Biogeochemical cycle of organic matter in a subtidal benthic environment in Marian Cove, King George Island, Antarctica

Abstract

The flux and composition of settling particles were measured in a subtidal benthic environment of Marian Cove, King George Island, from February 1998–January 2000. The total mass flux ranged between 2.47 g m⁻² d⁻¹ (August and September 1998) and 21.97 g m⁻² d⁻¹ (February 1999), and showed distinct seasonal variation: high in the summer and low in winter. Lithogenic particles constituted 70–95% of the total particles, while biogenic particles represented only 10%, except in spring when biogenic particles made up more than 30%. The fluxes of organic carbon, biogenic silica, nitrogen, and organic phosphorus all peaked in spring rather than in summer, with ranges of 4.4–34.0, 1.2–23.5, 0.48–5.56, and 0.01–0.15 mmol m⁻² d⁻¹, respectively. Fluxes of metals (Al, Ti, Cu, Cd, and Pb) showed temporal variability, similar to that of the total mass flux, but each metal had different enrichment factor (EF) values. The EF value of Cu correlated positively with fluxes in lithogenic components, while the EF value of Cd correlated with biogenic particle fluxes. The Cu flux is mainly related to substantial inflows of melt water laden with Cu- enriched lithogenic particles. The Cd flux is probably associated with organic matter deposition following phytoplankton blooms in the water column.