The global circulation is a critical regulator of the Earth's climate processes that can be affected by the overall ocean energetics. How internal waves transport and transfer turbulent kinetic energy into mean flow potential energy is therefore a key process in the ocean. Naturally occurring double-diffusive convection can lead to the formation of spatially periodic density profiles called thermohaline staircases. Drawing analogies with condensed matter physics, this project will identify the physical mechanisms that govern internal wave transport in periodically stratified environments. The first work-package will focus on internal wave band gaps and the formation of surface states. We will then investigate the consequences of Coriolis forces on the wave propagation in periodic stratifications. The third work-package will examine the influence of spatial disorder in the periodicity of the density profile. The final part will focus on energy transfer by turbulent mixing and interactions with mean flows, as well as feedback processes emerging from mixing induced stratification evolution and external vortex flows similar to the eddies found in the ocean.