Nutrients regeneration speed of sediment in harmful algae blooms (HAB) area of East China Sea

The fluxes of dissolved nutrients at sediment-water interface were investigated at 4 stations in the HAB area of East China Sea in May 2001 and May 2002. The benthic fluxes of nutrients were determined by incubating the sediment core samples with bottom seawater bubbled with air or nitrogen. The transfer of nutrients was more active under anoxic condition. The fluxes of dissolved nutrients were generally high at the stations close to the coast. The sediment was the source of SiO₃^2-, which accounted for 6% of primary production. For DIN and PO₄^3-, the sediment was the sink. DIN and PO₄³- adsorbed by sediment accounted for 5.9% and 67% of the riverine DIN and PO₄^3- inputs, respectively, and the inputs of SiO₃^2- accounted for 7.8 %.