Experiments were conducted to determine the dependence of denitrification rate on sediment COD using tubes filled with costal marine sediment both with and without polychaetes. In sediment samples with COD levels of 3.7 and 1.5 mg/g, denitrification rate were 24.2 and 21.2 N/m
2/day respectively, and redox potentials were -202 and -172mV, respectively. After 15days, the denitrification rate in the surface layer (0-2cm) of cores with polychaetes increased to 52.4 and 29.8mg N/m
2/day, respectively, even though redox potentials had increased to 14 and 21mV, respectively. Following 30 days, redox potentials had reached oxic conditions and denitrification rates decreased to 67% of that of controls (without polychaetes) . These result indicate that the effect of bioturbation on denitrification rate were influenced by sediment COD levels and redox potential.
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