As an experimental physicist and physical oceanographer I am interested in studying all aspects of turbulence in seas and oceans, mainly through in-situ observations. The complexity of the ocean demands a “multidisciplinary” approach for understanding. The projects I have contributed to reflect this (‘Frisian Front Project’, ‘Integrated North Sea Project’, ‘Processes of vertical exchange in shelf seas’, Faroe-Shetland Channel project ‘Processes above Continental Slopes’, ‘Slope-mixing’, ‘ANTARES’, ‘KM3NeT’). I acknowledge however the difficulties for multidisciplinary projects to be successful.
Within the scientific discipline of physical oceanography my interest focuses on the dynamical effects of density variations, ranging from diapycnal mixing via modification of oscillatory currents to internal waves. Over the years my research has always been based on the analysis of measurements obtained at sea, with emphasis on those from moored instrumentation. Slowly my interest changed from the dynamical impact of fronts and the modifications of barotropic currents by stratification to internal wave fluxes and interactions. Attempts to directly estimate internal wave-induced turbulent fluxes using ADCP and thermistor string date back to my post-doctoral stay in Canada. This resulted in a strong interest in the working of oceanographic instrumentation. Through the development of high-resolution temperature sensors and new mooring techniques in tight collaboration with NIOZ technicians, my research interest extended to highly nonlinear frontal bores and their impact on deep-ocean mixing. Searches are and were conducted on internal wave breaking over diverse sloping bottom topography ranging from nearly flat to very steep (compared to internal wave slopes) and from shallow (Texel-beach) to deep waters (Puerto Rico Trench). Turbulent mixing due to internal wave breaking has impact on sediment resuspension and deep-sea life. The effects of internal wave mixing on deep-sea life led to some new observations on very deep plankton migration following the cycles of moon and sun at depths where not a glimpse of surface light penetrates, which suggested a link to the fascinating science of clock-biology. The neutrino telescope infrastructure of KM3NeT offers the great opportunity to perform 3D moored observations on the internal wave-turbulent overturning scales.