biogeographical provinces and biogeochemical cycles

We are using our model to examine the development of biogeographical provinces in the model ocean. The simulations show clear and plausible organization of the emergent community structure by the physical regime: Strongly seasonal, high nutrient regimes are dominated by fast-growing bloom specialists, while stable, low-seasonality regimes are dominated by organisms that can grow at low nutrient concentrations, and are suited to oligotrophic conditions. In these latter regions we find a strong control by the phytoplankton on ambient nutrient concentrations (see Resource Control Theory section). The separation between these regions appears strongly linked to the physical environment, especially the annual range of the mixed layer depth.

Figure caption: Annual mean emergent biogeographical provinces. (a) Biogeography of four major functional groups; mapping four regimes according to the relative contributions of four major “functional groups”. The functional groups are determined by summing biomass contributions from four broad classes of initialized phytoplankton types (in descendingorder of shading): (i) Diatom-analogs (darkest), (ii) other large phytoplankton, (iii) other smallphytoplankton, (iv) Prochlorococcus-analogs (lightest). (See Follows et al. [2007]). (b) Ecotones; lines where the ecosystem transitions from dominance by one phytoplankton type to another. (From Dutkiewicz et al, 2009).

For more information

  • Dutkiewicz, S., M.J. Follows and J. Bragg. Modeling the coupling of ocean ecology and biogeochemistry, 2009: Global Biogeochemical Cycles, 23, GB4017, doi:10.1029/2008GB003405. PDF.
  • IMBER IMBIZO Workshop, Miami, FL, 9-13 November 2008. “Ecological Control of Subtropical Nutrient Concentrations.” S. Dutkiewicz, M.J. Follows, and J.G. Bragg. Oral and poster presentation. See poster (PDF).