This book gives an overview of statistical turbulence-modelling with applications to oceanography and limnology. It discusses how these models can be derived from the Navier-Stokes equations, step by step simplifications result in models applicable to numerical simulations for realistic solutions. Results from one-dimensional simulations are shown for various oceanic and limnic water column studies. The integration of these turbulence models in three-dimensioanl models is discussed and some selected results are shown. The two-equation turbulence models prove to be a good compromise between...