The response of the ocean to atmospheric perturbation varies geographically and according to the individual characteristics of regional air/land/water masses; thus, the oceanic response to climate change projections has to be rigorously evaluated in a geographically specific context of air-sea heat energy exchange, bio-physical interactions, and relevant processes of regional-scale variability. In such context, we will use an existing ocean model to conduct a continuous simulation from 1990 to 2050 to quantify the potential changes of the physical and biogeochemical regimes in the Gulf of Mexico. First, we will initialize the model from a climatological equilibrium state in 1990 and conduct a twenty-five-year reanalysis (1990-2015) to evaluate/validate the model using independent observational data in order to provide a baseline of model accuracy and uncertainty. Subsequently, we will conduct two 50-year projection simulations (2000-2050) forced by the state-of-the-art Large Ensemble (LE) outputs pertaining to two Representative Concentration Pathways (RCP): RCP 4.5 and RCP 8.5. These climate scenarios, developed by the Intergovernmental Panel for Climate Change (IPCC) represent, in terms of green house gas emissions, an aggressive climate policy (RCP 4.5), and a business as usual (RCP 8.5) disposition; respectively. Correspondingly, these RCP scenarios were explicitly chosen in order to have a cone of uncertainty under realistically low and high climate projections. Lastly, we will conduct quantitative analyses of the results to develop a comprehensive assessment report of climate-relevant impacts on the ocean physics and biogeochemistry in the Gulf of Mexico along with a quantitative description of the uncertainty inherent in those estimates.