patterns of phytoplankton diversity

Our numerical simulations show an equator-to-pole decrease in the diversity of phytoplankton species.  Super-imposed on this gradient in the simulation are regions of high phytoplankton diversity which occur in association with areas of energetic flow including western boundary currents. These latter regions reflect a strong contribution from rapid advective transport (e.g. swift Western Boundary Currents) which sustains populations of organisms far from their “optimal” habitat.  We use an idealized model to show that the timescale of variability in the resource supply can lead to the poleward  gradient of diversity.

Figure caption: Global map of the diversity of modeled phytoplankton species types (left), defined as the number of species comprising greater than 0.1% of the total biomass at that location. The diversity includes species that are present at any point during the year. The right panel shows the zonal mean of the figure on the left.  These data are the average of ten unique model runs.

For more information

  • Barton, A.D., S. Dutkiewicz, G. Flierl, J. Bragg, and M.J. Follows: Patterns of Diversity in Marine Phytoplankton. Science, in press.
  • AGU Fall Meeting, San Francisco, California, USA, December 15-19, 2008. “What Regulates Spatial Gradients in Marine Phytoplankton Diversity?” Barton, A.D., M.J. Follows, S. Dutkiewicz, and J. Bragg. B31F-0355. Poster presentation. See poster (PDF).
  • Modeled diversity globally. Modelled phytoplankton species richness from eddy permitting solution.