Management of coastal ecosystem has become a pivotal issue for northern Bay of Bengal, which is extremely dynamic due to the influences of monsoonal climate. Particularly, the primary productivity acts as the base of food web and indicator of ecosystem health for this region, but extremely varying with nutrient fluxes that are largely depending on river discharges from GBM and other river systems. This program is initiated to develop ecosystem models for primary productivity estimation considering the nutrients inputs along with the hydro-dynamic characteristics of the coastal system. The model use ‘kinetics of enzyme theory’ and ‘Michaelis-Menten’ nutrient uptake approaches to determine the effects of nutrients on phytoplankton growth. The model is supported by the field observational data related to nutrients, temperature, light, salinity, hydrodynamic forces and other biological processes that influences the primary productivity. Moreover, OiLAB has extensive spatio-temporal field monitoring program to monitor the plankton diversity and their biomass (i.e. Chlorophyll) to validate the model outputs.