University of Tasmania, Australia

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CSIRO-UTAS PhD Program in Quantitative Marine Science

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Nicholas Roden

Mr Nicholas Roden

PhD Candidate, CSIRO-UTAS PhD Program in Quantitative Marine Science



Contact Details

Contact Campus Sandy Bay Campus
Building UTAS
Telephone + 61 3 62325265
Research Project

 Acidification and carbonate chemistry of shelf waters in the Australian Antarctic Territory.



Prof. Tom Trull (IMAS), Dr. Bronte Tilbrook (CSIRO), Dr. Patti Virtue (IMAS), Dr. Elizabeth Shadwick (ACE CRC/CSIRO)


Project Description

The uptake of CO2 by the surface waters is causing ocean acidification, which refers to a decrease in the pH and dissolved carbonate ion concentration of seawater. The acidification changes are predicted to cause a decline in the growth of calcifying species, influence metabolic processes, and could lead to significant disruption of ecosystems. The surface waters of the Southern Ocean are where some of the most profound shifts in carbonate chemistry will occur with waters becoming undersaturated with respect to aragonite by the middle of the 21st century. Results obtained in 2008 near the Mertz Polynya, Adelie Land, indicate that some deeper parts of the Antarctic shelf are already exposed to carbonate understaurated waters, with respect to aragonite, the form of calcium carbonate precipitated by many important marine species. As CO2 uptake continues, the extent of the undersaturated waters will expand with potential to impact deep-sea reef communities that were recently discovered near the undersaturated waters. Similar changes in water chemistry are expected along the entire Antarctic coast with unknown consequences for ecosystems. The acidification changes that ecosystems are now exposed to along the shelf are poorly known and change in the future is likely to be complicated by climate related physical and biological feedbacks associated with the loss of sea-ice, increased stratification and intensification of winds (SAM response).
This project will focus on quantifying changes in acidification and carbonate chemistry in the shelf waters of the Australian Antarctic Territory. The research goals are: 1) determine the spatial variability in the carbonate chemistry along the Antarctic shelf, 2) establish the seasonality in the carbonate chemistry and use histroical data to assess longer term change, 3) determine how sea-ice cover, exchange with offshore waters and the seasonal evolution of the mixed layer and biology influence the carbonate chemistry and acidification change, and, 4) utilise biogeochemical models to predict future changes and evolution of ocean acidification/carbonate chemistry on the shelf. The data will be a key input to numerous studies now being undertaken where polar species are incubated at elevated CO2 levels and the results are used to infer acidifcation responses at the species level.