Exchange fluxes of nutrients across sediment-water interface in the Muping Marine Ranch and its adjacent waters in autumn

In this research, the surface sediment samples were collected from the Muping Marine Ranch and its adjacent area in November 2017.The exchange fluxes of nutrients across the sediment-water interface were estimated by a laboratory incubation method.In addition, the effects of dissolved oxygen and temperature on the fluxes were also studied.The results indicated that the average exchange fluxes of NO₂-N, NO₃-N, NH₄-N and PO₄-P across sediment-water interface were 1.01, -181.91, -268.41 and -45.69 μmol/(m²·d), respectively.The sediments acted as a "source" of NO₂-N and a "sink" of NO₃-N, NH₄-N and PO₄-P.Both dissolved oxygen and temperature had obvious influence on the fluxes.The results showed that the fluxes of NO₂-N, NH₄-N and PO₄-P were higher in the aerobic situation than in the anoxic situation, while that of NO₃-N showed the opposite trend; the fluxes of NO₂-N, NO₃-N and NH₄-N were higher at a higher temperature, but that of PO₄-P was opposite to them.