A global compilation of over 13 000 dissolved iron measurements : focus on distributions and processes in the Southern Ocean
Date
2011-11
Authors
Tagliabue, A.
Mtshali, T.
Aumont, O.
Bowie, A. R.
Klunder, M. B.
Roychoudhury, A. N.
Swart, S.
Journal Title
Journal ISSN
Volume Title
Publisher
Copernicus Publications
Abstract
Due to its importance as a limiting nutrient for phytoplankton growth in large regions of
the world’s oceans, ocean water column observations of concentration of the tracemetal
iron (Fe) have increased markedly over recent decades. Here we compile
> 13 000 global measurements of dissolved Fe (dFe) and make this available to the
community. We then conduct a synthesis study focussed on the Southern Ocean,
where dFe plays a fundamental role in governing the carbon cycle, using four regions,
six basins and five depth intervals as a framework. Our analysis reveals the importance
of biological activity and dFe inputs in governing the inter-region and inter-basin differences in surface dFe, respectively. In deep waters, the major controls of interregion
and inter-basin dFe variability are ligand distributions and deep dFe inputs or
water mass characteristics, respectively. We find that even in regions where many dFe
measurements exist, the processes governing the seasonal evolution of dFe remain
enigmatic, suggesting that, aside from broad sub-Antarctic–Antarctic trends, biological activity might not the major driver of dFe variability. Nevertheless, missing measurements
during key seasonal transitions make it difficult to better quantify and understand
surface water replenishment processes and the seasonal Fe cycle. Statistical
differences exist in the measured dFe between measurements taken over the period
1989–2002 and 2003–2008, which may reflect progress in clean sampling and analysis techniques. Finally, we detail the degree of seasonal coverage by region, basin
and depth. By synthesising prior measurements we suggest a role for different processes
and highlight key gaps in understanding, which we hope can help structure
future research efforts in the Southern Ocean.
Description
Publication of this article was funded by the Stellenbosch University Open Access Fund.
The original publication is available at http://www.biogeosciences-discuss.net/
The original publication is available at http://www.biogeosciences-discuss.net/
Keywords
Iron measurement -- Southern Ocean, Iron -- Research -- Southern Ocean, Iron -- Distributions and processes
Citation
Tagliabue, A. et al. 2011. A global compilation of over 13 000 dissolved iron measurements: focus on distributions and processes in the Southern Ocean. Biogeosciences Discussions, 8, 11489-11527, doi:doi:10.5194/bgd-8-11489-2011.