Interannual variability of vertical particle fluxes in the Ross Sea (Antarctica)

Abstract

This study presents new data on biogenic and terrigenous particle fluxes collected by an oceanographic mooring (Mooring A) deployed in the south-western Ross Sea (Antarctica) in the frame of the Italian Long-Term Ecological Research network (LTER-Italy). Results from the years 2005 and 2008 document high mass fluxes during the summer and early autumn seasons, not coincident with the algal bloom. Downward particle fluxes exhibit a high inter-annual variability of both particulate fluxes and composition that seem related to the different factors as the phytoplankton increases, occurring between the beginning of February and the end of March, to the variations in the sea ice extent and to the resuspension and/or lateral advection processes. The flux variability may have been influenced by Iceberg B-15 that resided in the investigated area between 2000 and 2005. The decoupling of biogenic silica and organic carbon cycles is documented by differences in the rates of their respective key processes: biogenic silica dissolution and organic carbon degradation.