Aeolian dust in Terra Nova Bay Polynya, Antarctica
Cliff Atkins

Authors

Cliff Atkins
School of Geography, Environment & Earth Sciences, Victoria University of Wellington, PO Box 600, Wellington 6140

Gavin Dunbar
Antarctic Research Centre, Victoria University of Wellington, PO Box 600, Wellington 6140

Nick Golledge
Antarctic Research Centre, Victoria University of Wellington, PO Box 600, Wellington 6140 & GNS Science, PO Box 30 368, Lower Hutt 5040

Abstract

Aeolian dust is an important but poorly-constrained source of iron (Fe)-bearing sediment into the Ross Sea. Iron is an essential nutrient critical for triggering vast phytoplankton blooms each summer. These blooms are major productivity events, which influence an important biogeochemical cycle that draws-down atmospheric CO₂, alters the oceanic food web and contributes biogenic sediment to the seafloor. Understanding these fundamental modern processes is essential for interpreting records of past environmental change in the region and predicting how they might change in a warming Antarctic and Southern Ocean. Terra Nova Bay (TNB) is an ideal location to examine the Fe-driven biogeochemical cycle because the interactions between dust, phytoplankton growth and nutrient supply from ocean upwelling thought to occur in the Ross Sea are found here. Strong katabatic airflow crosses the Transantarctic Mountains and Nansen Ice Shelf adjacent to the well-studied TNB polynya where intense phytoplankton blooms occur. We deployed custom built dust traps on the ice shelf and collected snow and firn samples to measure the flux of dust into the polynya. Initial results show that dust distribution and composition is strongly related to areas of exposed rock and the complex katabatic airflow. Aeolian sediment is concentrated into a ‘dusty corridor’ several km wide on the northern part of the ice shelf in the vicinity of ‘Hells Gate’, suggesting a concentrated point source for most of the Fe-bearing dust entering the polynya. Future work will focus on providing a greater spatial coverage of dust traps and numerical modelling to better quantify the flux. This will contribute to an improved understanding on the impact of dust on primary productivity and biogeochemical cycling in the region.