Standard Presentation 2024 Australian Marine Sciences Association Annual Meeting combined with NZMSS

Ocean Pathways to Australian Beaches: Plastic Pollution and Bluebottle Dynamics Along Southeastern Australia (#435)

Gaby C. G. Mayorga Adame 1 2 , Amandine Schaeffer 1 3 , Jordan Gacutan 4 , Moninya Roughan 1 2 , Luca Ferraro 2 , Natacha Bourg 5 , Daniel Lee 1 3 , Daniel Hewitt 1 3
  1. Centre for Marine Science and Innovation, UNSW, Sydney, NSW, Australia
  2. School of Biological, Earth and Environmental Sciences, UNSW, Sydney, NSW, Australia
  3. School of Maths & Stats, University of New South Wales, Sydney, NSW, Australia
  4. Sustainable Development Reform Hub, Sydney
  5. Seatech, USTV , Toulon, Var, France

Drifting dynamics of many objects are critical issues affecting coastal ecosystems and beachgoers along Southeastern Australia. In this presentation, we will describe the use of oceanographic modelling techniques to unravel the pathways of plastics and bluebottles (Physalis physalis) along eastern Australia. Using Lagrangian particle tracking, we trace the origins and pathways of plastic debris collected on Southeastern Australian beaches over a decade, identifying major marine sources and seasonal variability. Concurrently, we employ a similar approach to investigate the drift patterns of bluebottles, considering ocean currents and the wind effect on their specific left- and right-handed morphologies.  Based on one year of bluebottle stranding observations off Sydney, we identify their likely source, provide suggestions about their lifetime, and show the influence of the East Australian Current in their arrival to south-east Australia.  By informing models  with empirical data, we offer unprecedented insights into plastic pollution and bluebottle distribution within coastal ecosystems. Our findings not only enhance understanding of the respective drifting object but also provide a framework for actionable intelligence for policymakers to implement effective mitigation strategies. This integrated approach underscores the value of oceanographic modelling in addressing complex challenges for sustainable coastal management.