Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
Biogeosciences, 11, 5445-5461, 2014
https://doi.org/10.5194/bg-11-5445-2014
© Author(s) 2014. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
08 Oct 2014
Understanding predicted shifts in diazotroph biogeography using resource competition theory
S. Dutkiewicz1, B. A. Ward2, J. R. Scott1, and M. J. Follows3 1Center for Global Change Science and Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
2Laboratoire des Sciences de l'Environnement Marin, Institut Universitaire Européen de la Mer, Plouzané, France
3Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
Abstract. We examine the sensitivity of the biogeography of nitrogen fixers to a warming climate and increased aeolian iron deposition in the context of a global earth system model. We employ concepts from the resource-ratio theory to provide a simplifying and transparent interpretation of the results. First we demonstrate that a set of clearly defined, easily diagnosed provinces are consistent with the theory. Using this framework we show that the regions most vulnerable to province shifts and changes in diazotroph biogeography are the equatorial and South Pacific, and central Atlantic. Warmer and dustier climates favor diazotrophs due to an increase in the ratio of supply rate of iron to fixed nitrogen. We suggest that the emergent provinces could be a standard diagnostic for global change models, allowing for rapid and transparent interpretation and comparison of model predictions and the underlying mechanisms. The analysis suggests that monitoring of real world province boundaries, indicated by transitions in surface nutrient concentrations, would provide a clear and easily interpreted indicator of ongoing global change.

Citation: Dutkiewicz, S., Ward, B. A., Scott, J. R., and Follows, M. J.: Understanding predicted shifts in diazotroph biogeography using resource competition theory, Biogeosciences, 11, 5445-5461, https://doi.org/10.5194/bg-11-5445-2014, 2014.
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