[A-OS09] Marine ecosystems and biogeochemical cycles: theory, observation and modeling

[AOS09-13] A phytoplankton model with dynamic stoichiometry based on a new instant acclimation scheme: good reproduction of the subsurface chlorophyll maximum and primary production

*Yoshio Masuda¹, Yasuhiro Yamanaka¹, Takafumi Hirata¹, Hideyuki Nakano² (1.Graduate School of Environmental Earth Science, Hokkaido University, 2.Meteorological Research Institute)

Keywords:phytoplankton, acclimation, stoichiometry, chlorophyll, primary production

Oceanic phytoplankton adjust to a change in surrounding environment, where the chlorophyll/carbon and nitrogen/carbon rations are changed. Based on Smith et al. (2015), we introduced new phytoplankton acclimation scheme into a biogeochemical model combined with an OGCM. The scheme is based on the assumption of instant acclimation; that is, phytoplankton stoichiometry (chl:C:N:Fe) is uniquely determined by a surrounding environmental condition. Therefore, it can represent dynamic stoichiometry with low computational costs. The model well reproduces the latitudinal distribution of the subsurface chlorophyll maximum. The simulated net primary production is similar to the observed, and it is underpinned by the good reproduction of chlorophyll distribution and variable nitrogen/carbon ratio.