Keynote lecture: Turbulent transport and mixing in a stratified lake

Over the last 10 years we have been carrying out detailed measurements of the turbulent transport in stratified lakes. These include measurement in the surface layer, the subsurface layer, the epilimnion, the metalimnion, the hypolimnion and the benthic boundary layer. An overall picture has now emerged as to the energy transfer pathways from the wind to the turbulence in the water column. Further, not only has the energy flux path been clarified, but also the efficiency of mixing and the role of the irreversible and reversible fluxes is beginning to become clearer. These findings have major consequences for the biological and chemical processes operating in the various parts of the water column. The talk will aim to provide a quantitative overview of the flux path, the buoyancy flux partitioning and the implications of these for the biological and chemical processes. As an illustration results from a numerical simulation will be shown.