The Tasmanian Coastal Modelling & Information System (TCMIS) is a high-resolution numerical modelling framework developed by CSIRO to enable the prediction of coupled biogeochemical and hydrodynamical processes in coastal and estuarine environments around Tasmania. In this poster, we showcase recent work undertaken to understand the dynamics and evolution of Storm Bay and Macquarie Harbour — two key coastal waterways in which the impact of various environmental and anthropogenic stressors is assessed with respect to long-term system stability and sustainability. We highlight the role of comprehensive pelagic-benthic coupling in predicting overall system behaviour and response to changing human and environmental inputs and climate dynamics.