Fluxes and composition of settling particles during summer in an Antarcticshallow bay of Livingston Island, South Shetlands

A moored experiment using a sediment trap was conducted at Johnson's Dock, Livingston Island from 11 December 1997 to 24 February 1998, as part of the EASIZ Programme activities carried out at the Juan Carlos I Spanish Antarc tic base. Total mass vertical fluxes ranged from 23,235 mg m(-2) day(-1) to 89,073 mg m(-2) day(-1) during the experiment, with a mean value of 42.857 mg m(-2) day(-1). Lithogenic components were the major contributors to the settling particulate flux. Organic components accounted for a low fraction of the settling particulate matter, showing an inverse relation to total m ass flux. Nevertheless. the fluxes of organic components at Johnson's Dock are as high as in the open sea. The increases in chlorophyll a in water wer e related to increases in the organic carbon content, which dominated over inorganic carbon during the whole experiment. Calcium carbonate particles s ettle without being significantly altered in the water column and are disso lved in the upper centimetres of the bottom sediments, once they are buried . The settling material consisted of fine particles, with coarse clasts tra nsported by icebergs. Antarctic shallow environments receive important sedi ment fluxes from the erosion and transport action of ice.