Ocean Acidification

Production of aragonite shells by many marine organisms via calcification requires adequate availability of seawater carbonate ions (CO₂), which is often represented by the aragonite saturation state of seawater: Ω=(Ca²⁺)(CO₃^2-)/λ, where λ is the solubility coefficient of calcium carbonate in the form of aragonite. Changes in Ω_arag are explicitly linked to rises and falls in oceanic partial pressure of CO₂ (pCO²) through alterations in equilibrium CO₂ chemistry in seawater. The coastal Southern Ocean ecosystem in particular, is most vulnerable to future declining Ω_arag via anthropogenic CO₂, uptake (Orr et al. 2005, McNeil & Matear 2008) since pteropods (aragonite secreting zooplankton) make up a large proportion of its biomass (Accomero et al. 2003, Hunt et al. 2008). Spatio-temporal variability in surface ocean Ω_arag is scarce for coastal Antarctic waters. Here, we report data on seasonal variability of Ω_arag from two independent Antarctic sites (Ross Sea and Prydz Bay).

McNeil B. I., Sweeney C., & Gibson J. A. E., 2011. Short Note: Natural seasonal variability of aragonite saturation state within two Antarctic coastal ocean sites. Antarctic Science 23(4):411-412. Article (subscription required).