Dr Kathryn Wiltshire1,2,3, Dr Sarah Catalano1,2,3, Ms Rachel Nicholls1, Dr Chinglen Tensubam1, Dr Christopher Bolch1, Dr Michael Doane1, Dr Hugo Bastos de Oliviera1, A/Prof Mark Doubell1,2,3
1S.A.R.D.I. Aquatic And Livestock Sciences, West Beach, Australia, 2Adelaide University, Adelaide, Australia, 3Flinders University of SA, Bedford Park, Australia
Biography:
Kathryn Wiltshire is a Research Scientist in the South Australian Research and Development Institute’s Marine Biosecurity Subprogram. She has expertise in applying and assessing molecular techniques for biosecurity monitoring and ecosystem assessment, and in Bayesian spatiotemporal modelling techniques. Her research includes developing models investigating relationships between eDNA and environmental factors to investigate species occurrences and associations. Her current role includes investigating and applying molecular technologies and spatial modelling to better understand harmful algal blooms (HABs) and their environmental impact, and determining how to integrate eDNA with other technologies to provide effective monitoring and detection for HABs and invasive species.
Abstract:
During 2025-2026, South Australia’s gulfs experienced a large-scale harmful algal bloom (HAB) event dominated by Karenia dinoflagellate species. Water samples collected across both gulfs over multiple months were analysed using DNA metabarcoding targeting the 28S rRNA gene and with species-specific qPCR assays for Karenia cristata and K. mikimotoi. In-situ oceanographic data were collected simultaneously with eDNA water samples using conductivity, temperature, and depth (CTD) profiling casts. To improve the monitoring and detection of HAB events, hyperspectral ocean colour observations from NASA's Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) satellite mission were integrated with the field observations. Hyperspectral PACE satellite products corresponding to the eDNA sampling dates were extracted to create a comprehensive spatiotemporally matched dataset. This dataset encompassed locations spanning a broad range of HAB intensities and species compositions, including waters free of HAB taxa. Statistical models incorporating spatial and temporal effects were applied to investigate relationships between the presence and relative abundance of Karenia species, as determined by eDNA analyses, and environmental variables including CTD-derived temperature and salinity, and hyperspectral PACE-derived ocean colour products. This integrated analysis helped us better understand environmental associations of two HAB-forming Karenia species while also evaluating the potential of hyperspectral PACE observations for HAB monitoring, species discrimination, and the early detection of emerging bloom events.