Interannual properties of the CO 2 system in the Southern Ocean south of Australia

• Published in: Antarctic Science
• Main Authors: Laika, H.E., Goyet, C., Vouve, F., Poisson, A., Touratier, F.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 2009
• Subjects: Geology; Ecology, Evolution, Behavior and Systematics; Oceanography; Antarctic; Indian; Southern Ocean; Antarc*; Antarctic Science; Sea ice
• Online Access: http://dx.doi.org/10.1017/s0954102009990319; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102009990319

Abstract In order to quantify the temporal variations of ocean properties, the MINERVE programme was designed to perform time-series measurements in the Southern Indian Ocean south of Australia. In the sub-Antarctic region (SAR, 48.5 ± 6.0°S), the mean CO 2 flux increased from spring to summer from -6.8 mmol.m -2 .d -1 in October 2005 to -9.9 mmol.m -2 .d -1 in February 2006. In the Permanent Open Ocean Zone (POOZ, 57.5 ± 3.0°S), we observed lower pCO 2 in summer than in spring (340 and 398 μatm, respectively). The mean CO 2 flux showed large temporal variations from -0.2 mmol.m -2 .d -1 in October 2005 to -8.2 mmol.m -2 .d -1 in February 2006. The large temporal variation was associated with increased phytoplankton biomass. In the Continental Antarctic Zone (66.0 ± 1.0°S), the mean CO 2 flux decreased from +14.9 mmol.m -2 .d -1 in October 2005 to -8.4 mmol.m -2 .d -1 in February 2006. In winter and spring, deep water mixing and seasonal sea-ice strongly increase pCO 2 sea above atmospheric level. In contrast, during summer, the effect of biological CO 2 uptake decreased pCO 2 sea . Furthermore, these data allowed us to parameterize A T and C T as a function of temperature and salinity.