew/0000-0002-5144-7799; Townsend, Ashley/0000-0002-2972-2678 25 |
| Tags | : | - |
| Fichier attaché | : | - |
| Citation | : |
Lannuzel D, Bowie AR, Remenyi T, Lam P, Townsend A, Ibisanmi E, Butler E, Wagener T, Schoemann V (2011) Distributions of dissolved and particulate iron in the sub-Antarctic and Polar Frontal Southern Ocean (Australian sector). Deep-sea Res Pt II 58: 2094-2112 | doi: 10.1016/j.dsr2.2011.05.027
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