Digital twin simulations distinguish anthropogenic nutrient impacts from natural variability in a complex coastal ecosystem with salmon aquaculture
Dr Karen Wild-Allen1, Dr Mark Baird1, Dr Jenny Skerratt1, Dr Clothilde Langlais1
1CSIRO Oceans & Atmosphere, Hobart, Australia
The response of coastal ecosystems to anthropogenic nutrient enrichment is challenging to observe due to multiple nutrient sources, rapid transformations and the limitations of nutrient sampling methods. Early detection of broadscale impacts are particularly difficult to distinguish from the natural temporal evolution and variability present in coastal waters. We use the CSIRO EMS 3D hydrodynamic, sediment, optical and biogeochemical model to construct a digital twin simulation of southeast Tasmania, Australia, for the purpose of quantifying the impact of the expanding salmon aquaculture industry on coastal water and sediment quality. This region includes multiple estuaries, complex coastal morphology and is influenced by seasonally modulated ocean boundary currents. The numerical model was statistically validated against observations from satellites, moorings, landers, gliders and discrete samples over a hindcast period of 5 years to confirm that it is ‘fit for purpose’. The model characterises the seasonal and interannual variability in the regional circulation, nutrient supply, water quality and sediment dynamics. Multiple digital twin scenario simulations (with more or less salmon aquaculture) predict changes in water and sediment quality due to contrasting nutrient load. The model is now running in near real time and has the capability to distinguish anthropogenic nutrient impacts from natural variability to better characterise the drivers of variability in monthly monitoring data. This research has been conducted in collaboration with environmental regulators to inform future decisions on salmon aquaculture.
Biography:
Karen Wild-Allen is a Principal Research Scientist and leads the Coastal Environmental Biogeochemical Modelling team in CSIRO Oceans & Atmosphere, based in Hobart. Karen is an expert in multiscale model validation, autonomous nutrient observing systems and simulation of alternative management scenarios.
