Abstract:The nitrification and denitrification rates in the sediments of the feeding and non-feeding areas of the shrimp culture pond were measured by applying acetylene inhibition technique, and the N2O concentration in the surface water was determined by GC-ECD during July~August, 2009. The results showed that the rates of nitrification, denitrification, and nitrate reduction ranged between 10.70～337.47 μmol/m2·h, 1.10～17.92 μmol/m2·h, 0.09～7.48 mmol/m2·h respectively. Concentrations of N2O in the surface water was 5.98～10.9 nmol/L and the air-water flux of N2O ranged between 1.76～3.89 μmol/m2·d. Nitrification and denitrification process in the sediments of the shrimp pond showed both significant regional differences and significant seasonal variations. In mid-August, nitrification and denitrification rates reached the highest values, and in the whole culture period, nitrification rates in the feeding area were 2~10 folds of the non-feeding area, and denitrification rates in the feeding area were 1~4 folds of the non feeding area. Denitrification played an important role in the nitrogen cycle of the shrimp pond ecosystem, removing inorganic nitrogen at 2.80 g/d, accounting for 2.34% of the total input of inorganic nitrogen and 2.56% of the total output in the shrimp pond.
