Abstract. Influence of long term trends in the climate parameters (average temperature, wind speed and solar irradiance) on phytoplankton and nutrient in the Baltic Sea was studied with an integrated three-dimensional coupled sea-ice ecological model. Simple ecosystem has been added to the sea-ice model and it has been used to estimate variability of the phytoplankton and nutrient during long term changes of the main atmospheric forces. Several numerical experiments were conducted to test the sensitivity of the model to changes of the main physical parameters such as temperature, wind speed, solar and thermal radiation (in different configurations). Influences of variability of these parameters on phytoplankton and nutrient (total inorganic nitrogen) is presented and discussion on relevance to expected future climate change is provided.