Various spatiotemporal scales of the deep water in the Baltic Proper were investigated in this thesis. From high resolution hydrographic grids small-scale mixing processes were analysed in the wake of the warm Major Baltic Inflow into the Eastern Gotland Basin in 1997/98. Heat and salt diffusivities were identified, as well as the decay rate of temperature and salt intrusions caused by the inflow. From 2 at the eastern outlet of the Stolpe Channel deployed ADCPs in 2006, dynamics of the dense bottom current and associated volume and salt transports were examined. Characteristic fluctuations of 2-4 days were found in the deep water and their steering mechanism analysed. Currents and volume transports simulated by the MOM4 model were precisely reproduced and matched estimated transports from ADCPs and therefore used for budget calculations in the Stolpe Channel.