Modelling the response of microbial food web to an increase of atmospheric CO2 partial pressure in a marine Mediterranean coastal ecosystem (Brusc Lagoon, France)

In both models, the increase of atmospheric pCO2 leads to a decrease of pH that is countered by the phytoplankton carbon assimilation. The phytoplankton presence limits the decrease of pH due to the increase of atmospheric pCO2. In the MDIC model, the phytoplankton and the microbial loop were not influenced by atmospheric pCO2 increase, considering modelled processes. The total inorganic carbon concentration was not limiting for phytoplankton compared to nitrogen or phosphorus. In the MCO2 model, pCO2 increase leads to a weak increase of phytoplankton and nano- and microprotozoa biomass. Another hand, more significant changes on carbon fluxes and organism productions could be occurred.