Phytoplankton growth formulation in marine ecosystem models: Should we take into account photo-acclimation and variable stoichiometry in oligotrophic areas?

► We compare phytoplankton growth formulations with increasing complexity, after tuning through microgenetic algorithm. ► The most flexible models, i.e., with variable ratios, are necessary to reproduce observations under oligotrophic regimes. ► Photo-acclimation (variable Chl:C) is needed to reproduce the subsurface chlorophyll maximum in summer. ► Non-Redfield stoichiometry (variable C:N) is needed to simulate more realistic primary production estimates. ► No clear difference is detected between quota (non-Redfield) formulations with diagnostic or prognostic chlorophyll.