History of benthic colonisation beneath the Amery Ice Shelf, East Antarctica

Abstract

This study presents compelling evidence for a diverse and abundant seabed community that developed over the course of the Holocene beneath the Amery Ice Shelf, East Antarctica. Fossil analysis of a 47 cm long sediment core revealed a rich modern fauna dominated by filter feeders (sponges and bryozoans). The down-core assemblage indicated a succession in the colonisation of this site. The lower portion of the core (before ∼9600 yr BP) was completely devoid of preserved fauna. The first colonisers (at ∼10 200 yr BP) were mobile benthic organisms. Their occurrence was matched by the first appearance of planktonic taxa, indicating a retreat of the ice shelf following the last glaciation to within sufficient distance to advect planktonic particles via bottom currents. The benthic infauna and filter feeders emerged during the peak abundance of the planktonic organisms, indicating their dependence on the food supply sourced from the open shelf waters of Prydz Bay. Understanding patterns of species succession in this environment has important implications for determining the potential significance of future ice shelf collapse. © Inter-Research 2007.