Biophysical Connectivity in a Tidal Basin, A Case Study of the Durban Habour

Intertidal flats, seagrass beds, salt marshes, and mangroves are typical features of tidal basins and estuaries. My study focuses on understanding the biophysical connection between the different habitats in these ecosystems. Tide-driven flows provide a useful mechanism for this connectivity. To fully analyse tidal flushing and its effects on the advection and mixing of substances, numerical models of the hydrodynamics and/or multi-parametric observations can be useful. For my research, the connectivity between a grove of Avicennia Marina (mangroves) and the Durban harbour’s intertidal flats (or sandbanks) was used as a case study. Simulations of the tide-driven flow in the harbour are carried out using the Delft 3D hydrodynamic model. Delft 3D was also used to simulate the movement of neutrally buoyant particles released at various locations in the harbour. Flow transects were measured across the harbour during the neap and spring tide to validate the model results. The Sontek M9 River Surveyor Acoustic Doppler Current Profiler was used for this survey. Stable light isotope analysis was done on biotic and abiotic samples taken from the harbour to understand the mangrove-sandbank interaction further. Benthic macroinvertebrates constitute most of these samples.

Prosper Bopoto

BSc Eng (Civil)