Microscale distribution of nitrification activity in sediment determined with a shielded microsensor for nitrate.

摘要: Microprofiles of O2 and NO3- were measured simultaneously in freshwater sediment with microsensors which completely free from electrical interference because coaxial designs. Depth profiles nitrification (NO3- production) denitrification consumption) subsequently determined by computer simulation the microprofiles. The nitrifying bacterial community responded very quickly to changes environmental conditions, new steady-state microprofiles usually approached within a few hours after perturbation. Nitrification started introduction previously anoxic layers, suggesting prolonged survival nitrifiers during anaerobiosis. Changes availability NH4+ greatly affected profile, there was high rate coupled nitrification-denitrification under conditions occurred right above oxic-anoxic interface. Addition C2H2 rapidly removed peaks, indicating that production due mainly autotrophic nitrification.