Nutrient exchanges at the sediment-water interface and the responses to environmental changes in the Yellow Sea and East China Sea

Release from the sediment is an important nutrient source to the water column of global oceans, especially for marginal seas with active biogeochemical processes. Benthic nutrient biogeochemistry and its responses to environmental changes were investigated in the eastern marginal seas of China using a two-layer diffusion-advection-reaction diagenetic model. Overall, the sediment represented the primary nutrient source with fluxes of--342 +/- 197,-1.25 +/- 0.50, and -114 +/- 56 x 10(8) mol/month for dissolved inorganic nitrogen (DIN), phosphate, and silicate, respectively. This could contribute up to -42% of nutrients requested by primary production (PP), with a DIN/SiO32-/PO(4)(3-& nbsp;)molar ratio of 273:91:1, which was higher than that in the overlying water (49:47:1). Future benthic nutrient fluxes were predicted under two environmental change scenarios (increasing and decreasing PP and biogenic silica). Our study may help rebuild nutrient budgets in the future and formulate environmental management policies in marginal seas.