Abstract Monthly averaged satellite imagery of chlorophyll a in the south-western sector of the Atlantic Ocean shows intense and recurrent blooms around the Antarctic Peninsula, the Island of South Georgia and the South Sandwich Islands. Analysis of a 10 year long time series of SeaWiFS ocean color images allows studying seasonal trends and inter-annual variability. Although specific areas show a regular pattern of low or high productivity, certain years appear to be strikingly productive or well below the climatological average. Circulation patterns, continental shelves as well as Antarctic Circumpolar Front are shown to be the major factors controlling extension of highly productive patches.