Numerical Models for Monitoring and Forecasting Ocean Biogeochemistry: a short description of present status

The ability to model biogeochemical features in the ocean is a key factor in predicting the health of the ocean: it involves the representation of processes and cycles of chemical elements (such as carbon, nutrients, and oxygen) and the dynamics of living organisms such as phytoplankton, zooplankton, and bacteria. This paper gives an overview of the main modelling aspects aimed at describing the low trophic levels of marine ecosystems and shows how they can be coupled with advection and diffusion models. The complexity of biogeochemical models can vary considerably depending on the topics of interest, assumed hypotheses, and simplifications of the numerical parameterizations. The paper also discusses the uncertainties in the numerical solution due to the lack of knowledge about the parameterizations, the initial and boundary conditions, the lack of a robust observation network, and the high computational cost of running such models.