The course deals with the biogeochemical cycles of carbon, nitrogen, phosphorus, and silicon in a global oceanic perspective. The chemical, biological and physical aspects of the cycles are discussed. The course includes deep-sea circulation, gas exchange between atmosphere and oceans, biological production, the biological pump, and the budgets of carbon, nitrogen, phosphorus, and silicon including the role of sediments. The calcium carbonate cycle, and the relationship between the carbon cycle and the climate are discussed. The course has a modeling focus.