Australian shelf sediment transport responses to climate change-driven ocean perturbations

Abstract

How will Australia's shelf and coastal seabed respond to climatic stress? Climate change is likely to impact ocean circulation, ocean temperature and salinity and sea-level fluctuations. Recent global ocean models have increased in reliability and predictability, with considerable advances in coupling climatic, oceanographic and sedimentary processes. Several models have been successful in reproducing surface sediment transport in both coastal and deep-sea areas. However, studies have yet to attempt a predictive assessment of how climate change influences long-term regional seabed responses. Using a process-based stratigraphic forward model, we have developed a method that could be applied worldwide to assess the impact of climate change-driven ocean perturbations on the seabed. Here, we present results of a fifty-year seabed sediment transport forecast of selected regions of the Australian Shelf. The results depict changes to sediment composition and seabed topography as a consequence of climate change-driven sediment mobility, erosion and carbonate growth. The predicted maximum of seabed changes is around 2 m of erosion or accretion over the next fifty years. Most of the near-shore seabed sediments are coarsening due to combined effects of waves and tides. Increasing floods, storms and cyclonic events lead to significant changes to many coral reefs.