Guy D Williams
Institute for Marine and Antarctic Studies (IMAS), Australia

Suppression of Prydz Bay's polynya-driven Antarctic Bottom Water production by melting ice shelves


A fourth production region for the globally important Antarctic Bottom Water (AABW) has been attributed to Dense Shelf Water (DSW) formation in the Cape Darnley Polynya (CDP), adjoining Prydz Bay in East Antarctica. A weak DSW signal detected upstream from the CDP was attributed to Prydz Bay, but considered minor. Extensive foraging by instrumented Elephant seals from 2011-2013 now provides the the first complete assessment of DSW formation in Prydz Bay. After a complex evolution involving the opposing contributions of three polynyas (positive) and two ice shelves (negative), DSW (salinity 34.65—34.7) formed in the south-western corner of Prydz Bay is exported through Prydz Bay Channel to provide a distinct, fresh contribution to Cape Darnley Bottom Water. Elsewhere, the freshwater input from the Amery and West Ice Shelves suppresses DSW formation. This study highlights the susceptibility of Antarctic Bottom Water to increased freshwater input from the enhanced melting of ice shelves.

Time and place
Tuesday 19 April 2016, 11.15
Room C609, Arrhenius Laboratory, 6th floor