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

Influence Of Weather Patterns And Coastal Hydrodynamics On OAE Efficiency In Inshore Tasmanian Waters (#643)

Harris Anderson 1 , mathieu mongin 1 , Elizabeth Shadwick 1 , Sharon Hook 1 , Richard Matear 1 , Cathryn Wynn-Edwards 1 , Pearse Buchanan 1
  1. CSIRO, Battery Point, TAS, Australia

Ocean alkalinity enhancement (OAE) is an emerging marine carbon dioxide removal technology, which increases ocean pH and allows for the uptake of additional atmospheric CO2. As global interest in OAE increases and deadlines for emissions targets get closer, understanding the OAE capacity in Australian waters is becoming increasingly critical. Here we present results from alkalinity point-source addition scenarios in Tasmanian coastal waters using a high-resolution coupled hydrodynamic-biogeochemical model. Conservative rates of alkalinity addition are estimated based on renewable energy generation in Tasmania and the energy consumption of sodium hydroxide (NaOH) generation by electrochemical methods. We then assess the rate-dependent likelihood that coastal waters are impacted by alkalinity addition finding a suitable addition rate within the above parameters. Local wind and tide conditions are shown to strongly influence dispersal rates and the areal impact of the alkalinity plume. Model results indicate that within weeks to months, the carbon sequestration efficiency of coastal waters in Tasmania is comparable with that of global circulation model studies.