Cycling of organic Fe-binding ligands in a 3D biogeochemical model


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Christoph.Voelker [ at ] awi.de

Abstract

The abundance of organic Fe-binding ligands strongly influences the bioavailability and photochemical cycling of dissolved iron (DFe) as well as the reactive fraction of DFe available for particle adsorption, and thus its residence time. New insights into the sources and fate of these ligands have been gained over the last decade and patterns of spatial variability are beginning to emerge. Most biogeochemical models including DFe, however, fix organic ligands to an observed mean concentration. Here we show sensitivity studies with a global biogeochemical model including simplistic assumptions on the release of iron-binding ligands from biogenic particles, and on their biological degradation. We compare the resulting ligand distribution with a compilation of ligand measurements. Despite the heterogenous nature of the compiled data that includes very different opproaches to measure iron complexing capacity, some trends on deep ligand profiles and their interbasin variability begin to emerge. These trends are well reproduced by the model. Closer to the surface, disagreements between model and observations show that the simplistic model is missing important processes, such as photochemical degradation, siderophore production, and biological uptake.



Item Type
Conference (Talk)
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Not peer-reviewed
Publication Status
Published
Event Details
American Society for Limnology and Oceanography Annual Meeting, 17 Feb 2013 - 22 Feb 2013, New Orleans, USA.
Eprint ID
32624
Cite as
Ye, Y. , Tagliabue, A. and Völker, C. (2013): Cycling of organic Fe-binding ligands in a 3D biogeochemical model , American Society for Limnology and Oceanography Annual Meeting, New Orleans, USA, 17 February 2013 - 22 February 2013 .


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