Post-depositional processes: What really happens to new atmospheric iron in the ocean's surface?
| Type | : | ACL |
|---|---|---|
| Nature | : | Production scientifique |
| Au bénéfice du Laboratoire | : | Oui |
| Statut de publication | : | Publié |
| Année de publication | : | 2013 |
| Auteurs (2) | : | BRESSAC Matthieu GUIEU Cecile |
| Revue scientifique | : | Global Biogeochemical Cycles |
| Volume | : | 27 |
| Fascicule | : | 3 |
| Pages | : | 859-870 |
| DOI | : | 10.1002/gbc.20076 |
| URL | : | <go to isi>://wos:000325488600022 |
| Abstract | : | Abiotic iron removal processes such as scavenging can significantly and rapidly modify iron distribution in the dissolved-colloidal-particulate continuum. Therefore, these processes could be considered, in addition to ligand complexation, as a major control on atmospheric iron dissolution in seawater. In this work, we investigated the seasonal abiotic processes occurring once dust deposited on surface seawater using a series of artificial seeding experiments (allowing us to take into consideration the settling of particles on a 1m depth layer). Here, we demonstrate that atmospheric dissolved iron concentration ([DFe]) is driven by the processes governed by the dissolved organic matter (DOM) pool. Following artificial dust seeding, an order magnitude range increase in the [DFe] (12 - 181nmolL(-1)) was observed depending on the season. Under high and fresh DOM conditions (spring and summer), the rapid formation of aggregates induced a negative feedback on the [DFe] through scavenging, while a fraction of the DFe was likely organically complexed. In contrast, in low-DOM surface waters (winter), aggregation was not observed, allowing a very large transient increase in [DFe] (181nmolL(-1)) before being removed by adsorption onto settling particles. A key result of the findings is that depending on the age and quantity of DOM, the lithogenic carbon pump is likely a major pathway for organic carbon export. Modeling studies should therefore relate both atmospheric iron dissolution in seawater and the intensity of the subsequent biological response, to the age and quantity of DOM. |
| Mots-clés | : | - |
| Commentaire | : | Times Cited: 4 4 |
| Tags | : | - |
| Fichier attaché | : | - |
| Citation | : |
Bressac M, Guieu C (2013) Post-depositional processes: What really happens to new atmospheric iron in the ocean's surface? Global Biogeochem Cy 27: 859-870 | doi: 10.1002/gbc.20076
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