Deep-Sea Research II, Southern Ocean GLOBEC Special Issue Variability in the freshwater balance of northern Marguerite Bay, Antarctic Peninsula: results from δ18O

• Main Authors: Michael P. Meredith, Mark A. Br, Margaret I. Wallace, Andrew Clarke, Melanie J. Leng, Ian A. Renfrew, Nicole P. M. Van Lipzig, John C. King
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Antarctic; Antarctic Peninsula; Austral; Marguerite; Marguerite Bay; Southern Ocean; The Antarctic; Antarc*; Sea ice
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.464.6803; http://nora.nerc.ac.uk/1681/1/meredith_et_al._with_figs.pdf

We investigate the seasonal variability in freshwater inputs to the Marguerite Bay region (Western Antarctic Peninsula) using a time series of oxygen isotopes in seawater from samples collected in the upper mixed layer of the ocean during 2002 and 2003. We find that meteoric water, mostly in the form of glacial ice melt, is the dominant freshwater source, accounting for up to 5 % of the near-surface ocean during the austral summer. Sea ice melt accounts for a much smaller percentage, even during the summer (maximum around 1%). The seasonality in meteoric water input to the ocean (around 2 % of the near-surface ocean) is not dissimilar to that of sea ice melt (around 2 % in 2002 and 1 % in 2003), contradicting the assumption that sea ice processes dominate the seasonal evolution of the physical ocean environment close to the Antarctic continent. Three full-depth profiles of oxygen isotopes collected in successive Decembers (2001, 2002 and 2003) indicate that around 4 m of meteoric water is present in the water column at this time of year, and around 1 m of sea ice formed from this same water column. The predominance of glacial melt is significant, since it is known to be an important factor in the operation of the ecosystem, for example by providing a source of nutrients and modifying the physical