Antoine Saint-Amand , Alana Grech, Severine Choukroun, Emmanuel Hanert

A major coal mine project in Queensland, Australia, is currently under review. It is planned to be located about 10 km away from the Great Barrier Reef World Heritage Area (GBRWHA). Sediment dispersal patterns and their impact on marine ecosystems have not been properly assessed yet. Here, we simulate the dispersal of different sediment types with a high-resolution ocean model, and derive their environmental footprint. We show that sediments finer than 32 µm could reach dense seagrass meadows and a dugong sanctuary within a few weeks. The intense tidal circulation leads to non-isotropic and long-distance sediment dispersal patterns along the coast. Our results suggest that the sediments released by this project will not be quickly mixed but rather be concentrated where the most valuable ecosystems are located. If accepted, this coal mine could therefore have a far-reaching impact on the GBRWHA and its iconic marine species.