Fluxes and budgets of biogenic elements at the sediment-water interface of Marian Cove, King George Island

Fluxes of dissolved oxygen and nutrients and vertical fluxes of particulate organic elements were investigated in the subtidal benthic environment of Marian Cove, King George Island, Antarctica, using in situ benthic chambers and near-bottom sediment traps. Fluxes of dissolved oxygen, ammonium, phosphate, and silicate were comparable to those measured in temperate regions. Sediment oxygen consumption was a good indicator of organic respiration and elemental efflux at the benthic boundary layer of Marian Cove, with good positive correlations with ammonia (r2 = 0.67), phosphate (r2 = 0.57), and the C:N:P ratio (106:11.5:1.15) in the chamber water. A positive relationship (r2 = 0.58) between settling particulate organic carbon flux and chl a concentration suggests that water column biomass and production are direct sources of settling particles. According to element budgets in summer assessed using the fluxes, Jin and the sum of Jout and Jburial were 15.9 ± 8.1 and 22.6 ± 8.2 mmol m-2 d-1 for carbon, 2.02 ± 0.54 and 2.46 ± 0.82 mmol m-2 d-1 for nitrogen, 0.07 ± 0.03 and 0.23 ± 0.08 mmol m-2 d-1 for phosphorus, and 12.4 ± 2.7 and 13.5 ± 5.0 mmol m-2 d-1 for silicon, respectively. There was a broad balance between sediment organic input and remineralized output for carbon and nitrogen at the benthic boundary layer of Marian Cove.